Botanical Studies (2006) 47: 339-368.

*

Corresponding author: E-mail:

wfang@imm.ac.cn; Tel: +86-10-63036794; Fax: +86-10-63017757.

review paper

Structure-activity relationships of oleanane- and ursane-

type triterpenoids

Hua SUN

1,2,3

, Wei-Shuo FANG

1,3,

*, Wen-Zhao WANG

1,3

, and Chun HU

2

1

Institute of Materia Medica, Chinese Academy of Medical Sciences, Beijing 100050, P.R. China

2

Shenyang Pharmaceutical University, Shenyang, Liaoning province, 110016, P.R. China

3

Key Laboratory of Bioactive Substances and Resources Utilization of Chinese Herbal Medicine (Peking Union Medical

College), Ministry of Education, P.R. China

(Received September 21, 2005; Accepted March 2, 2006)

ABSTRACT. The chemistry of oleanane- and ursane-type triterpenoids has been actively explored in recent

years, and their biological and pharmacological activities of these compounds have been found to span a

variety of properties. These include antitumor, anti-viral, anti-inflammatory, hepatoprotective, gastroprotective,

antimicrobial, antidiabetic, and hemolytic properties as well as many others. This review summarizes the

isolation and structure modifications of these triterpenoids as well a s the biological and pharmacologica l

activities discovered in the past ten years, with an emphasis on their structure-activity relationships.

Keywords: Antidiabets; Anti-inflammatory; Antimicrobial; Antitumor; Antiviral; Gastroprotective;

Hepatoprotective; Oleanane; Structure-activity relationship; Ursane.

Abbreviations: GI

50

, concentration required to inhibit tumor cell growth by 50%; ED

50

, concentration

caused 50% inhibition of cell proliferation in vitro; CC

50

, 50% cytotoxic concentration; LC

50,

50% lethal

concentration; TI, in vitro therapeutic index; MIC, minimum inhibitory concentration; PKC, protein kinase

C; HLE, human leukocyte elastase; UISO-SQC-1, squamous cervix carcinoma; OVCAR-5, human ovarian

cancer; fMLP; N-formyl-methionyl-leucyl-phenylalanine; PMA, phorbol-12-myristate-13-acetate; AA,

arachidonic acid; A LT , alanine aminotransferase; ID

50

, doses inhibiting the oedematous response by 50%.

CONTeNTS

INTRODUCTION ............................................................................................................................................................. 340

ANTITUMOR ACTIVITIES

............................................................................................................................................. 340

ANTI-VIRAL ACTIVITIES

.............................................................................................................................................. 347

ANTI-INFLAMMATORY ACTIVITIES

.......................................................................................................................... 350

In vivo studies

.............................................................................................................................................................. 350

Inhibition of cyclooxygenase (COX) activity

............................................................................................................. 350

Inhibition of complement activity

............................................................................................................................... 353

Inhibition of elastase

................................................................................................................................................... 354

Inhibition of intercellular adhesion molecule (ICAM-1) expression induced by TNF-£\

........................................... 354

HEPATOPROTECTIVE ACTIVITIES

............................................................................................................................. 355

GASTROPROTECTIVE ACTIVITIES

............................................................................................................................ 356

ANTIMICROBIAL ACTIVITIES

..................................................................................................................................... 356

ANTI-DIABETES ACTIVITIES

....................................................................................................................................... 358

HEMOLYTIC ACTIVITIES

.............................................................................................................................................. 360

MISCELLANEOUS .......................................................................................................................................................... 362

Spasmolytic activity

................................................................................................................................................... 362

Antipruritic activity

.................................................................................................................................................... 362

Anti-thrombotic activity

............................................................................................................................................. 362

Inhibitory activity of ethanol absorption

.................................................................................................................... 363

Effects on nonmalignant prostate cell proliferation

................................................................................................... 363

LITERATURE CITED.

...................................................................................................................................................... 364

340

Botanical Studies, Vol. 47, 2006

iNTrODUCTiON

Oleanolic acid (OA) (3£]-hydroxy-olea-12-en-28-oic

acid) and its isomer, ursolic acid (UA) (3£]-hydroxy-urs-

12-en-28-oic acid) are triterpenoid compounds which

exist widely in nature in free acid form or as aglycones

for oleanane- and ursane-type triterpenoid saponins (Liu,

1995). Oleanane and ursane are also called £]-amyrane

and £\-amyrane, respectively. Saponins glycosylated at

either C-3 or C-28 are termed monodesmosides, and

those glycosylated at both C-3 and C-28 are termed

bisdesmosides. These types of triterpene saponins

exhibit diverse activities, which may be attributable to

the different substructures in the A-, C-, E-rings or other

positions. Many comprehensive reviews of two type

triterpenoids have been published covering different areas

of interest, such as isolation and structure determination

(Joseph, 1999; 2000; 2001a; 2001b; 2002; 2003; 2005a;

2005b), and pharmacological activities (Liu, 1995;

Safayhi et al., 1997; Setzer and Setzer, 2003; Rios et al.,

2000; Baglin et al., 2003), but reviews of structure-activity

relationships are scarce. In this review, our discussion

will focus mainly on the chemistry and pharmacology

of oleanane- and ursane-type triterpenoids discovered in

the past ten years, with an emphasis on the relationships

between their structures and activities. These triterpenoids

are often mentioned simultaneously because they share

similar structural features and pharmacological activities.

In addition, other pentacyclic triterpenoids such as those

of the lupane type are often cited in order to compare their

structures and activities with those of oleanane and ursane

type triterpenoids.

HO

COOH

1

2

3

4 5

6

7

8

9

10

1 1

1 2

1 3

1 4

15

16

17

1 8

19 2 0 21

22

23 24

25 26

2 7

28

2 9 30

A B

C D

E

OA

HO

COOH

1

2

3

4 5 6

7

8

9

1 0

11

1 2

13

1 4

1 5

16

1 7

18

1 9 2 0 21

22

23 24

2 5 26

27

2 8

29

3 0

A B

C

E

D

UA

aNTiTUMOr aCTiviTieS

U A has been reported to be effective at different

stages for tumor prevention and inhibition, e.g. inhibiting

tumorigenesis (Huang et al., 1994), differentiation

(Lee et al., 1994), and promotion (Tokuda et al., 1986),

Moreover, UA and OA have exhibited potent activity

against human leukemia and lymphoma cells. For

example, UA was effective against P3HR1 cells (IC

50

=2.5

£gg/mL) and chronic myelogenous leukemia cells K562

(IC

50

=17.8 £gg/mL), while OA inhibited the growth of

P3HR1 cells (IC

50

=26.74 £gg/mL) (Chiang et al., 2003).

They also showed anti-angiogenic activities, with UA

(IC

50

=5 £gM) found more active than OA (IC

50

=20 £gM)

(Sohn et al., 1995). Bioassay-guided fractionation of

Polylepis racemosa led to the isolation of four cytostatic

triterpenoids UA and 1-3 (GI

50

=6.9~>250 £gg/mL), in

which the 19-OH substituted compound 1 was the most

active (GI

50

=6.9~25 £gg/mL) (Neto et al., 2000).

Six triterpenes UA, OA and 4-7 were isolated from

stem bark of Physocarpus intermedius, and their ED

50

values against five different tumor cells are shown in

Table 1 (Kim et al., 2000). While introduction of 2£\-OH

substituents showed almost no influence on their activity,

9£\-OH in the UA series was detrimental to activity.

Coffemoylation of 3£]-OH enhanced antitumor activity by

several times.

Compound 6, Corosolic acid, has also been isolated

from the fruit of Crataegus pinnatifida var. psilosa. It

displayed both cytotoxicity and PKC inhibition. The ED

50

values of 6 and UA are shown in Table 2. Both compounds

were selectively more potent against solid cancer cells

HeLa S

3

and SNU C

4

. Besides, it incompletely inhibited

rat brain PKC activity in vitro by concentrations higher

than 20 £gg/mL (Ahn et al., 1998).

R

4

R

3

R

1

R

2

COOH

1 R

1

=OH R

2

=H R

3

=H R

4

=OH

2 R

1

=OAc R

2

=H R

3

=H R

4

=OH

3 R

1

=OH R

2

=R

3

=O R

4

=OH

R

1

O

COOH

R

2

O

HO

HO

4 R

1

=

R

2

=H

7 R

1

=H R

2

=OH

R

2

R

1

COOH

HO

5 R

1

=

B

-OH R

2

=OH

6 R

1

=

A

-OH R

2

=H

SUN

et al. ¡X Structure-activity relationships of oleanane- and ursane-type triterpenoids

341

Table 3. Cytotoxic activity was determined by the MTT.

CC

50

(£gg/mL)

HSC-2

HSG

HGF

UA

29

48

25

OA

130

230

>500

6

10

12

12

7

21

26

24

13

21

25

24

14

102

148

184

15, 16

22

30

50

H SC -2 : hu m a n o ra l s q ua m o u s c e l l c ar c i no m a ; HS G:

human salivary gland tumor; HGF: human normal gingival

fibroblasts.

It is interesting to note that the cinnamoyl substituent

can be found in oleanane and ursane type triterpenoids that

exhibit antitumor activity. Compounds 4, 8, 9, and 10 were

reported to inhibit both free radical and cyclooxygenase

I activity (IC

50

=0.9~4.6 £gg/mL) (Hamburger et al.,

2003). Cis-3-O-p -hydroxycinnamoyl ursolic acid (11)

(GI

50

=18.8~46.4 £gM) was slightly more effective than

its trans-isomer (12) (GI

50

=40~25-100 £gM) in inhibiting

tumor growth against nine different tumor cell lines

(Murphy et al., 2003).

However, the presence of the cinnamoyl segment might

not always increase antitumor activity. Callus cultures

induced from an axenic leaf of Eriobotrya japonica

(Rosaceae) produced nine triterpenes OA, UA, 6, 7, 13,

14, 15 and 16. All of these triterpenes exhibited significant

activity in terms of CC

50

against HSC-2, HSG and HGF

(Table 3), but the activity of the mixture of cinnamoyl

esters 15 and 16 was weaker than either non esterified 6 or

13 (Taniguchi et al., 2002). Moreover, when UA, 27-p-Z-

coumaroyloxy UA (17) and 27-p-E-coumaroyloxy UA

(18) were isolated through a bioactivity-guided fraction

from aerial parts of Viburnum jucundum Morton, only UA

exhibited cytotoxic activity with ED

50

values of ca. 3 £gg/

mL against HCT-15, UISO-SQC-1 and OVCAR-5 (Rios

et al., 2001).

Table 1. Inhibition ED

50

(£gg/m L) of tumor cell proliferation

with UA, OA and 4-7.

A549 SK-OV-3 SK-MEL-3 XF498 HCT15

UA

4.2 3.6 4.6

4.5 4.4

OA 16.4 12.4 18.5 >30 12.1

4

1.6 1.6 1.7

19.8 1.7

5 >30 18.4 >30

30 >30

6

4.4 3.9 5.1

5.5 4.7

7 19.4 18.4 19.8 >30 15.3

Cisplantin 1.4 0.9 0.8

0.9 2.2

A549: non sm all ce ll lung; SK-OV-3: ovary; SK-ME L-3:

me lanoma; XF498: central nerve s ystem ; HCT15: colon;

Cisplantin was positive control.

Table 2. ED

50

(£gg/mL) of corosolic acid and UA against tumor

cells.

Hep G

2

SNU-C

4

HeLa S

3

K-562

6

4.8

0.4

1.0

4.3

UA

3.0

1.4

1.5

12.5

Hep G

2

: hum an hepatocellular carcinoma; SUN-C

4

: human

colorectal cancer; HeLa S

3

: human cervix carcinoma.

R=

O

HO

OH

RO

COOH

8

RO

9

RO

10

HO

COOH

O

O

OH

18

HO

COOH

O

O

OH

17

RO

COOH

O

HO

HO

11 R=

O

HO

HO

12 R=

R

COOH

HO

HO

O

HO

15 R=

O

HO

16 R=

13 R=OH

14 R=O=

342

Botanical Studies, Vol. 47, 2006

Due to its ability to repair damaged DNA (Narayan

and Wilso, 1996), DNA polymerase is a potential target

for adjuvant antitumor therapy, i.e., selective inhibition of

this enzyme by other noncytotoxic agents could possibly

potentiate chemotherapeutic effects of other DNA-

damaging agents. UA at 100 £gM was tested for inhibitions

of calf DNA polymerase £\, rat DNA polymerase £], plant

DNA polymerase I (£\-like), and DNA polymerase II

(£]-like). The percent inhibitions were 92%, 86%, 0%,

and 9%, respectively (Mizushina et al., 2000). Four

triterpenoids (OA, UA, 19 and 20) were isolated from

Baeckea gunniana, and all showed inhibition of DNA

polymerase £] (IC

50

=2.5~4.8 £gM). Because 19 and 20

displayed slightly more potent inhibitory activity than that

of UA and OA, it is proposed that the exocyclic double

bond on their E-ring might contribute to this improvement

(Deng et al., 1999).

A new polyacylated oleanane triterpene 21 and OA

were isolated from Couepia polyandra. They inhibited

the lyase activity of DNA polymerase £], with IC

50

values

of 13.0 and 8.8 £gM, respectively (Chaturvedula et al.,

2003a).

Three acetyl-boswellic acid analogues 22, 23 and

24 were investigated for their topoisomerase inhibitory

activity, and the relative activity 22>23>24 was observed.

The IC

50

values for the inhibition of topoisomerase I

and II£\ catalytic activities by 22 were 3 £gM and 1 £gM,

respectively. Other structurally related pentacyclic

triterpenes, ¡Xincluding OA, UA, £\-amyrin (25), £]-amyrin

(26), betulinic acid (27), and 18-£]-glycyrrhetinic acid

( 28), ¡Xwere tested for both types of topoisomerase

inhibition. However, neither the amyrin isoforms nor

2 8 had significant effects at the concentration range

observed for 22. Of all the compounds, 27 was the

most effective with IC

50

values of 43 £gM and 5 £gM for

topoisomerase I and II£\, respectively. An analysis of their

structural features concluded that the shared pentacyclic

ring architecture was important but not sufficient for the

inhibition of topoisomerases. Moreover, the combination

of carboxyl group at C-4 and two methyl groups at C-20

were important for enhancing the inhibitory activity of

the molecule toward both topoisomerases (Syrovets et al.,

2000).

A/B¡Vring partial analogues (29-33) of OA were

enantioselectively synthesized. These compounds showed

cytotoxicity against human malignant melanoma cell SK-

MEL (IC

50

=112~ 484 £gM), except for 31, which was not

active (Assefa et al., 2001). Some partial analogous e.g.

32 and 33 had activity almost comparable to OA.

Tritepene saponins have been extensively explored

as antitumor agents. Pentacyclic triterpene glycosides

have been reported to be active against various tumors.

Considering the diverse structures of both aglycones and

attached sugars among various species, one can expect

that they will play important roles in anticancer drug

discovery.

HO

COOH

19

HO

COOH

20

CH

3

COO

COOH

OCOCH

3

CH

3

COO

21

AcO

COOH

22

AcO

COOH

23

AcO

COOH

O

24

HO

25

HO

26

27

HO

COOH

28

HO

COOH

O H

SUN

et al. ¡X Structure-activity relationships of oleanane- and ursane-type triterpenoids

343

Triterpene saponins 34-37 from Polyscias amplifolia,

together with two monoglycosides 38 and 39 formed

by the partial hydrolysis of 34 and 35, exhibited

cytotoxicity against A2780 ovarian cancer cells (Table 4)

(Chaturvedula et al., 2003b). The isolated cinnamoylated

compounds 40 (IC

50

=13.5 £gg/mL) and 41 (IC

50

=13.0 £gg/

mL) from Acacia tenuifolia also showed weak activity

against A2780 ovarian cancer. Moreover, saponins 42

and 43, which possess unique aminosugar moieties, were

isolated along with 40 and 41. These exhibited significant

activity against the M109 lung cancer cell line, with

IC

50

values of 1 £gM (Seo et al., 2002). Compound 4 3

was synthesized and tested for cytotoxic activity against

the A2780 and M109 lung cancer cell lines with the

IC

50

0.8 and 1.0 £gg/mL, respectively (Sun et al., 2003).

The above results clearly indicated the importance of

3-O-aminosugar, and the activity was compromised by the

presence of C-16 and C-21 substituents in 40 and 41, as

compared to 43.

Nine triterpenes (44-52) containing OA or hederagenin

aglycones were isolated from the roots of Pulsatilla

chinensis and tested for their cytotoxic activity against

HL-60 human leukemia cells (IC

50

=2.3~>10 £gg/mL).

Compound 46 was the only one that differed in C-3

sugar substituents in these saponins and no activity

was detected. The results suggested that the glycoside

HO

COOCH

3

H

H

31

HO

H

H

CN

32

HO

COOH

29a p-COOH

29b m-COOH

29c o-COOH

30a p-COOH

30b m-COOH

30c o-COOH

HO

COOH

33a p-COOH

33b m-COOH

33c o-COOH

O

H

3

CO

COOH

Table 4. Cytotoxicity against A2780 of compounds 35-43.

IC

50

(£gg/mL)

OA

20.4

35

6.7

36

9.2

37

10.8

38

9.6

39

8.9

40

8.6

41

13.5

42

13.0

43

0.8

O

COOH

O

OH

O

O

O

HO

OH

R

O

NHCOCH

3

HO

HO

O

40 R=

O

OH

HO

HO

41 R=

O

OH

HO

HO

O

O

HO

OH

R

HO

HO

O

RO

COOH

O

OH

OH

HO

OH

O O

OH

HO

34 R=

35 R=

O

OH

OH

HO

OH

O

O

HO

OH

O

OH

OH

HO

OH

36 R=

37 R=

O

OH

HO

O

O

OH

OH

HO

OH

38 R=

O

HO

HO OH

39 R=

O

HO OH

OH

O

COOR

2

O

O

HO

OR

3

O

Me

HO

OH

R

4

O

R

1

R

1

R

2

R

3

R

4

44 H H H H

45 OH H H H

47 H H H

B

-D-Glc

48 OH H H

B

-D-Glc

48aOH Me H

B

-D-Glc

49 H H

B

-D-Glc H

50 OH H

B

-D-Glc H

O

HO

HO OH

Glc=

OH

O

OH

HO

HO

O

HO

HO

O

COOH

O

OH

O

O

O

HO

OH

R

O

NHCOCH

3

HO

HO

O

40 R=

O

OH

HO

HO

41 R=

O

OH

HO

HO

O

COOH

O

O

HO

OH

R

O

NHCOCH

3

HO

HO

O

O

OH

HO

HO

42 R=

43 R=

O

OH

HO

HO

RO

COOH

O

OH

OH

HO

OH

O O

OH

HO

34 R=

35 R=

O

OH

OH

HO

OH

O

O

HO

OH

O

OH

OH

HO

OH

36 R=

37 R=

O

OH

HO

O

O

OH

OH

HO

OH

38 R=

O

HO

HO OH

39 R=

O

HO OH

OH

COOR

2

344

Botanical Studies, Vol. 47, 2006

moiety attached to C-3 of the aglycone was essential for

cytotoxicity (Mimaki et al., 1999). In addition, there was

no significant difference in activity between the OA-based

and hederagenin-based saponins. The presence of a C-28

methyl ester imposed no influence on the activity.

Compound 49 (Hederacolchisid A

1

) was also isolated

from Hedera colchica K. Koch, and exhibited moderate

in vitro antiproliferative activities against six human cell

lines as well as normal human fibroblasts. Comparison

of the cytotoxicity of 49 (IC

50

4.5~12 £gM) with 44 (IC

50

9~15 £gM), 4 5 (IC

50

24~36 £gM), 50 (IC

50

24~32 £gM),

53 (IC

50

18~41 £gM), and 54 (IC

50

26~47 £gM) from the

same plant offers some new information about structure-

activity relationships. The sugar sequence OA-3-O-

£\-

L

-rhamnopyranosyl (1¡÷2)-£\-

L

-arabinopyranoside

at C-3 appears essential for antitumor activity of OA

monodesmosides. Unlike the previous results (Mimaki et

al., 1999), monodesmesides with OA as aglycone were

more active in this study than those with hederagenin

(Barthomeuf et al., 2002).

A study of the synergistic effect of saponins on an

additional anticancer drug cisplatin showed that the

triterpene saponins jenisseensosides A, B, C, and D

(55-58) increased the accumulation and cytotoxicity of the

anticancer agent cisplatin in human colon tumor cells. In

contrast, the saponin 59 without the acyl moiety (trans-

or cis-p-methoxycinnamoyl acid) attached to sugar did

not exert such an effect (Gaidi et al., 2002). This agrees

with recent findings that acylating groups might be crucial

substructures due to their assumed pore-forming capacity.

Saponins 60-67 were tested for any observed difference in

the cytotoxic activity between acylated and non-acylated

states. It was concluded that the number and structure

of sugar chains did not play an important role in their

cytotoxic properties, and that acylated saponins were more

toxic than non-acylated ones (Barbato et al., 1997).

Superoxide generation can cause DNA damage

and thereby initiate tumor-genesis (Gerhauser et al.,

2003). Five compounds (UA, 1, 25, 68, 69) isolated

from Diospyros kaki were tested for stimulus-induced

superoxide generation. Compound 1 inhibited fMLP, PMA

and AA-induced superoxide generation more effectively

than its 24-hydroxy derivative 69.

The hydroxyl group at

R

3

and carboxyl group at R

2

appear to decrease superoxide

generating activity by the three stimuli (Chen et al., 2002).

Moreover, the effects of six compounds (OA, O A

3-acetate, 44, 49, 70, 71) isolated from Anemone raddeana

on fMLP, PMA, and AA-induced superoxide generations

were investigated. A methyl group at C-14 caused stronger

suppression of the fMLP-induced superoxide generation

than a hydroxylmethyl at this position. Diglycoside

7 0 more strongly suppressed PMA and AA-induced

superoxide generation than triglycoside 71 (Lu et al.,

2001).

40 R=

O

OH

HO

HO

41 R=

O

OH

HO

HO

O

OH

HO

HO

42 R=

43 R=

O

OH

HO

HO

O

COOR

2

O

O

HO

OR

3

O

Me

HO

OH

R

4

O

R

1

R

1

R

2

R

3

R

4

44 H H H H

45 OH H H H

47 H H H

B

-D-Glc

48 OH H H

B

-D-Glc

48aOH Me H

B

-D-Glc

49 H H

B

-D-Glc H

50 OH H

B

-D-Glc H

O

HO

HO

OH

Glc=

OH

RO

COOH

OH

O

OH

HO

HO

O

OH

HO

HO

OH

53 R=

54 R=

O

OH

HO

O

OH

HO

O

O

COOH

OH

HO

HO

46

R

O

HO

R

O

O

OH

OHO

HO

O

O

O

OH

HO O

HO

O

O

OH

HOHO

HO

O

R

1

R

2

51 H H

51a Me H

52 H

B

-D-Glc

SUN

et al. ¡X Structure-activity relationships of oleanane- and ursane-type triterpenoids

345

O

HO

HO

O

HO

HO

O

O

O

HO

HOOC

OH

OH

OH

O

O

HOOC

O

O

O

O

HO

OH

O

HO

HO

OH

OH

O

O H

3

C

O

O

HO

O CH

3

O

H

3

C

OH

O

R

61 R=H

62 R=Xyl

O

HO

HO

OH

Xyl=

O

OH

HO

HO

O

HO

HO

HOOC

O

OH

O

O

CHO

O

O

Me

OR

2

OH

O

OH

O

Me

HO

HO OR

1

55 R

1

=Glc R

2

=

MeO

O

56 R

1

=Glc R

2

=

O

MeO

57 R

1

=H R

2

=

MeO

O

58 R

1

=H R

2

=

O

MeO

O

OH

HO

HO OH

O

O

O

O

OH

HO

HO OH

59

O

OH

HO

HO OH

O

O

O

O

OH

HO

HO OH

60

O

O

CH

2

OH

O

OH

HO

O

H

3

C

OH

O

O

HO

OH

O

O H

3

C

O

O

HO

R

2

OH

3

C

OH

HO

HO

HO

O

R

1

O

HO

HOH

2

C

OH

63 R

1

=H R

2

=H

64 R

1

=H R

2

=I

65 R

1

=Glc R

2

=H

65 R

1

=Glc R

2

=I

66 R

1

=Glc R

2

=II

O

O

OH

H

3

C

O

H

3

C

O

O

O

OH

H

3

C

O

H

3

C

O

H

3

C

II =

I =

R

1

R

2

R

3

HO

R

1

R

2

R

3

68 CH

3

CH

2

OH H

69 CH

2

OH COOH OH

COOH

OH

O

O

O

HO

RO

O

Me

HO

OH

HO

70 R=H

71 R=Glc

346

Botanical Studies, Vol. 47, 2006

Table 5. NO inhibitory activities of olean- and urs-12-ene triterpenoids with various 1-en-3-one functionalities.

R

2

O

R

1

O

R

2

O

R

1

U

R

2

O

R

1

D

Type

R

1

R

2

IC

50

(£gM)

72

O

H

CO

2

Me

31

73

O

H

CO

2

H

5.6

74

D

H

CO

2

Me

>40

75

D

H

CO

2

H

13

76

U

H

CO

2

H

13

77

O

OH

CO

2

H

27

78

O

CONH

2

CO

2

Me

14

79

O

OMe

CO

2

H

30

80

O

CO

2

Me

CO

2

Me

0.9

81

O

CO

2

Me

CO

2

H

2.2

82

O

CO

2

H

CO

2

Me

0.8

83

O

CO

2

H

CO

2

H

0.07

84

O

CHO

CO

2

Me

Toxic

85

O

CHO

CO

2

H

Toxic

86

O

Br

CO

2

Me

>40

87

O

Br

CO

2

H

7.3

88

O

Cl

CO

2

Me

>40

89

O

Cl

CO

2

H

>40

90

O

CN

CO

2

Me

0.7

91

O

CN

CO

2

H

0.6

92

U

CN

CO

2

Me

5.1

93

U

CN

CO

2

H

6.2

OA

>40

UA

Toxic

Figure 1. St ruct ure-a cti vity re la tions hi ps of 1 -en-3-one

derivatives of oleanane triterpenoids.

R

2

O

R

3

R

1

R

4

23 2 4

A

E

1

2

3

4

ursane type

oleanane type

R

3

=CH

3

, R

4

=H

R

3

=H, R

4

=CH

3

Inhibitors of nitric oxide (NO) production in

macrophages are potential cancer chemopreventive

and anti-inflammatory drugs (Ohshima and Bartsch,

1994). Gribble et al. synthesized a series of OA and UA

derivatives as inhibitors of NO production induced by

interferon-£^ in mouse macrophages (Honda et al., 1997;

1999; 2000a, b and 2002). Some structures and activities

were summarized as shown below in Figure 1 and Tables

5-7.

Generally, (1) oleanane and ursane triterpenoids with

various enone functionalities in A-ring showed stronger

activity. More specifically, a 1-en-3-one functionality in

A-ring was important for significant activity (Table 5).

(2) Carboxyl, methoxycarbonyl, and nitrile groups at

SUN

et al. ¡X Structure-activity relationships of oleanane- and ursane-type triterpenoids

347

C-2 enhanced activity, while hydroxyl, aminocarbonyl,

methoxy, chloride, and bromide groups decreased it. A

formyl group did not confer activity but only toxicity. (3)

23, 24-Dimethyl groups were also important for significant

activity, as 73 was more potent than 23, 24-dinorolean-

1-en-3-one derivative 75. (4) The effect of a free acid or

ester form at C-28 was ambiguous. For some analogues,

triterpenoids bearing C-28 the carboxyl group were more

potent than C-28 methyl; esters, but for others similar

activity or even less potent activities were observed when

C-28 was carboxylic acid. (5) The oleanane skeleton was

usually more potent than the ursane skeleton.

The SARs of modified ring-C oleanane and ursane

triterpenoids with .

12

functionality (Table 6) were also

summarized as follows:

(1) A 9(11)-en-12-one functionality in ring C could

enhance activitiy about 10-100 times; (2) 12-en-11-

one,

13(18)-en-11-one, and 12-one functionalities also

enhanced potency, and a 9(11)-ene functionality showed

similar potency to the original 12-ene; (3) The saturated

ring C, 11, 13(18)-diene, and 9, 11-epoxide were less

potent than the original 12-ene; as indicated in compounds

110-112. (4) The combination of a 9(11)-en-12-one

functionality with nitrile and carboxyl groups at C-2

enhanced the potency in a synergistic way; Triterpenoids

such as 115, 116 and 119 (IC

50

=0.1 nM level) were about

10,000 times more potent than 73. (5) The combination

of a 9(11)-en-12-one functionality with amide and formyl

groups at C-2 did not enhance potency as strongly as

a nitrile or carboxyl group; (6) The combination of a

12-en-11-one and 13(18)-en-11-one functionalities with

nitrile group at C-2 also strongly enhanced the potency as

9(11)-en-12-one series by two orders of magnitude.

CDDO (11 6) showed almost the strongest NO

inhibitory activity (Table 6) among those synthetic

derivatives of OA. Moreover, it could also inhibit

proliferation of many tumor lines at sub M level and

induced cell differentiation of human myeloid leukemia

(Suh et al., 2000).

Based on structures of highly active triterpenoids

CDDO, 115 and 11 9 (Table 6), a series of oleanane

triterpenoids (123-148) with various substituents at

the C-28 were synthesized (Table 7). Some important

SARs regarding substituents at C-17 were also provided:

(1) Nitrile group enhanced potency and ester moieties

decreased potency. The less polar the ester, the less was

its potency. (2) The carbonyl pyrazole was much less

potent than that of 28-COOH, while carbonyl imidazole

had higher potency, which might have arisen from high

reactivity of imidazole with nucleophiles.

Moreover, many tricyclic compounds (149-157), as

simplified CDDO with same A, B, and C ring architecture,

were synthesized and tested for NOS inhibitory activity,

the IC

50

values were between 0.002 and 1.6 £gM, in which

(¡Ó)-80 showed the most potential (IC

50

=0.002 £gM). It was

found that the most active compound 157 was only about

one-fourth as potent as CDDO, so a nitrile group at this

position enhanced potency among the typical electron-

withdrawing groups such as in compounds 154 and 156 at

C-13. Since 151 and 152 were more potent than 149 and

150, the bis-enone structure for high potency in relatively

small molecules is important (Favaloro et al., 2002).

aNTi-viraL aCTiviTieS

Saponins 158 and 159 were isolated from Gymnoladus

chinensis (Nakashima et al., 1989) and Gleditsia japonica,

respectively. Both compounds exhibited potent anti-

HIV effects against HIV replication in H-9 cells. Their

derivatives (160-173) were prepared and evaluated for

anti-HIV activity (Table 8). The monoterpenyl moieties

in 158 and 159 were found to play an important role in

modulating the anti-HIV activity of these compounds.

In addition, methylation of 28-COOH increased activity

while introduction of n-butyryl or valeryl groups to the

C-3 and/or C-16 hydroxy group decreased it compared to

that of 167 (Konoshima et al., 1995).

A series of natural and semi-synthetic OA, UA and

betulinic acid (27) derivatives have been isolated (Ma et

al., 2002; Kashiwada et al., 1998) or synthesized. Some

relationships of anti-HIV activities and structures were

summarized in Table 9.

(1) Esters especially dicarboxylic acid hemiesters of

3-OH in OA, tended to increase inhibitory activity (Ma et

al., 1999). For the 3-acyl chains within five carbons, the

HIV-1 PR inhibitory activity of the compounds increased

as the lengths of the 3-acyl chains increased (Ma et al.,

2000). (2) Methylation of the 28-COOH or the carboxyl

OR

O

NC

149 R=H

150 R=Ac

151 R=Ac

152 R=H

OR

O

NC

O

O

NC

O

153

154 R=CO

2

CH

3

155 R=COOH

156 R=CONH

2

157 R=CN

O

NC

O

R

348

Botanical Studies, Vol. 47, 2006

Table 6. NO inhibitory activity of olean-1-en-3-one and urs-1-en-3-one triterpenoids with various C-ring functionalities.

R

2

O

R

1

O

R

2

O

R

1

U

Type

Structure of ring C

R

1

at C-2

R

2

at C-17

IC

50

(£gM)

94

O

H

CO

2

Me

2.8

95

O

H

CO

2

H

1.1

96

U

H

CO

2

Me

8.9

97

U

H

CO

2

H

5.1

98

O

H

CH

2

OAc

>40

99

O

H

CH

2

OH

3.0

100

O

H

CHO

3.8

101

O

CN

CO

2

Me

0.02

102

O

CN

CO

2

H

0.04

103

U

CN

CO

2

Me

0.1

104

U

CN

CO

2

H

0.8

105

O

H

CO

2

H

2.6

106

O

CN

CO

2

H

0.07

107

O

H

CO

2

Me

14

108

O

H

CO

2

H

3.3

109

O

H

CO

2

H

5.2

110

O

H

CO

2

H

8.5

111

O

H

CO

2

H

9.7

112

O

H

CO

2

H

36

113

O

H

CO

2

Me

0.7

114

O

H

CO

2

H

0.2

115

O

CN

CO

2

Me

0.0001

116

O

CN

CO

2

H

0.0002

117

O

CO

2

Me

CO

2

Me

Toxic

118

O

CO

2

Me

CO

2

H

0.1

119

O

CO

2

H

CO

2

Me

0.0008

120

O

CO

2

H

CO

2

H

0.2

121

O

CONH

2

CO

2

Me

0.1

122

O

CHO

CO

2

Me

0.1

H

O

H

H

O

H

H

O

O

H

O

H

O

H

H

O

H

H

O

O

H

O

H

O

H

H

O

H

H

O

O

H

O

H

O

H

H

O

H

H

O

O

H

O

H

O

H

H

O

H

H

O

O

H

O

H

O

H

H

O

H

H

O

O

H

O

H

O

H

H

O

H

H

O

O

H

O

H

O

H

H

O

H

H

O

O

H

O

SUN

et al. ¡X Structure-activity relationships of oleanane- and ursane-type triterpenoids

349

Table 7. NO inhibitory activities of compounds 123-148.

O

R

1

R

2

O

R

1

R

2

IC

50

(£gM)

123 CN

CN 0.0035

124

CN

CO

2

H 1.68

125

CO

2

Et

CN

0.80

126

CO

2

Et

CO

2

H 7.93

127 CO

2

CH

2

CH=CH

2

CN

1.33

128

CO

2

(CH

2

)

3

CH

3

CN

6.65

129

CO

2

CN

4.45

130 CO

2

CH

2

Ph

CN

4.35

131

CO

2

(CH

2

)

7

CH

3

CN

60.4

132 CO-

D

-Glc(OAc)

4

CN

0.07

133

CO-

D

-Glc

CN

10.1

134

CONH

2

CN

0.098

135

CONHNH

2

CN

0.26

136

CONHMe

CN

0.58

137 CONH(CH

2

)

2

CH

3

CN

1.50

138

CONH(CH

2

)

5

CH

3

CN

14.9

139

CONHPh

CN

28.6

140

CONHCH

2

Ph

CN

9.2

141

CONMe

2

CN

1.55

142 CON(n-Pr)

2

CN

32.9

143

CON

CN

0.80

144

CON

CN

0.95

145

CON N

CN

1.00

146

O

CON

CN

2.4

147

N

CON

CN

0.014

148

N

CON

CN

12.0

group in the C-3 hemiester chain decreased the inhibitory

activity against HIV-1 PR significantly (Kashiwada et al.,

1998). Methylation at both sites led to complete loss of

activity, e.g. 210 (Ma et al., 1999). (3) Replacement of the

28-COOH with a methyl group resulted in a significant

loss of activity (25 vs UA; 26 vs OA) (Kashiwada et al.,

1998). (4) The structure of E-ring might play an important

role in anti-HIV potency. Derivatives of betulinic acid, 27,

were more potent than those of UA and OA (Kashiwada

et al., 2000). (5) Saturation of the C

12

-C

13

double bond

could be a major cause of anti-HIV activity enhancement

(238-240), while a C-3 acyl side chain was essential for

optimal activity. In addition, changing the C

28

-carboxyl

to aminomethyl could significantly enhance anti-HIV

activity (241, 242) (Zhu et al., 2001). (6) Replacement of

C-3 hemiester in the OA series with hemi-amide retained

activity (219-223 vs 204-205) (Ma et al., 1999).

Oleanane-type triterpenoid saponins (243-258) were

examined for the anti-herpes virus (anti-HSV-1) activity

(Table 10). It has been found that (1) the trisaccharide

glycosides were more potent than the disaccharide

glycosides. The order of activity was 247> 250>>253.

(2) The saponins having a glucosyl unit in the central

sugar moiety seemed to show greater action. Among

the trisaccharide group, the order of activity was

245>244>246>>243. (3) The carbonyl group at C-22

would be more effective than the hydroxyl group in anti-

HSV-1 activity, while the hydroxyl group at C-24 could

reduce the activity. Comparing the activities of a group

having the same trisaccharide, the order of potency was

254>247>243 (Kinjo et al.,

2001).

Table 8. HIV inhibitory effects for 158-173.

Compd

ED

50

(£gM)

IC

50

(£gM)

158

1.1

9.8

159

2.7

14

160

>100

43

161

>100

37

161a

9.9

22

162

13

50

163

95

63

164

100

>100

165

42

74

166

8

40

167

3.1

4.9

168

5.1

7.6

169

2.3

13

170

27

27

171

15

>160

172

30

180

173

31

54

350

Botanical Studies, Vol. 47, 2006

aNTi-iNFLaMMaTOrY aCTiviTieS

in vivo studies

OA and UA inhibited the Croton oil-induced ear

oedema in mice in a dose-dependent manner, and UA

(ID

50

=0.14 £gMoles/cm

2

) was twofold more

potent than

O A (ID

50

=0.36 £gMoles/cm

2

) and indomethacin (ID

50

=0.26

£gMoles/cm

2

), which was used as a reference non-steroidal

anti-inflammatory drug (NSAID) (Ismaili et al., 2001 and

2002; Baricevic et al., 2001).

The anti-inflammatory activities of ten triterpenoids

[ 25, 26, 68, 259, 260,

OA, Hederagenin ( 261) , 28,

£\-glycyrrhetinic acid (262), and lupeol (263)] were

evaluated. It was found that the basic carbon skeletons

had no influence on the activity; the presence of a C-28

or C-30 carboxylic group and an alcoholic group at C-28

increased the activity in carrageenan and TPA-induced

edemas in mice (Recio et al., 1995).

The following mechanistic aspects of anti-inflammatory

activities of OA and U A derivatives have been

investigated.

inhibition of cyclooxygenase (COX) activity

UA was a selective inhibitor of COX-2 catalyzed

prostaglandin biosynthesis, with IC

50

value of 130 £gM and

a COX-2/COX-1 selectivity ratio of 0.6. OA (IC

50

295

£gM) was found to be less active than UA, but showed a

similar selectivity ratio (0.8). Furthermore, no significant

inhibition on COX-2 or COX-1 was observed by 28

(Ringbom et al., 1998). 1 £gM or less of CDDO (116)

blocked expression of both iNOS and COX-2 protein

(Syrovets et al., 2000). Compounds 247, 260 and 3-epi-

UA (264) (assayed at 10 £gM) blocked the inductive effect

of lipopolysaccharide on the production of PGE

2

, while

OA and UA did not substantially suppress the production

of PGE

2

(Suh et al., 1998). Compounds 5 and 9 strongly

O

OH

OH

OH

HOCH

2

O

O

O

OH

O

CH

3

OH

OH OH

O

OH

OH

OH

O

CH

3

OH OH

O

O

CH

2

OH

OH

O

O O

O

OH

OH

OH

O

OH

OH

O

O

CH

2

OH

OH

OH

O O

CH

2

OH

O

O

O

OH

OH

HO

OH

O

O

O

O

158

O

CH

3

OH

O O

O

OH

OH

OH

O

CH

3

OH OH

O

O

CH

2

OH

OH

O

O O

O

OH

OH

OH

O

OH

OH

O

O

CH

2

OH

OH

OH

O O

O

O

O

OH

OH

HOH

2

C

HO

O O

CH

3

OH

OH

159

RO

CH

2

OH

OH

O

O

HO

164 R=Glc

6

-Ara

2

-Xyl

165 R=H

O

OH

OH

OH

O

OH

OH OH

CH

3

Ara=

Rham=

R

1

O

OR

2

COOR

3

Glc

6

-Ara

2

-Xyl H Glc

2

-Rham

Glc

6

-Ara

2

-Xyl H H

Glc

6

-Ara

2

-Xyl H Me

Glc

6

-Gra H H

Glc

H H

H

H H Me

Ac H Me

Ac Ac H

Butyryl H Me

Butyryl Butyryl Me

Valeryl H Me

Valeryl Valeryl Me

H H

160

161

161a

162

163

165

167

168

169

170

171

172

173

SUN

et al. ¡X Structure-activity relationships of oleanane- and ursane-type triterpenoids

351

Table 9. HIV inhibitory effects for derivatives of OA, UA and 28.¡@

R

2

R

1

O

R

2

R

1

U

R

2

R

1

L

Type

R

1

R

2

IC

50

(£gM)

25

U

CH

3

OH

80

UA

U

COOH

OH

8

174

U

COOCH

3

OH

14

175

U

COOH

OCOCH

3

13

176

U

COOH

OCOCOOH

7

177

U

COOH

OCOCH

2

COOH

6

178

U

COOH

OCO(CH

2

)

2

COOH

6

179

U

COOH

OCO(CH

2

)

3

COOH

4

180

U

COOCH

3

OCO(CH

2

)

3

COOCH

3

>50

181

U

COOH

OCOC(CH

3

)

2

CH

2

COOH

30.7

182

U

COOH

OCOCH

2

C(CH

3

)

2

COOH

49.5

183

U

COOH

OCOCH

2

C(CH

3

)

2

CH

2

COOH

7

184

U

COOH

OCOCH

2

OCH

2

COOH

48.2

185

U

COOH

OCOCH

2

CH(CH

3

)

2

>18.5

186

U

COOH

OCOCH

2

C(CH

3

)

3

>18

187

U

COO

-

K

+

OH

1.8

27

L

COOH

OH

9

188

L

COOCH

3

OH

>25

189

L

COOH

COCOOH

7

190

L

COOH

OCOCH

2

COOH

6

191

L

COOH

OCO(CH

2

)

2

COOH

6

192

L

COOH

OCO(CH

2

)

3

COOH

4

193

L

COOH

OCOCH

2

C(CH

3

)

2

CH

2

COOH

4

194

L

COOCH

3

OCO(CH

2

)

2

COOCH

3

40

195

L

COOH

OCOCH

2

C(CH

3

)

2

COOH

7.0

26

O

CH

3

OH

>100

OA

O

COOH

OH

8

196

O

COOCH

3

OH

20

197

O

COOH

OCOCH

3

9

198

O

COOH

OCOCOOH

20

199

O

COOH

OCOCH

2

COOH

8

200

O

COOH

OCO(CH

2

)

2

COOH

4

201

O

COOH

OCO(CH

2

)

3

COOH

4

202

O

COOCH

3

OCO(CH

2

)

3

COOCH

3

>50

203

O

COOH

OCOCH

2

C(CH

3

)

2

COOH

19.2

204

O

COOH

OCO(CH

2

)

4

COOH

3.0

205

O

COOCH

3

OCO(CH

2

)

4

COOH

7.5

206

O

COOH

OCO(CH

2

)

6

COOH

3.0

352

Botanical Studies, Vol. 47, 2006

Type

R

1

R

2

IC

50

(£gM)

207

O

COOH

OCO(CH

2

)

8

COOH

4.0

208

O

COOH

OCOCH

2

C(CH

3

)

2

CH

2

COOH

3.8

209

O

COOH

OCO(CH

2

)

4

COOCH

3

5.6

210

O

COOCH

3

OCO(CH

2

)

4

COOCH

3

>20

2 11

O

COOH

OCO(CH

2

)

4

CH

3

>20

212

O

COOH

=O

5.5

213

O

COOCH

3

=O

20

214

O

COOH

=NOH

5.5

215

O

COOCH

3

=NOH

9.5

216

O

COOCH

3

£\-NH

>20

217

O

COOCH

3

£]-NH

>20

218

O

COOH

=NOCO(CH

2

)

4

COOH

5.5

219

O

COOCH

3

=NOCO(CH

2

)

4

COOH

4.0

220

O

COOH

£]-NHCO(CH

2

)

4

COOH

3.0

221

O

COOCH

3

£]-NHCO(CH

2

)

4

COOH

3.0

222

O

COOH

£\-NHCO(CH

2

)

4

COOH

2.1

223

O

COOCH

3

£\-NHCO(CH

2

)

4

COOH

3.5

224

O

COOCH

3

£]-NHCO(CH

2

)

4

CONH(CH

2

)

3

COOH

6.0

225

O

COOCH

3

£]-NHCO(CH

2

)

4

CONH(CH

2

)

3

COOCH

3

>20

226

O

COOH

£]-NHCO(CH

2

)

4

CONH-£]-OA-28-OH

3.3

227

O

COOCH

3

£]-NHCO(CH

2

)

4

CONH-£]-OA-28-OCH

3

>20

228

O

CONH(CH

2

)

5

COOH

COOH

1.7

229

O

CONH(CH

2

)

5

COOH

OCO(CH

2

)

4

COOH

1.7

Type

R

1

R

2

IC

50

(£gg/mL)

230

O

COOH

OCOC(CH

3

)

2

CH

2

COOH

9.7

231

O

COOH

OCOCH

2

OCH

2

COOH

22.1

232

O

COOH

OCOCH

2

CH(CH

3

)CH

2

COOH

27.5

233

O

COOH

O

COOH

O

4.4

234

O

COOH

O

COOH

O

4.7

235

O

COO

-

K

+

OH

34.3

RO

COOH

R

EC

50

(£gg/mL)

EC

50

(£gg/mL)

236

H

0.5

OA

1.7

237

2.6

201

7.1

238

0.1

232

8.3

239

0.1

208

1.5

240

0.1

234

1.2

Table 9. (Continued)

C O O H

O

C O O H

O

C O O H

O

C O O H

O

SUN

et al. ¡X Structure-activity relationships of oleanane- and ursane-type triterpenoids

353

RO

CH

2

NHR

R

EC

50

(£gg/mL)

241

0.1

242

0.1

Table 9. (Continued)

C OOH

O

COOH

O

RO

CH

2

OH

OH

243 R=S

1

244 R=S

3

245 R=S

2

246 R=S

4

249 R=S

5

251 R=S

6

252 R=S

7

256 R=H

247 R=S

1

248 R=S

3

250 R=S

5

253 R=S

7

257 R=H

RO

CH

3

OH

254 R=S

1

255 R=S

4

RO

CH

2

OH

O

258 R=H

O

COOH

OH

OH

O

O

OH

O

OH

HO

O

OH

OH

Me

OH

S

5

S

1

=

O

COOH

OH

OH

O

O

OH

O

HO

O

OH

OH

Me

OH

OH

S

6

O

COOH

OH

OH

O

O

OH

O

O

OH

OH

Me

OH

OH

O

COOH

OH

OH

O

O

OH

O

O

OH

OH

Me

OH

OH

S

7

S

2

=

S

3

= S

4

=

inhibited the formation of 6-keto-PGF

1£\

with an IC

50

value of approximately 0.12 £gM, and synthesis of TXB

2

catalyzed by COX-2 with an IC

50

value in the range of

0.4~2.5 £gM (Hamburger et al., 2002). Platycodin D (265),

isolated from the root of Platycodon grandiflorum A. DC.

(Campanulaceae), suppressed PGE

2

production at 10 £gM

in rat peritoneal macrophages stimulated by TPA (Kim et

al., 2001).

inhibition of complement activity

Complement plays a role in various functions of

the adaptive immune response. Yet overactivation of

complement is implicated in various inflammatory

diseases. A/B¡Vring partial analogues (29a-c, 30a-c

and 33b) of OA also showed complement inhibitory

activity (IC

50

=72.3~633 £gM). The lack of complement

inhibitory activity with compounds 31 and 32 showed the

importance of the free carboxylic group for complement

inhibition. The lack of complement inhibitory activity

with compounds 33a and 33c while the compound 33b

retained

the activity may indicate that the meta position of

the carboxylic group was more favorable for complement

inhibitory activity (Assefa et al., 2001).

Some semisynthetic analogues of OA (Table 11) were

evaluated for their complement inhibitory and cytotoxic

activities. The amide derivatives (268 and 269), OA-11-

oxo 273, and the 3-acyl derivatives (203, 208 and 231)

have retained the complement inhibitory activity. Among

these, compounds 269 and 231 showed potency superior

to OA. Both showed a moderate improvement in vitro TI

in comparison with OA (Assefa et al., 1999).

354

Botanical Studies, Vol. 47, 2006

inhibition of elastase

The hydrolysis of blood vessel elastin by HLE

promotes the transendothelial migration of stimulated

proinflammatory cells. The IC

50

values for elastase

inhibition by UA and O A were 4.4 and 6.4 £gM,

respectively (Ying et al., 1991). The £\-boswellic acid

(274), acetyl-11-keto-£]-boswellic acid (AKBA) ( 275),

25, 26, UA, and 28 were tested for the inhibitory activity

of HLE. Dual inhibition of 5-lipoxygenase and HLE

was unique to boswellic acid series. UA and amyrins,

which possessed no 5-LO inhibitory properties, blocked

the activity of HLE, but 28 had no inhibitory effects at

concentrations up to 20 £gM (Safayhi and Sailer, 1997).

The presence of an 11-keto group and hydrophilicity on

the A-ring of the pentacyclic ring system was crucial for

AKBA¡¦s potent 5-LO inhibitory activity (Sailer et al.,

1996).

In another report, UA, 27, 263, and 276 were evaluated

as potential inhibitors of HLE. Among these triterpenes,

UA and 263 showed marked HLE inhibitory activity

with IC

50

values of 4.4 and 1.9 £gM, respectively. The

appearance of HLE inhibition may depend on the presence

and the orientation of two reactive groups in the tested

molecules (Mitaine-Offer et al., 2002).

inhibition of intercellular adhesion molecule

(iCaM-1) expression induced by TNF-£\

ICAM-1 is a member of the immunoglobulin

superfamily of adhesion molecules, and appears to lead to

acute and chronic inflammation. The inhibitory effects of

oleanane-type triterpenoids from fabaceous plants on the

TNF-£\-induced expression of ICAM-1 on THP-1 human

monocytic leukemia cells were reported. The activity

Table 11. Classical complement inhibition and cytotoxicity of

OA, 196, 197, 203, 208, 212, 231, and 266-273.

Complement inhibition

IC

50

(£gM)

Cytotoxicity

IC

50

(£gM) TI

OA

72.3

112

1.55

197

NA

NA

0.06

266

NA

70

267

NA

NA

268

146.6

115

0.78

269

31.8

127

3.99

270

NA

NA

271

NA

105

196

NA

103

272

NA

NA

273

233.7

131

0.56

203

108.3

77

0.71

231

31.4

93

2.96

208

103.0

86

0.83

212

NA

31

Table 10. Anti-HSV-1 activity, cytotoxicity and selectivity index of 243-258.

Anti-HSV-1 activity (IC

50

, £gM)

Cytotoxicity (CC

50

, £gM)

Selectivity index (CC

50

/IC

50

)

243

>75.0

¡V

¡V

244

27.4

115

4.2

245

21.0

>332

>15.8

246

43.0

>343

>13.7

247

43.2

119

2.8

248

22.3

698

31.3

249

>75.0

¡V

¡V

250

64.1

641

10.0

251

54.0

>393

>7.3

252

>75.0

¡V

¡V

253

>75.0

¡V

¡V

254

19.1

>332

>17.4

255

25.1

>343

>13.7

256

5.6

116

20.7

257

37.8

>141

>3.7

258

61.4

504

8.2

SUN

et al. ¡X Structure-activity relationships of oleanane- and ursane-type triterpenoids

355

of oleanane saponins and sapogenins against ICAM-1

expression appears to be dependent upon the position of

the hydroxyl group, in particular upon the status of the

C-21 and C-24 positions, and of the glycosyl group at C-3

position (Ahn et al., 2002).

HepaTOprOTeCTive aCTiviTieS

OA has been successfully used as an oral drug to treat

human acute and chronic liver diseases in China (Qu,

1981). UA has been observed to be more potent than OA

in decreasing chemically induced liver injury in mice (Liu

et al., 1994).

O A 3£]-phthalic monoester disodium salt (277) w as

synthesized in order to increase the solubility of OA in

water. Compound 277 inhibited the rising of serum ALT

caused by D-galactosamine and CCl

4

, and dramatically

decreased liver fat storage, in addition to alleviating the

condition of the degeneration of hepatic cells and necrosis

(Wan et al., 1998).

OA sodium salt (278) obviously inhibited the rising

of ALT and serum phosphatase caused by CCl

4

when

hypodermically injected (100, 50, and 30 mg/kg) (Zhang

et al., 2000). When cadmium is administered as CdCl

2

to animals, most of it accumulates initially in the liver.

Accordingly, the acute toxic effects of cadmium are

observed mainly in the liver. Several triterpenes were

investigated for the effect on cadmium toxicity in Hep

G2 cells. Among them, 18£\-glycyrrhetinic acid (262) and

18£]-glycyrrhetinic acid (28) had no protective effects,

OA, UA, and glycyrrhizin (279) exhibited weak effects,

and betulin (280) and uvaol (281) were more effective in

HO

R

5

R

2

R

4

R

1

R

3

R

1

=OH, R

2

=COOH,

R

3

=CH

3

, R

4

=OH, R

5

=CH

3

259

R

1

=H, R

2

=CH

2

OH,

R

3

=H, R

4

=CH

3

, R

5

=CH

3

260

R

1

=H, R

2

=COOH,

R

3

=H, R

4

=CH

3

, R

5

=CH

2

OH

261

HO

COOH

O

H

262

HO

263

HO

COOH

264

CH

2

OH

OH OH

OH

O

CH

2

OH

OH OH

O

Me

OH OH

O

O

OH

OH

O

O

O

OH

OH

O

HOH

2

C CH

2

OH

HO

OH O

O

265

266 R

1

=COCH

3

, R

2

=CONH

2

267 R

1

=H, R

2

=CONH

2

271 R

1

=H, R

2

=CH

2

OH

R

2

R

1

O

268 X=1

269 X=4

270 X=10

CONH(CH

2

)

X

COOH

HO

272 R=COCH

3

273 R=H

COOH

RO

O

HO

COOH

274

O

O

276

HO

d=11.2

263

AcO

COOH

O

275

356

Botanical Studies, Vol. 47, 2006

reducing the toxicity of CdCl

2

. Betulin (280), in particular,

almost completely abolished the cytotoxicity of CdCl

2

at

concentrations as low as 0.1 £gg/mL (Miura et al., 1999).

GaSTrOprOTeCTive aCTiviTieS

OA displayed gastroprotective effects in three different

experimentally induced gastric ulcer models in rats

(Astudillo et al., 2001). Five semi-synthetic derivatives

of OA (OA-28-methyl ester, 282, OA-3-acetyl, OA-

3-oxo, an d OA-3-oxo-28-methyl ester) were assessed

for gastroprotective effects in the HCl/ethanol ulcer

model in mice. The lesion index was 15.7~39.3 mm.

Oxidation of the OH at C-3 reduced the activity of OA

and its derivatives, while methylation of the 28-COOH

with or without acetylation at C-3 did not affect the

gastroprotective activities of the compounds (Astudillo et

al., 2001).

Eight glycosides (283-290) of OA were examined for

the effects on ethanol- or indomethacin-induced gastric

mucosal lesions in rats. Saponins 283, 284 and 287 were

effective on ethanol- or indomethacin-induced lesions,

but 285, 286, 288, 290 and their aglycone O A did not

show such effects. Diglycoside 289 did not inhibit the

indomethacin-induced lesions, but 288 (50 mg/kg) did

have gastroprotective effect. The results demonstrated that

the 3-O-glycoside moiety was essential for the activity,

and the 28-ester glucoside reduced the activity (Matsuda

et al., 1998b).

aNTiMiCrOBiaL aCTiviTieS

O A was reported to have antimicrobial activity

against B. subtilis (MIC=8 £gg/mL), methicillin-sensitive

(MIC=8 £gg/mL) and resistant (MIC=64 £gg/mL) S. aureus.

In this study, 3-O -(E)-hydroxycinnamoyl OA (5) d id

not show antimicrobial activity (Woldemichael et al.,

2003b). In a separate study OA-28-methyl ester showed

weak antibacterial activity against M. luteus and E. coli

(Weimann et al., 2002).

RO

COOH

O

H

279 R=

A

-D-Glc(1 2)

B

-D-Glc(1

HO

COONa

278

O

COONa

ONa

O

O

277

HO

CH

2

OH

280

HO

CH

2

OH

281

AcO

COOCH

3

282

COOH

OR

3

OR

4

OR

2

O

COOR

1

H

R

1

R

2

R

3

R

4

283 H H H H

284 H H Xyl H

285 Glc H Xyl H

286 Glc H H Ara(f)

287 H H H Ara(f)

288 Glc Glc H H

289 H Glc H H

HO

O

O

OH

OH

CH

2

OH

OH

H

290

SUN

et al. ¡X Structure-activity relationships of oleanane- and ursane-type triterpenoids

357

E. coli. Only compound 303, a monodesmosidic saponin

with OA as aglycone, showed inhibitory activity. The

MIC values of 303 were 64 ppm against C. albicans,

and 128 ppm against S. epidermidis and B. cereus. The

MIC value of reference chloramphenicol was 16 ppm

for S. epidermidis and B. cereus. The other saponins

(54, 304-307) showed no inhibitory activity. Thus, it

was presumed the antibacterial activity was related to

the presence of a monodesmosidic saponin with OA as

aglycone (Bedir et al., 2000).

OA and UA also showed trypanocidal activity. UA

stopped the movement of all T. cruzi epimastigotes at

the minimum concentration (MC

100

) of 88 £gM after 48

h of incubation. OA was less active (MC

100

=550 £gM),

and 27 was inactive (Abe et al., 2002). In contrast, the

methyl esters (UA- and OA-28-methyl ester) and acetates

(UA- and OA-3-acetyl) of UA and OA were not active,

but OA-3-oxo (IC

50

=294.9 £gM), 308 (IC

50

=402.3 £gM)

and 309 (IC

50

=56.6 £gM) retained the activity. These

results suggested the importance of the polar groups to

trypanocidal activity (Cunha et al., 2003).

Two OA saponins, 290 and 310, from Viguiera

decurrens showed insecticidal activity, and their LC

50

values were 1380 and 80 £gg/mL against Epilachna

varivestis larvae, respectively (Marquina et al., 2001).

3-epi-OA (300) possessed antiprotozoal activity

(IC

50

=18.8 £gM against L. donovani promastigotes; and

28.3 £gM against P. falciparum)

(Camacho et al., 2000).

Four saponins (49, 50, 311 and 312) were isolated from

Serjania salzmanniana and were mollusicidal, causing

70-100% mortality at 10 ppm against Biomphalaria

alexandrina. The saponins also showed antifungal activity

against Cryptococcus neoformans and Candida albicans

with MIC at inhibitory concentrations of 8 and 16 £gg/mL,

respectively (Ekabo and Farnsworth, 1996).

OA, UA, 25, £\-amyrin acetate (291), UA-3-acetyl,

and 292-295 were isolated from Alyxia insularis Kanehira

& Sasaki, and examined for antimicrobial activity. Only

two compounds, both of which contained an 11-carbonyl

group (292, 293), showed inhibitory activity on the growth

of S. epidermidis, M. luteus, S. aureus, B. subtilis, and

S. faecium (at 100 and 50 £gg/mL) (Wang et al., 1993).

Compounds 296-299 were isolated from Dillenia papuana

and showed antibacterial activity (Table 12). It was

presumed that the carboxylic group and £G

12, 13

double bond

played an important role in antibacterial activity (Nick et

al., 1994). The MICs of OA, OA-3-oxo, 3-epi-OA (300),

28, 301, and 302 against M. tubercular were 50, 16, 16,

128, 64 and 64, respectively. It was concluded that the low

polarity pentacyclic triterpenes with a hydroxyl or keto

group in the A or B ring and an acid group in the E ring

possess moderate antitubercular activity (Caldwell et al.,

2000).

3-epi-UA (264) and 300 showed antimycobacterial

activity with MIC values of 8 and 16 £gg/mL, respectively

(Woldemichael et al., 2003a). Six triterpene saponins 54,

and 303-307, were isolated from Hedera helix L., and

tested against C. albicans, B. cereus, S. epidermidis and

Table 12. Antibacterial activity of 296-299.

Minimum growth inhibition (£gg)

B. subtilis E. coli M. luteus

296

2.4

2.4

1.2

297

2.0

1.0

1.0

298

2.0

5.0

2.0

299

1.0

1.0

1.0

Positive control: Chloramphenicol MGI=0.1, 0.04, and 0.04

£gg, respectively.

AcO

291

292 R

1

=Ac, R

2

=COOH, R

3

=O

293 R

1

=H, R

2

=COOH, R

3

=O

294 R

1

=Ac, R

2

=CH

3

, R

3

=O

R

1

O

R

2

R

3

HO

O

O

295

O

HOOC

HO

296

HO

HOOC

O

297

O

HOOC

OH

298

HO

COOH

300

O

O

COOH

O

HOOC

299

358

Botanical Studies, Vol. 47, 2006

Various dosages (1.9 to 3.0 g/kg) of OA could affect

the survival, growth, and development of the larvae of

heliothis zea. This might be one of the plant¡¦s defense

mechanisms against phytophagous insects (Argandona

and Faini, 1993). OA, UA, and their synthesized 3-O-fatty

acid ester analogues (313-318) were examined for

antifeedant activity against the agricultural pest tobacco

caterpillar S. litura larvae. At the dosages of 150, 100, 50

£gg/mL, all of the compounds showed antifeedant activity.

At 150 £gg/mL dose, all the tested compounds showed

more than 50% activity, except compounds OA and 318.

At 100 £gg/mL dose, the compounds showed 40~78%

activity, while compound 318 again showed the lowest

activity. Even at 50 £gg/mL, compounds

314-317

exhibited

more than 50% activity. Compounds 316 (74%) and

317

(71%) were found to exhibit exceptionally potent activity

at 50 £gg/mL (Mallavadhani et al., 2003).

aNTi-DiaBeTeS aCTiviTieS

Many late complications of diabetes are associated

with hypoglycemia. OA glycosides (283, 286, 287,

and 319-324) from the root of Aralia elata, which has

been used for treating diabetes, were examined for

hypoglycemic activity in the oral sucrose tolerance in

rats (Table 13). It was concluded the 3-O-glycoside

moiety was essential to the activity, while the 28-ester

glucosidal moiety significantly reduced the activity. In the

3-O-oligoglycoside structure, the 3¡¦-O-glucopyranosyl

moiety tended to decrease the activity, while the 4¡¦

-O-arabinofuranosyl moiety increase it (Yoshikawa et

al., 1994; 1996a, b; Fujimura et al., 1996). The 6¡¦-methyl

ester of the glucuronic acid (325) moiety strongly reduced

the activity (Matsuda et al., 1998c). The above summaries

for SARs were substantiated further by bioassay results

of compounds (326-329) from Beta vulgaris L., among

which 327 and 329 showed hypoglycemic activity, 328

showed weaker activity, and 326 was inactive (Yoshikawa

et al., 1996c). O A sodium salt (278) (s.c. 20 mg/kg¡Pd)

obviously reduced blood sugar (Zhang et al., 2000).

Table 13. Inhibitory effects of 283, 286, 287, 319-324,

326-329 (100 mg/kg, p.o.) on the rise in plasma glucose level

by oral sucrose tolerance test.

Plasma glucose concentration (mg/dl)

0.5 h

1 h

2 h

319

18.2

18.7

15.5

320

76.6

44.9

18.9

321

27.7

33.4

36.4

323

71.4

45.4

32.4

322

31.9

28.1

29.5

287

18.0

23.0

16.6

283

26.9

24.4

28.6

324

55.2

37.4

20.0

286

36.0

17.7

20.6

OA

82.8

58.1

30.8

326

81.1

48.9

23.4

327

36.1

41.9

31.2

328

66.9

39.3

12.4

329

39.1

30.0

23.4

HO

O

297

O

298

HO

300

HO

O

O

301

HO

COOH

302

O

OH

HO

HO

OH

303 R

1

=H, R

2

=

, R

3

=H

O

OH

HO

HO

OH

304 R

1

=OH, R

2

=

, R

3

=H

OH

O

OH

HO

OH

O

OH

HO

O

CH

2

OH

305 R

1

=OH, R

2

=H, R

3

=

O

OH

HO

HO

OH

306 R

1

=OH, R

2

=

, R

3

=

OH

O

OH

HO

OH

O

OH

HO

O

CH

2

OH

O

OH

HO

HO

OH

307 R

1

=H, R

2

=

, R

3

=

OH

O

OH

HO

OH

O

OH

HO

O

CH

2

OH

O

COOR

3

R

1

O

OR

2

HO

HO

OH

HO

R

1

COOH

R

2

308 R

1

=CH

3

, R

2

=OH

309 R

1

=COOH, R

2

=H

O

299

SUN

et al. ¡X Structure-activity relationships of oleanane- and ursane-type triterpenoids

359

manner, similar to the dose-dependent insulin production

by glucose in INS-1 cells. OA-28-aldehyde also enhanced

insulin secretion by about 4ng/mg in those concentrations

(Zhang et al., 2004).

Slowing gastric emptying will prolong the postprandial

absorption of food, with a resultant improvement in blood

glucose control. OA and its oligoglycosides (283-290,

333) were examined for their effects on gastric emptying

in mice, and the 3-O-glycosides moiety was found to be

essential. The 2¡¦-O-£]-D-glucopyranosyl moiety of the

glucuronic acid reduced the activity, and the 28-ester

glucose moiety markedly reduced it (Matsuda et al.,

1999).

Inhibition of £\-glucosidase can prevent late

complications of diabetes by decreasing the postprandial

rise in blood glucose (Bischoff, 1994). OA and its five

synthetic derivatives (OA-28-methyl ester, OA-3-acetyl,

330, 331 and 332) were found to inhibit £\-glucosidase,

with IC

50

values of 11.16, 55.097, 19.012, 7.97, 89.71

and 21.63 £gM, respectively. Compound 330 was the most

potent among them (Ali et al., 2002).

OA and OA-28-aldehyde were reported to stimulate

insulin production in INS-1 cells. At 12.5 £gg/mL, O A

increased insulin production by 87.97 ng/mg of protein

in INS-1 cells. At 25 and 50 mg/ml of OA, the secretion

of insulin was reduced considerably in a dose-dependent

O

O

O

OH

O

OH

HO

OH

O

OH

HO

HO

MeOOC

310

313 R

1

=CH

3

, R

2

=H, R

3

=CH

3

, n=10

314 R

1

=CH

3

, R

2

=H, R

3

=CH

3

, n=12

315 R

1

=CH

3

, R

2

=H, R

3

=CH

3

, n=14

316 R

1

=CH

3

, R

2

=H, R

3

=CH

3

, n=16

317 R

1

=H, R

2

=R

3

=CH

3

, n=14

318 R

1

=H, R

2

=R

3

=CH

3

, n=16

CH

3

(CH

2

)

n

COO

COOH

R

3

R

2

R

1

311 R

1

=CHO, R

2

=H

312 R

1

=CH

2

OH, R

2

=

O

O

HO

O

O

Me

HO

OH

R

2

O

O

OH

OH

OH

OH

O

R

1

COOH

O

OH

HO

OH

O

OH

OH

H

OH

O

CH

2

OH

OH

OH

OH

H

O

O

O

H

OH O

COOR

319 R=H

320 R=Glc

R

1

R

2

R

3

R

4

Xyl Gal H H

H Gal H H

Xyl Gal H Glc

H Gal Ara Glc

H Ara(p) H H

321

322

323

324

333

O

OR

2

H

O

COOR

4

COOH

OR

1

OR

3

O

OH

OH

OH

H

O

O

H

O

COOH

COOCH

3

OH

OH

325

COOR

360

Botanical Studies, Vol. 47, 2006

HeMOLYTiC aCTiviTieS

Hemolytic activity is one of the well known

characteristics of triterpene saponins. Monodesmosidic

OA disaccharides and trisaccharides (335-355) were

prepared and their hemolytic activity compared (Table 14).

The authors concluded that for lactosides of glycyrrhetic

acid, its 11-deoxo and 18£\-derivatives, and their methyl

esters (335-341), it was found that 28-COOH might

be a basic requirement for strong hemolytic activity of

lactosides. Compound 357, which possessed no detectable

hemolytic properties, differed from the highly active 341

only by interchanged positions of a methyl. Esterification

increased the hemolytic activity, but esterification of the

most OA lactoside 341 led to the almost non-hemolytic

compound 340. The linkage between rings D and E

had remarkable influenced on the activity of esters of

glycyrrhetic acid lactosides (Ullah et al., 2002). A separate

study showed that the connectivity between the sugar

units strongly influenced the hemolytic activity of OA

disaccharides (341-346). The 1¡÷4 linked saponin 341

showed the highest activity. £]-configuration of the outer

anomeric position showed higher potency in the 1¡÷6

linked saponins, while 1¡÷2 linked glycosides exhibited

very low hemolytic properties. Linkage positions 3 or 4

were structural requirements for higher hemolytic activity.

The 1¡÷3 linked saponin was more active than the 1¡÷

4 linked one, but the hemolytic activities of 1¡÷6 and 1

¡÷2 linked analogues were less active (Seebacher et al.,

2000). It was also found that OA trisaccharides (347-350)

usually proved to be less potent than the corresponding

disaccharides. A £\-configuration of the terminal sugar

residue was able to enhance hemolytic activity (Seebacher

et al., 1999).

Glycyrrhetic acid disaccharides (351-355) were not

found to possess detectable hemolytic properties, so the

influence of the structure of the aglycon on the hemolytic

activity is crucial (Ullah et al., 2000).

Table 14. Hemolytic index (HI) of compounds 335-350.

Saponin

Class

HI

335

Monosacchride

<1000

336

Monosacchride

<1000

337

Monosacchride

<1000

338

Monosacchride

135000

339

Monosacchride

19500

340

Monosacchride

10000

341

Monosacchride

150700

342

Disacchride

100100

343

Disacchride

3400

344

Disacchride

3400

345

Disacchride

22000

346

Disacchride

35000

347

Trisacchride

22000

348

Trisacchride

11000

349

Trisacchride

19500

350

Trisacchride

<2000

OH

H

OH

319 R=H

320 R=Glc

H Gal H H

Xyl Gal H Glc

H Gal Ara Glc

H Ara(p) H H

322

323

324

333

OH

325

HOOC O

O

O

O

COOR

COOH

OH

O

HOOC

HO

H

326 R=Glc

327 R=H

HOOC

O

OH

O

O

O

COOR

COOH

OH

HO

HOOC

328 R=Glc

329 R=H

HO

OHO CO

330

AcO

OAc

O CO

331

O

O O CO

332

HO

COOH

334

SUN

et al. ¡X Structure-activity relationships of oleanane- and ursane-type triterpenoids

361

Membrane-disrupting activity may cause hemolysis

and other various biological activities. Fifteen triterpenoid

saponins were classified into four types based on their

chemistries and membrane-disrupting activities (Hu et al.,

1996).

I: 356-359. Are glycosylated at two sites (C-3 and

C-28), and the carboxylic group of the glucuronic acid

residue connecting to C-3 was esterified by an alkyl group.

Their actions are so strong that they can cause catastrophic

rupture when sufficiently accumulated.

II: 360-363. Are glycosylated at a single site (C-3).

They bind to the liposomal membrane more strongly than

type I, but not enough to cause membrane disruption.

III: 290, 286 and 324. Are glycosylated at two

sites (C-3 and C-28), and the carboxylic group of the

glucuronic acid was free. Although these saponins bind

to the membrane as efficiently as type I, their disruptive

ability was much weaker.

IV: 283, 333 and 322. Are glycosylated at a single

site (C-3) with two carboxylic groups. Their membrane

disrupting activity could only be shown in the presence of

cholesterol.

335 R

1

=H, R

2

=

B

-D-galp-(1

m

4)-

B

-D-glc-(1

m

338 R

1

=CH

3

, R

2

=

B

-D-galp-(1

m

4)-

B

-D-glc-(1

m

351 R

1

=H, R

2

=

B

-D-glc-(1

m

2)-

B

-D-glc-(1

m

352 R

1

=H, R

2

=

B

-D-glc-(1

m

3)-

B

-D-glc-(1

m

353 R

1

=H, R

2

=

A

-D-glc-(1

m

4)-

B

-D-glc-(1

m

354 R

1

=H, R

2

=

B

-D-glc-(1

m

4)-

B

-D-glc-(1

m

355 R

1

=H, R

2

=

B

-D-glc-(1

m

6)-

B

-D-glc-(1

m

R

2

O

COOR

1

H

O

336 R

1

=H, R

2

=

B

-D-galp-(1

m

4)-

B

-D-glc-(1

m

339 R

1

=CH

3

, R

2

=

B

-D-galp-(1

m

4)-

B

-D-glc-(1

m

R

2

O

COOR

1

H

O

337 R

1

=H, R

2

=

B

-D-galp-(1

m

4)-

B

-D-glc-(1

m

R

2

O

COOR

1

H

340 R

1

=CH

3

, R

2

=

B

-D-galp-(1

m

4)-

B

-D-glc-(1

m

341 R

1

=H, R

2

=

B

-D-galp-(1

m

4)-

B

-D-glc-(1

m

342 R

1

=H, R

2

=

B

-D-galp-(1

m

3)-

B

-D-glc-(1

m

344 R

1

=H, R

2

=

B

-D-galp-(1

m

2)-

B

-D-glc-(1

m

343 R

1

=H, R

2

=

A

-D-galp-(1

m

2)-

A

-D-glc-(1

m

345 R

1

=H, R

2

=

A

-D-galp-(1

m

6)-

B

-D-glc-(1

m

346 R

1

=H, R

2

=

B

-D-galp-(1

m

6)-

B

-D-glc-(1

m

R

2

O

COOR

1

H

347 R

1

=H, R

2

=

B

-D-glc-(1

m

2)-

B

-D-glc-(1

m

6)-

B

-D-glc-(1

m

348 R

1

=H, R

2

=

B

-D-glc-(1

m

3)-

B

-D-glc-(1

m

6)-

B

-D-glc-(1

m

349 R

1

=H, R

2

=

A

-D-glc-(1

m

4)-

B

-D-glc-(1

m

6)-

B

-D-glc-(1

m

350 R

1

=H, R

2

=

B

-D-glc-(1

m

2)-

B

-D-glc-(1

m

6)-

B

-D-glc-(1

m

O

OH

HO

HO OH

galp=

O

OR

1

H

O

COOR

4

COOR

3

OH

OR

2

R

1

R

2

R

3

R

4

H H Bu Glu

356

H H Me Glu

357

H Ara Me Glu

358

Gal H Me Glu

359

H H Me H

360

H Ara Me H

361

Gal H Me H

363

Gal H Bu H

362

362

Botanical Studies, Vol. 47, 2006

MiSCeLLaNeOUS

Oleanane- and ursane-type triterpenoids have many

other activities besides the above nine activities, but they

have been researched and reported less. The following

activities, which have structure-activity relationships, are

introduced briefly all together.

Spasmolytic activity

Eucalyptanoic acid (364) and its acetyl (365) an d

acetylmethyl (366) derivatives, as well as O A and OA

acetyl (197) and acetylmethyl (282) derivatives, were

tested for spasmolytic activity (Table 15). Among them,

the presence of the 28-COOMe and C-9(11) double bond

enhanced the activity, while the acetoxy group at C-3

decreased it (Begum et al., 2002).

antipruritic activity

OA 3-O-monodesmosides (283-285, 288, 289, and

367-370) were examined for the antipruritic effects

using a compound 48/80-induced pruritic model in mice

(Table 16). OA 3-O-monodesmosides showed antipruritic

effects, while O A and its 3, 28-O-bisdesmosides did not.

Moreover, the 3-O-glucuronides showed more potent

activity than the corresponding 3-O-glucosides (Kubo et

al., 1997; Matsuda et al., 1998a).

anti-thrombotic activity

OA showed inhibitory effects on blood platelet

aggregation. It not only inhibited blood platelet

aggregation induced by adenosine 5¡¦-diphosphate

(ADP) and collagen in old mice, but also increased

electrophoretic mobility at therapeutical dosage (75-300

mg/kg) (Liu and Wang, 1993). Compounds 371, 372,

UA and OA were isolated from Chaenomeles sinensis,

and tested for the inhibitory activity of tissue factor (TF),

which could accelerate the blood clotting. Among these

compounds, only 371 and its aglycone 371a inhibited TF

activity, and IC

50

values were 0.036 and 0.028 mM/unit,

respectively. However, 372, UA, OA and the dimethyl

ester derivative 371b o f 371a showed no inhibitory

activity. These results indicated that the presence of two

free carboxyl groups of 371a played an important role

in exerting the inhibitory activity on TF (Lee and Han,

2003).

R

2

O

COOR

1

364 R

1

=R

2

=H

365 R

1

=H, R

2

=CH

3

CO

366 R

1

=CH

3

, R

2

=CH

3

CO

Table 15. Effect on Spontaneous conreactions and K

+

-

inducedcontractions.

Effect (% inhibition)

Spontaneous

conreactions

K

+

-induced

contractions

364

58.2

31.1

365

No effect

No effect

366

95.3

85.9

OA

No effect

No effect

197

No effect

No effect

282

67.7

35.5

O

H

R

1

OH

OR

2

OR

3

O

COOH

367 R

1

=CH

2

OH, R

2

=R

3

=H

368 R

1

=CH

2

OH, R

2

=Xyl, R

3

=H

369 R

1

=COOH, R

2

=Ara, R

3

=H

370 R

1

=COOH, R

2

=Glc, R

3

=Glc

Table 16. Effects on compound 48/80-induced scratch behavior

in mice.

Dose (mmol/kg) Inhibition (%)

OA

0.05

13.7

0.2

9.9

283

0.05

-0.9

0.2

52.4

284

0.05

2.2

0.2

65.8

288

0.05

16.0

0.2

2.0

367

0.05

-4.5

0.2

17.0

368

0.05

28.5

0.2

48.9

289

0.05

-16.8

0.2

64.0

369

0.065

4.2

0.13

58.9

370

0.05

43.6

0.10

43.6

285

0.05

-1.1

0.11

9.4

Positive control was diphenhydramine hydrochloride, which

inhibitions were 26.4 and 84.7 at dosage 0.05 and 0.2 mmol/

kg, respectively.

SUN

et al. ¡X Structure-activity relationships of oleanane- and ursane-type triterpenoids

363

inhibitory activity of ethanol absorption

Excessive consumption of ethanol is known to

profoundly affect nearly every organ in the body. OA

3-O-monodesmosides (321, 373, 375 and 376) were

found to show potent inhibitory activity on ethanol

absorption, while 3, 28-O-bisdesmosides (323, 374,

377 and 378) lacked the inhibitory activity (Table 17).

Some OA 3-O-monodesmosides were found to show

potent inhibitory activity on ethanol absorption, while

3, 28-O-bisdesmosides lacked the inhibitory activity

(Yoshikawa et al., 1993 and 1996c).

effects on nonmalignant prostate cell

proliferation

Eight synthesized A-ring cleaved oleanane and ursane

analogues (379-386) were assessed for their ability to

inhibit cell proliferation in NRP.152 (nonmalignant)

prostate cells (Table 18). It was found that each pair

of ursane and oleanane derivatives exhibited similar

activities, and A-ring cleaved compounds were more

active. In A ring cleaved series, both conversions of

nitriles corresponding aldehydes and reduction of the

nitriles to the amines resulted in increased activity (Finlay

et al., 1997).

HO

HOOC

COO-Glc

HO

371

HO

CH

3

OOC

COOCH

3

HO

371b

HO

HOOC

COOH

HO

HO

372

HO

HOOC

COOH

HO

371a

O

H

COOH

OR

3

OR

2

OR

1

O

COOR

4

R

1

R

2

R

3

R

4

Gal Gal H H

Gal Gal H Glc

H Glc H H

H Glc Ara(f) H

H Glc H Glc

H Glc Ara(f) Glc

373

374

375

376

377

378

Table 17. Inhibitory activity of 321, 323, 373-378 on ethanol

absorption.

Dose

(mg/kg p.o.)

Ethanol absorption in blood (mg/ml)

1 h

2 h

3 h

321

25

0.11

0.13 0.02

50

0.01

0.04 0.01

100

0

0

0

373

25

0.56

0.19 0.01

50

0.50

0.19 0.02

100

0.25

0.18 0.02

341 100

0.57

0.24 0.04

374 100

0.57

0.23 0.04

375

25

0.26

0.20 0.03

50

0.03

0.04 0.02

100

0.03

0.02 0.01

376

25

0.42

0.21 0.03

50

0.34

0.18 0.01

100

0.08

0.09

0

377 100

0.58

0.21

0

378 100

0.56

0.23 0.04

Table 18. Inhi bit ory ac ti vit y o n NRP 15 2 pro s ta te ce ll

proliferation.

Compound IC

50

(£gM) Compound IC

50

(£gM)

386

0.3

OA

>5.0

385

0.7

UA

>5.0

383

1.5 OA-3-oxo

>5.0

384

2.4 UA-3-oxo

>5.0

379

3.8

381

>5.0

380

>5.0

382

>5.0

364

Botanical Studies, Vol. 47, 2006

LiTeraTUre CiTeD

Abe, F., T. Yamauchi, T. Nagao, J. Kinjo, H. Okabe, H. Higo,

and H. Akahane. 2002. Ursolic a cid as a trypanocidal

constituent in rosemary. Biol. Pharm. Bull. 25(11 ):

1485-1487.

Ahn, K.S., J.H. Kim, S.R. Oh, B.S. Min, J. Kinjo, and H.K. Lee.

2002. Effects of oleanane-type triterpenoids from fabaceous

plants on the expression of ICAM-1. Biol. P harm. Bull.

25(8): 1105-1107.

Ahn, K.S ., M.S . Hahm , E.J. Park, H.K. Lee, and I.K. Kim.

1998. Corosolic acid isolated from the fruit of Crataegus

pinnatifida var. psilosa is a protein kinase C inhibitor as

well as a cytotoxic agent. Plant. Med. 64: 468-470.

Ali, M.S ., M. Jahangir, S .S . Hus san, and M.I. Choudhary.

2002. Inhibition of £\-glucosidase by oleanolic acid and its

synthetic derivatives. Phytochemistry 60: 295-299.

Argandona, V.H. and F.A. Faini. 1993. Oleanolic acid content in

Baccharis linearis and its effects on Heliothis zea larvae.

Phytochemistry 33(6): 1377-1379.

Ass efa, H., A. Nimrod, L. Wa lker, and R. S indelar. 1999.

S yn the s is an d e va lua t ion of pot e nti a l c om pl e me nt

inhibitory semisynthetic analogs of oleanolic acid. Bioorg.

Med. Chem. Lett. 9: 1889-1894.

Ass efa, H., A. Nimrod, L. Wa lker, and R. S indelar. 2001.

Enantioselective synthesis and complement inhibitory assay

of A/B-ring partial analogues of oleanolic acid. Bioorg.

Med. Chem. Lett. 11: 1619-1623.

Astudillo, L., J.A. Rodriguez, and G. Schmeda-Hirs chmann.

2001. Gastroprotective activity of oleanolic acid derivatives

on experimentally induced gastric lesions in rats and mice.

J. Pharm. Pharmacol. 54: 583-588.

Baglin, I., A-C. Mitaine-Offer, M. Nour, K. Tan, C. Cave, and

M-A. La caille-Dubois. 2003. A re view of natural and

modified betulinic, ursolic and echinocystic acid derivatives

as potential antitumor and anti-HIV agents. Mini Rev. Med.

Chem. 3(6): 525-539.

B a rb at o , F ., M.L . L a R ot on da , a nd F. Qu ag l ia . 19 97 .

Chr oma tog raphi c i ndex es on i mm obi liz ed a rti fic ia l

m em brane s fo r loca l a nes the tic s : rel ati ons hips wit h

activity data on closed sodium channels. Pharm. Res. 14:

1699-1705.

B ari c evi c, D., S . S o sa , R . De ll a L ogg ia , A. T uba ro, B .

Simonovska, A. Krasna, and A. Zupancic. 2001. Topical

anti-inflammatory activity of Salvia officinalis L. leaves: the

relevance of ursolic acid. J. Ethnopharmacol. 75: 125-132.

Barthomeuf, C., E. Debiton, V. Mshvildadze, E. Kemertelidze,

and G. Balansard. 2002. In vitro activity of hederacolchisid

A1 compared with other saponins from Hedera colchica

against proliferation of human carcinoma and melanoma

COOH

NC

COOH

NC

379 380

COOH

HO

O

381

COOH

HO

O

COOH

H

O

COOH

H

O

383 384

382

COOH

H

2

N

COOH

H

2

N

385

386

SUN

et al. ¡X Structure-activity relationships of oleanane- and ursane-type triterpenoids

365

cells. Plant. Med. 68: 672-675.

Bedir, E., H. Kirmizipekmez, O. Sticher, and I. Calis. 2000.

Trit erpe ne s apo nins from the fruit s of h ede ra he lix.

Phytochemistry 53: 905-909.

Begum, S ., I. Sultana, B.S . Siddiqui, F. Shaheen, and A.H.

Gil ani . 2002 . S truc ture an d s pas m ol yti c a cti vit y of

eucalyptanoic acid from Eucalyptus camaldulens is var.

obtusa and synthesis of its active derivative from oleanolic

acid. J. Nat. Prod. 65: 1939-1941.

Bi s cho ff, H. 19 94. P ha rm ac olo gy of al pha -glu cos i das e

inhibition. Eur. J. Clin. Invest. 24: 3-10.

C al d we ll , C. G., S . G. F ra nz b la u , E . S u ar e z, a nd B .N.

Timmermann. 2000. Oleanane triterpenes from junellia

tridens. J. Nat. Prod. 63: 1611-1314.

Camac ho, M.R., R. Mata , P. Casta neda, G.C. Kirby, D.C.

Warhurst, S.L. Croft, and J.D. Phillipson. 2000. Bioactive

compounds from Celaenodendron mexicanum. Plant. Med.

66: 463-468.

Cha turve dula , V.S.P., Z.J . Gao, S .M. Hech t, S .H. J one s,

and D.G.I. Kings ton. 2003a. A new a cylated oleanane

triterpenoid from couepia polyandra that inhibits the lyase

activity of DNA polymerase £]. J. Nat. Prod. 66: 1463-1465.

Ch a t ur ve d ul a , V.S . P., J . K. S ch i l l in g , J .S . M i l le r, R .

Andriantsiferana, V.E. Ras amison, and D.G.I. Kingston.

200 3b. New cy tot ox ic ol ea na ne s a pon ins f rom t he

in fr uc t e s c en c e s o f p ol y s c ia s a m pl i fol i a f rom t he

madagascar rainforest. Plant. Med. 69: 440-444.

Chen, G., H.W. Lu, C.L. Wang, K. Yamashita, M. Manabe,

S.X. Xu, and H. Kodama. 2002. Effect of five triterpenoid

compounds is ola ted from leaves of dios pyros ka ki on

st im ulus -induc ed s upero xide ge nera tion a nd tyros yl

phosphorylation in human polymorphonuclear leukocytes.

Clin. Chim. Acta 320: 11-16.

Chiang, L.C., W. Chiang, M.Y. Chang, L.T. Ng, and C.C. Lin.

2003. Antileukemic activity of selected natural products in

Taiwan. Am. J. Chin. Med. 31(1): 37-46.

Cunha, W.R., C. Martins, D.S. Ferreira, A.E.M. Crotti, N.P.

Lopes, and S . Albuquerque. 2003. In vitro trypanocidal

activity of triterpenes from miconia s pecies. Plant. Med.

69: 470-472.

Deng, J.Z., S.R. Starck, and S.M. Hecht. 1999. DNA polymerase

£] inhibitors from baec ke a gunnia na . J . Nat . P rod. 62:

1624-1626.

Eka bo, O.A. and N.R. F arns worth. 1996. Antifung al and

molluscicidal saponins from serjania salzmanniana. J. Nat.

Prod. 59(4): 431-435.

Favaloro, F.G., Jr., T. Honda, Y. Honda, G.W. Gribble, N. Suh,

R. Risingsong, and M.B. Sporn. 2002. Design and synthesis

of tricyclic compounds with enone functionalities in rings

A and C: A novel class of highly active inhibitors of nitric

oxide production in mouse macrophages. J. Med. Chem.

45(22): 4801-4805.

Finlay, H.J., T. Honda, G.W. Gribble, D. David, E.B. Nicole,

N. Suh, C. Williams, and M.B. Sporn. 1997. Novel A-ring

cleaved analogs of oleanolic acids and ursolic acids which

affect growth regulation in NRP.152 prostate cells. Bioorg.

Med. Chem. Lett. 7(13): 1769-1772.

Fujimura, H., J. Yamahara, M. Yoshikawa, and T. Yabuchi. 1996.

Saccharide S bsorption Inhibitor. JP 08040912 A2 13 Feb

Heisei, Jpn. Kokai Tokkyo Koho., 5 pp.

Gaidi, G., M. Correia, B. Chauffert, J.L. Beltramo, H. Wagner,

and M.A. L acai lle-Dubois . 2002. S aponins -medi ated

potentiation of cisplatin accumulation and cytotoxicity in

human colon cancer cells. Plant. Med. 68: 70-72.

Gerhauser, C., K. Klimo, E. Heiss, I. Neumann, A. Gamal-

Eldeen, J. Knauft, G.Y. Liu, S. Sitthimonchai, and N. Frank.

2003. Mechanis m-based in vitro screening of potential

cancer chemopre ventive agents . Mutat. Res. 523-524:

163-172.

Hamburger, M., U. Riese, H. Graf, M.F. Melzig, S. Ciesielski, D.

Baumann, K. Dittmann, and C. Wegner. 2002. Constituents

i n e v e ni ng p ri m ro s e oi l wi t h ra d ic a l s c a ve ng i ng ,

cy clo oxyge na s e, a nd ne ut rophi l e la st as e inh ibi tory

activities. J. Agric. Food Chem. 50: 5533-5538.

Hamburger, Matthias . Ger. Offen. 2003. Antiinfla mmatory

or P re - ne op la s t ic L e s i on In hi bi t in g M ed i ca m e nt s

Containing Caffeic Acid Triterpene or Sterol Esters Having

Radical Scavenging Action, Also Useful In Cosmetic Or

Nutraceutical Compositions. DE 10215055 A1 30 Oct., 20

pp.

Honda, T., H.J. Finlay, G.W. Gribble, N. Suh, and M.B. Sporn.

1997. New enone derivatives of oleanolic acid and ursolic

acid as inhibitors of nit ric oxide production in mouse

macrophages. Bioorg. Med. Chem. Lett. 7: 1623-1628.

Honda, T., B.V. Rounds, L. Bore, F.G. Jr. F avaloro, G.W.

Gribble, N. Suh, Y.P. Wang, and M.B. Sporn. 1999. Novel

synthetic oleanane triterpenoids: A series of highly active

inhibitors of nitric oxide production in mouse macrophages.

Bioorg. Med. Chem. Lett. 9: 3429-3434.

Honda, T., G.W. Gribble, N. Suh, H.J. Finlay, B.V. Rounds, L.

Bore, F.G. Jr. Favaloro, Y.P. Wang, and M.B. Sporn. 2000a.

Novel synthetic oleanane and ursane triterpenoids with

various enone functionalities in ring A as inhibitors of nitric

oxide production in mouse macrophages. J. Med. Chem.

43: 1866-1877.

Honda, T., B.V. Rounds, L. Bore, H.J. Finlay, F.G. Jr. Favaloro,

N. Suh, Y.P. Wang, M.B. Sporn, and G.W. Gribble. 2000b.

Synthetic oleanane and ursane triterpenoids with modified

rings A and C: A series of highly active inhibitors of nitric

oxide production in mouse macrophages J. Med. Chem. 43:

4233-4246.

Honda, T., Y. Honda, F.G. Jr. F aval oro, G.W. Gri bble, N.

Suh, A.E. Place, M.H. Rendi, and M.B. Sporn. 2002. A

novel dicyanotriterpenoid, 2-cyano-3, 12-dioxooleana-1,

9(11)-dien-28-onitrile, active at picomolar concentrations

for inhibition of nitric oxide production. Bioorg. Med.

Chem. Lett. 12: 1027-1030.

Hu, M., K. Konoki, and K. Tac hiba na . 1996. Chole sterol-

independent membrane disruption caused by triterpenoid

366

Botanical Studies, Vol. 47, 2006

saponins. Biochim. Biophys. Acta. 1299: 252-258.

Huang, M.T., C.T. Ho, Z.Y. Wang, T. Ferraro, Y.R. Lou, K.

Sta uber, W. Ma, C. Georgi adi s, J.D. L askin, and A.H.

Conney. 1994. Inhibition of skin tumorigenesis by rosemary

and its constituents carnosol and ursolic acid. Cancer Res.

54: 701-708.

Ismaili, H., S. Sosa, D. Brkic, S. Fkih-Tetouani, A. Ilidrissi, D.

Touati, R.P. Aquino, and A. Tubaro. 2002. Topical anti-

inflammatory activity of extracts and compounds from

Thymus broussonettii. J. Pharm. Pharmacol. 54: 1137-1140.

Ismaili, H., S. Tortora, S. Fkih-Tetouami, A. Ilidrissi, R. Della

Loggia, A. Tubaro, and R. Aquino. 2001. Topical anti-

inflammatory activity of thym us willdenowii. J . P harm.

Pharmacol. 53: 1645-1652.

Joseph, D.C. and A.H. Robert. 1999. Triterpenoids. Nat. Prod.

Rep. 16: 221-240.

Joseph, D.C. and A.H. Robert. 2000. Triterpenoids. Nat. Prod.

Rep. 17: 463-482.

Joseph, D.C. and A.H. Robert. 2001a. Triterpenoids. Nat. Prod.

Rep. 18: 131-147.

Joseph, D.C. and A.H. Robert. 2001b. Triterpenoids. Nat. Prod.

Rep. 18: 560-578.

Joseph, D.C. and A.H. Robert. 2002. Triterpenoids. Nat. Prod.

Rep. 19: 494-513.

Joseph, D.C. and A.H. Robert. 2003. Triterpenoids. Nat. Prod.

Rep. 20: 640-659.

Joseph, D.C. and A.H. Robert. 2005a. Triterpenoids. Nat. Prod.

Rep. 22: 230-248.

Joseph, D.C. and A.H. Robert. 2005b. Triterpenoids. Nat. Prod.

Rep. 22: 487-503.

Kashiwada, Y., H.K. Wang, T. Nagao, S. Kitanaka, I. Yasuda,

T. Fujioka, T. Yamagishi, L.M. Cosentino, M. Kozuka, H.

Okabe, Y. Ikeshiro, C.Q. Hu, E. Yeh, and K.H. Lee. 1998.

Anti-AIDS agents. 30. anti-HIV activity of oleanolic acid,

pomolic acid, and structurally related triterpenoids. J. Nat.

Prod. 61: 1090-1095.

Kashiwada, Y., T. Nagao, A. Hashimoto, Y. Ikeshiro, H. Okabe,

L.M. Cosentino, and K.H. Lee. 2000. Anti-AIDS agents

38. anti-HIV activity of 3-o-acyl ursolic acid derivatives. J.

Nat. Prod. 63: 1619-1622.

Kim, Y.K., S.K. Yoon, and S.Y. Ryu. 2000. Cytotoxic triterpenes

from stem bark of Physocarpus intermedius. Plant. Med.

66: 485-486.

Kim, Y.P., E.B. Lee, S.Y. Kim, D. Li, H.S. Ban, S.S. Lim, K.H.

S hin, and K. Ohuchi. 2001. Inhibition of pros taglandin

E2 production by platycodin D isolated from the root of

Platycodon grandiflorum. Plant. Med. 67: 362-364.

Kinjo, J., K. Yokomizo, T. Hirakawa, Y. Shii, T. Nohara, and

M. Uyeda. 2000. Anti-herpes virus activity of fabaceous

triterpenoidal saponins. Biol. Pharm. Bull. 23(7): 887-889.

Konoshima, T., I. Yasuda, Y. Kashiwada, L.M. Cosentino, and

K.H. Lee. 1995. Anti-aids agents, 21. triterpenoid saponins

as anti-HIV principles from fruits of gleditsia japonica and

gymnocladus chinesis, and a structure-activity correlation.

J. Nat. Prod. 58(9): 1372-1377.

Kubo, M., H. Matsuda, Y. Dai, Y. Ido, and M. Yoshikawa. 1997.

Studies on kochiae fructus. I. antipruritogenic effect of

70% ethanol extract from kochiae fructus and its active

component. Yakugaku Zasshi. 117(4): 193-201.

Lee, H.Y., H.Y. Chung, K.H. Kim , J .J. Lee, and K.W. Kim.

1994. Induct ion of different iat ion in the cult ured F 9

teratocarcinoma stem cells by triterpene acids. J. Cancer

Res. Clin. Oncol. 120: 513-518.

Lee, M.H. and Y.N. Han. 2003. A new in vitro tissue factor

inh ibit ory trit erpe ne from the fru its of cha enom el es

sinensis. Plant. Med. 69: 327-331.

Liu, J. 1995. Pharmacology of oleanolic acid and ursolic acid. J.

Ethnopharmacol. 49: 57-68.

Liu, J., Y.P. Liu, Q. Mao, and C.D. Klaassen. 1994. The effects

of 10 triterpenoid compounds on experimental liver injury

in mice. Fund. Appl. Toxicol. 22: 34-40.

Liu, Y.L. and H.S. Wang. 1993. The effects of oleanolic acid on

some functions of blood platelet aggregation in old mice. J.

Shenyang College Pharm. 10(4): 275-278.

Lu, J.C., Q.S. Sun, K. Sugahara, Y. Sagara, and H. Kodama.

2001. E ffect of s ix compounds isolate d from rhizome

of Anemone raddeana on the superoxide generation in

human neutrophil. Biochem. Biophys. Res. Commun. 280:

918-922.

Ma, C.M., N. Na kamura, and M. Hatt ori. 2000. Che mica l

m odi fic ati on of ole ane ne typ e tr ite rpe nes a nd t hei r

inhibitory activity against HIV-1 protease dimerization.

Chem. Pharm. Bull. 48(11): 1681-1688.

Ma, C.M., N. Nakamura, H. Miyashiro, M. Hattori, and K.

Shimotohno. 1999. Inhibitory effects of constituents from

cynomorium songaricum and related triterpene derivatives

on HIV-1 protease. Chem. Pharm. Bull. 47(2): 141-145.

Ma, C.M., N. Nakamura, M. Hattori, and S .Q. Cai. 2002.

Isolation of malonyl oleanolic acid hemies ter as anti-

HIV protease substance from the stems of cynomorium

songaricum. Chin. Pharm. J. 37(5): 336-338.

Mallavadhani, U.V., A. Mahapatra, S.S. Raja, and C. Manjula.

2003. Antifeedant activity of some pentacyclic triterpene

acids and their fatty acid ester analogues. J. Agric. Food

Chem. 51: 1952-1955.

Marqui na, S., N. Maldonado, M.L. Garduno-Ram irez , E .

Aranda, M.L. Villarreal, V. Navarro, R. Bye, G. Delgado,

and L. Alvarez. 2001. Bioactive oleanolic acid saponins

and other constituents from the roots of Viguiera decurrens.

Phytochemistry 56: 93-97.

Matsuda, H., Y. Dai, Y. Ido, T. Murakami, H. Mats uda, M.

Yoshikawa, and M. Kubo. 1998a. S tudi es on Kochiae

Fructus. V. Antipruritic effects of oleanolic acid glycosides

and the structure-requirement. Biol. Pharm. Bull. 21(11):

1231-1233.

Mat suda, H., Y.H. Li, T. Muraka mi, J . Ya maha ra, and M.

Yoshikawa. 1998b. P rotective effects of oleanolic acid

oligoglycoside s on ethanol- or indomethac in-i nduce d

SUN

et al. ¡X Structure-activity relationships of oleanane- and ursane-type triterpenoids

367

gastric mucosal lesions in rats. Life Sci. 63(17): PL245-250.

Matsuda, H., Y.H. Li, T. Murakami, N. Murakami, J. Yamahara,

and M. Yoshikawa. 1998c. Antidiabetic principles of natural

medicines. III. S tructure-related inhibitory activity and

action mode of oleanolic acid glycosides on hypoglycemic

activity. Chem. Pharm. Bull. 46(9): 1399-1403.

Mats uda, H., Y.H. Li, T. Murakam i, J. Yam ahara , a nd M.

Yoshikawa. 1999. Structure-related inhibitory activity of

oleanolic acid glycosides on gas tric emptying in m ice.

Bioorg. Med. Chem. 7: 323-327.

Mi ma ki, Y., M. Kuroda, T. As an o, a nd Y. S a shi da. 1999.

Triterpene saponins and lignans from the roots of pulsatilla

chinensis and their cytotoxic activity against HL-60 cells. J.

Nat. Prod. 62: 1279-1283.

Mitaine-Offer, A.C., W. Hornebeck, M. Sauvain, and M. Zeches-

Ha nrot. 2002. Tri terpenes and phytoste rol s as human

leucocyte elastase inhibitors. Plant. Med. 68: 930-932.

Miura , N., Y. Mats um oto, S . Miyai ri, S . Ni shi yam a, and

A. Na ganum a. 1999. P rote ct ive e ffe cts of tri terpe ne

compounds against the cytotoxicity of cadmium in HepG2

cells. Mol. Pharmacol. 56: 1324-1328.

Mizushina, Y., A. Iida, K. Ohta, F. Sugawara, and K. Sakaguchi.

2000. Novel triterpenoids inhibit both DNA polymerase and

DNA topoisomerase. Biochem. J. 350: 757-763.

Murphy, B.T., S.L. Mackinnon, X.J. Yan, G.B. Hammond, A.J.

Vaisberg, and C.C. Neto. 2003. Identification of triterpene

hydroxycinnamates with in vitro antitumor activity from

whole cranberry fruit (Vaccinium macrocarpon). J. Agric.

Food Chem. 51: 3541-3545.

Nakashima, H., K. Ohubo, Y. Honda, T. Tamura, S. Matsuda,

and N. Yamamoto. 1989. Inhibitory effect of glycosides like

saponin from soybean on infectively of HIV in vitro. AIDS

3: 655-658.

Narayan, S ., F. He, and S.H. Wilso. 1996. Activation of the

human DNA polymerase beta promoter by a DNA-

alkylating agent through induced phosphorylation of cAMP

response element-binding protein-1. J. Biol. Chem. 271:

18508-18513.

Neto, C.C., A.J. Vaisberg, B.N. Zhou, D.G. Kingston, and G.B.

Ha mmond. 2000. Cytotoxic trite rpe ne aci ds from the

peruvian medicinal plant polylepis racemosa. Plant. Med.

66: 483-484.

Nick, A., A.D. Wright, and O. S ticher. 1994. Antibacterial

triterpenoid acids from dillenia papuana. J. Nat. Prod.

57(9): 1245-1250.

Ohs hima, H. and H. Bartsch. 1994. Chronic infections and

inflammatory processes as cancer risk factors: possible role

of nitric oxide in carcinogenesis. Mutat. Res. 305: 253-264.

Qu, R.Y. 1981. Olea nolic ac id in trea ting virus hepatit is.

Guangzhou Med. J. 3: 41-43.

Rec io, M.C., R.M. Giner, S. Manez , a nd J .L. Rios . 1995.

Structural requirements for the anti-inflammatory activity

of natural triterpenoids. Plant. Med. 61: 182-185.

Ringbom, T., L. Segura, Y. Noreen, P. Perera, and L. Bohlin.

1998. Ursolic acid from Plantago major, a se lec tive

inhibitor of cyclooxygenase-2 catalyz ed prostaglandin

biosynthesis. J. Nat. Prod. 61: 1212-1215.

Rios , J.L ., M.C. Recio, S . Manez, and R.M. Gi ner. 2000.

Bioactive natural products, P art C. Elsevier. Stud. Nat.

Prod. Chem. 22: 93-143.

Rios, M.Y., A. Gonzalez-Morales, and M.L. Villarreal. 2001.

Sterols, triterpenes and biflavonoids of Viburnum jucundum

and cytotoxic activity of urs olic acid. P lant. Med. 67:

683-684.

Safayhi, H. and E.R. Sailer. 1997. Anti-inflammatory actions of

pentacyclic triterpenes. Plant. Med. 63: 487-493.

Safayhi, H., B. Rall, E.R. S ailer, and H.P.T. Ammon. 1997.

Inhibition by boswellic acids of human leukocyte elastase.

J. Pharmacol. Exp. Ther. 281: 460-463.

Sailer, E.R., L.R. Subramanlan, B. Rall, R.F. Hoernlein, H.P.T.

Amm on, a nd H. S afa yhi. 1996. Acetyl -11-ket o-beta-

boswellic acid (AKBA): structure requirements for binding

and 5-lipoxygenase inhibitory activity. Br. J. P harmacol.

117: 615-618.

Seebacher, W., R. Weis, J. Jurenitsch, K. Rauchensteiner, and

E. Haslinger. 2000. S ynthes is and hemolytic properties

of arvensoside B isomers. Monatshefte fur Chemie. 131:

985-996.

Seebacher, W., R. Weis, J. Jurenitsch, K. Rauchensteiner, and

E. Haslinger. 1999. S ynthesis and hemolytic activity of

oleanolic acid trisaccharides. Monatshefte fur Chemie. 130:

1383-1391.

Seo, Y., J. Hoch, M. Abdel-Kader, S. Malone, I. Derveld, H.

Adams, M.C.M. Werkhoven, J.H. Wis se, S .W. Mamber,

J.M. Dalton, and D.G.I. Kingston. 2002. Bioactive saponins

from scacia tenuifolia from the suriname rainforest. J. Nat.

Prod. 65: 170-174.

Setzer, W.N. and M.C. Setzer. 2003. Plant-derived triterpenoids

as potential antineoplastic agents. Mini Rev. Med. Chem.

3(6): 540-556.

Sohn, K.H., H.Y. Lee, H.Y. Chung, H.S. Young, S.Y. Yi, and

K.W. Kim. 1995. Anti-angiogenic activity of triterpene

acids. Cancer Lett. 94(2): 213-218.

Suh, N., T. Honda, H.J. Finlay, A. Barchowsky, C. Williams,

N.E. Benoit, J.W. Xie, C. Nathan, G.W. Gribble, and M.B.

Sporn. 1998. Novel triterpenoids suppress inducible nitric

oxide synthas e (iNOS ) and induci ble cyclooxyge na se

(COX-2) in mouse macrophages. Cancer Res. 58: 717-723.

Suh, N., Y.P. Wang, T. Honda, G.W. Gribble, E. Dmitrovsky,

W.F. Hickey, R.A. Maue, A.E. Place, D.M. Porter, M.J .

Spinella, C.R. Williams, G.F. Wu, A.J. Dannenberg, K.C.

Flanders, J.J. Letterio, D.J. Mangelsdorf, C.F. Nathan, L.

Nguyen, W.W. Porter, R.F. Ren, A.B. Roberts, N.S. Roche,

K. Subbaramaiah, and M.B. Sporn. 1999. A novel synthetic

oleanane triterpenoid, 2-cyano-3,12-dioxoolean-1,9-dien-

28-oic acid, with potent differentiating, antiproliferative,

and anti-inflammatory activity. Cancer Res. 59: 336-341.

Sun, J.S., X.W. Han, and B. Yu. 2003. Synthesis of a typical

N-acetylglucosamine-containing s aponin, oleanolic acid

368

Botanical Studies, Vol. 47, 2006

3-yl £\-l-arabinopyranosyl-(1¡÷2)-£\-l-arabinopyranosyl-(1

¡÷ 6 )-2 -a ce t a mi do - 2-d eo xy -£] -d- gl uc op yr an os i de .

Carbohyd. Res. 338: 827-833.

Syrovets, T., B. Buchele, E. Gedig, J.R. Slupsky, and T. Simmet.

2000. Acetyl-boswellic acids are novel catalytic inhibitors

of human topois omerases I and II£\. Mol. P harmcol. 58:

71-81.

Taniguchi, S., Y. Imayoshi, E. Kabayashi, Y. Takamatsu, H. Ito,

T. Hatano, H. Sakagami, H. Tokuda, H. Nishino, D. Sugita,

S. Shimura, and T. Yoshida. 2002. Production of bioactive

triterpenes by Eriobotrya japonica calli. Phytochemis try

59: 315-323.

Tokuda, H., H. Ohigashi, K. Koshimizu, and I. Yohei. 1986.

Inhibitory effects of ursolic and oleanolic ancid on skin

tumor promotion by 12-O-tetradecanoylphorbol-13-acetate.

Cancer Lett. 33: 279-285.

Ul l a h , N . , W. S e e ba c he r R . We i s , J . J u re n i t s c h, K.

Rauchensteiner, and E. Haslinger. 2000. Synthesis and

hemol ytic properties of glycyrrhetic a cid glycos ides .

Monatshefte fur Chemie. 131: 787-794.

Ulla h, N., W. S e eba che r, E . Has li nger, J . Ju reni ts ch, K.

Ra uc he ns t ei ne r, an d R . Wei s . 20 02. S yn the s is an d

hemolytic properties of lactosides of glycyrrhetic acid

derivatives. Monatshefte fur Chemie. 133: 139-150.

Wan, L., X.F. Chen, and Z.H. Jiang. 1998. The protective effects

of OLA-PENa on experimental liver injury in rats. Chin.

Pharm. J. 33(2): 80-83.

Wang, S .P., J.S . Lai, and K.F. Huang. 1993. S tudies on the

constituents of the leaves of alyxia insularis kanehira &

sasaki. Chin. Pharm. J. 45(4): 329-336.

Weima nn, C., U. Goranss on, U. P ongprayoon-Claes on, P.

Claeson, L. Bohlin, H. Rimpler, and M. Heinrich. 2002.

Spasmolytic effects of baccharis conferta and some of its

constituents. J. Pharm. Phamcol. 54: 99-104.

Woldemichael, G.M., S.G. Franzblau, F.Q. Zhang, Y.H. Wang,

and B.N. Timmermann. 2003a. Inhibitory effect of sterols

from ruprechtia triflora and diterpenes from calceolaria

pinnifolia on the growth of mycobacterium tuberculosis.

Plant. Med. 69: 628-631.

Wol de michael, G.W., M.P. Singh, W.M. Maiese , a nd B.N.

Timmermann. 2003b. Constituents of antibacterial extract

of Caesalpinia paraguariensis Burk. Z. Naturforsch. 58c:

70-75.

Ying, Q.L., A.R. Rinchart, S.R. Simon, and J.C. Cheronis. 1991.

Inhibition of hum an leucocyte elastase by urs olic acid.

Evidence for a binding site for pentacyclic triterpenes .

Biochem. J. 277: 521-526.

Yos hikawa , M., E . Ha rada , H. Mat suda , T. Muraka mi, J .

Yamahara, and N. Murakami. 1993. Elatosides A and B,

potent inhibitors of ethanol absorption in rats from the bark

of Aralia elata Seem.: the structure-activity relationships of

oleanolic acid oligoglycosides. Chem. Pharm. Bull. 41(11):

2069-2071.

Yoshi ka wa , M., H. Ma tsuda, E . Hara da , T. Muraka mi, N.

Wariishi, J. Yamahara, and N. Murakami. 1994. Elatoside

E, a new hypoglycemic principle from the root cortex of

Aralia elata Seem.: structure-related hypoglycemic activity

of oleanolic acid glycosides. Chem. Pharm. Bull. 42(6):

1354-1356.

Yoshikawa, M., T. Murakam i, E . Harada, N. Murakam i, J .

Yamahara, and H. Matsuda. 1996a. Bioactive saponins

and glycosides. VII. On the hypoglycemic principles from

the root cortex of A ralia elata Seem.: structure related

hypoglycemic activity of oleanolic acid oligoglycos ide.

Chem. Pharm. Bull. 44(10): 1923-1927.

Yoshikawa, M., T. Murakam i, E . Harada, N. Murakam i, J .

Yamahara, and H. Matsuda. 1996b. Bioactive s aponins

and glycosides. VI. Elatosides A and B, potent inhibitors

of ethanol absorption, from the bark of Aralia elata Seem.

(Araliaceae): the s tructure-requirement in oleanolic acid

glucuronide-saponins for the inhibitory activity. Chem.

Pharm. Bull. 44(10): 1915-1922.

Yoshikawa, M., T. Mura kam i, M. Ka doya, H. Matsuda, O.

Muraoka, J. Yamahara, and N. Murakami. 1996c. Medicinal

foodstuff. III. Sugar beet. (1): Hypoglycemic oleanolic acid

oligoglycosides, betavulgarosides I, II, III, and IV, from the

root of Beta vulgaris L. (Chenopodiaceae). Chem. Pharm.

Bull. 44(6): 1212-1217.

Z hang, W.D., W.Q. Wa ng, Z .Q. Qin, B.L . Wang, and J.Q.

Zhou. 2000. Caryophyllin acid sodium and application

in pharmacy thereof. Faming Zhuanli Shenqing Gongkai

Shuomingshu. CN 1248583 A 29 Mar, 6 pp.

Zha ng, Y.J., B. J aya prakas am , N.P. S eera m, L .K. Ol son,

D. Dewitt, and M.G. Nair. 2004. Insulin se cretion and

cyclooxygenase enzyme inhibition by cabernet sauvignon

grape skin compounds. J. Agric. Food Chem. 52: 228-233.

Zhu, Y.M., J.K. Shen, H.K. Wang, L.M. Cosentino, and K.H.

Lee. 2001. Synthesis and anti-HIV activity of oleanolic acid

derivatives. Bioorg. Med. Chem. Lett. 11: 3115-3118.