TITLE	Antioxidant activities of mucilages from different Taiwanese yam cultivars
AUTHOR	Shyr-Yi LIN Department of Internal Medicine, School of Medicine, Taipei Medical University, Taipei, Taiwan Hao-Yu LIU Graduate Institute of Pharmacognosy, Taipei Medical University, Taipei, Taiwan 110 Yeh-Lin LU Graduate Institute of Pharmacognosy, Taipei Medical University, Taipei, Taiwan 110 Wen-Chi HOU Graduate Institute of Pharmacognosy, Taipei Medical University, Taipei, Taiwan 110
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ABSTRACT	The antioxident effects of crude mucilages (CM) and partially purified mucilages (PPM) from three different Taiwanese yam cultivars¡Xincluding Dioscorea alata L. cv. Tainong 1 (TN1), Dioscorea alata L. cv. Tainong 2 (TN2), and D. alata L. var. purpurea (Roxb.) Ming-Jen (MJ)¡Xwere evaluated, including 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, hydroxyl radical, and superoxide radical scavenging activities Electron spin resonance (ESR) spectrometry was used to measure hydroxyl radical scavenging activities. The IC50 stands for the concentration required for 50% scavenging activity. The IC50 of CM and PPM against DPPH radical was 0.329, 0.279; 0.547, 0.653; and 0.847, 0.631 mg/ml, respectively, for TN1, TN2 and MJ. The IC50 of CM and PPM against hydroxyl radical by spectrophotometry was 0.668, 1.146; 1.461, 1.096; and 0.946, 1.554 mg/ml, respectively, for TN1, TN2 and MJ. The IC50 of CM and PPM against superoxide radical was 0.802, 0.368; 0.681, 0.258; and 0.086, 0.148 mg/ml, respectively, for TN1, TN2 and MJ. Using ESR to detect hydroxyl radicals, the IC50 of PPM against hydroxyl radical was 0.083, 0.47, and 0.004 mg/ml, respectively, for TN1, TN2 and MJ. The results demonstrated that different cultivars of yams exhibited different antioxidant ability, and the purification process was able to partially increase the antioxidant activity of the mucilage polysaccharide. Taken together, these results suggest that mucilage polysaccharides of the yam tuber might play an important role on antiradicals and antioxidants.
KEYWORD	1,1-diphenyl-2-picrylhydrazyl (DPPH) radical; Electron spin resonance (ESR); Hydroxyl radical; Mucilage; Superoxide radical; Yam;
ARTICLE INFO	Botanical Bulletin of Academia Sinica, Volume 46 Number 3 July 2005, page 183-188, 6 pages
PUBLISHER	Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan, Republic of China