TITLE	Isolation and phytotoxic effects of helvolic acid from plant pathogenic fungus Sarocladium oryzae
AUTHOR	Johannes Scheng-Ming Tschen Department of Botany, National Chung Hsing University, Taichung, Taiwan 402, Republic of China Li-Ling Chen Department of Botany, National Chung Hsing University, Taichung, Taiwan 402, Republic of China Shean-Tzong Hsieh Department of Botany, National Chung Hsing University, Taichung, Taiwan 402, Republic of China Tian-Shung Wu Department of Chemistry, National Cheng Kung University, Tainan, Taiwan, Republic of China
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ABSTRACT	In this study, we isolate helvolic acid, an antibiotic metabolite, from the rice sheath rot pathogen Sarocladium oryzae. The fungus is cultured in potato-sucrose broth. The metabolite is extracted by ethyl acetate, and its antibiotic activity is tested with Bacillus subtilis. Helvolic acid is soluble in chloroform, acetone, ethyl acetate, methanol, ethanol, and alkali water. The substance is stable at an active temperature of 22°C_100°C and is also active at various hydrogen ion levels (pH 3_11). Also, helvolic acid is identified with thin-layer chromatography and further characterized by UV, IR, NMR, and Mass spectroscopy. The toxic effects of helvolic acid on seedlings of Graminae include growth retardation and chlorosis. These effects are reduced about 40% by treating with Hoagland's solution and can be reduced to around 30% by treating with magnesium solution.
KEYWORD	Antibiotic; Helvolic acid; Phytotoxic substance; Plant pathogenic fungus; Sarocladium oryzae;
ARTICLE INFO	Botanical Bulletin of Academia Sinica, Volume 38 Number 4 October 1997, page 251-256, 6 pages
PUBLISHER	Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan, Republic of China