We discovered two novel phytotoxins produced by the pathogenic fungus, Botrytis cinerea. Among the twentyfive
B. cinerea isolates, which were obtained from various host plants in 1994 and 1996, twenty-two showed
strong or moderate pathogenicity on five plants such as cucumber, tomato, red pepper, tobacco and Chinese
cabbage. The culture filtrate of the B. cinerea 2-16 strain showed the most potent phytotoxic activity in a
tobacco leaf-wounding assay. Two novel phytotoxins were isolated from the liquid cultures of B. cinerea 2-16
by ethyl acetate extraction, flash silica gel column chromatography, silica gel column chromatography,
Sephadex LH-20 column chromatography, preparative TLC and subsequently preparative HPLC. Their
chemical structures were determined to be 3-O-acetyl botcinol and 3-O-acetyl botcinolide, respectively, by
mass and NMR spectral analyses. These two phytotoxins caused leaf necrosis in a leaf-wounding bioassay,
and significant electrolyte leakage from leaf tissues of tobacco. In the two bioassays tested, 3-O-acetyl botcinol
exhibited stronger phytotoxic activity than 3-O-acetyl botcinolide. This is the first report on the production of
both 3-O-acetyl botcinol and 3-O-acetyl botcinolide from B. cinerea.