Fusaric and 9,10-dehydrofusaric acids and their methyl esters from Fusarium nygamai

Fusaric and 9,10-dehydrofusaric acids and their corresponding methyl esters were isolated from the culture filtrates of Fusarium nygamai. The methyl esters were characterized by chemical and spectroscopic methods and reported here for the first time as naturally occurring products. When assayed on tomato leaves and seedlings at 2.7 x 10(-3) and 2 x 10(-4) M, respectively, fusaric and 9,10-dehydrofusaric acids and their methyl esters showed wide chlorosis rapidly evolving into necrosis as well as a strong inhibition of root elongation, respectively. When assayed at 10(-4) M on brine shrimps (Artemia salina), fusaric and 9,10-dehydrofusaric acids did not prove to be toxic, while their methyl esters showed a toxicity level of 50%, expressed as mortality.