MICROBIAL METABOLITES OF OPHIOBOLIN-A AND ANTIMICROBIAL EVALUATION OFOPHIOBOLINS

Ophiobolin A [1], 3-anhydroophiobolin A [2], ophiobolin B [3], and oph iobolin L [4] were isolated from fermentation broths of Cochliobolus h eterostrophus. Preliminary screening showed that a number of organisms were capable of metabolizing the sesterterpene ophiobolin A [1]. Larg e-scale transformations of ophiobolin A [1] with Polyangium cellulosum produced 6 and 7 while Pseudomonas aeruginosa produced 8. Resting-cel l preparations of Penicillium patulum afforded 9 and 10. The structure s of these metabolites were established by spectroscopic methods and b y comparison of the spectral data with those of the starting material. The antimicrobial activity of the ophiobolins was also evaluated.