ISOLATION, STRUCTURE ELUCIDATION, AND ANTIFUNGAL ACTIVITY OF A MANUMYCIN-TYPE ANTIBIOTIC FROM STREPTOMYCES-FLAVEUS

A manumycin-type antibiotic, SW-B, has been isolated from the solid ag ar culture of Streptomyces flaveus strain A-11. The structure was dete rmined by mass spectrometry and one- and two-dimensional NMR spectrosc opy. SW-B was detected at R(f) 0.5 on the TLC plate developed with chl oroform-methanol (90:10 v/v). The UV spectrum of SW-B in methanol show ed peaks at 208 and 260 nm. The antibiotic SW-B was confirmed to be a derivative of a manumycin-type antibiotic, 2,4,6-trimethyldeca-(2E,4E) -dienamide (C13H23NO, 209.1780). SW-B showed strong antifungal activit y against Phytophthora capsici, Magnaporthe grisea, Cladosporium cucum erinum, and Alternaria mall. However, it lacked antimicrobial activity against yeast and bacteria.