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 agar culture of Streptomyces flaveus strain A-11. The structure was determined by mass spectrometry and one- and two-dimensional NMR spectroscopy. SW-B was detected at R f 0.5 on the TLC plate developed with chloroform−methanol (90:10 v/v). The UV spectrum of SW-B in methanol showed 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-(2 E,4 E )-dienamide (C 13 H 23 NO, 209.1780). SW-B showed strong antifungal activity against Phytophthora capsici, Magnaporthe grisea, Cladosporium cucumerinum, and Alternaria mali . However, it lacked antimicrobial activity against yeast and bacteria.