Manumycin-type Derivatives from a Streptomyces sp. Associated with Meson Bee Osmia cornifrons

Two new manumycin-type derivatives named as cornifronin A and cornifronin B, and one known analogue antibiotic SW-B were isolated from the liquid fermentation of Streptomyces sp. OC1401 obtained from body surface of a meson bee Osmia cornifrons. The structures of all isolates were identified by spectroscopic methods (HRESIMS, IR, 1D and 2D NMR) and comparison with literature data. The antibacterial and antifungal activities of these manumycin-type derivatives were evaluated by disc diffusion method and more accurate data on the antibacterial activity were obtained through the MIC (Minimum Inhibitory Concentration) and MBC (Minimal bactericidal concentration) values.