Antineoplastic Agents. 570. Isolation and Structure Elucidation of Bacillistatins 1 and 2 from a Marine Bacillus silvestris

Two new cyclodepsipeptides designated bacillistatins 1 (1) and 2 (2) have been isolated from cultures of a sample of Bacillus silvestris that was obtained from a Pacific Ocean (southern Chile) crab. Each 12-unit cyclodepsipeptide strongly inhibited growth of a human cancer cell line panel, with GI(50)'s of 10(-4)-10(-5) mu g/mL, and each compound was active against antibiotic-resistant Streptococcus pneumoniae. ne structures were elucidated by a combination of X-ray diffraction and mass and 2D NMR spectroscopic analyses, together with chemical degradation.