Bingchamides A and B, two novel cyclic pentapeptides from the Streptomyces bingchenggensis: fermentation, isolation, structure elucidation and biological properties.

Two novel cyclic pentapeptides, bingchamides A (1) and B (2), have been isolated from the organic extracts of the mycelium of Streptomyces bingchenggensis. The structures of 1 and 2 were elucidated on the basis of extensive 1D and 2D NMR, as well as HRESI-MS, electrospray ionization-MS, UV and IR spectroscopic data analysis. Bingchamides A (1) and B (2) exhibited in vitro cytotoxicity toward human colon carcinoma cell line HCT-116 with the IC(50) values of 14.1 and 18.0 microg ml(-1), respectively. The bingchamides A (1) and B (2) scaffolds are probably promising structures for the development of new antitumor agents.