MK800-62F1, a new inhibitor of apoptotic cell death, from Streptomyces diastatochromogenes MK800-62F1. I. Taxonomy, fermentation, isolation, physico-chemical properties and biological activity

A new compound, MK800-62F1, was isolated from a cultured broth of Streptomyces diastatochromogenes MK800-62F1. It inhibited H₂O₂-induced apoptosis in human small cell lung carcinoma Ms-1 cells as well as in human T-cell leukemia Jurkat cells. In addition, MK800-62F1 also inhibited camptothecin-induced apoptosis in Jurkat cells, which was mediated by intracellular H₂O₂ generation. MK800-62F1 did not exhibit antioxidative activity in vitro, suggesting that inhibition of apoptosis by MK800-62F1 was not due to the scavenging of H₂O₂, rather it was due to the modulation of the downstream event of H₂O₂ generation.