Antibacterial and cytotoxic metabolites of termite-associated Streptomyces sp. BYF63.

Four anthraquinone derivatives, termstrin A, B, C and D (1-4), were isolated and purified from termite-associated Streptomyces sp. BYF63. Their structures were elucidated on the basis of extensive spectroscopic analyses (HR-ESI-MS, 1D and 2D NMR). Compounds 1 and 4 were found to possess potent antibacterial activities against Staphylococcus aureus, with the zone of inhibition (ZOI) values of 12.85 and 11.17 mm, respectively, which were comparable to that of penicillin sodium with ZOI of 13.15 mm. Furthermore, metabolite 1 showed moderate cytotoxicities against melanoma cell line A375 and gastric cancer cell line MGC-803, with IC50 values of 22.76 and 36.65 μM, respectively, which were less than those of referenced adriamycin.