(+)-BE-7585A and its derhodinosyl derivative, two cytotoxic 2-thiosugar-containing angucyclines, derived from an actinomycete Amycolatopsis sp. JS6.

(+)-BE-7585A (1) and its derhodinosyl derivative (2), two rare 2-thiosugar-containing angucyclines, together with their biosynthetic precursor sakyomicin A (3), were isolated from the culture broth of the rare actinomycete Amycolatopsis sp. JS6. Their planar structures were determined by 1D/2D NMR and HRESI-MS data analyses, and the absolute configurations were established by comparison of ECD spectra. Compounds 1 and 2 exhibited weak to modest cytotoxicity against human cervical adenocarcinoma HeLa S3 cells and acute promyelocytic leukemia HL-60 cells, which was much less potent than that of 3, indicating the hydroxy group at C-12b and the substitution at C-5 by the thiodisaccharide moiety of the aglycon may contribute to the cytotoxicity.