Grincamycins I – K, Cytotoxic Angucycline Glycosides Derived from Marine-Derived Actinomycete Streptomyces lusitanus SCSIO LR32

Three new angucycline glycosides, designated grincamycin I (1), J (2), and K (3), together with the known congener A-7884 (4), were isolated from marine-derived actinomycete Streptomyces lusitanus SCSIO LR32. The structures of the new compounds were elucidated by comprehensive spectral data analysis. Compounds 2 and 4 exhibited antitumor activity against human cancer cells MDA-MB-435, MDA-MB-231, NCI-H460, HCT-116 and HepG2, and human normal breast epithelial cell MCF10A with IC50 values ranging from 0.4 to 6.9 µM. In addition, A-7884 (4) demonstrated antimicrobial activity against Micrococcus luteus with an MIC value of 1.95 µg/mL.