Angucycline Glycosides from an Intertidal Sediments Strain Streptomyces sp. and Their Cytotoxic Activity against Hepatoma Carcinoma Cells

Four angucycline glycosides including three new compounds landomycin N ( ), galtamycin C ( ) and vineomycin D ( ), and a known homologue saquayamycin B ( ), along with two alkaloids 1-acetyl-β-carboline ( ) and indole-3-acetic acid ( ), were isolated from the fermentation broth of an intertidal sediments-derived sp. Their structures were established by IR, HR-ESI-MS, 1D and 2D NMR techniques. Among the isolated angucyclines, saquayamycin B ( ) displayed potent cytotoxic activity against hepatoma carcinoma cells HepG-2, SMMC-7721 and plc-prf-5, with IC values 0.135, 0.033 and 0.244 μM respectively, superior to doxorubicin. Saquayamycin B ( ) also induced apoptosis in SMMC-7721 cells as detected by its morphological characteristics in 4',6-diamidino-2-phenylindole (DAPI) staining experiment.