GKK1032B from endophytic Penicillium citrinum induces the apoptosis of human osteosarcoma MG63 cells through caspase pathway activation.

Chemical investigation of the culture extract of an endophytic Penicillium citrinum from Dendrobium officinale, afforded nine citrinin derivatives (1-9) and one peptide-polyketide hybrid GKK1032B (10). The structures of these compounds were determined by spectroscopic methods. The absolute configurations of 1 and 2 were determined for the first time by calculation of electronic circular dichroism (ECD) data. Among them, GKK1032B (10) showed significant cytotoxicity against human osteosarcoma cell line MG63 with an IC50 value of 3.49 µmol·L-1, and a primary mechanistic study revealed that it induced the apoptosis of MG63 cellsvia caspase pathway activation.

Germacrane-type sesquiterpenoids with cytotoxic activity from Sigesbeckia orientalis.

Eleven new highly oxygenated germacrane-type sesquiterpenoids (1-11) and 16 known analogues (12-27) were isolated from the aerial parts of Sigesbeckia orientalis. Their structures, including absolute configurations, were determined by comprehensive spectroscopic methods especially NMR and ECD analyses. Compounds 13, 21 and 23 possessing an 8-methacryloxy group showed stronger in vitro cytotoxicity against human A549 and MDA-MB-231 cancer cell lines than other co-metabolites, with IC50 values ranging from 6.02 to 10.77 µM comparable to the positive control adriamycin.