Antiangiogenic effect of chamigrane endoperoxides from a Thai mangrove-derived fungus.

As part of our ongoing efforts to investigate natural products with potential for use as cancer treatments, we have recently disclosed the cytotoxicity of unique nor-chamigrane (1) and chamigrane (2, 3) endoperoxides from a Thai mangrove-derived fungus. Reinvestigation of this fungus in a large-scale fermentation led to the isolation of an additional new chamigrane endoperoxide (4) and one known analogue (5). Among these isolated metabolites, compound 3 (merulin C) exhibited potent antiangiogenic activity mainly by suppression of endothelial cell proliferation and migration in a dose-dependent manner, and its effect is mediated by reduction in the phosphorylation of Erk1/2. Merulin C also displayed promising activity in a rat aortic ring sprouting (ex vivo) and a mouse Matrigel (in vivo) assay.