Bicyclic lactones and racemic mixtures of dimeric styrylpyrones from the leaves of: Miliusa velutina

Abstract

A unique class of eight bicyclic lactones with a C18 carbon architecture, named velutinones A-H (1-8), three new dimeric styrylpyrones, velutinindimers A-C (9-11), five known compounds, the kawapyrone, yangonin (12), three flavonoids (13-15), and an acetogenin, cananginone H (16) were isolated from the leaves of Miliusa velutina. The absolute configurations of 2 and 5 were assigned by Mosher's method, whereas ECD, optical rotations, and X-ray crystallographic analysis indicated the racemic nature of compounds 10 and 11. Compounds 2-4 and 7-11 showed antimalarial activity with IC50 values in the range of 5.4-10.0 μM. Moreover, 1-4 and 6-8 displayed cytotoxicity against the KB, MCF7, and NCI-H187 cancer cell lines and Vero cell lines with IC50 values in the range of 4.0-24.1 μM.