Cytotoxic phenolic compounds from Chionanthus retusus

Cytotoxicity-guided fractionation and purification of MeOH extract from Chionanthus retusus Lindl. et Paxton resulted in the isolation of compounds. Fourteen phenolic compounds were isolated from the EtOAc soluble fraction, and their structures were determined by spectroscopic analysis. Isolated compounds were identified as phillygenin (1), scopoletin (2), pinoresinol (3), kaempferol (4), aromadendrin (5), 2-(4-hydroxyphenyl)ethanol (6), 3,3′,5,5′,7-pentahydroxyflavanone (7), luteolin (8), quercetin (9), apigenin (10), chrysoeriol (11), phillyrin (12), oleuropein (13), (7R,8R)-guaiacylglycerol (14). All compounds except for 12 and 13 were isolated for the first time from this plant and genus Chionanthus. Anti-proliferative effect of isolated compounds were evaluated by the sulforhodamin B assay against four human tumor cell lines (A549, SK-OV-3, SK-MEL-2, and HCT15). Compounds 4 and 8–10 were significantly active with ED50 values of 1.84–6.35 μg/mL. Also, compounds 1, 3, 5 and 7 revealed cytotoxic effects at concentrations below 30 μg/mL.