Objective   To investigate the structure-activity relationship for 21 anthocyanins in inhibiting oxidized injury of endothelial cells

and explore the structural characteristics of anthocyanins closely related to their effects.   Methods   Endothelial cells were treated by ox-LDL

at different concentrations of 50

100

150 or 200 μg/ml

and MTT assay was used to determine IC

50

. After pre-incubated for 2 h with different concentrations (50

100 or 200 μmol/L) of anthocyanins and then treated with 100 μg/ml ox-LDL for another 24 h in endothelial cells

MTT assay was used to detect the cellular viability. After pre-treated for 2 h with different anthocyanins with 100 μmol/L and treated with ox-LDL for another 24 h

MDA and NO level in the culture media were both measured according to the methods of assay kits. Structure-activity relationship was analyzed according to the respective cellular viability

MDA and NO level.   Results   Cellular viability was significantly inhibited by ox-LDL in a dose-dependent manner

and the IC

50

was 100 μg/ml. A significant correlation was observed among the effect of anthocyanins on cell viability

MDA production and NO release. The inhibitory effects of anthocyanins in ox-LDL-injured endothelial cells were positively related to the total number of hydroxyl groups and hydroxyl substitutions in B ring. 3′

4′-ortho-dihydroxyl substitution on B-ring and a 3-hydroxyl group on C-ring significantly enhanced the inhibitory effect of anthocyanins

yet methoxylation or glycosylation significantly decreased the effect. 6-hydroxylation substitution might attenuate the inhibitory effect of anthocyanins

while substitution at C5 or C5′ showed no significant influence on the effect of anthocyanins. Anthocyanin with monosaccharose substitution was much stronger than that with disaccharose substitution

while there was no significant difference between anthocyanins with glucoside and that with galacotoside substitution. Delphinidin and delphinidin-3-glucoside were respectively the most effectual anthocyanidin or anthocyanin.   Conclusion   3′

4′-ortho-dihydroxyl substitution on B-ring and a 3-hydroxyl group on C-ring are the main structural requirements for anthocyanins in suppressing ox-LDL-induced injury in endothelial cells.