Protective effect of quercetin on the homocysteine-injured human umbilical vein vascular endothelial cell line (ECV304).

Homocysteine is responsible for the occurrence of many cardiovascular diseases for instance by injuring the vascular endothelial cells. Quercetin has many beneficial effects on the cardiovascular system, but it is unknown whether it provides protection against homocysteine-injured vascular endothelial cells. The aim of the present study was to investigate the protective effect and mechanism of quercetin on the homocysteine-injured human umbilical vein vascular endothelial cell line (ECV304) (i.e. morphology, viability and nuclear factor kappa B (NF-kappaB) expression of ECV304 injured with 1.0 mM homocysteine) by determination of lipid peroxidant and endothelium-derived factors in the cultural medium of homocysteine-injured ECV304. Quercetin at 6.25, 12.5, 25, 50 and 100 microM attenuated the morphological changes and increased viability of homocysteine-injured ECV304 in a dose-dependent manner (P < 0.05 or P < 0.01 versus the homocysteine-injured group). At the same time, quercetin at 12.5, 25 and 50 microM decreased malondialdehyde level, endothelin release and NF-kappaB expression, and increased superoxide dismutase activity, nitric oxide and 6-keto-prostaglandin F1alpha releases in homocysteine-injured ECV304 (P < 0.05 or P < 0.01 versus the homocysteine-injured group). These results suggest that quercetin has a protective effect on homocysteine-injured vascular endothelial cells by antioxidant and anti-inflammatory mechanisms.