Cytoprotective and antioxidant effects of Echium amoenum anthocyanin-rich extract in human endothelial cells (HUVECs)

Echium amoenum Fisch. & C.A. Mey. is used for the treatment of various diseases in traditional medicine. This plant is a major source of anthocyanins with beneficial cardiovascular properties such as anti-atherosclerotic and antihypertensive effects. In the present study, the protective and antioxidant effects of anthocyanin-rich E. amoenum extract were evaluated on human vascular endothelial cells (HUVECs) under oxidative stress. Cell viability and oxidative status were assessed on H2O2-induced oxidative stress (0.5 mM H2O2 for 2 h) in HUVECs pretreated by anthocyanin-rich extract from the petals of E. amoenum (25-1000 µg/ml). Cytoprotective effect of the extract was evaluated by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The hydroperoxides concentration and ferric reducing antioxidant power (FRAP) were assessed in intra- and extra-cellular fluid of pretreated cells. Pretreatment of HUVECs with E. amoenum extract at the concentrations of 100-1000 µg/ml reduced the cell death resulted from the exposure to H2O2 in a concentration-dependent manner. E. amoenum extract decreased hydroperoxides concentration and increased FRAP value in both intra- and extra-cellular fluid at different concentration ranges. Moreover, it did not show cytotoxic effects at the concentration range of 25-1000 µg/ml. These results suggest antioxidant and protective effect of anthocyanin-rich extract of the petals of E. amoenum against H2O2-induced oxidative stress in HUVECs. However, further investigations are needed for understanding the detailed mechanisms of cytoprotective effects of this traditional herbal medicine.