Protective effects of four kinds of flavonoids of Astragalus membranaceus on the endothelial function

Objective To investigate the protective effects of flavonoids(formononetin,calycosin-7 -o-β-D-glucopyranoside(CG),calycosin and 2'-OH-3',4'-dimethoxyisoflavanone-7-o-β-D-glucopyranoside (DG)) extracted from Astragalus membranaceus planted in Gansu province on angiotensinⅡ(AngⅡ)-induced the injury of human umbilical vein endothelial cells(HUVECs) in vitro.Methods Different groups of cultured HUVECs were incubated with AngⅡ(1μmol/L), formononetin,CG,calycosin and DG extracted from Radix astragali planted in Gansu province respectively for 24 hours.The apoptosis of HUVECs was detected by flow cytometry.NO and endothelin-1(ET-1) contents of the HUVECs cultured medium were measured by nitrate reductase method and radioimmunoassay respectively.Results It was found that incubation with AngⅡfor 24 hours increased HUVECs' apoptosis(P0.05) and ET-1 content(P0.05) reduced production of NO(P0.05).Formononetin,CG,calycosin and DG significantly decreased AngⅡ-induced HUVECs' apoptosis(P0.05).They inhibited ET-1 release(all P0.05) and increased NO contents(P0.05).There were no significant differences between the four kinds of flavones.Conclusion AngⅡcan directly cause endothelial injury and dysfunction,four kinds of flavonoids of Astragalus membranaceus inhibit AngⅡ-induced HUVECs' damage in vitro and have demonstrated a protective effect on endothelial cells.