Alpha-Asarone Protects Endothelial Cells from Injury by Angiotensin II

α-Asarone is the major therapeutical constituent of Acorus tatarinowii Schott. In this study, the potential protective effects of α-asarone against endothelial cell injury induced by angiotensin II were investigated in vitro. The EA.hy926 cell line derived from human umbilical vein endothelial cells was pretreated with α-asarone (10, 50, 100 µmol/L) for 1 h, followed by coincubation with Ang II (0.1 µmol/L) for 24 h. Intracellular nitric oxide (NO) and reactive oxygen species (ROS) were detected by fluorescent dyes, and phosphorylation of endothelial nitric oxide synthase (eNOS) at Ser(1177) was determined by Western blotting. α-Asarone dose-dependently mitigated the Ang II-induced intracellular NO reduction (P < 0.01 versus model) and ROS production (P < 0.01 versus model). Furthermore, eNOS phosphorylation (Ser(1177)) by acetylcholine was significantly inhibited by Ang II, while pretreatment for 1 h with α-asarone partially prevented this effect (P < 0.05 versus model). Additionally, cell viability determined by the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay (105~114.5% versus control, P > 0.05) was not affected after 24 h of incubation with α-asarone at 1–100 µmol/L. Therefore, α-asarone protects against Ang II-mediated damage of endothelial cells and may be developed to prevent injury to cardiovascular tissues.