Endothelium-Dependent Relaxation Effects of Actinidia arguta Extracts in Coronary Artery: Involvement of eNOS/Akt Pathway

Cardiovascular diseases (CVD) are the major cause of death globally. Bioavailability of nitric oxide, antioxidative activity, and regulation of ionic homeostasis are the key targets for prevention of CVD. Actinidia arguta (AA) has shown promising effect for anticancer, anti-hypercholesterolemia, and antioxidant agents. However, the vascular effect of AA remains unclear. Therefore, we investigated the vascular relaxation of AA extract as well as the underlying mechanisms. Vascular reactivity was assessed in organ baths using porcine coronary arteries and antioxidant properties were assessed using 2,2-diphenyl-1-picrylhydrazyl (DPPH). Methanol extract of AA stem (AASE) induced significantly vasorelaxation of porcine coronary artery and its effects is endothelium-dependent without cytotoxicity effects. In addition, ASSE scavenged reactive oxygen species (ROS) in vitro and strongly inhibited NADPH-oxidase activity, which is major source of ROS in vasculature. AASE strongly and dose-dependently activate endothelial nitric oxide synthase (eNOS), the major vascular protective enzyme, and Akt, the upstream signaling protein of eNOS, in porcine coronary artery endothelial cell. Altogether, these results have demonstrated that AASE is a potent endothelium-dependent vasodilator and this effect was involved in, at least in part, Akt/eNOS/NO pathway with strong anti-oxidant properties. The present findings indicate that AA stem could be a valuable candidate of herbal medicine for cardiovascular diseases associated with endothelial dysfunction and atherosclerosis.