05. 11 ginsenosides (Rg1, Re, Rf, Rh1, Rg2, Rb1, Rc, Rb2, Rg3, Rk1, and Rg5) were analyzed by HPLC. HPLC chromatograms of REKRG and KRG are shown in Fig. 1. The amount of Rg1, Re, Rf, Rh1, Rg2, Rb1, Rc, Rb2, Rg3, Rk1, and Rg5 was 0.6, 1.9, AT13387 molecular weight 12.3, 5, 4.2, 3.8, 1.2, 1,

100, 12, and 21 in REKRG and 2.9, 4.2, 0.3, 0.1, 0.2, 5.9, 2.2, 2.1, 0.3, 0.05, and 0.12 in KRG. These results show that the concentration of ginsenoside Rg3 in REKRG is ∼300 times greater than in KRG (Table 1). Because Rg3 enhances eNOS phosphorylation and NO production [20], we next examined whether REKRG has an effect on Akt and eNOS activation in endothelial cells. HUVECs were incubated with 0.1–1 μg/mL REKRG for 24 hours. Cells were then harvested and processed for Western blot analysis. REKRG concentration-dependently stimulated Ser-437 phosphorylation of Akt and Ser-1177 phosphorylation of eNOS (Fig. 2A, 2B). We also examined NO levels in the culture medium after HUVECs were exposed to 0.1–1 μg/mL REKRG for 24 hours. NO levels were increased compared with control (Fig. 2C). These results show that REKRG stimulates the Akt/eNOS signaling pathway, leading to increased Selleckchem GDC0199 NO production in endothelial cells. It is well known that Rg3 has an anti-inflammatory effect [18]. Therefore, we next examined the effect of REKRG

on TNF-α-induced increases in ICAM-1 and COX-2 expression in HUVECs. TNF-α increased ICAM-1 and COX-2 expression at both the protein and messenger RNA (mRNA) levels in HUVECs (Fig. 3A, 3B). However, the TNF-α-induced increases in VCAM-1 and COX-2 expression at the protein and mRNA levels in HUVECs were blunted by REKRG in a concentration-dependent manner (Fig. 3A, 3B), suggesting that REKRG can inhibit inflammatory proteins and possibly the for early stage of atherosclerosis. Many studies have shown that various ginsenosides, including Rg3, have a beneficial effect on vascular function [20]. Therefore, we investigated whether REKRG affects acetylcholine-induced relaxation in rat aortic rings. Acetylcholine-induced relaxation was measured in the presence of REKRG in an

organ bath. In WKY rat aortic rings, endothelium-dependent vasorelaxation was not affected by 1 μg/mL REKRG treatment (Fig. 4A). However, compared with control rings, 1 μg/mL REKRG treatment improved impaired endothelium-dependent vasorelaxation in SHR aortic rings (Fig. 4B). REKRG (10 mg/kg) was administered to rats for 6 weeks by gastric gavage. We next examined the effect of REKRG on serum NO levels. Compared with controls, 10 mg/kg REKRG increased serum NO levels in SHRs (Fig. 5A). NO inhibits smooth muscle cell migration and proliferation [7]; therefore, we next examined the vascular structure is changed by REKRG in SHR. Digitalized microphotographs of histological sections were used to measure vessel wall thickness and cross sectional area (Fig. 5B, 5C).