Induction of inducible nitric oxide synthase by ginsenosides in cultured porcine endothelial cells

Mechanism of Nitric oxide (NO) production by ginsenosides was investigated in cultured porcine endothelial cells. beta -Nicotinamide adenine dinucleot ide phosphate (beta -NADPH) staining showed that the NO production was sign ificantly enhanced by the presence of 40 mug/ml ginsenosides with 10 muM L- arginine after 12 h incubation. NO production was suppressed by addition of 0.5 muM N-omega-Nitro-L-arginine (L-NNA), an inhibitor of NO synthases (NO Ss), to the incubation medium. In addition, the immunoreactive signals of i nducible NOS (iNOS) were appeared in endothelial cells after 12-h incubatio n of ginsenosides, whereas the signals were not observed in non-treated cel ls. Our findings suggest that ginsenosides can enhance NO production by ind uction of iNOS in addition to its direct effect on endothelial cells by inc reasing intracellular Ca2+ concentration. (C) 2000 Elsevier Science Inc. Al l rights reserved.