Coompo Research Chemicals

Ginsenoside Rh2 (G-Rh2) isolated from the root of Panax ginseng has been shown to have anti-cancer proliferation, differentiation and chemopreventive effects in certain cancer cell types. G-Rh2 significantly inhibited the cell growth in a concentration- dependent manner, which effect was reversible, and induced a G1 arrest in cell cycle progression. G-Rh2 treatment down-regulated the protein level of cyclin D3 but upregulated the expression of cyclin-dependent kinase (Cdk) inhibitor p21WAF1/CIP1. The increased levels of p21 were associated with increased binding of p21 and Cdk2 concomitant with marked decrease in Cdk2 and cyclin E-dependent kinase activities with no changes in Cdk2 and cyclin E expression. G-Rh2 markedly reduced the phosphorylated retinoblastoma protein (pRb) and enchanced association of unphosphorylated pRb and the transcription factor E2F-1. G-Rh2 inhibited the growth of MCF-7 cells, by inducing protein expression of p21 and reducing the protein levels of cyclin D which resulted in the down-regulation of cyclin/Cdk complex kinase activity, decreasing phosphorylation of pRb, and inhibiting E2F release.

G-Rh2 suppresses the growth of A375-S2 cells in vitro by inducing apoptosis. G-Rh2-induced apoptosis is partially dependent on caspase-8 and caspase-3 pathway in A375-S2 cells. Other apoptotic pathways might be also related to the induction of apoptosis by G-Rh2.

Ginsenoside Rh2, had the most potent inhibitory activity on β-hexosaminidase release from RBL-2H3 cells and in the passive cutaneous anaphylaxis reaction. The inhibitory activity of ginsenoside Rh2 was more potent than that of disodium cromoglycate, a commercial antiallergic drug. This compound showed membrane stabilizing action upon differential scanning calorimetry and inhibited nitric oxide (NO) and prostaglandin E2 (PGE2) in lipopolysaccharide-stimulated RAW cells. However, this ginsenoside Rh2 did not inhibit the activation of hyaluronidase and did not scavenge active oxygen. These results suggest that ginsenoside Rh2 can exhibit antiallergic activity originating from cell membrane-stabilizing activity and antiinflammatory activity by the inhibition of NO and PGE2 production.