Inhibitory effects by oral administration of ginsenoside Rh₂ on the growth of human ovarian cancer cells in nude mice

Abstract

Recently two new compounds, ginsenosides Rh₁ and Rh₂, have been isolated from an ethanol extract of the processed root ofPanax ginseng CA Meyer, and Rh₂ (but not Rh₁) has been found to cause growth inhibition of cultured B16 melanoma cells. We have also demonstrated that Rh₂ caused inhibition of cultured human ovarian cancer cell (HRA) proliferation. The effect of oral administration of Rh₂ on tumor growth and survival of nude mice bearing HRA cells was examined. Nude mice were inoculated subcutaneously in the right flank with 10⁶ HRA cells. After 7 days of tumor inoculation 2 mg/kgcis-diamminedichloroplatinum(II) (cisplatin) was administered intraperitoneally once a week for 5 weeks. In Rh₂-treated groups. Rh₂ was dissolved in absolute ethanol, adjusted with distilled water to 1, 15, and 120 μM, and 0.4 ml of each concentration was administered orally by canula every day for 90 days, from the next day of tumor inoculation. The tumor volume, hematocrit and body weight were measured every week. On days 56 and 63 after tumor inoculation, the tumor volumes in all groups treated with Rh₂ were significantly less than those in an ethanol-treated control group and also in cisplatin treated group. After 70 days, the tumor growth in nude mice treated with 15 μM and 120 μM Rh₂ was significantly inhibited compared to that in a cisplatin treated group as well as a control group. Consequently, the survival of nude mice treated with 15 μM and 120 μM Rh₂ was also significantly prolonged, compared to that of cisplatin treated mice. No toxic effects were observed in any of the mice.