Abstract
Recently two new compounds, ginsenosides Rh1 and Rh2, have been isolated from an ethanol extract of the processed root of Panax 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 10(6) HRA cells. After 7 days of tumor inoculation 2 mg/kg cis-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 microM, 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 microM and 120 microM 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 microM and 120 microM Rh2 was also significantly prolonged, compared to that of cisplatin treated mice. No toxic effects were observed in any of the mice.