NON MAJOR GINSENOSIDES CONTRIBUTE TO THE RELAXATION OF PANAX GINSENG IN RABBIT CORPUS CAVERNOSUM

The corporal relaxant effects of total ginsenosides and nine subfractions (F1~F9) separated from it were evaluated in the rabbit corpus cavernosal strips in vitro. In the tissues precontracted by phenylephrine (PE, 3×10^(-6) M), ginsenosides induced a dose-dependent (from 1 to 20 mg/ml) relaxing effect on rabbit corpus cavernosal strips with an EC50 of 3.65±0.27 mg/ml. Three pure ginsenoside-Rg1, Rb1, and Re, at optimal dosages, do not affect the vascular tone at al in PE precontracted corpus cavernosum. Total ginsenosides was further subfractionated by column chromatography and obtained nine fractions (F1~F9). Among them, F2 (0.1~5 mg/ml) displayed the most potent relaxing activity and turned out to be more effective (EC50=0.49±0.03 mg/ml) than total ginsenosides. Additionally, TLC analysis revealed that F2 contained some other components different from Rg1, Rb1 and Re. These findings suggest none of Rg1, Rb1 and Re contributes to the beneficial effect of total ginsenosides. In summary, F2 may possibly be used as a drug for intracavernosal injection therapy of impotence. However, further separation and identification the components of F2 and in vivo study are needed before clinical use in an oral form.