Ginsenoside Rg1 improves male copulatory behavior via nitric oxide/cyclic guanosine monophosphate pathway

Ginsenoside Rg1 is the purified ingredient from ginseng, there has been little research on the effect of Rg1 on male copulatory behavior and its mechanism of action.

The purpose of this study was to investigate the effect of ginsenoside Rg1 on copulatory behavior of male mice and the mechanism of its action.

Male mice were treated with Rg1 intraperitoneally; three elements of copulatory behavior (mounting, intromission, pelvic thrusting) were assessed. After final treatment and behavior determination, nitric oxide (NO) concentration were determined by spectrophotometry method. Plasma testosterone, cyclic guanosine monophosphate (cGMP) in corpus cavernosum both in vivo and in vitro were measured by radioimmunoassay. Rabbit corpus cavernosum segments were incubated with Rg1 (0.05, 0.5 and 5 microM) in the presence of exogenous NO donor sodium nitroprusside (SNP) (10 microM), and the cGMP level was measured. The half maximal inhibitory concentration (IC50) of Rg1 for phosphodiesterase type 5 (PDE5) inhibitors was determined by measuring the conversion of cGMP to 5'-mononucleotides. Sildenafil was set as a positive control. MAIN COME OUT MEASURES: Mounting and intromission frequency, pelvic thrusts, serum testosterone, NO level, cGMP accumulation, IC50 for PDE5.

Rg1 (10 mg/kg) significantly increased mounting and pelvic thrusting frequency and numbers of intromission of male mice from d16 to d20. Rg1 increased serum testosterone concentration, enhanced NO release, and cGMP accumulation in corpus cavernosum both in vivo and in vitro. The IC50 of sildenafil and Rg1 for PDE5 were 4.24 +/- 0.78 and 12.47 +/- 2.31 nmol/L.

Ginsenoside Rg1 improved copulatory behavior of male mice and this may attribute to its actions at both testosterone level and signal transduction pathway in corpus cavernosum. NO/cGMP pathway appeared to play a key role in mediating the effect of Rg1 on male sexual function. These experimental data provide evidence that Rg1 could be a promising new drug for erectile dysfunction and low libido.