Potent Phosphodiesterase Inhibition and Nitric Oxide Release Stimulation of Anti-Impotence Thai Medicinal Plants from “MANOSROI III” Database

Seven plants in the top rank were selected from the "MANOSROI III" database using the two Thai keywords which meant impotence and sexual tonic. Boesenbergia rotunda (L.) Mansf. extract [EDP1-001(1)] gave the highest PDE inhibition activity of 4.36-fold sildenafil, a standard anti-impotence drug. Plumbago indica Linn. extract [EDP2-001(1)] exhibited the highest NO release stimulation activity of 666.85% which was 1.50-fold acetylcholine, a standard drug. Most selected plant extracts were nontoxic to EA.hy926 cells at 1.0 mg/mL. EDP1-001(1) exhibited the LD50 value of acute oral toxicity in male ICR mice of over 5,000 mg/kg body weight. EDP1-001(1) also indicated the improvement of sexual behaviors in the paroxetine-induced sexual dysfunction male mice with the evaluation of number of courtships (NC), mount frequency (MF), intromission frequency (IF), and ejaculatory frequency (EF) at 87.67 ± 6.17, 121.00 ± 23.50, 36.00 ± 3.21, and 13.67 ± 2.96 which were 2.63-, 1.27-, 0.53-, and 0.62-fold sildenafil-treated mice at day 14 of the treatments, respectively. The present study has not only confirmed the traditional use of Thai plants for the treatment of ED but also indicated the potential and application of the "MANOSROI III" database for Thai plant selection to be developed as ED food supplements.