Flavonoids and prenylhydroquinones from the prepared folium of Epimedium sagittatum Maxim. and their inhibition against phosphodiesterase5A.

An effort to identify novel active substances of the prepared folium of Epimedium sagittatum Maxim. (PFES) that was an important herb for male erectile dysfunction (ED) was taken. At present, phosphodiesterase-5A (PDE5A) is the most important target of new drugs for the treatment of ED. Therefore, the inhibition ingredients in PFES were systematically screened for the first time in this study. Eleven compounds, including eight new flavonoids and three prenylhydroquinones were isolated: sagittatosides DN (1-11), and their structures were elucidated by spectra and chemical analyses. Among them, a novel prenylflavonoid with oxyethyl group (1) was obtained and three prenylhydroquinones (9-11) were firstly isolated from Epimedium. All compounds were analyzed for the inhibition against PDE5A by molecular docking, and they all showed significant binding affinity as same as sildenafil. Their inhibitory activities were verified, and the results showed compound 6 had significant inhibition against PDE5A1. The isolation of new flavonoids and prenylhydroquinones with inhibitory activities of PDE5A from PFES implied that this herb might be a good source for the treatment of ED agents finding.