Bioactive constituents from the leaves of Metapanax delavayi with anti-benign prostatic hyperplasia activities

Abstract

In the course of our continuing search for biologically active compounds from medicinal sources, we further investigated the aqueous extract of Metapanax delavayi (Franch.) J. Wen & Frodin (Araliaceae) leaves. Five undescribed terpene glycosides, liangwanosides B–F referring to two megastigmane glycosides, one monoterpene glycoside, and two sesquiterpene glycosides, together with seven known compounds were isolated. Their chemical structures were elucidated by detailed spectroscopy (1D/2D NMR), HRESIMS data analysis, hydrolysis, and comparison of experimental and calculated electronic circular dichroism (ECD) data. The biological evaluation of benign prostate hyperplasia (BPH) inhibition revealed that some compounds, including liangwanosides B–D, benzyl-O-α-L-rhamnopyranosyl-(1 → 6)-β-D-glucopyranoside, methyl 2-O-β-D-glucopyranosylbenzoate, and 3,4-dihydroxybenzaldehyde, exhibited moderate inhibitory activity against BPH-1 cells with inhibition rates ranging from 13.8% to 23.8% at 100 μM. Among them, liangwanoside B showed the comparable effect to positive control (finasteride) at 100 μM, and its possible mechanism was then explored by molecular docking studies.