Two new diarylheptanoids and a new phenylhexanol derivative from the bulbils of Dioscorea opposita Thunb. and their α-glucosidase inhibitory activity

Abstract

• Two new diarylheptanoids ( 1 – 2 ) and a new phenylhexanol derivative ( 3 ), along with seven known compounds ( 4 – 10 ) were isolated from the bulbils of Dioscorea opposita Thunb.. • The absolute configurations of compounds 1 – 2 were deduced by comparison of the experimental and calculated ECD spectra. • The α -glucosidase inhibitory effects of all the isolated compounds were evaluated. • Molecular docking and molecular dynamics simulations of compound 7 bound α -glucosidase were performed Two previously undescribed diarylheptanoids, diosniponol E ( 1 ) and F ( 2 ), and a new phenylhexanol derivative, (rel-2 R ,4 R )-6-(4-hydroxy-3-methoxyphenyl)-hexane-1,2,4-triol (3), together with seven known compounds, were isolated from the bulbils of Dioscorea opposita Thunb.. Their structures were elucidated by HRESIMS and 1D/2D NMR as well as by comparison with the literature, and absolute configurations of compounds 1 and 2 were deduced by comparison of their experimental and calculated electronic circular dichroic (ECD) spectra. All the isolated compounds were evaluated in vitro for their α -glucosidase inhibitory activity. The results indicated that compounds 3 and 7 exhibited inhibitory effect against α -glucosidase with the IC 50 values of 16.2 ± 2.2 and 8.7 ± 1.6 μ M, respectively. Molecular docking experiments were performed to identify the probable binding mode of compound 7 in the binding sites of α -glucosidase and molecular dynamics simulations were performed to evaluate the stability over time of the main interactions observed in docking experiments.