Dihydro-β-​agarofuran sesquiterpenoids from the seeds of Celastrus paniculatus Willd. and their α-glucosidase inhibitory activity

Three previously undescribed dihydro-β-agarofuran sesquiterpenoids (1–3) along with eight known sesquiterpenoids (4–11) were isolated from the seeds of C. paniculatus. The structures of these compounds were determined on the basis of UV, IR, HR-MS (ESI), 1D and 2D NMR data obtained, and their absolute configurations were further confirmed by single-crystal X-ray diffraction. All these compounds were evaluated for their α-glucosidase and α-amylase inhibition, and antiglycation properties. Compounds 1, 3, 4, 5, 7 and 11 showed good α-glucosidase inhibition with IC50 values, 39.56 ± 0.761, 35.60 ± 0.843, 36.54 ± 0.173, 44.83 ± 0.453, 42.58 ± 0.209 and 45.84 ± 0.356 μM respectively. Molecular docking studies revealed that these compounds bind effectively to the active sites of the protein 3A4A, which supports the observed α-glucosidase inhibitory activity.