Phenolic Glycosides from Viburnum chinshanense Leaves and their α-Amylase and α-Glucosidase Inhibitory Activity.

The phytochemical investigation of Viburnum chinshanense leaves led to the isolation and identification of four new phenolic glycosides, viburninsides A-D (1-4), and eight known analogues (5-12). The structures of the four undescribed compounds were determined by spectroscopic techniques, including 1D NMR, 2D NMR, and HRESIMS, and their containing sugar units were confirmed by acid hydrolysis and HPLC analysis of the monosaccharide's chiral derivatives. Additionally, the α-amylase and α-glucosidase inhibitory activities of the isolated compounds were assessed. Compounds 1, 2, 4, 9, and 10 exhibited potential inhibitory activities against α-amylase and α-glucosidase with IC50 values ranging from 35.07 μM to 47.42 μM and 18.27 μM to 43.65 μM, respectively. Molecular docking analysis of compound 4 with the strongest inhibition against the target enzymes was also conducted.