Potent α-glucosidase inhibitors from the roots of Panax japonicus C. A. Meyer var. major

Bioassay-guided fractionation of the CHCl₃ soluble portion of the roots of Panax japonicus C. A. Meyer var. major afforded an active fraction with inhibitory activity against baker's yeast α-glucosidase with an IC₅₀ value 1.02 mg/mL. Furthermore, the active fraction isolated contained three previously unreported polyacetylenes, designated panaxjapynes A-C, together with 11 other compounds, including four polyacetylenes, five phenolic compounds, a sesquiterpenoid, and a sterol glucoside. The structures of the compounds were elucidated by spectroscopic and chemical methods. Compared with the control acarbose (IC₅₀ 677.97 μM), six compounds were shown to be more potent α-glucosidase inhibitors with IC₅₀ values in the range 22.21-217.68 μM.