Lignans With α -Glucosidase Inhibitory Activity from Codonopsis pilosula

The chemical constituents of Codonopsis pilosula (Franch.) Nannf. were isolated and purified by column chromatography. Two lignans were obtained from an ethanol extract of the roots of C. pilosula, including one new lignan [diethyl lithospermate ( 1 )] and one new natural product [diethyl lithospermate B ( 2 )]. The structures of these compounds were identified using spectroscopic data. The α -glucosidase inhibitory effects of all compounds were measured by the p -nitrophenyl- α -D-glucopyranoside method. Compounds 1 and 2 exhibited good inhibitory activity with half-maximal inhibitor concentrations of 0.79 ± 0.03 μM and 0.16 ± 0.02 μM, respectively.