Prenylated Phenolic Compounds from the Aerial Parts of as PTP1B and α-Glucosidase Inhibitors.

(liquorice) is a well-known medicinal plant. Its roots and rhizomes are used as the popular Chinese herbal medicine Gan-Cao. An ethanol extract of the aerial parts of showed antidiabetic effects on db/db mice. It decreased the blood glucose level by 30.3% and increased the serum insulin level by 41.8% compared to the control group. Eighty-six phenolic compounds (-) were obtained from the aerial parts, including the new prenylated isoflavanones (-), isoflavans (-), and a 2-phenylbenzofuran (). The structures were identified by NMR and HRESIMS data analyses, and the absolute configurations were established by comparing the calculated and experimental ECD spectroscopic data. Compounds , , and inhibited PTP1B with IC values of 5.9, 6.7, and 5.3 μM, respectively. Compound and the known compounds glycycoumarin () and glyurallin A () inhibited α-glucosidase with IC values of 20.1, 0.1, and 0.3 μM, respectively. Compound at 10 μM increased the glucose uptake rate to 95% in an insulin resistance HepG2 cell model ( < 0.01).