Four New Flavonoids with α-Glucosidase Inhibitory Activities from Morus alba var. tatarica

Four new flavonoids, mortatarins A–D (1–4, resp.), along with eight known flavonoids (5–12) were isolated from the root bark of Morus alba var. tatarica. Their structures were established on the basis of spectroscopic data analysis, and the absolute configuration of 4 was determined by analysis of its CD spectrum. All isolates were tested for inhibitory activities against α-glucosidase. Compounds 4, 7, and 8 exhibited a significant degree of inhibition with IC50 values of 5.0±0.3, 7.5±0.5, and 5.9±0.2 μM, respectively.