Flavonoids and isoflavonoids from Sophorae Flos improve glucose uptake in vitro.

Glucose uptake assay-guided fractionations on the methanol extract of Sophorae Flos led to the isolation of the flavonoids rutin (1), narcissin (2), quercetin (3), tamarixetin (4), and kaempferol (5) and the isoflavonoids cajanin (6), genistein (7), orobol (8), and pratensein (9). Among them, 1, 4, 5, 6, 8, and 9 significantly improved basal glucose uptake in HepG2 cells. Their improving effects were concentration dependent. Compounds 4, 5, 6, and 9 exhibited effects stronger than that of rosiglitazone, which has been used as an antidiabetic drug. However, 2, 3, and 7 did not show any improving effects. Stimulating glucose uptake into peripheral cells may be responsible for reducing the level of blood glucose in the circulation. Therefore, these findings demonstrate a potential to develop these flavonoids and isoflavonoids as hypoglycemic drugs.