Study on hypoglycemic activities of flavonoids of Brassica napus L. bee pollen in vitro

The crude alcoholic extract of Brassica napus L. bee pollen was treated by solvent extraction and macroporous resin, and α-glucosidase inhibition test on the depurated flavonoids in vitro was carried out. The components which had the strongest inhibitory effect on α-glucosidase were analyzed by IR and LC-MS.Results showed that the flavonoids played a vital role in inhibiting α-glycosidase enzymes. The purity of PEFS-3 which was made by AB-8 macroporous resin was 68.77%, and its IC50 was 72.16μg/m L, far less than the IC50 of acarbose (1124.86μg/m L) . Based on IR and LC-MS, five main components were identified in PEFS-3, and four kinds among them were flavonoid aglycones:Quercetin-3-O-β-D-pyranoid glucose base- (1→2) -β-Dpyranoid glycosidase, Kaempferol-3, 4 '-double-O-β-D-pyranoid glycosidase, Isohtamnetin-3-O-β-D-pyranoid glucose base- (1→2) -β-D-pyranoid glycosidase, Kaempferol-3-O-β-D-pyranoid glucose base- (1→2) -β-D-pyranoid glycosidase, and the fifth one was inferred to be sec-O-glucosylhamaudol or flavanol, its specific structure still need further confirmation.