Abstract:

Ethanol (80% concentration) extract of rape pollen was hydrolyzed with hydrochloric acid and the resulting hydrolysate was analyzed for the qualification and quantitation of flavonol by thin layer chromatography (TLC), UV-Vis spectroscopy and HPLC, and was subjected to antioxidant activity evaluation. TLC results showed that bands with 0.59 and 0.71 of Rf value were quercetin and kaempferol, respectively. The contents of quercetin and kaempferol in the hydrolysate were 0.40 mg/g and 3.98 mg/g, respectively. The scavenging capacity of rape pollen ethanol extract against DPPH free radicals was poorer than that of its hydrolysate. Preparative high performance liquid chromatography was used to separate a flavonol, which was identified as kaempferol 3-O-(2＂-O-β-D-glucopyranosyl)-β-D-glucopyranoside by MS and NMR. In this work, TLCDPPH was used to track the antioxidant activity of flavonol in rape pollen, which will provide useful references for further studying the antioxidant activity of active compounds in rape pollen.

Key words: rape pollen, flavonol, antioxidant activity