Abstract:  Gueldenstaedtia multiflora Bge (GMB) was extracted with chloroform:methanol (1:2) in a ultrasonator, and the extraction was then partitioned with petroleum ether, EtOAc and BuOH successively. Antioxidant activity (AA) of the extractions was evaluated by using Schaal method, and compared with that of BHT. The EAF (ethyl acetate-soluble fraction) exhibited the highest AA, which was greater than that of BHT. Furthermore, bioactivity-guided chromatographic fractionation was conducted by repeated column chromatography over a silica gel, RP-18, and Sephadex LH-20 to obtain three pure antioxidant compounds. Their structures were determined by interpretation of the 1D and 2D NMR, as well as mass spectral data. The result demonstrated that quercetin 3-O-β-D-glucopyranoside, apigenin and 4’,7-dihydroxyflavone were the major antioxidative constituents in GMB. The AA of the compounds decreased in the following order: quercetin 3-O-β-D-glucopyranosid >apigenin > 4’,7-dihydroxyflavone>EAF>BHT. The AA of phenolic compounds is correlated to their chemical structures. In general, the AA of phenolics depends mainly on the number of hydrogen-donating hydroxyl groups on the aromatic ring of the phenolic molecules.

Key words:  , Gueldenstaedtia multiflora Bge； edible oil and fat； antioxidant activity； antioxidative constituent；