Free radical scavenging and total phenolic contents from methanolic extracts of Ulmus davidiana

초록

A methanolic (MeOH) extract of Ulmus davidiana was analyzed for antioxidant activity using model systems, including 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, hydroxyl radical ((OH)-O-center dot) scavenging, reducing power, and total phenolic content. The MeOH extract exhibited strong antioxidant activity in the tested model systems. Among fractions using several solvents, the ethyl acetate (EtOAc)-soluble fraction, which exhibited strong antioxidant activity, was further purified by silica-gel and Sephadex LH-20 column chromatography. The (-)-Catechin (1) and (-)-catechin-7-O-beta-D-apiofuranoside (2) were isolated as the active principles. Compounds I and 2 exhibited strong antioxidant activity on DPPH radicals, with IC50 values of 6.37 +/- 0.02 mu M and 6.41 +/- 0.03 mu M, respectively, and strong activity on (OH)-O-center dot radicals at 10 mu g/ml, with 53.65 +/- 0.01% and 52.56 +/- 0.01% inhibition. U. davidiana extracts may be exploited as biopreservatives in food applications as well as for health supplements of functional food, to alleviate oxidative stress. (c) 2007 Elsevier Ltd. All rights reserved.

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