In vitro antioxidant activity and inhibitory effect, on oleic acid-induced hepatic steatosis, of fractions and subfractions from oat (Avena sativa L.) ethanol extract

Oats (Avena sativa L.) were extracted with 80% aqueous ethanol and the extract was successively isolated by liquid–liquid partition to yield n-hexane, ethyl acetate, n-butanol and water layers. Among them, the ethyl acetate (EA) layer exhibited the highest total phenolic content (TPC), the strongest DPPH radicalscavenging activity and an inhibitory effect on an oleic acid-induced (OA-induced) fatty liver model in vitro. Thus, it was further fractionated by a Sephadex LH-20 column into three subfractions (SF1– SF3). SF3 was the most active subfraction in all the assays above, the yield being 1.70% of the dry weight of the EA fraction. The major components in SF3 were identified as avenanthramides Bc, Bp and Bf by HPLC analysis, with contents of about 5.20%, 9.19% and 8.06% of the dry weight of SF3, respectively. Also, the avenanthramides Bc, Bp and Bf all had significant inhibitory effects on oleic acid-induced (OAinduced) fatty liver. 2010 Elsevier Ltd. All rights reserved.