Antioxidant Activities of Solvent Extracts of Chaenomeles sinensis (Thouin) Koehne Fruits from Laoshan

The solvent extract of Chaenomeles sinensis (Thouin) Koehne fruits from Laoshan was prepared by extracting with a mixture of chloroform and methanol (1:2, V/V) in a Soxhlet extractor and fractionated by sequential extraction with petroleum ether, ethyl acetate and n-butyl alcohol. The antioxidant activities (AA) of the extract and its fractions including petroleum ether-soluble fraction (PEF), ethyl acetate-soluble fraction (EAF), n-butyl alcohol-soluble fraction (BF) and water-soluble residue (WR) was evaluated by four different assays, namely, the pyrogallol autoxidation, the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, the 1,10-phenanthroline-Fe2+-H2O2 and the potassium ferricyanide reduction methods and compared with those of two artificial preservatives such as butylated hydroxytoluene (BHT) and gallic acid (GA). Among the extract and its four fractions, EAF exhibited the highest AA at four different concentrations. This fraction presented lower superoxide free radical scavenging activity but higher DPPH radical scavenging activity than BHT at all concentrations tested and its DPPH radical scavenging activity was also higher than that of GA at 50 μg /ml. Its hydroxyl free radical scavenging activity and reducing power both were higher than those of BHT but lower than those of GA at all concentrations tested.