ANTIOXIDANT ACTIVITY OF CRUDE PHENOLIC EXTRACTS
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Publication date: 2003-03-31
Pol. J. Food Nutr. Sci. 2003;53(Special issue 1s):166-169
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ABSTRACT
Blueberry leaves were extracted with ethanol (95%, v/v) or aqueous acetone (70%, v/v). The crude extracts so obtained were evaporated to near dryness and then lyophilized. The antioxidant activity of these phenolic extracts was evaluated using the b-carotene-linoleate, 2,2-diphenyl-1-picrylhydrazyl radical (DPPH●) and 2-thiobarbituric acid reactive substances (TBARS) assays. The content of crude tannins in ethanol and acetone extracts of blueberry leaves was 181 and 213 mg catechin equivalents/g extract, respectively. The antioxidant activity of phenolic extracts using the β-carotene-linoleate model system was comparable to that exhibited by the synthetic antioxidant butylated hydroxyanisole (BHA). The DPPH● scavenging effect of crude phenolic extracts, at 100 μg/assay, was over 90%. Inhibition of meat lipid oxidation ranged from 36.6 to 100% for crude phenolics of the ethanol extract at 200- and 1000-ppm addition levels, respectively. Similar inhibitory effects were observed for crude extracts of blueberry leaves phenolics from the aqueous acetone preparation.