石榴皮提取物的抗氧化作用研究

分别以水、甲醇、丙酮和乙酸乙酯为溶剂,对石榴皮中的多酚进行了提取,得到4种提取物。采用油脂过氧化值(POV)法和二苯三硝基苯肼(DPPH)自由基法研究了提取物的抗氧化活性。结果显示,4种提取物均具有抗油脂过氧化和清除DPPH自由基的能力,其抗氧化活性随添加量的增加而增加。4种提取物中,丙酮提取物的抗油脂过氧化作用最大,其次为水提取物和甲醇提取物,乙酸乙酯提取物的抗油脂过氧化作用最小。当丙酮提取物添加量为猪油质量的0.1%时,其抗油脂过氧化活性接近添加量为0.02%茶多酚或BHT。4种提取物对DPPH自由基的清除能力大小顺序依次为:水提取物、丙酮提取物、甲醇提取物和乙酸乙酯提取物。浓度为0.0175 mg/mL的水提取物对DPPH自由基的清除率高达85.2%,高于BHT,但略低于茶多酚。石榴皮多酚是一种有效的天然抗氧化剂。

Antioxidant activity of pomegranate peel extracts

Water,methanol,acetone and ethyl acetate were used to extract polyphenols from pomegranate peels.The antioxidant activity of the dried extracts was characterized by peroxide value(POV) assay in lard and 1,1-diphenyl-2-picryl hydrazyl(DPPH) radical method.All the extracts could inhibit lard peroxidation and scavenge DPPH free radical.Their antioxidant activity was increased with their concentrations.In lard system,acetone extract showed the highest inhibitory activity on lipid peroxidation,followed by water,methanol and ethyl acetate extracts.When acetone extract was at 0.1%(g/g lard),its antiliperoxidation was close to that of 0.02% pure green tea polyphenols or 0.02% BHT. In DPPH system,the extracts had the following order of DPPH radical scavenging activity: water extract>acetone extract>methanol extract>ethyl acetate extract.The water extract exhibited 85.2% radical-scavenging rate at 0.0175 mg/mL,which was lower than that of pure green tea polyphenols but much higher than that of BHT.