苦荞麸乙醇粗提物各极性成分的抗氧化活性研究

Antioxidant Activity of Each Polar Composition from Tartary BuckwheatBran Ethanol Extracts

目的:寻找苦荞麸乙醇粗提物中抗氧化活性最强的部分,为分离该部分的有效成分提供参考。方法:以苦荞麸为原料,用95%乙醇提取苦荞麸总黄酮粗提物;水悬浮,乙酸乙酯、正丁醇萃取,测定各萃取相以及苦荞麸总黄酮粗提物的总酚和总黄酮含量;通过DPPH·的清除能力、ABTS·+的清除能力、总还原力以及抑制β-胡萝卜素褪色能力的测定,比较不同萃取相和粗提物的抗氧化性。结果:乙酸乙酯相的总酚和总黄酮含量最高,抗氧化活性最强。乙酸乙酯萃取物的DPPH·清除能力(EC5078.86μg/mL)优于芦丁(EC50135.71μg/mL),弱于VC(EC5071.26μg/mL);ABTS·+清除能力(EC5029.79μg/mL)优于芦丁(EC5072.96μg/mL)和VC(EC50112.71μg/mL),还原力高于芦丁和槲皮素,抑制β-胡萝卜素褪色的能力(EC50101.24μg/mL)低于BHT(EC5015.80μg/mL)。苦荞麸粗提物和萃取物的总酚和总黄酮含量与DPPH·和ABTS·+清除率EC50值呈负相关性。结论:乙酸乙酯萃取物具有很强的抗氧化活性,优于粗提物。据此分离苦荞麸乙醇粗提物乙酸乙酯相的抗氧化成分。

In order to find the strongest antioxidant activity part in tartary buckwheat bran ethanol extracts,and provide reference for further isolating the active constituent in the part.Different solvents such as ethyl acetate,n-butanol and distilled water were used to extract tartary buckwheat bran extracts obtained by 95% ethanol.The contents of total phenolics and flavonoids in different solvent extracts were analyzed.Meanwhile,DPPH·,ABTS·＋ scavenging capacity,reducing power and inhibition of β-carotene bleaching were determined to compare antioxidant activity of four different solvent extracts.Results indicated that ethyl acetate extract had the highest content of total phenolics and flavonoids and the strongest antioxidant activity.The DPPH· scavenging capacity of ethyl acetate extract（EC50 78.86 μg/mL） was higher than rutin（EC50 135.71 μg/mL） and lower than VC EC50 71.26 μg/mL）;the ABTS·＋ scavenging capacity（EC50 29.79 μg/mL）was higher than rutin（EC50 72.96 μg/mL） and VC EC50 112.71 μg/mL）;the reducing power was higher than rutin and quercetin;the capacity of β-carotene bleaching inhibition（EC50 101.24 μg/mL）was lower than BHT（EC50 15.80 μg/mL）.The correlation between the EC50 values of DPPH· and ABTS·＋ scavenging capacity and phenolic and flavonoids content of four different solvent extracts were found.The datum suggested that ethyl acetate extracts had stronger antioxidant activity and higher than tartary buckwheat bran extracts.According to the result,antioxidant constituents in ethyl acetate extract were isolated purposively.