豆腐柴提取物不同极性部位的总酚、总黄酮含量及体外抗氧化活性

目的:研究豆腐柴提取物不同极性部位的体外抗氧化活性。方法:用甲醇提取豆腐柴减压浓缩后得豆腐柴提取物,依次用石油醚、三氯甲烷、乙酸乙酯、正丁醇萃取,得包括水相的五个不同极性部位,测定各极性部位的总多酚、总黄酮含量,比较各极性部位清除DPPH、ABTS、FRAP自由基的能力。结果:豆腐柴提取物的不同极性部位中乙酸乙酯相的总酚、总黄酮含量最高(总酚含量（635.935±6.529）mg GAE·g^-1,总黄酮含量（953.018±21.774）mg QE·g^-1),各极性部位均提示有一定的抗氧化活性,且自由基清除力在一定范围呈显著的剂量效应关系,乙酸乙酯相与石油醚相、水相的抗氧化能力差异性较大（p<0.01）。结论:豆腐柴提取物各极性部位都具有一定的抗氧化活性,可能与总酚、总黄酮含量有关,乙酸乙酯相抗氧化活性强于VC,可重点对该极性部位进一步分离纯化。 

Total polyphenol,flavonoid contents and antioxidant capacities of different polarity parts in extracts from Premna microphylla Turcz in vitro

Objective: The antioxidant capacities of different polarity parts in extracts from Premna microphylla Turcz leaves were studied. Methods: Different polarities of extracts were classified by different polarity solvents, such as petroleum ether, chloroform, ethyl acetate, N-butyl alcohol and water, the content of total flavonoids was determined and the antioxidant activity was compared by FRAP, DPPH and ABTS+. Results: The contents of total phenolics and total flavonoids in the ethylacetate phase were the highest ( 635.935 ± 6.529 mg GAE-1and 953.018 ± 21.774 mg QE·g^-1) , all polarity parts were promoted to have a certain antioxidant activity and there was a significant dose-effect relationship, the antioxidant capacity of ethyl acetate phase and petroleum ether phase was different ( p < 0.01) . Conclusion: The different polarity fractions of extracts from Premna microphylla Turcz had certain antioxidant abilities which were related to contents of total phenolics and total flavonoids.The free radical scavenging capacity of ethyl acetate was stronger than that of VC, it can be further separated and purified.