扁担藤不同极性成分抗氧化活性研究

目的:研究扁担藤不同极性成分体外抗氧化活性。方法:以抗坏血酸和茶多酚为阳性对照,采用铁离子还原/抗氧化能力(FRAP)、清除羟自由基(OH.)和2,2’-连氨-(3-乙基苯并噻唑林-6-磺酸)二氨盐]自由基(ABTS+.)测定法,评价扁担藤总提取物、石油醚层、乙酸乙酯层、正丁醇层和水层5个不同极性成分在质量浓度为0.005～0.050 g·L-1范围内对铁离子的还原/抗氧化能力和清除OH.,ABTS+.能力。结果:扁担藤不同极性成分的Fe3+还原/抗氧化能力均弱于抗坏血酸,除水层外,均强于茶多酚;当浓度为0.050 g·L-1时,不同极性成分的铁离子还原/抗氧化能力为:抗坏血酸(FRAP值2 377.8)>总提取物(FRAP值683.8)>乙酸乙酯层(FRAP值419.8)>石油醚层(FRAP值201.8)>正丁醇层(FRAP值185.8)>茶多酚(FRAP值73.8)>水层(FRAP值63.8);乙酸乙酯层清除OH.的能力(IC500.028 g·L-1)均强于抗坏血酸(IC500.044 g·L-1)和茶多酚(IC500.032 g·L-1);各不同极性成分清除ABTS+.的能力均强于茶多酚(IC500.416 g·L-1),且乙酸乙酯层(IC500.008 g·L-1)强于抗坏血酸(IC500.011 g·L-1)。结论:扁担藤具有较好的抗氧化能力,为开发功能性抗氧化剂提供科学依据。

Antioxidant Activity of Different Polarity Chemical Constituents from Tetrastigma planicaule

Objective:To study the antioxidant activity of different polarity chemical constituents from Tetrastigma planicaule. Method: The capacity of ferric reducing antioxidant power (FRAP) and scavenging hydroxyl free radical (OH·) and·) of the total extracts, petroleum ether fraction, ethylacetate fraction, n-butanol fraction and water fraction from T. planicaule were evaluated by FRAP assay, OH·scavenging assay, and ABTS⁺·scavenging assay at different concentration (0.005-0.050 g·L^-1). Results were compared with that of positive control vitamin C(VC) and tea polyphenol. Result: First, ferric reducing antioxidant power of different polarity chemical constituents from T. planicaule were weaker than VC, but higher than tea polyphenol except water fraction. When the concentration of different polarity chemical constituents was 0.050 g·L^-1, ferric reducing antioxidant power was as follows: VC (FRAP value 2 377.8)>total extracts (FRAP value 683.8)>ethyl acetate (FRAP value 419.8)>petroleum ether (FRAP value 201.8)>n-butanol (FRAP value 185.8)>tea polyphenol (FRAP value 73.8)>water (FRAP value 63.8). Secondly, the results demonstrated that OH·scavenging activity in ethylacetate fraction (IC₅₀ 0.028 g·L^-1) was higher than VC (IC₅₀ 0.044 g·L^-1) and tea polyphenol (IC₅₀ 0.032 g·L^-1). Finaly, different polarity chemical constituents showed higher ABTS⁺·scavenging activity than tea polyphenol (IC₅₀ 0.416 g·L^-1), also ethylacetate fraction (IC₅₀ 0.008 g·L^-1) was higher than VC (IC₅₀ 0.011 g·L^-1). Conclusion: T. planicaule has a strong antioxidative activity, which provides scientific basis for exploiting functional antioxidant.