金花葵花总黄酮的提取及体外抗氧化活性

采用响应面法对金花葵花总黄酮的溶剂提取条件进行优化,并通过人工构建自由基来考察金花葵花总黄酮的体外抗氧化能力。实验结果表明,金花葵花总黄酮的最适提取条件:乙醇浓度75%（V/V）、液料比30∶1,提取温度60℃,提取时间2.50 h,在此条件下的黄酮得率为126.67 mg/g干重。体外抗氧化实验表明:金花葵花总黄酮对超氧阴离子自由基有很强的清除能力,IC₅₀为207.1μg/m L,且效果优于VC;金花葵花总黄酮对DPPH自由基和羟基自由基有较强的清除作用,IC₅₀分别为37.5μg/m L和754.7μg/m L,金花葵花总黄酮对Fe3+的具有一定的还原作用,是VC的83%,但均稍差于VC。金花葵花总黄酮具有较高的体外抗氧化能力。 

Extraction of total flavonoids from Hibiscus manihot L.flower and their antioxidant activity in vitro

This test used solvent extraction of flavonoids from Hibiscus manihot L.flower by using response surface methodology to optimize the extraction conditions, and the antioxidant activity in vitro was evaluated by artificial free radicals in detail. The optimal extraction conditions were as follows: the volume fraction of ethanol 75%, ratio of liquid to solid 30 ∶ 1, extraction temperature 60 ℃, extraction time 2.5 h. Under this optimum conditions, the actual yield of flavonoids was 126.67 mg/g dry weight.The total flavonoids in Hibiscus manihot L.flower had a good scavenging effect on superoxide anion radical with a 50%inhibition concentration ( IC₅₀) of 207.1 μg/m L and which was better than that of ascorbic acid.The extracts also had a good scavenging effect on DPPH radical and hydroxyl radical with IC₅₀ of 37.5 μg/m L and 754.7 μg/m L respectively, which were a little lower than that of ascorbic acid.The extract also showed a certain reduction ability and it was 83% times as much as that of ascorbic acid.In general, total flavonoids from Hibiscus manihot L.flower had a high antioxidant activity.