裂叶荨麻根总黄酮提取工艺优化及抗氧化活性评价

通过单因素及正交试验考察裂叶荨麻根总黄酮的最佳提取工艺,采用分光光度法测定根提取物石油醚相、乙酸乙酯相、正丁醇相和水相的总黄酮含量,以DPPH自由基清除率、羟基自由基清除率和总还原力为指标评价裂叶荨麻根各萃取相的抗氧化活性。结果表明,裂叶荨麻根中总黄酮最佳提取工艺为料液比1∶15,乙醇浓度700mL/L,提取温度60℃,提取时间2h,提取物中总黄酮含量为50.53mg/g;各萃取相总黄酮含量为乙酸乙酯相(70.62 mg/g)>正丁醇相(45.48 mg/g)>水相(18.76 mg/g)>石油醚相(10.23mg/g),抗氧化活性为乙酸乙酯相>正丁醇相>水相>石油醚相,各萃取相抗氧化活性与总黄酮含量呈正相关。说明裂叶荨麻根具有抗氧化活性,乙酸乙酯相及正丁醇相的抗氧化活性作用较好,为将裂叶荨麻开发为抗氧化食品及药品提供了理论依据。

Optimization of Extraction Process of Total Flavonoids from UrticafissaRoots and Evaluation of Antioxidant Activity

The optimum extraction process of total flavonoids fromUrticafissaroots was studied by single factor and orthogonal experiments.The total flavonoid contents of petroleum ether phase,ethyl acetate phase,n-butanol phase and water phase of extract were determined by spectrophotometry.The DPPH free radical scavenging rate,hydroxyl radical scavenging rate and total reducing power were used to evaluate the antioxidant activity of each extraction phase of Urtica fissaroots.The results showed that the best extraction processes of total flavonoids of Urticafissaroots were 1∶15 for the ratio of solid to liquid,70%for the ethanol concentration,60℃for the extraction temperature,and 2 hfor the extraction time.The total flavonoid content of the extract was 50.53 mg/g.The order of the total flavonoid contents of extraction phases were ethyl acetate phase(70.62 mg/g)>n-butanol phase(45.48 mg/g)>water phase(18.76 mg/g)>petroleum ether phase(10.23 mg/g).The order of the antioxidant activity was ethyl acetate phase>n-butanol phase>water phase>petroleum ether phase.The antioxidant activity of each extraction phase was positively correlated with the total flavonoid content.Urtica fissa root has antioxidant activity,ethyl acetate phase and n-butylate phase are better.The results provided the theoretical basis for the development of Urtica fissa roots for the antioxidant foods and medicines.