柿叶总黄酮提取工艺优化及其抗氧化活性

Optimization of the Extraction Technology of Total Flavonoids and in Vitro Antioxidant Activity of Extract from Persimmon Leaves

目的:优化柿子叶总黄酮的回流提取工艺,并评价其抗氧化活性。方法:以总黄酮提取量为指标,根据单因素实验的结果,通过响应面法与正交法分别得出最佳的回流提取总黄酮的条件,确定最优工艺条件,并在最优工艺条件下,以VC作为对照,通过柿子叶总黄酮对DPPH自由基、羟自由基等的清除作用来评价其抗氧化活性。结果:正交试验设计的最佳提取工艺为:乙醇浓度为40%,提取温度50℃,料液比为1∶50(g/m L)和提取时间为120 min,总黄酮提取量为18.11 mg/g。响应面法的最佳提取工艺为:乙醇浓度为50%,提取温度50℃,料液比为1∶60(g/m L)和提取时间为120 min,总黄酮提取量为18.21 mg/g。响应面法总黄酮提取量比正交试验法提高了0.55%。但从经济角度考虑,低乙醇浓度和低料液比能节约成本和能耗,而两者提取率几乎没有差别。因此,正交试验更适合柿叶总黄酮提取工艺。同时在正交试验法最佳工艺条件下,柿叶总黄酮对DPPH自由基、羟自由基和超氧阴离子的IC50分别为8.0、18.0、76.0μg/m L,体外抗氧化试验结果表明,柿叶总黄酮对DPPH自由基、OH自由基均具有较强的清除能力,明显高于抗坏血酸,而对超氧阴离子自由基具有一定的清除能力,但清除能力低于同浓度的抗坏血酸。结论:正交试验提取柿叶总黄酮工艺合理可行,经济节约,可适用于工业生产。提取物具有较强的抗氧化活性。

Objective:To optimize the reflux extraction technology of the total flavonoids from persimmon leaves and evaluate the antioxidant activity of the extract.Methods:The best conditions of extracting total flavonoids from persimmon leaves by reflux extraction were screened by orthogonal and response surface method based on single factor experiments with the yield of total flavonoids as index.Meanwhile,the antioxidant capacity was measured by scavenging of DPPH·and hydroxyl free radical,with VCas the control.Results:The results showed that optimal process obtained by orthogonal test were as follows:Ethanol concentration was 40%,extraction temperature was 50℃,ratio of raw material to liquid was 1∶50(g/m L)and extraction time was 120 min,the yield of total flavonoids was 18.11 mg/g.The results showed that optimal process obtained by response surface were ethanol concentration was 50%,extraction temperature was 50℃,ratio of raw material to liquid was 1∶60(g/m L)and extraction time was 120 min,the yield of total flavonoids was 18.21 mg/g,the total flavonoids content extracted by the response surface methodology was increased by 0.55% compared with orthogonal test.From an economic perspective,low ethanol concentration and low feed-liquid ratio could save cost and energy consumption,and the extraction rate of the two was almost the same.Therefore,it was more suitable for the extraction process of total flavonoids from persimmon leaves.Under the optimal extraction process of orthogonal test,IC50 of total flavonoids from persimmon leaves to DPPH free radical,hydroxyl radical and uperoxide free radical were 8.0,18.0,76.0μg/m L,respectively.The results of in vitro antioxidant test showed that the scavenging effects of total flavonoids extract from persimmon leaves to DPPH·and hydroxyl radical were better than that of vitamin C solution at the same concentration.And superoxide free radical was lower than that of ascorbic acid.Conclusion:The orthogonal method to optimize the extraction of persimmon leaf flavonoids technology was rational and feasible,economical and economical,it could be applied to industrial production,and the extract exhibited strong antioxidant activity.