龙利叶多酚提取条件优化及其抗氧化活性研究

在单因素试验的基础上,采用正交试验优化龙利叶中多酚的提取工艺,并研究其抗氧化活性,以期为龙利叶多酚的开发应用提供理论依据。提取剂采用乙醇溶液,研究乙醇体积分数、料液比、提取温度、提取时间、提取次数这5个因素对龙利叶多酚提取的影响。结果表明,龙利叶多酚最优提取条件如下:乙醇体积分数60%、料液比1︰30、提取时间30 min、提取温度60℃。在此条件下龙利叶多酚的得率为4.38 mg/g。龙利叶多酚清除DPPH·自由基的半抑制浓度(IC50)为1.91 g/mL,抗坏血酸的IC50为6.75 g/mL。还原力的测定中,当吸光度同为0.5时,龙利叶多酚与抗坏血酸质量浓度分别为9.94 g/mL与32.06 g/mL,表明龙利叶多酚对DPPH·自由基的清除能力以及还原力均强于抗坏血酸。

Optimization of Extraction Conditions and Antioxidant Activities of Polyphenols from Sauropus rostratus Miq.

Based on single factor test,extraction conditions of polyphenols from Sauropus rostratus Miq. were optimized by orthogonal test,and antioxidant activities of the polyphenols were investigated to provide scientific basis for the development and application of the polyphenols. Ethanol was used for polyphenols extraction. The factors such as ethanol concentration, solid-liquid ratio, extraction temperature, time and extraction times were studied. The optimum extraction conditions were obtained by orthogonal experiment and determined as follows:60% ethanol,solid-liquid ratio of 1:30,60 ℃,30 min and the extraction rate of polyphenols from Sauropus rostratus Miq. was 4. 38 mg/g. The 50% inhibition concentrations(IC50) of polyphenols from Sauropus rostratus Miq. and ascorbic acid were 1. 91 g/mL and 6. 75 g/mL respectively for scavenging DPPH ·. Reducing power was determined, and concentrations of polyphenols extracted and ascorbic acid were 9 . 94 g/mL and 32 . 06 g/mL respectively with absorbance of 0 . 5 . Results showed that free radical scavenging activities on DPPH · and reducing power of polyphenols from Sauropus ros-tratus Miq. were better than those of ascorbic acid.