响应面优化玛咖叶总黄酮提取工艺及其抗氧化活性研究

Response Surface Methodology for Optimization of Extracting Total Flavonoids from Maca Leaves and Antioxidant Evaluation

摘要:

采用响应面法优化云南丽江产玛咖叶总黄酮的提取条件。在单因素试验基础上，选择乙醇体积分数、提取温度、料液比为影响因子，应用Box-Benhnken中心组合法进行3因素3水平试验设计，以玛咖叶总黄酮得率为响应值，进行响应面分析，并比较玛咖叶总黄酮的体外抗氧化活性。结果表明，玛咖叶总黄酮的最佳提取条件为乙醇体积分数65%、提取温度64 ℃、料液比29:1（mL/g），在此条件下，玛咖叶总黄酮的得率可达到(2.49±0.02)%。同时建立了乙醇溶液提取玛咖叶总黄酮的二次数学模型，对目标产物提取具有良好的预测作用。玛咖叶总黄酮体外清除羟自由基、1, 1-二苯基苦基苯肼（DPPH?）自由基和超氧阴离子自由基的IC50值分别0.605、0.165、0.425 mg/mL，其清除3种自由基的能力均高于相同浓度的2, 6-二叔丁基对甲酚（BHT），但低于L-抗坏血酸。

Abstract:

Response surface methodology (RSM) was employed to optimize the extraction conditions of total flavonoids from Maca leaves collected from Lijiang (Yunnan province). Based on single-factor tests, Box-Benhnken center composite experiment was carried out with three factors, including alcohol concentration, extraction temperature, solid-to-solvent ratio. RSM was used to determine the effect of prime factors on the yield of flavonoids. Besides, the antioxidant activity in vitro of flavonoids from maca leaves was evaluated. Results showed that the optimum extraction conditions by RSM were ethanol concentration 65%, extraction temperature 64 ℃, and solid-to-liquid ratio 29:1 (mL/g). Under these conditions, the extraction yield of total flavonoids was (2.49±0.02) %, which was close to the measured value. Thus, the fitted quadratic regression model was valid. The IC50 of the obtained total flavonoids against hydroxyl, superoxide anion and DPPH radicals were 0.605, 0.425 mg/mL and 0.165 mg/mL, respectively. The scavenging impact of the three radicals was more effective than that of 2,6-di-tert-butyl-4-methyl phenol (BHT) at the same concentration, but lower than vitamin C.