Optimization of ultrasound-assisted extraction of procyanidins from perilla seed hull and their antioxidant activities in vitro

Abstract Ultrasound-assisted extraction (UAE) was used to extract procyanidins (PC) from the perilla seed hull. Four independent variables, namely, liquid-to-solid ratio, ethanol concentration, UAE time, and UAE temperature were investigated. Response surface methodology was performed on the basis of results of single-factor tests. The optimal conditions for PC extraction were as follows: a liquid-to-solid ratio of 15:1, an ethanol concentration of 62%, a UAE time of 29 min, and a UAE temperature of 53 °C. Under these conditions, the experimental yield of PC was 2.185 mg/g (n = 3), which is correlated with the predicted value of 2.2 mg/g. The extracted and purified PC showed excellent antioxidant activity against 2,2-diphenyl-1-picrylhydrazyl, hydroxyl, and 2,2’-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) radicals in vitro.

摘要：本研究采用超声辅助提取法（Ultrasound-assisted extraction, UAE）从紫苏籽壳中提取原花青素（procyanidins, PC）。选取液料比、乙醇体积分数、超声提取时间及超声提取温度四个自变量开展实验，基于单因素试验结果采用响应面法（Response surface methodology）进行工艺优化。最终得到原花青素的最优提取工艺参数为：液料比15:1、乙醇体积分数62%、超声提取时间29 min、超声提取温度53 ℃。在此最优条件下，原花青素的实测得率为2.185 mg/g（n=3），与预测值2.2 mg/g高度吻合。经提取纯化得到的原花青素在体外对2,2-二苯基-1-苦基肼基（2,2-diphenyl-1-picrylhydrazyl）、羟自由基及2,2'-联氮-双(3-乙基苯并噻唑啉-6-磺酸)（2,2’-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid)）自由基均表现出优异的抗氧化活性。