Li Ya, Li Sha, Lin Sheng-Jun, Zhang Jiao-Jiao, Zhao Cai-Ning, Li Hua-Bin
Guangdong Provincial Key Laboratory of Food, Nutrition and Health, Department of Nutrition, School of Public Health, Sun Yat-Sen University, Guangzhou 510080, China.
School of Chinese Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong 999077, China.
Molecules. 2017 Sep 6;22(9):1481. doi: 10.3390/molecules22091481.
Our previous study reported that the fruit of , an edible wild fruit, possessed strong antioxidant activity. In this study, a microwave-assisted extraction (MAE) method was established to extract antioxidants from the fruit of . The influence of five parameters, including ethanol concentration, solvent/material ratio, extraction time, extraction temperature and microwave power, was investigated by single-factor experiments. Three factors, namely ethanol concentration, solvent/material ratio, extraction time, were found to exert a major influence on extraction efficacy, and were further studied by response surface methodology to investigate their interactions. Ethanol concentration of 36.89%, solvent/material ratio of 29.56 mL/g, extraction time of 71.04 min, temperature of 40 °C, and microwave power of 400 W were found to be the optimal condition. The TEAC value was 198.16 ± 5.47 µmol Trolox/g DW under the optimal conditions, which was in conformity to the predicted value (200.28 µmol Trolox/g DW). In addition, the MAE method was compared with two conventional methods (Soxhlet extraction and maceration extraction). Results showed that the antioxidant capacity of the extract obtained by MAE method was stronger than that obtained by maceration (168.67 ± 3.88 µmol Trolox/g DW) or Soxhlet extraction (114.09 ± 2.01 µmol Trolox/g DW). Finally, several phenolic compounds in the extract were identified and quantified by UPLC-MS/MS, which were rutin, gallic acid, protocatechuic acid, epicatechin, epicatechin gallate, 2-hydrocinnamic acid, -coumaric acid, quercetin, chlorogenic acid and ferulic acid.
我们之前的研究报道称，一种可食用野生水果的果实具有很强的抗氧化活性。在本研究中，建立了一种微波辅助萃取（MAE）方法来从该水果的果实中提取抗氧化剂。通过单因素实验研究了乙醇浓度、溶剂/物料比、萃取时间、萃取温度和微波功率这五个参数的影响。发现乙醇浓度、溶剂/物料比、萃取时间这三个因素对萃取效率有主要影响，并通过响应面法进一步研究它们之间的相互作用。发现乙醇浓度为36.89%、溶剂/物料比为29.56 mL/g、萃取时间为71.04分钟、温度为40℃、微波功率为400W是最佳条件。在最佳条件下，TEAC值为198.16±5.47 μmol Trolox/g DW，与预测值（200.28 μmol Trolox/g DW）相符。此外，将MAE方法与两种传统方法（索氏提取和浸渍提取）进行了比较。结果表明，通过MAE方法获得的提取物的抗氧化能力强于通过浸渍法（168.67±3.88 μmol Trolox/g DW）或索氏提取法（114.09±2.01 μmol Trolox/g DW）获得的提取物。最后，通过超高效液相色谱-串联质谱法（UPLC-MS/MS）对提取物中的几种酚类化合物进行了鉴定和定量，它们是芦丁、没食子酸、原儿茶酸、表儿茶素、表儿茶素没食子酸酯、2-羟基肉桂酸、对香豆酸、槲皮素、绿原酸和阿魏酸。
