鲜莲结合酚的提取及其抗氧化活性分析

Extraction and Antioxidant Capacity of Bound Phenolics from Fresh Lotus Seeds

以建宁鲜莲为原料,研究溶剂酸碱、碱浓度、料液比和提取时间对鲜莲结合酚得率的影响并比较不同极性部位结合酚的抗氧化性能。采用中心组合设计优化其结合酚提取工艺,并结合总抗氧化能力、1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl,DPPH)自由基和羟自由基清除法对鲜莲结合酚的抗氧化活性进行测定,结果表明,鲜莲结合酚最佳提取工艺条件为Na OH溶液浓度2.8 mol/L、料液比1∶25(g/m L)、水解时间3.7 h,在此条件下,实测结合酚得率达(8.483±0.063)mg/g(以鲜莲干质量计),此外,通过体外抗氧化能力评价方法得出鲜莲结合酚具有较强的总抗氧化能力以及清除DPPH自由基和羟自由基能力,其中以乙酸乙酯、正丁醇萃取相的抗氧化能力较强,且在一定质量浓度范围内,结合酚浓度与其抗氧化活性呈明显的线性关系。综上所述,鲜莲富含结合酚类成分,而正丁醇相和乙酸乙酯相具有较强抗氧化能力。

The extraction of bound phenolics from fresh lotus seeds from Jianning was optimized using a central composite design. Optimization experiments were carried out by investigating the effect of solvent p H, alkali concentration, solid-tosolvent ratio and extraction time on extraction efficiency. The extract was fractionated with solvents of different polarities and the resulting fractions were comparatively evaluated for their antioxidant activity by total antioxidant capacity, 1,1-diphenyl-2-picrylhydrazyl（DPPH）, and hydroxyl radical scavenging assays. The results showed that the optimum extraction conditions were determined as follows： Na OH concentration, 2.8 mol/L; solid-to-solvent ratio, 1：25（g/m L）; and extraction time, 3.7 h. Under these conditions the yield of bound phenolics was（8.483 ± 0.063） mg/g of dry matter. In addition, all the fractions possessed high total antioxidant capacity, DPPH and hydroxyl radical scavenging capacity in a dose-dependent manner. Among these, ethyl acetate and n-butanol fractions showed higher antioxidant activity. In conclusion, fresh lotus seeds contained abundant bound phenolics and the ethyl acetate and n-butanol fractions exhibited higher antioxidant capacity.