论文部分内容阅读
【目的】比较荔枝果肉不同酚类成分群的总酚、总黄酮和缩合单宁含量、单体酚组成及抗氧化活性差异,明确荔枝果肉中发挥抗氧化作用的有效酚类成分,为揭示荔枝果肉发挥健康效应的物质基础提供依据。【方法】利用C18硅胶层析柱将荔枝果肉多酚提取物分离成F1、F2、F3和F4共4个不同的酚类成分群,分析各成分群的总酚、总黄酮和缩合单宁含量及单体酚组成,采用铁离子还原能力(ferric reducing ability of plasma,FRAP)、1,1-二苯基-2-苦基苯肼(1,1-diphenyl-2-picrylhydrazy,DPPH)自由基消除能力、氧自由基吸收能力(oxygen radical absorbance capacity,ORAC)及细胞抗氧化能力(cellular antioxidant ability,CAA)4种抗氧化活性评价体系比较这4个成分群的抗氧化活性大小。【结果】荔枝果肉多酚提取物可以分为F1、F2、F3和F4共4个酚类成分群,其中F2的得率高达36%,其他成分群得率分别为18.71%、16.79%、21.12%;各酚类成分群的总酚、总黄酮和缩合单宁含量分别介于218.86—499.78 mg GAE·g~(-1) DW、414.94—1 285.45 mg RE·g~(-1) DW、83.35—483.43 mg CE·g~(-1) DW。4个成分群中F2的总酚、总黄酮和缩合单宁含量最高,对荔枝果肉多酚提取物相应的贡献率最大,分别为50.31%、54.24%、72.06%,均高于其余3个成分群的贡献率;其次是F3和F4;F1的最低。经HPLC分析和鉴定发现F2成分群主要为原花青素B2、表儿茶素等单体酚,F3仅含槲皮素-3-O-芸香糖-7-O-α-L-鼠李糖苷一种单体酚,F4中含有芦丁等。抗氧化活性评价结果显示,4个成分群的FRAP抗氧化能力大小顺序为F2>F3>F4>F1;DPPH消除能力的IC50值分别为27.00、9.76、19.41和16.25μg·m L~(-1),其中F2的IC50值最小,即DPPH消除能力最强,其次是F4、F3,F1最弱;ORAC抗氧化能力顺序为F2>F3>F4>F1,CAA抗氧化能力顺序为F2>F3>F4、F1,其中F2的ORAC和CAA抗氧化能力分别为8.36 mmol TE·g~(-1)DW和190.71μmol QE·g~(-1) DW,对荔枝果肉多酚提取物ORAC和CAA值的贡献率分别高达50.42%和84.91%。【结论】荔枝果肉4个酚类成分群间的总酚、总黄酮和缩合单宁含量及抗氧化活性均存在显著差异,各成分群的单体酚组成亦各有特点,其中F2成分群的得率及总酚、总黄酮和缩合单宁含量最高,抗氧化活性最好,是荔枝果肉抗氧化作用的最主要酚类物质。
【Objective】 The objective of this study was to compare the contents of total phenols, total flavonoids and condensed tannins, the composition of phenolics and the antioxidant activity in different phenolic components of litchi chinense fruit, and find out the effective phenolic components that play an antioxidant role in litchi chinense fruit. The basis of the material basis of the healthy effects of the pulp is provided. [Method] The polyphenol extracts of litchi pulp were separated into four different phenolic components F1, F2, F3 and F4 by C18 silica gel column, and the contents of total phenols, total flavonoids and condensed tannins And monomeric phenols. Ferric reducing ability of plasma (FRAP), 1,1-diphenyl-2-picrylhydrazy (DPPH) The antioxidant activity of four antioxidant systems were compared among four antioxidant systems: oxygen free radical scavenging capacity (ORAC) and cellular antioxidant ability (CAA). 【Result】 The results showed that the polyphenol extracts of litchi pulp could be divided into four groups of phenols: F1, F2, F3 and F4. Among them, the yield of F2 was as high as 36%, and the yield of other components were 18.71%, 16.79%, 21.12 %, Respectively. The contents of total phenols, total flavonoids and condensed tannins of each phenolic component ranged from 218.86 to 499.78 mg GAE · g -1 DW, 414.94-1 285.45 mg RE · g -1 DW, 83.35-483.43 mg CE · g -1 DW. The contents of total phenols, total flavonoids and condensed tannins in F2 were the highest among the four groups, and the corresponding contribution rates were 50.31%, 54.24% and 72.06% respectively, which were higher than the other three components Group contribution rate; followed by F3 and F4; F1 lowest. HPLC analysis and identification found that the F2 component of the main proanthocyanidin B2, epicatechin and other monomeric phenol, F3 only contains quercetin -3-O- rutinose -7-O-α-L-rhamnoside a Monophenol, F4 contains rutin and so on. The results of antioxidant activity showed that the order of FRAP antioxidant capacity of four components was F2> F3> F4> F1. The IC50 values of DPPH elimination were 27.00, 9.76, 19.41 and 16.25 μg · m L -1 ), Of which F2 had the lowest IC50 value, that is, DPPH had the strongest elimination ability, followed by F4, F3 and F1 the weakest. The order of ORAC antioxidant activity was F2> F3> F4> F1 and that of CAA was F2> F3> F4 and F1. The antioxidant activity of ORAC and CAA of F2 was 8.36 mmol TE · g -1 DW and 190.71 μmol QE · g -1 DW, respectively. The ORAC and CAA values of litchi pulp polyphenol extract The contribution rates were as high as 50.42% and 84.91% respectively. 【Conclusion】 The contents of total phenolic, total flavonoid and condensed tannin and antioxidative activity of four phenolic components in litchi fruit are significantly different, and the individual phenolic composition of each component group also has its own characteristics. Among them, F2 component Yield and total phenols, flavonoids and condensed tannins content of the highest antioxidant activity of the best litchi pulp antioxidant the most important phenolic compounds.