不同品种龙眼核多酚的提取及其抗氧化和抑菌活性研究

Study on the extraction, antioxidant and antibacterial activities of polyphenols from different varieties of longan kernels

中文关键词:  龙眼核  多酚  品种  抗氧化  抑菌

英文关键词:longan kernel  polyphenol  varieties  antioxidant  antibacterial

中文摘要:

      目的 了解龙眼核多酚的生物活性在品种的区别, 提高对龙眼核多酚的生物利用率。方法 以不同品种的龙眼核样品为研究对象(分别来自储良龙眼、大广眼、双孖木龙眼、水涨龙眼、凤梨穗龙眼、泰国龙眼、石峡龙眼、福眼8个品种), 经过预处理后提取纯化的龙眼核多酚, 采用2,2-联苯基-1-苦基肼基(2,2-diphenyl- 1-picrylhydrazyl, DPPH)自由基清除能力测试、2,2’-氨基苯并三唑-6-磺酸[2,2’-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid, ABTS)]以及抑菌圈实验对其抗氧化和抗菌功能进行分析, 比较不同品种之间的差异。结果 各品种龙眼核多酚均表现出较强的抗氧化能力, DPPH自由基及ABTS阳离子自由基清除率最高分别可达98.70%和91.88%。龙眼核多酚对金黄色葡萄球菌、李斯特菌和枯草芽孢杆菌的生长均具有显著的抑制效果, 抑菌圈直径在17.0~22.6 mm。各品种龙眼核多酚半抑制浓度结果显示双孖木抑制金黄色葡萄球菌率最高, 为82.50%; 石峡抑制李斯特菌率最高, 为84.6%; 泰国抑制枯草芽孢杆菌率最高, 为83.8%。相关性分析结果显示, 总酚含量与DPPH自由基和ABTS阳离子自由基之间相关系数均大于0.9, 说明8个品种龙眼核多酚具有良好的抗氧化能力; 福眼龙眼总酚含量与其抗枯草芽孢菌和抗李斯特菌表现出中等相关(相关系数0.8~0.9), 双孖木龙眼和石峡龙眼对金黄色葡萄球菌相对于其他品种龙眼有抑制作用, 泰国龙眼对枯草芽孢杆菌有较强的抑制作用(相关系数?0.9), 储良龙眼对李斯特菌有强抑制作用(相关系数?0.9)。结论 本研究分析了不同品种龙眼的核多酚在总酚含量以及抗氧化和抗菌方面差异, 这些差异可以筛选出不同用途的龙眼核多酚, 为不同品种的龙眼核多酚的生物活性提供了参考依据。

英文摘要:

      Objective To enhance the bioavailability of longan kernels, investigate the bioactive properties of their polyphenols from different cultivars. Methods In this study, polyphenolic compounds were extracted and purified from longan kernels of 8 cultivars (Chuliang, Daguangyan, Shuangzimu, Shuizhang, Fenglisui, Thai, Shixia and Fuyan). The antioxidant and antibacterial functions were analyzed by 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging capacity test, 2,2’-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and inhibition zone experiment, and the differences among different varieties were compared Results Polyphenols from all longan kernels exhibited substantial antioxidant activity, with DPPH and ABTS highest scavenging rates reaching 98.70% and 91.88%, respectively. Moreover, these polyphenols effectively inhibited the growth of Staphylococcus aureus, Listeria monocytogenes and Bacillus subtilis, with inhibition zone diameters ranging from 17.0 to 22.6 mm. The results of the half-maximal inhibitory concentration of polyphenols extracted from longan kernels of different cultivars indicated that Shuangzimu longan exhibited the highest inhibition rate against Staphylococcus aureus, at 82.50%. Similarly, Shixia longan showed the highest inhibition rate against Listeria monocytogenes, at 84.60%. Thai longan had the highest inhibition rate of Bacillus subtilis, which was 83.8%. Correlation analysis showed that the correlation coefficients between total phenol content and DPPH free radical and ABTS cation free radical were higher than 0.9, indicating that 8 varieties of longan kernel polyphenols had good antioxidant capacity. The total phenol content of Fuyan longan showed medium correlation to its resistance to Bacillus subtilis and Listeria monocytogenes (correlation coefficient 0.8–0.9). Specifically, Shuangzimu and Shixia longans demonstrated inhibitory effects against Staphylococcus aureus, while Thai longan showed strong inhibitory ability against Bacillus subtilis, and Shuliang longan effectively inhibited Listeria monocytogenes. Conclusion This study investigates the variation in total phenolic content as well as the antioxidant and antibacterial properties of longan kernel polyphenols across different cultivars. These observed differences may provide targeted selection of longan kernel polyphenols for specific applications and serve as a reference for understanding their biological activities across cultivars.