多糖对乳铁蛋白与表没食子儿茶素没食子酸酯聚集的影响

Effect of Polysaccharides on LF-EGCG Aggregation

采用浊度法、DLS和荧光法研究6种多糖(高甲酯化果胶、低甲酯化果胶、阿拉伯胶、β-环糊精、β-燕麦葡聚糖和β-酵母葡聚糖)对乳铁蛋白与表没食子儿茶素没食子酸酯(EGCG)聚集的影响,结果表明:除β-酵母葡聚糖外,其余多糖均能有效抑制乳铁蛋白与EGCG聚集引起的浑浊;6种多糖均能使溶液的粒径减小;离子型多糖能够使溶液的ζ-电位减小,同时增强EGCG对乳铁蛋白的荧光淬灭效应,而β-环糊精和β-酵母葡聚糖使荧光淬灭效应降低。总之,在水溶液体系,多糖通过不同机制影响乳铁蛋白与EGCG的聚集。

The present work studies the inhibition of aggregation of lactoferrin （LF） and EGCG by different polysac- charides. Several analytical approaches, namely, nephelometry, dynamic light scattering （DLS） and fluorescence quench- ing were used. Nephelometry and DLS showed that the presence of the ionic polysaccharides in solution reduced the for- mation of insoluble aggregates, and increased ~＇-potential of the solution. The fluorescence quenching measurements showed that ionic polysaccharides increase the quenching effect of EGCG on LF fluorescence, whereasβ-cyclodextrin re- duce the quenching effect of EGCG on LF fluorescence. The results obtained for β-cyclodextrin strongly suggest that the main mechanism by which it inhibit LF-EGCG aggregation is by molecular association between β-cyclodextrin and EGCG, competing with protein aggregation. In the case of ionic polysaccharides, the results obtained provide evidence that the main mechanism by which they reduce LF-EGCG aggregation is by forming a polysaccharide-LF-EGCG com- plex, enhancing its solubility in aqueous medium.