茶皂素β-D-葡萄糖醛酸酶水解物的结构分析

Structural analysis of β-D-glucuronidase hydrolysate of tea saponins

茶皂素有较强的溶血性,但经β-D-葡萄糖醛酸苷酶水解后溶血性降低。该研究利用正丁醇和乙酸乙酯分别对茶皂素及其β-D-葡萄糖醛酸苷酶酶解产物进行萃取纯化,采用超高效液相-质谱鉴定酶解前后茶皂素各组分含量的变化,从而分析其结构变化。结果表明,酶解后乙酸乙酯提取物中糖苷型茶皂素从75.06%降为5.24%,苷元型组分从6.76%增至67.05%。正丁醇提取物中糖苷型茶皂素从51.61%降为34.98%,从而推断可能是β-D-葡萄糖醛酸苷酶酶解后,茶皂素亲水性的糖基与疏水性的配基分离,两亲性下降,从而使其溶血性降低。

Tea saponins showed strong hemolytic activity, which could be decreased by the hydrolysis of β-D-glucuronidase. In this study, tea saponins and their β-D-glucuronidase hydrolysates were extracted and purified with n-butanol and ethyl acetate. The contents changes of tea saponins compo-nents were identified by UPLC-MS before and after hydrolysis, and then the structure changes were analyzed. The results showed that the glycoside saponins were degraded by hydrolysis, their contents in ethyl acetate and n-butanol fraction were reduced from 75.06% to 5.24%, and 5 1 .6 1 % to 34. 98%, respectively, while these aglycons in ethyl acetate increased from 6.76% to 67.05%. It suggested that the decrease of hemolytic activity of tea saponins hydrolysates was probably due to the reduction in amphipathic affinity, which was generated by the dissociation of saponins into hydrophilic glycosyl derivatives and hydrophobic saponins ligand, after β-D-glucuronidase hydrolyzation.