Novel tea catechin derivatives have been synthesized, and a structure-activity study, related to the capacity of these and other polyphenols to bind dihydrofolate reductase (DHFR), has been performed. The data showed an effective binding between all molecules and the free enzyme, and the dissociation constants of the synthetic compounds and of the natural analogues were on the same order. Polyphenols with a catechin configuration were better DHFR inhibitors than those with an epicatechin configuration. Antiproliferative activity was also studied in cultured tumour cells, and the data showed that the activity of the novel derivatives was higher in catechin isomers. Derivatives with a hydroxyl group para on the ester-bonded gallate moiety presented a high in vitro binding to DHFR, but exhibited transport problems in cell culture due to ionization at physiologic pHs. The impact of the binding of catechins to serum albumin on their biological activity was also evaluated. The information provided in this study could be important for the design of novel medicinal active compounds derived from tea catechins. The data suggest that changes in their structure to avoid serum albumin interactions and to facilitate plasmatic membrane transport are essential for the intracellular functions of catechins.
我们合成了新型茶
儿茶素衍
生物,并对这些衍
生物和其他
茶多酚结合二氢叶酸还原酶(DHFR)的能力进行了结构-活性研究。数据显示,所有分子都能与游离酶有效结合,而且合成化合物和天然类似物的解离常数相同。
儿茶素结构的多
酚比
表儿茶素结构的多
酚对 DHFR 的抑制效果更好。此外,还在培养的肿瘤细胞中研究了抗增殖活性,数据显示,
儿茶素异构体的新型衍
生物活性更高。酯键合
没食子酸酯分子上带有羟基的衍
生物与 DHFR 的体外结合力较高,但在
细胞培养过程中,由于在生理 pH 值下会发生电离,因此会出现转运问题。研究还评估了
儿茶素与
血清白蛋白的结合对其
生物活性的影响。本研究提供的信息对于设计从茶叶
儿茶素中提取的新型药用活性化合物非常重要。数据表明,改变
儿茶素的结构以避免与
血清白蛋白的相互作用并促进质膜转运,对于
儿茶素的细胞内功能至关重要。