College of Agriculture & Biotechnology, Zhejiang University, Zijingang Campus, Hangzhou 310058, China.
Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, Zhejiang University, Zijingang Campus, Hangzhou 310058, China.
Molecules. 2020 Feb 15;25(4):858. doi: 10.3390/molecules25040858.
-methylation of flavonoids is an important modification reaction that occurs in plants. -methylation contributes to the structural diversity of flavonoids, which have several biological and pharmacological functions. In this study, an -methyltransferase gene () was isolated from the fruit peel of , which encoding a multifunctional -methyltransferase and could effectively catalyze the methylation of 3'-, 5'-, and 7-OH of flavonoids with vicinal hydroxyl substitutions. Substrate preference assays indicated that this recombinant enzyme favored polymethoxylated flavones (PMF)-type substrates in vitro, thereby providing biochemical evidence for the potential role of the enzyme in plants. Additionally, the cytotoxicity of the methylated products from the enzymatic catalytic reaction was evaluated in vitro using human gastric cell lines SGC-7901 and BGC-823. The results showed that the in vitro cytotoxicity of the flavonoids with the unsaturated C2-C3 bond was increased after being methylated at position 3'. These combined results provide biochemical insight regarding CrOMT2 in vitro and indicate the in vitro cytotoxicity of the products methylated by its catalytic reaction.
黄酮类化合物的 -甲基化是一种重要的修饰反应，发生在植物中。-甲基化有助于黄酮类化合物的结构多样性，它们具有多种生物学和药理学功能。在这项研究中，从 的果皮中分离出一个 -甲基转移酶基因（），它编码一种多功能的 -甲基转移酶，能够有效地催化具有邻位羟基取代的黄酮类化合物的 3'、5'和 7-OH 的甲基化。底物偏好性测定表明，该重组酶在体外优先催化多甲氧基黄酮（PMF）-型底物，从而为该酶在植物中的潜在作用提供了生化证据。此外，还通过体外用人胃细胞系 SGC-7901 和 BGC-823 评估了酶催化反应中甲基化产物的细胞毒性。结果表明，具有不饱和 C2-C3 键的黄酮类化合物在 3'位甲基化后，其体外细胞毒性增加。这些综合结果提供了 CrOMT2 体外的生化见解，并表明其催化反应产生的产物的体外细胞毒性。
