Department of Pharmacognosy, College of Pharmaceutical Sciences, Matsuyama University, 4-2 Bunkyo-cho, Matsuyama 790-8578, Ehime, Japan.
Department of Nutritional Science, Faculty of Health and Welfare Science, Okayama Prefectural University, 111 Kuboki, Soja 719-1197, Okayama, Japan.
Molecules. 2023 Sep 11;28(18):6563. doi: 10.3390/molecules28186563.
Despite the various biological activities exhibited by water chestnut (the fruit of the genus), the phenolic compounds present in its extract require comprehensive characterization. Accordingly, we analyzed a 80% methanol extract of commercially available water chestnut and identified a new hydrolyzable tannin dimer termed trapadin A. Additionally, 22 known compounds, including 10 hydrolyzable tannin monomers and 2 dimers, were also detected in the extract. Spectroscopic and chemical methods were used to elucidate the structure of trapadin A, revealing it to be a hydrolyzable tannin dimer formed from units of tellimagrandin II and 1,2,3,6-tetra--galloyl-β-d-glucose. Moreover, the 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity assay used to determine the half-maximal effective concentration values for the 23 compounds isolated from water chestnut indicated significant radical scavenging activity associated with hydrolyzable tannins. Notably, trapadin A, the new hydrolyzable tannin dimer, exhibited the highest activity value among the tested compounds.
尽管菱角（菱属的果实）具有多种生物活性，但其中提取物所含的酚类化合物需要进行全面的特征描述。因此，我们分析了市售菱角的 80%甲醇提取物，从中鉴定出一种新的可水解单宁二聚体，命名为 trapadin A。此外，该提取物中还检测到 22 种已知化合物，包括 10 种可水解单宁单体和 2 种二聚体。我们采用光谱和化学方法阐明了 trapadin A 的结构，证实它是由 tellimagrandin II 和 1,2,3,6-四-O-没食子酰基-β-D-葡萄糖单元形成的可水解单宁二聚体。此外，我们还采用 1,1-二苯基-2-苦基肼自由基清除活性测定法来确定从菱角中分离得到的 23 种化合物的半数最大有效浓度值，结果表明与可水解单宁相关的具有显著的自由基清除活性。值得注意的是，在所测试的化合物中，新型可水解单宁二聚体 trapadin A 表现出最高的活性值。
