Three oligomeric hydrolysable tannins, coriariins K, L, and M, which were previously undescribed, together with five known hydrolysable tannins were isolated from dried leaves of Coriaria japonica. Their structures were determined based on 1D and 2D NMR spectroscopy, HR-ESI-MS, and ECD spectroscopy experiments. Among the isolated compounds, coriariin M has a unique trimer structure where both dehydrodigalloyl and valoneoyl group linkages were found between the hydrolysable tannin monomers. Dimeric hydrolysable tannins coriariins K and L, having a dehydrodigalloyl group as the linking unit, were structurally related to coriariin A, the main hydrolysable tannin of this plant species. Additionally, the complexation of the eight hydrolysable tannins isolated in this study with bovine serum albumin (BSA) to form water-soluble macromolecules was analyzed using native polyacrylamide gel electrophoresis (PAGE). A comparison of the behaviors of the oligomeric hydrolysable tannins suggested the participation of the hexahydroxydiphenoyl group and the importance of the molecular sizes of the hydrolysable tannins in the formation of macromolecules.

中文翻译：

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Coriariin M，一种三聚可水解单宁，以脱氢二没食子酰基和丙戊酰基团作为连接单元，并伴随来自 Coriaria japonica 的二聚可水解单宁

从 Coriaria japonica 的干叶中分离出三种寡聚可水解单宁、coriariins K、L 和 M，以前未描述过，以及五种已知的可水解单宁。它们的结构是基于 1D 和 2D NMR 光谱、HR-ESI-MS 和 ECD 光谱实验确定的。在分离的化合物中，coriariin M 具有独特的三聚体结构，其中在可水解的单宁单体之间发现了脱氢二没食子酰基和丙戊酰基键。具有脱氢二没食子酰基作为连接单元的二聚体可水解单宁coriariins K和L在结构上与coriariin A相关，后者是该植物物种的主要可水解单宁。此外，使用天然聚丙烯酰胺凝胶电泳 (PAGE) 分析了本研究中分离的八种可水解单宁与牛血清白蛋白 (BSA) 形成水溶性大分子的络合。低聚可水解单宁的行为比较表明六羟基联苯酰基的参与以及可水解单宁的分子大小在大分子形成中的重要性。