Proanthocyanidin Dimers and Trimers from Vitis vinifera Provide Diverse Structural Motifs for the Evaluation of Dentin Biomodification
Proanthocyanidin Dimers and Trimers from Vitis vinifera Provide Diverse Structural Motifs for the Evaluation of Dentin Biomodification
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DOI：
10.1021/acs.jnatprod.8b00953
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发表时间：
2019-09-01
影响因子：
5.1
通讯作者：
Pauli, Guido F.
中科院分区：
文献类型：
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作者：
Phansalkar, Rasika S.;Nam, Joo-Won;Pauli, Guido F.
为探索原花青素（PAC）对牙本质的生物改性作用，开发新型牙科生物材料，本研究对9种葡萄籽提取物（GSE）中的B型PAC进行了植物化学和牙科学评价。在七个分离的二聚体（1-7）中，四个新化合物（2，3，5和6）涉及相对罕见的对映儿茶素或对映表儿茶素单体黄烷-3-醇单元。低温NMR分析进行了与间苯三酚和电子圆二色性，使明确的结构表征和立体化学分配。此外，一个已知的（8）和一个新的（9）B型三聚体进行了表征。差示C-13 NMR化学位移（Δ-Δ）用于确定9的绝对构型，相对于作为可能的组成亚基的二聚体1和2。与二聚体相比，三聚体显示出上级牙本质生物改性性能。二聚体1-7在其胶原酶抑制活性方面表现出显著差异，同时增强牙本质硬度。这表明，PAC的结构特征，如聚合度，相对和绝对构型对牙本质生物力学和生物稳定性的增强有不同的影响。由于牙本质的机械增强和对蛋白水解生物降解的抗性都是功能性和稳定的牙本质基质的基本特性，结构上密切相关的PAC提出了一个新的度量，牙本质生物改性潜力（DBMP），可以合理化这两个属性。
Aimed at exploring the dentin biomodification potential of proanthocyanidins (PACs) for the development of dental biomaterials, this study reports the phytochemical and dental evaluation of nine B-type PACs from grape seed extract (GSE). Out of seven isolated dimers (1-7), four new compounds (2, 3, 5, and 6) involved relatively rare ent-catechin or ent-epicatechin monomeric flavan-3-ol units. Low-temperature NMR analyses conducted along with phloroglucinolysis and electronic circular dichroism enabled unequivocal structural characterization and stereochemical assignment. Additionally, one known (8) and one new (9) B-type trimer were characterized. Differential C-13 NMR chemical shifts (Delta delta) were used to determine the absolute configuration of 9, relative to the dimers 1 and 2 as the possible constituent subunits. Compared to the dimers, the trimers showed superior dentin biomodification properties. The dimers, 1-7, exhibited pronounced differences in their collagenase inhibitory activity, while enhancing dentin stiffness comparably. This suggests that PAC structural features such as the degree of polymerization, relative and absolute configuration have a differential influence on enhancement of dentin biomechanical and biostability. As mechanical enhancement to dentin and resistance to proteolytic biodegradation are both essential properties functional and stable dentin substrate, the structurally closely related PACs suggest a new metric, the dentin biomodification potential (DBMP) that may rationalize both properties.