New galloylated flavanonols from the Australian plant Glochidion sumatranum.
New galloylated flavanonols from the Australian plant Glochidion sumatranum.
复制标题
DOI：
10.1055/s-0030-1250071
复制
发表时间：
2010-07
期刊：
影响因子：
2.7
通讯作者：
S. Yin;M. Sykes;Rohan A. Davis;T. Shelper;V. Avery;D. Camp;R. Quinn
中科院分区：
文献类型：
--
作者：
S. Yin;M. Sykes;Rohan A. Davis;T. Shelper;V. Avery;D. Camp;R. Quinn
从澳大利亚植物算盘子（Glochidion sumatranum）的CH（2）Cl（2）/MeOH提取物的生物测定引导的分级分离导致分离四个新的没食子酰化黄烷醇，（2 R，3R）-二氢杨梅素-4 '-O-（3 ''-O-甲基）-没食子酸酯（1），（2 R，3R）-二氢杨梅素-3 '-O-（3“-O-甲基）-没食子酸酯（2），（2 R，3R）-二氢杨梅素-4 ′-O-没食子酸酯（3），和（2 R，3R）-二氢杨梅素-3 ′-O-没食子酸酯（4），沿着已知化合物，（2 R，3R）-二氢杨梅素（5）。化合物1-5的结构经核磁共振和质谱分析确定，其绝对构型通过CD数据与文献值的比较来确定。化合物1/2和3/4是在NMR和LC-MS研究期间显示通过酯交换相互转化的两对结构异构体。该过程涉及没食子酰基部分在二氢黄酮醇骨架的C-3'和C-4'之间的分子内迁移。化合物1和3被鉴定为更稳定的异构体。化合物1、3和5对革兰氏阴性细菌铜绿假单胞菌和革兰氏阳性细菌金黄色葡萄球菌显示出弱活性。
Bioassay-guided fractionation of the CH(2)Cl(2)/MeOH extract from the Australian plant Glochidion sumatranum resulted in the isolation of four new galloylated flavanonols, (2R,3R)-dihydromyricetin-4'-O-(3''-O-methyl)-gallate (1), (2R,3R)-dihydromyricetin-3'-O-(3''-O-methyl)-gallate (2), (2R,3R)-dihydromyricetin-4'-O-gallate (3), and (2R,3R)-dihydromyricetin-3'-O-gallate (4), along with the known compound, (2R,3R)-dihydromyricetin (5). The structures of 1-5 were determined by NMR and MS analysis and their absolute configuration was elucidated by comparison of the CD data with literature values. Compounds 1/2 and 3/4 are two pairs of structural isomers that were shown to interconvert by transesterification during NMR and LC-MS studies. This process involved the intramolecular migration of the galloyl moieties between C-3' and C-4' of the flavanonol skeleton. Compounds 1 and 3 were identified as the more stable isomers. Compounds 1, 3, and 5 showed weak activity against the gram-negative bacterium Pseudomonas aeruginosa and the gram-positive bacterium Staphylococcus aureus.