Diastereomeric Ellagitannin Isomers from Penthorum chinense

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• 作者：Manami Era ; Yosuke Matsuo ; Takuya Shii ; Yoshinori Saito ; Takashi Tanaka ; Zhi-Hong Jiang
• 刊名：Journal of Natural Products
• 出版年：2015
• 出版时间：August 28, 2015
• 年：2015
• 卷：78
• 期：8
• 页码：2104-2109
• 全文大小：262K
• ISSN：1520-6025

文摘

From the dried stem of Penthorum chinense (Penthoraceae), 1-O-galloyl-4,6-(R)-hexahydroxydiphenoyl (HHDP)-尾-d-glucose and 2鈥?4鈥?6鈥?trihydroxyacetophenone 4鈥?O-[4,6-(R)-HHDP]-尾-d-glucoside were isolated together with their (S)-HHDP isomers. Ellagitannins with a 4,6-(S)-HHDP-glucose moiety are widely distributed in the plant kingdom; however, 4,6-(R)-HHDP glucoses are extremely rare. Lowest-energy conformers of 1-O-galloyl-(S)- and (R)-HHDP-glucopyranoses were derived by density functional theory calculations, and the calculated ¹H and ¹³C NMR chemical shifts and the ¹H鈥?sup>1H coupling constants were in agreement with the experimental values. The results revealed a conformational difference of the diastereomeric macrocyclic ester rings. In addition, a new compound, 1鈥?3鈥?5鈥?trihydroxybenzene 1鈥?O-[4,6-(S)-HHDP]-尾-d-glucoside, was also isolated.