(±)-Homocrepidine A, a Pair of Anti-inflammatory Enantiomeric Octahydroindolizine Alkaloid Dimers from Dendrobium crepidatum

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• 作者：Yang Hu ; Chaofeng Zhang ; Xin Zhao ; Yue Wang ; Deqiang Feng ; Mian Zhang ; Haifeng Xie
• 刊名：Journal of Natural Products
• 出版年：2016
• 出版时间：January 22, 2016
• 年：2016
• 卷：79
• 期：1
• 页码：252-256
• 全文大小：342K
• ISSN：1520-6025

文摘

A pair of racemic indolizidine enantiomers, (±)-homocrepidine A (1), and a piperidine derivative, homocrepidine B (2), were isolated from Dendrobium crepidatum along with the known alkaloid crepidine (3). The racemic mixture of 1 was separated into a pair of enantiomers, (+)-1 and (?)-1, by HPLC using a chiral chromatographic substrate, which represents the first successful example of resolving indolizidine racemic mixtures. The absolute configurations of (+)-1 and (?)-1 were assigned from single-crystal X-ray diffraction data. The evaluation of anti-inflammatory activity with LPS-induced RAW 264.7 macrophages revealed that (+)-1 strongly inhibited the production of nitric oxide (IC₅₀, 3.6 μM) and significantly decreased the expression of inducible nitric oxide synthase, while (?)-1 and (±)-1 only had moderate inhibitory effects (IC₅₀, 22.8 and 14.7 μM). Compound 2 showed moderate anti-inflammatory activity (IC₅₀, 27.6 μM).