Guanidine Alkaloids and Pictet−Spengler Adducts from Black Cohosh (Cimicifuga racemosa)

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• 作者：Tanja Gdecke ; David C. Lankin ; Dejan Nikolic ; Shao-Nong Chen ; Richard B. van Breemen ; Norman R. Farnsworth ; Guido F. Pauli
• 刊名：Journal of Natural Products
• 出版年：2009
• 出版时间：March 27, 2009
• 年：2009
• 卷：72
• 期：3
• 页码：433-437
• 全文大小：112K
• 年卷期：v.72,no.3(March 27, 2009)
• ISSN：1520-6025

文摘

As an extension of work on the recently discovered nitrogenous metabolites from Cimicifuga/Actaea species, three new guanidine alkaloids have been isolated and characterized from C. racemosa (syn. A. racemosa) roots. Of these, cyclo-cimipronidine (1) and cimipronidine methyl ester (2) are congeners of cimipronidine (3), whereas dopargine (5) is a derivative of dopamine. By employing NMR- and MS-guided chemodiversity profiling of a polar serotonergic (5-HT₇) fraction, the guanidine alkaloids were initially detected in a clinical extract of black cohosh and were isolated along with a congener of salsolinol 4, 5, and 3-hydroxytyrosol 3-O-glucoside (7). The structures of 1, 2, and 5 were confirmed by 1D and 2D NMR spectroscopy as well as LC-MS and HRMS spectroscopy. A plausible biosynthetic relationship may be inferred between the homoproline-analogue cimipronidines and the dopamine-derived Cimicifuga alkaloids. These strongly basic and frequently zwitterionic nitrogenous metabolites contribute considerable chemical diversity to the polar serotonergic fraction of black cohosh.