HR-MALDI-MS Imaging Assisted Screening of 尾-Carboline Alkaloids Discovered from Mycena metata

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• 作者：Robert J. R. Jaeger ; Marc Lamsh枚ft ; Sebastian Gottfried ; Michael Spiteller ; Peter Spiteller
• 刊名：Journal of Natural Products
• 出版年：2013
• 出版时间：February 22, 2013
• 年：2013
• 卷：76
• 期：2
• 页码：127-134
• 全文大小：381K
• 年卷期：v.76,no.2(February 22, 2013)
• ISSN：1520-6025

文摘

Fruiting bodies of Mycena metata were screened for the presence of new secondary metabolites by means of HPLC-UV, LC-HR-ESIMS, and high-resolution matrix-assisted laser desorption/ionization mass spectrometry imaging (HR-MALDI-MS imaging). Thus, a new 尾-carboline alkaloid, 6-hydroxymetatacarboline D (1d), was isolated from fruiting bodies of M. metata. 6-Hydroxymetatacarboline D consists of a highly substituted 尾-carboline skeleton, which is likely to be derived biosynthetically from l-tryptophan, 2-oxoglutaric acid, l-threonine, and l-proline. The structure of the alkaloid was established by 2D NMR spectroscopic methods and HR-ESIMS. Moreover, by extensive application of LC-HR-ESIMS, LC-HR-ESIMS/MS, and LC-HR-ESIMS³ techniques we were able to elucidate the structures of a number of accompanying 尾-carboline alkaloids, 1a鈥?b>1c, 1e鈥?b>1i, and 2a鈥?b>2g, structurally closely related to 6-hydroxymetatacarboline D, which are present in M. metata in minor amounts. The absolute configuration of the stereogenic centers of the 尾-carboline alkaloids was determined by GC-MS comparison with authentic synthetic samples after hydrolytic cleavage and derivatization of the resulting amino acids.