Department of Chemistry and Biochemistry, University of California, Santa Cruz, Santa Cruz, California 95064, USA.
J Org Chem. 2011 Aug 5;76(15):6201-8. doi: 10.1021/jo2009593. Epub 2011 Jun 29.
Prenylated indole alkaloids are a diverse group of fungal secondary metabolites and represent an important biosynthetic class. In this study we have identified new halogenated prenyl-indole alkaloids from an invertebrate-derived Malbranchea graminicola strain. Using direct analysis in real time (DART) mass spectrometry, these compounds were initially detected from hyphae of the fungus grown on agar plates, without the need for any organic extraction. Subsequently, the metabolites were isolated from liquid culture in artificial seawater. The structures of two novel chlorinated metabolites, named (-)-spiromalbramide and (+)-isomalbrancheamide B, provide additional insights into the assembly of the malbrancheamide compound family. Remarkably, two new brominated analogues, (+)-malbrancheamide C and (+)-isomalbrancheamide C, were produced by enriching the growth medium with bromine salts.
前言吲哚生物碱是一类多样的真菌次生代谢产物，代表了一个重要的生物合成类别。在这项研究中，我们从一种来源于无脊椎动物的 Malbranchea graminicola 菌株中鉴定出了新的卤化前吲哚生物碱。使用实时直接分析（DART）质谱法，这些化合物最初是从在琼脂平板上生长的真菌菌丝中检测到的，而无需任何有机提取。随后，这些代谢物从人工海水中的液体培养中分离出来。两种新型氯化代谢物，命名为（-）-螺旋马拉巴酰胺和（+）-异马拉巴酰胺 B 的结构，为马拉巴酰胺化合物家族的组装提供了更多的见解。值得注意的是，通过在生长培养基中添加溴盐，富集了两种新的溴化类似物（+）-马拉巴酰胺 C 和（+）-异马拉巴酰胺 C。
