Spirocyclization reactions and antiproliferative activity of indole phytoalexins 1-methoxybrassinin and its 1-substituted derivatives
作者:Mariana Budovská、Martina Bago Pilátová、Viera Tischlerová、Ján Mojžiš
DOI:10.24820/ark.5550190.p009.958
日期:——
The effect of the reaction temperature and the solvent on the diastereoselectivity of the spirocyclization of 1-methoxybrassinin leading to 1-methoxyspirobrassinol methyl ether was studied. 1-Acyl derivatives of 1-methoxyspirobrassinol and 1-methoxyspirobrassinol methyl ether were prepared by the bromine-mediated spirocyclization reactions of derivatives of brassinin bearing an acyl group on the indole
作者:Budovská, Mariana、Pilátová, Martina Bago、Tischlerová, Viera、Mojžiš, Ján
DOI:10.3998/ark.5550190.p009.958
日期:——
The biosynthetic pathway of crucifer phytoalexins and phytoanticipins: De novo incorporation of deuterated tryptophans and quasi-natural compounds
作者:M. Soledade C. Pedras、Denis P. Okinyo-Owiti、Ken Thoms、Adewale M. Adio
DOI:10.1016/j.phytochem.2009.05.015
日期:2009.6
Although several biosynthetic intermediates in pathways to cruciferous phytoalexins and phytoanticipins are common, questions regarding the introduction of substituents at N-1 of the indole moiety remain unanswered. Toward this end, we investigated the potential incorporations of several perdeuterated D- and L-1'-methoxytryptophans, D- and L-tryptophans and other indol-3-yl derivatives into pertinent phytoalexins and phytoanticipins (indolyl glucosinolates) produced in rutabaga (Brassica napus L. ssp. rapifera) roots. In addition, we probed the potential transformations of quasi-natural compounds, these being analogues of biosynthetic intermediates that might lead to "quasi-natural" products (products similar to natural products but not produced under natural conditions). No detectable incorporations of deuterium labeled 1'-methoxytryptophans into phytoalexins or glucobrassicin were detected. L-tryptophan was incorporated in a higher percentage than D-tryptophan into both phytoalexins and phytoanticipins. However, in the case of the phytoalexin rapalexin A, both D- and L-tryptophan were incorporated to the same extent. Furthermore, the transformations of both 1'-methylindolyl-3'-acetaldoxime and 1'-methylindolyl-3'-acetothiohydroxamic acid (quasi-natural products) into 1'-methylglucobrassicin but not into phytoalexins suggested that post-aldoxime enzymes in the biosynthetic pathway of indolyl glucosinolates are not substrate-specific. Hence, it would appear that the 1-methoxy substituent of the indole moiety is introduced downstream from tryptophan and that the post-aldoxime enzymes of the glucosinolate pathway are different from the enzymes of the phytoalexin pathway. A higher substrate specificity of some enzymes of the phytoalexin pathway might explain the relatively lower structural diversity among phytoalexins than among glucosinolates. (C) 2009 Elsevier Ltd. All rights reserved.