RESUMO
Plumbago scandens L. is a Brazilian tropical/subtropical species that occurs along the coast. Chemically it is mainly represented by naphthoquinones, flavonoids, terpenoids and steroids. The aim of the present work is to study quantitative changes in the root metabolic production of Plumbago scandens during different physiologic developmental stages relative to floration. The results indicated the presence of four substances in the extracts: plumbagin, epi-isoshinanolone, palmitic acid and sitosterol, independent on developmental stage. The naphthoquinone plumbagin has always showed to be the major component of all extracts. Naphthoquinones exhibited their highest content during floration, while the content of the two others components decreased during this stage, revealing an inverse profile. The chemical composition changed depending on the plant requirements.
Plumbago scandens L. é uma espécie brasileira tropical/subtropical que ocorre ao longo da costa. Quimicamente, é principalmente representada por naftoquinonas, flavonóides, terpenóides e esteróides. objetivo do presente trabalho é estudar mudanças quantitativas da produção metabólica nas raízes de Plumbago scandens durante diferentes estágios de desenvolvimento fisiológico, relativos à floração. Os resultados indicaram a presença de quatro substâncias nos extratos: plumbagina, epi-isoshinanolona, ácido palmítico e sitosterol, independente do estágio de desenvolvimento. A naftoquinona plumbagina tem sempre mostrado ser o componente majoritário de todos os extratos. Naftoquinonas exibiram seus maiores conteúdos durante a floração, enquanto o conteúdo dos dois outros componentes decresceu durante este estágio, revelando um perfil inverso. A composição química modificou dependendo das necessidades da planta.
Assuntos
Naftoquinonas/química , Ácido Palmítico/química , Raízes de Plantas/química , Plumbaginaceae/química , Sitosteroides/química , Tetra-Hidronaftalenos/química , Cromatografia Gasosa , Naftoquinonas/metabolismo , Ácido Palmítico/metabolismo , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Plumbaginaceae/crescimento & desenvolvimento , Plumbaginaceae/metabolismo , Sitosteroides/metabolismo , Tetra-Hidronaftalenos/metabolismoRESUMO
A large number of proteins on the eukaryotic cell surface that play an important role in cellular metabolism are covalently modified with fatty acids like palmitic and myristic acids. While some of these proteins have transmembrane spanning segments, many others do not. Early hypothesis was that this co or posttranslational modification helped in membrane-association and the fatty acyl chain provided a stable membrane anchor. We have investigated the structure of peptides with these modifications and also their interaction with membranes. Our results indicate that the fatty acylated peptides, especially when the peptide segment is not hydrophobic, do not have strong affinity for membranes. The recent observations about the dynamic nature of fatty acid acylation as well as the importance of protein-protein interactions for function in fatty-acylated proteins suggest that membrane-association may involve factors other than only the fatty acid, either myristic or palmitic. Revised models depicting the possible role of fatty acids in modulating protein-protein interaction and their dynamics is presented.