RESUMO
Thirteen Psychotria alkaloids were evaluated regarding their interactions with acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and monoamine oxidases A and B (MAO-A and MAO-B), which are enzymatic targets related with neurodegenerative diseases. Two quaternary ß-carboline alkaloids, prunifoleine and 14-oxoprunifoleine, inhibited AChE, BChE and MAO-A with IC(50) values corresponding to 10 and 3.39 µM for AChE, 100 and 11 µM for BChE, and 7.41 and 6.92 µM for MAO-A, respectively. Both compounds seem to behave as noncompetitive AChE inhibitors and time-dependent MAO-A inhibitors. In addition, the monoterpene indole alkaloids (MIAs) angustine, vallesiachotamine lactone, E-vallesiachotamine and Z-vallesiachotamine inhibited BChE and MAO-A with IC(50) values ranging from 3.47 to 14 µM for BChE inhibition and from 0.85 to 2.14 µM for MAO-A inhibition. Among the tested MIAs, angustine is able to inhibit MAO-A in a reversible and competitive way while the three vallesiachotamine-like alkaloids display a time-dependent inhibition on this target. Docking calculations were performed in order to understand the binding mode between the most active ligands and the selected targets. Taken together, our findings established molecular details of AChE, BChE and MAO-A inhibition by quaternary ß-carboline alkaloids and MIAs from Psychotria, suggesting these secondary metabolites are scaffolds for the development of multifunctional compounds against neurodegeneration.
Assuntos
Alcaloides/química , Alcaloides/farmacologia , Inibidores da Colinesterase/química , Inibidores da Colinesterase/farmacologia , Inibidores da Monoaminoxidase/química , Inibidores da Monoaminoxidase/farmacologia , Psychotria/química , Colinesterases/metabolismo , Cinética , Modelos Moleculares , Monoaminoxidase/metabolismoRESUMO
Plants belonging to the Lippia genus have been widely used in ethnobotany throughout South and Central America and in tropical Africa as foods, medicines, sweeteners and in beverage flavouring. Various taxonomic problems involving some genera from Verbenaceae, including Lippia, have been reported. In this study, the metabolite profiling of fifteen extracts of various organs of six Lippia species was performed and compared using UHPLC-PDA-TOF-MS. Fourteen phenolic compounds that were previously isolated from L. salviaefolia Cham. and L. lupulina Cham. were used as references. The annotation of the remaining LC peaks was based on concomitant online high mass accuracy measurements and subsequent molecular formula assignments following these different steps: (i) elimination of non-coherent putative molecular formulae by heuristic filtering, (ii) verification of the occurrence of remaining molecular formulae in databases, (iii) cross search with reported compounds in the Lippia genus, (iv) match with reported UV spectra, (v) estimation of the chromatographic retention behaviour based on the log P parameter of reference compounds. This strategy is generic and time-saving, avoids isolation/purification procedures, enables an efficient LC peak annotation of most of the studied compounds and is well adapted for plant chemotaxonomic studies. Within this study, the interconversion of four flavanone glucoside isomers was additionally highlighted by analytical HPLC isolation and immediate analysis using fast UHPLC gradients. Dereplication results and hierarchical data analysis demonstrated that L. salviaefolia, L. balansae, L. velutina and L. sidoides displayed significant chemical similarities, while the compositions of L. lasiocalicyna and L. lupulina differed substantially.
Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Lippia/química , Espectrometria de Massas/métodos , Extratos Vegetais/química , Análise por Conglomerados , Flavanonas/análise , Flavanonas/química , Lippia/metabolismo , Metaboloma , Metabolômica/métodosRESUMO
Extracts from several plants of the family Bignoniaceae from Panama were submitted to a rapid DPPH TLC test for the detection of radical-scavenging activity. The MeOH extract of the stems of Jacaranda caucana, a tree that grows from Costa Rica to Colombia, was selected due to its interesting activity and the lack of phytochemical studies on the polar extract. This extract was partitioned between ethyl acetate, butanol, and water. The EtOAc fraction afforded two new phenylethanoid glycosides (1, 2), along with protocatechuic acid, acteoside, and jionoside D. Further purifications yielded isoacteoside and martynoside. The BuOH fraction afforded a new rhamnosyl derivative of sisymbrifolin (8), a neolignan. The structures were determined by means of spectrometric methods, including 1D and 2D NMR experiments and MS analysis.
Assuntos
Antioxidantes/isolamento & purificação , Antioxidantes/farmacologia , Bignoniaceae/química , Sequestradores de Radicais Livres/isolamento & purificação , Sequestradores de Radicais Livres/farmacologia , Glucosídeos/isolamento & purificação , Glucosídeos/farmacologia , Glicosídeos/isolamento & purificação , Glicosídeos/farmacologia , Lignanas/isolamento & purificação , Lignanas/farmacologia , Fenóis/isolamento & purificação , Fenóis/farmacologia , Plantas Medicinais/química , Antioxidantes/química , Sequestradores de Radicais Livres/química , Glucosídeos/química , Glicosídeos/química , Lignanas/química , Estrutura Molecular , Ressonância Magnética Nuclear Biomolecular , Panamá , Fenóis/química , Caules de Planta/químicaRESUMO
Chemical investigation of the methanol extract from the leaves of Arrabidaea patellifera, a Bignoniaceae from Panama, afforded mangiferin, isomangiferin, and six new derivatives (3'-O-p-hydroxybenzoylmangiferin, 3'-O-trans-coumaroylmangiferin, 6'-O-trans-coumaroylmangiferin, 3'-O-trans-cinnamoylmangiferin, 3'-O-trans-caffeoylmangiferin, and 3'-O-benzoylmangiferin). All these compounds had antioxidant and radical-scavenging activities, and four of them were relatively active in vitro against Plasmodium falciparum. The structures were determined by spectrometric and chemical methods, including 1D and 2D NMR experiments and MS analysis.