No abstract

Recebido em 31/12/09; aceito em 15/6/10; publicado na web em 22/9/10 Chemical COMPOUNDS OF LEAVES FROM SENNA SPECTABILIS (DC) IRWIN & BARNEBY var. excelsa (SCHRAD.) IRWIN & BARNEBY. From leaves of Senna spectabilis var. excelsa were isolated caffeine, the triterpenes lupeol, α-amyrin, β-amyrin, cycloeucalenol, friedelin and ursolic, oleanolic and betulinic acids, besides the steroids sitosterol and stigmasterol and their respective glucosides. The structures of these compounds were established by spectroscopic analysis including two-dimensional NMR methods and comparison with published spectral data. This paper deals with the first report of these compounds in S. spectabilis var. excelsa.Keywords: Senna spectabilis var. excelsa; triterpene; caffeine. INTRODUÇÃONo Brasil ocorrem 200 gêneros e 1.500 espécies da família Fabaceae. Presente na maioria dos ecossistemas brasileiros, é relatada como a família botânica mais bem representada na caatinga, com 293 espécies em 77 gêneros, constituindo aproximadamente um terço de todos os vegetais deste bioma. 3 Atividade laxativa comparável ao padrão bisacodil (princípio ativo da Lacto-purga ® ) e anti-inflamatória similar ao diclofenaco de sódio foi observada para o extrato das folhas de Senna macranthera. 4 Outras diversas atividades relevantes como antimicrobiana, analgésica, antiparasitária, inseticida, antitumoral e hepatoprotetora são comprovadas para várias espécies de Senna. O estudo químico das folhas de S. spectabilis var. excelsa (Schrad) levou ao isolamento e identificação de oito triterpenos pentacíclicos: quatro na forma pura (ácido betulínico, lupeol, cicloeucalenol, friedelina) e quatro como misturas (α-amirina, β-amirina, ácido ursólico e oleanólico). Apesar de serem substâncias conhecidas, este é o primeiro relato dessa classe química na espécie Senna spectabilis var excelsa. Também foram identificadas duas misturas de esteroides (estigmasterol e β-sitosterol) na forma livre e glicosilada, além de um alcaloide (cafeína) ainda inédito no gênero Senna. RESULTADOS E DISCUSSÃOO extrato etanólico das folhas de S. spectabilis var. excelsa (Schrad) através de técnicas cromatográficas levou ao isolamento dos triterpenos pentacíclicos ácido betulínico (1), lupeol (2), α-amirina e β-amirina (3 e 4), da fração não alcaloídica (FNA) (m = 13,5 g). A identificação foi possível após a análise dos dados espectrais de RMN 1 H, RMN 13 C e DEPT 135 e comparação com dados da literatura. A comparação dos dados obtidos com a literatura permitiu identificar o composto 1 como um triterpeno pentacíclico de esqueleto lupano denominado ácido betulínico. O tratamento cromatográfico da fração diclorometânica levou ao isolamento e identificação de (5), (6) (7)

Abstract:The aim of this study was to evaluate the in vitro antioxidant effects of 12-[(2R,5R,6R)-5-hydroxy-6-methylpiperidin-2-yl]dodecan-2-one (iso-6-cassine; ISO) and the anticonvulsant effects of ISO on pilocarpine-induced seizures in rats. Wistar rats were treated with 0.9% saline (i.p., control group), pilocarpine (400 mg/kg, i.p., pilocarpine group), and the association of ISO (1.0 mg/kg, i.p.) plus pilocarpine (400 mg/kg, i.p.), 30 min after administration of ISO (ISO plus pilocarpine group). After the treatments all groups were observed for 1h. The antioxidant effect of ISO on the pilocarpine model was assessed by determining the activity of glutathione peroxidase (GPx), glutathione-Stransferase (GST) and catalase (CAT) as well as the levels of reactive species (RS) and lipid peroxidation (LP). In vitro, ISO (5 μM) reduced RS and LP. ISO (1.0 mg/kg) and abolished seizures and death induced by pilocarpine in rats. ISO protected against the increase in the RS and LP levels, GST activity as well as the inhibition of GPx activity caused by pilocarpine. In addition, ISO increased the catalase activity in hippocampus of seized rats. In conclusion, the dta suggest that ISO can present anticonvulsant and antioxidant properties in the pilocarpine model of seizures in rats.

No abstract

This study was aimed at investigating the anticonvulsant activity of lipoic acid (LA) against pilocarpine-induced seizures as well as the effects of this metabolic antioxidant on the hippocampal extracellular concentrations of amino acid neurotransmitters glutamate, aspartate, glycine and glutamate and γ-aminobutyric acid (GABA). In vivo microdialysis demonstrated that an intraperitoneal administration of pilocarpine induced a pronounced increment of hippocampal glutamate and aspartate concentrations, whereas no significant change was observed in the levels of glycine or GABA. LA (10, 20 or 30 mg/kg) pretreatment completely blocked pilocarpine-evoked increases in extracellular glutamate and aspartate concentrations. Significant reductions in hippocampal GABA and glycine concentrations were also observed although not as pronounced as those shown by glutamate and aspartate. Based on the finding that LA protected rats against pilocarpine-induced seizures, it could be suggested that the reduction in inhibitory amino acid neurotransmitters levels was comparatively minor and offset by a more pronounced reduction in glutamate and aspartate extracellular concentrations. Therefore, the fact that LA could drastically reduce pilocarpine-induced increases in glutamate and aspartate should account, at least partly, for its anticonvulsant activity observed in pilocarpine-induced seizure in rats.