Constituintes químicos e estudos toxicológicos do óleo essencial extraído das folhas de Citrus limon Burn (Rutaceae) / Chemical constituents and toxicological studies of the essential oil extracted from Citrus limon Burn (Rutaceae)

A caracterização química do óleo essencial de folhas de Citrus limon (Rutaceae) resultou na identificação de mistura de monoterpenos (limoneno, linalol, cis-óxido de limoneno, trans-óxido de limoneno, citronelal, neral, geranial, nerol e acetato de geranil). As estruturas dos compostos do óleo essencial foram identificadas por GC/MS, por comparação com dados da literatura. Os efeitos da administração crônica oral do óleo essencial de folhas de Citrus limon foram investigados sobre parâmetros bioquímicos e hematológicos em camundongos Swiss machos. Os animais (n = 10/grupo) foram tratados por via oral diariamente durante 30 dias com óleo essencial de folhas de Citrus limon, nas doses de 50, 100 ou 150 mg kg-1 de massa corporal e os parâmetros bioquímicos e hematológicos avaliados. O tratamento não causou nenhuma morte ou toxicidade nos animais. A administração do óleo essencial não alterou os parâmetros bioquímicos e hematológicos e a massa dos órgãos, exceto por diminuição de 21 e 11% em uréia e ácido úrico, respectivamente, e 9%, nos níveis plasmáticos de aspartato transaminase (AST). Para os parâmetros hematológicos, houve pequenas mudanças nas contagens de neutrófilos, linfócitos, eosinófilos e monócitos, mas estes não foram diferentes dos valores de referência. Além disso, houve diminuição significativa nos triglicerídeos detectado nos animais tratados com dose de 150 mg kg-1 de óleo essencial. Em conclusão, a administração crônica de óleo essencial não induziu nenhum efeito de risco na maioria dos parâmetros bioquímicos e hematológicos estudados em camundongos Swiss machos. No entanto, a diminuição dos níveis de uréia e ácido úrico em doses elevadas, sugere um possível efeito de insuficiência renal e aumento no teor de AST, sugerindo possível sobrecarga hepática que deve ser investigada com mais detalhe.

The chemical characterization of the essential oil of Citrus limon (Rutaceae) leaves resulted in the identification of a mixture of monoterpenes (limonene, linalool, cis-limonene-oxide, trans-limonene-oxide, citronellal, neral, geranial, nerol e geranyl acetate). The structures of the compounds of essential oil were identified by GC/MS by comparison with literature data. The effects of the chronic oral administration of the essential oil of Citrus limon leaves were investigated on biochemical and hematological parameters in male adult Swiss mice. These animals (n=10/group) were orally treated daily for 30 days with essential oil of Citrus limon leaves with doses of 50, 100 or 150 mg kg-1 body weight and the biochemical and hematological parameters were evaluated. The treatment did not cause any deaths or toxicity in the animals. The administration of essential oil did not change biochemical and hematological parameters and organ weight, except for decreases of 21 and 11% in blood urea nitrogen and uric acid respectively, and 9%, in aspatate transaminase (AST) plasma level. For the hematological parameters, there were slight changes in which neutrophil, lymphocytes, eosinophils and monocyte counts were not different from the reference values. In addition, with respect to serum triglyceride a significant decrease was detected in mice treated with a dose of 150 mg kg-1 of essential oil from Citrus limon. In conclusion, the chronic administration of essential oil of Citrus limon leaves did not induce any harzadous effects on most of the biochemical and hematological parameters studied in male adult Swiss mice. However, the decrease in the levels in blood urea nitrogen and uric acid in high doses, suggests a possible effect of renal insufficiency and an increase in AST content, which in its turn, suggests a possible hepatic overload which should be investigated in more details.

Acetylcholinesterase inhibition by somes promising Brazilian medicinal plants.

A microplate assay and a thin-layer chromatography (TLC) "in situ" assay based on the Ellman assay was used to screen for acetylcholinesterase inhibitors from ethyl acetate and methanol extracts of Brazilian medicinal plants of families that, according to the literature, have traditional uses that might be connected with acetylcholinesterase inhibition. Eighteen species belonging to Convolvulaceae, Crassulaceae, Euphorbiaceae, Leguminosae, Malvaceae, Moraceae, Nyctaginaceae and Rutaceae families were tested. The most active plants were Ipomoea asarifolia (IC50 = 0.12 mg/mL), Jatropha curcas (IC50 = 0.25 mg/mL), Jatropha gossypiifolia (IC50 = 0.05 mg/mL), Kalanchoe brasiliensis (IC50 = 0.16 mg/mL) and Senna alata (IC50 = 0.08 mg/mL). The most promising extracts were the Jatropha gossypiifolia and Senna alata species assuming there were compounds with a similar activity to galanthamine, which should contain about 1% of an active compound, or if present at lower levels even more active compounds than galanthamine (IC50 = 0.37 x 10-3 mg/mL) should be present.

Lipoic acid effects on glutamate and taurine concentrations in rat hippocampus after pilocarpine-induced seizures / Efeitos do ácido lipóico nas concentrações de glutamato e taurina no hipocampo de ratos após convulsões induzidas por pilocarpina

Pilocarpine-induced seizures can be mediated by increases in oxidative stress and by cerebral amino acid changes. The present research suggests that antioxidant compounds may afford some level of neuroprotection against the neurotoxicity of seizures in cellular level. The objective of the present study was to evaluate the lipoic acid (LA) effects in glutamate and taurine contents in rat hippocampus after pilocarpine-induced seizures. Wistar rats were treated intraperitoneally (i.p.) with 0.9 percent saline (Control), pilocarpine (400 mg/kg, Pilocarpine), LA (10 mg/kg, LA), and the association of LA (10 mg/kg) plus pilocarpine (400 mg/kg), that was injected 30 min before of administration of LA (LA plus pilocarpine). Animals were observed during 24 h. The amino acid concentrations were measured using high-performance liquid chromatograph (HPLC). In pilocarpine group, it was observed a significant increase in glutamate content (37 percent) and a decrease in taurine level (18 percent) in rat hippocampus, when compared to control group. Antioxidant pretreatment significantly reduced the glutamate level (28 percent) and augmented taurine content (32 percent) in rat hippocampus, when compared to pilocarpine group. Our findings strongly support amino acid changes in hippocampus during seizures induced by pilocarpine, and suggest that glutamate-induced brain damage plays a crucial role in pathogenic consequences of seizures, and imply that strong protective effect could be achieved using lipoic acid through the release or decrease in metabolization rate of taurine amino acid during seizures.

As convulsões induzidas pela pilocarpina podem ser mediadas através do aumento do estresse oxidativo cerebral e das alterações na concentração dos aminoácidos. O presente estudo sugere que compostos antioxidantes podem produzir neuroproteção contra a neurotoxicidade em nível celular causada pelas convulsões. O objetivo deste estudo foi avaliar os efeitos do ácido lipóico (AL) no conteúdo de glutamato e taurina no hipocampo de ratos durante convulsões induzidas por pilocarpina. Ratos Wistar foram tratados por via intraperitoneal com solução salina 0,9 por cento (controle), pilocarpina (400 mg/kg, pilocarpina), AL (10 mg/kg) e com a associação de AL (10 mg/kg); 30 min após com pilocarpina (400 mg/kg), que foi injetada 30 min após a administração de AL (AL + pilocarpina). Os animais foram observados durante 24 horas. As concentrações de aminoácidos foram determinadas por HPLC. No hipocampo dos ratos do grupo pilocarpina foi observado um aumento significativo de 37 por cento na concentração de glutamato e uma diminuição de 18 por cento no nível de taurina, quando comparado ao grupo controle. O pré-tratamento com o antioxidante reduziu significativamente o nível de glutamato em 28 por cento e aumentou em 32 por cento os níveis de taurina no hipocampo dos ratos, quando comparado ao grupo pilocarpina. Nossos resultados sugerem que ocorrem alterações na concentração dos aminoácidos no hipocampo de ratos durante as convulsões induzidas por pilocarpina, e que o glutamato pode desempenhar um papel crucial na fisiopatologia das convulsões, e que o efeito protetor poderia ser alcançado com pré-tratamento com ácido lipóico, provavelmente pelo aumento da liberação ou redução da taxa de metabolização dos aminoácidos durante as convulsões.

Effects of immature cashew nut-shell liquid (Anacardium occidentale) against oxidative damage in Saccharomyces cerevisiae and inhibition of acetylcholinesterase activity.

The cashew tree (Anacardium occidentale) represents one of the major cheapest sources of non-isoprenoid phenolic lipids, which have a variety of biological properties: they can act as molluscicides, insecticides, fungicides, have anti-termite properties, have medicinal applications, and demonstrate antioxidant activity in vitro. Immature cashew nut-shell liquid (iCNSL) is a unique natural source of unsaturated long-chain phenols. Their use has stimulated much research in order to prepare drug analogues for application in several fields. The objective of the present study was to determine whether iCNSL has antioxidant properties when used in strains of the yeast Saccharomyces cerevisiae and to measure the inhibitory activity of acetylcholinesterase. The constituents were identified using thin-layer chromatography, gas chromatography-mass spectrometry, Fourier transform infrared spectroscopy, and (1)H and (13)C nuclear magnetic resonance. The iCNSL contains anacardic acid, cardanol, cardol, and 2-methyl cardol. Immature cashew nut oil contains triacylglycerols, fatty acids, alkyl-substituted phenols, and cholesterol. The main constituents of the free fatty acids are palmitic (C(16:0)) and oleic acid (C(18:1)). iCNSL has excellent protective activities in strains of S. cerevisiae against oxidative damage induced by hydrogen peroxide and inhibits acetylcholinesterase activity. iCNSL may have an important role in protecting DNA against damage induced by reactive oxygen species, as well as hydrogen peroxide, generated by intra- and extracellular mechanisms.