Ensaios pré-clínicos em ratos tratados com 1, 3-diestearil-2-oleilglicerol, constituinte isolado de Platonia insignis / Pre clinical trials in rats treated with 1, 3 -distearoyl-2-oleoylglycerol (TG1) constituent isolated from Platonia insignis

Introdução: Avaliou-se a toxicidade aguda de 1,3-diestearil-2-oleil-glicerol (TG1), composto obtido de Platonia insignis Mart. (bacurizeiro), após administração oral em ratos Wistar. Métodos: A toxicidade aguda foi analisada através dos parâmetros hematológicos e bioquímicos. A análise de citotoxicidade in vitro foi feita pelo método do sal 3-(4,5-dimetil-2-tiazol)-2,5-difenil-2-H-brometo de tetrazolium (MTT). Os tecidos cerebrais e hepáticos foram avaliados histopatologicamente. Resultados: O tratamento agudo com TG1(dose de 30 mg kg -1) não produziu alterações hematológicas e histopatológicas nas áreas cerebrais e hepáticas. A redução dos níveis das enzimas transaminase (AST) e fosfatase alcalina (ALKP) pode sugerir proteção hepática. As análises bioquímicas da aspartato aminotransferase, ALKP e do ácido úrico apresentaram seus níveis reduzidos, conferindo preservação dos rins e fígado dos animais (p<0,05). TG1 não revelou potencial citotóxico pelo método MTT. Conclusão: O tratamento com TG1 não produz alterações hematológicas, bioquímicas, histopatológicas cerebrais e hepáticas em ratos o que caracteriza uma baixa toxicidade.

Introduction: The aim of this study was to assess the acute toxicity of 1,3-distearoyl-2-oleoylglycerol (TG1), a compound isolated from Platonia insignis Mart. (bacurizeiro). Methods: The acute toxicity was analyzed by biochemical and hematological parameters. The cytotoxic study was conducted by the MTT method. The histopathological study was conducted in brain and liver tissues. Results: Acute treatment with TG1 (dose of 30 mg. kg -1) did not change the general behavior pattern of rats and not result in hematological and histological changes in the liver. The reduced levels of transaminase and alkaline phosphatase (ALKP) enzymes may suggest even certain liver protection. The biochemical analyzes demonstrated low levels of aspartate aminotransferase, ALKP and uric acid, providing preservation of kidneys and livers of animals (p<0.05). TG1 this study did not reveal cytotoxic potential by MTT method. Conclusion: These results indicate that treatment with TG1 not produce hematological, biochemical and histopathological alterations in rats suggesting low toxicity

Efeito do tratamento agudo do óleo essencial de Citrus sinensis (L) Osbeck na aquisição da memória espacial de ratos avaliada no labirinto aquático de Morris / Effect of oral treatment with essential oil of Citrus sinensis (L) Osbeck in the retention of spatial memory in rats evaluated in the Morris water maze

A Doença de Alzheimer está relacionada a prejuízos na aquisição e retenção da memória, processos que podem ser estudados no laboratório por meio de modelos animais, entre eles o labirinto aquático de Morris, que avalia a memória espacial em ratos. Estudos sobre as propriedades biológicas do gênero Citrus destacam atividades importantes como antioxidantes e anticolinesterásica. O objetivo desse trabalho é avaliar os efeitos do tratamento agudo com o óleo essencial de folhas (OEF) de Citrus sinensis (L.) Osbeck no processo de aquisição da memória espacial em ratos Wistar, utilizando o paradigma do labirinto aquático de Morris. O óleo essencial de Citrus sinensis possui em sua composição principalmente compostos da classe dos monoterpenos, como o limoneno (20,14%), citronelol (30,42%) e o geranial (31,42%). Os animais foram tratados previamente com doses do óleo essencial (OE) de C. sinensis (L.) Osbeck de 50, 100 e 200 mg/kg e realizados testes de campo aberto e do labirinto aquático de Morris. A aquisição da memória espacial é avaliada pelo tempo que o animal leva para localizar a plataforma depois de ter sido treinado. Nos resultados do campo aberto foi demonstrado que os animais não apresentam estímulo motor quando tratados com o óleo essencial de Citrus sinensis e os resultados do labirinto aquático foram significativamente menores na latência para encontrarem a plataforma submersa do que o grupo controle negativo [p<0,01] indicando uma capacidade de memória maior nos animais tratados, mas que devem ser reforçados por outros testes de memória preconizado na literatura.

Alzheimer?s disease is related to damage in memory acquisition and retention that can be studied in the laboratory through animal studies, including the Morris water maze, which assesses the spatial memory in rats. The Citrus has many studies on biological activities that are important for memory function as antioxidants and anticholinesterase. The objective of this study is to evaluate the effects of acute treatment with the essential oil of leaves (EOL) from Citrus sinensis (L.) Osbeck in the acquisition of spatial memory in rats, using the paradigm of the Morris water maze. The essential oil of Citrus sinensis has in composition mainly composed of the class of monoterpenes such as limonene (24.14%), citronellol (30.42%) and geranial (31,42%). The animals were previously untreated with doses of essential oil (EO) of Citrus sinensis 50, 100 e 200 mg/kg and the open test conducted and the Morris water maze task. The acquisition of memory space is evaluated by time the animal takes to locate the platform after having been trained. The results of the open was demonstrated that animals do not exhibit motor stimulus when treated with the essential oil of Citrus sinensis and the results of water maze were significantly lower in to find the submerged platform than the negative control group [p<0.01] indicating an increased memory capacity in the treated animals, but must be reinforced by other memory tests recommended by the literature.

Evaluation of effects of dichloromethane fraction from Platonia insignis on pilocarpine-induced seizures

The objective of present study was to evaluate the antioxidant and anticonvulsant activities of dichloromethane fraction (DMF) from Platonia insignis Mart., Clusiaceae. The DMF from P. insignis (2 mg/kg) was tested by intraperitoneal (i.p.) to evaluate effects on lipid peroxidation level, nitrite formation, as well as on locomotor and anticonvulsant activities. Wistar rats were treated with, (saline/Tween 80 0.5 percent, i.p., control group), DMF (2 mg/kg, i.p., DMF group), pilocarpine (400 mg/kg, i.p., P400 group), or the combination of DMF (2 mg/kg, i.p.) and pilocarpine (400 mg/kg, i.p., DMF plus P400). After the treatments all groups were observed for 24 h. In P400 group rats there was a decrease in the motor activity when compared with control group. In DMF plus P400 co-administered rats was observed an increase in motor activity when compared with P400 group. In P400 group rats there was a significant increase in lipid peroxidation and nitrite levels. In DMF plus P400 co-administered rats, antioxidant treatment significantly reduced the lipid peroxidation level and nitrite content after seizures. Previous findings strongly support the hypothesis that oxidative stress occurs in rat striatum during pilocarpine-induced seizures, and our results imply that strong neuprotective effect on this brain region could be achieved using DMF from P. insignis.

Evaluation of central nervous system effects of Citrus limon essential oil in mice

The central nervous system (CNS) depressant and anticonvulsant activities of Citrus limon (L.) Osbeck, Rutaceae, essential oil (EO) were investigated in animal models. The EO (50, 100 and 150 mg/kg) injected by oral route (p.o.) in mice caused a significant decrease in the motor activity of animals when compared with the control group, up to thirty days after the administration and the dose of 150 mg/kg significantly reduced the remaining time of the animals on the Rota-rod apparatus. Additionally, C. limon essential oil was also capable to promote an increase of latency for development of convulsions induced by pentylenetetrazole (PTZ). The administration of FLU (10 mg/kg, i.p.), GABA A-benzodiazepine (GABA-BZD) receptor antagonist, antagonized the effect of C. limon essential oil at higher dose. This C. limon essential oil was also capable to promote an increase of latency for development of convulsions induced by picrotoxin (PIC) at higher dose. In the same way, the anticonvulsant effect of the EO was affected by pretreatment with flumazenil, a selective antagonist of benzodiazepine site of GABA A receptor. These results suggest a possible CNS depressant and anticonvulsant activities in mice that needs further investigation.

Avaliação do potencial neuroprotetor do óleo essencial de Citrus limon em hipocampo e corpo estriado de camundongos após convulsões induzidas pela pilocarpina / Evaluation of neuroprotective potential of Citrus limon essential oil in hippocampus and striatum of mice after pilocarpine-induced seizures

The seizures can produce neuronal damage in several brain structures. The aim of this study was to investigate the potential neuroprotective effect of essential oil of Citrus limon (EOCL) on the histopathological changes observed in the hippocampus and striatum of mice after seizures induced by pilocarpine. Adult Swiss mice were 2 months old. The animals were divided into four groups. The first group was treated with 0.05 percent Tween 80 (control group) and the second with pilocarpine (400 mg/kg group P400). The third and fourth group were treated with EOCL (150 mg/kg) and 30 min after received P400 (P400 +/- EOCL group) or 0.05 percent Tween 80, respectively. After treatment, all groups were observed for 24 h, then sacrificed and their brains removed for histopathological analysis. The group P400, presented with seizures that progressed to status epilepticus in 75 percent of animals. Pretreatment with OECL produced a 25 percent reduction in this index. Groups P400 and P400 + EOCL showed 83.33 percent and 25 percent of animals with brain damage in the hippocampus, respectively. In the striatum of group P400 was a compromise of 75 percent. In turn, in the striatal region of group EOCL P400 + was seen a decrease of 58.34 percent in this neuronal damage. The seizures induced by pilocarpine are installed by the cholinergic system and produce brain damage. According to our results we suggest that the EOCL may modulate epileptogenesis and promote neuroprotective effects during the seizures in the model investigated.

As convulsões podem produzir danos neuronais em diversas estruturas cerebrais. O objetivo desse estudo foi investigar o potencial efeito neuroprotetor do óleo essencial de Citrus limon (OECL) nas alterações histopatológicas observadas no hipocampo e corpo estriado de camundongos após convulsão induzida por pilocarpina. Foram utilizados camundongos Swiss adultos com 2 meses de idade. Os animais foram divididos em 4 grupos. O primeiro grupo foi tratado com Tween 80 0,05 por cento (grupo controle) e o segundo com pilocarpina (400 mg/kg, grupo P400). Já o terceiro e quarto grupo foram tratados com OECL (150 mg/kg), e 30 min depois receberam P400 (grupo OECL + P400) ou Tween 80 0,05 por cento 0.9 por cento (grupo OECL), respectivamente. Após os tratamentos, todos os grupos foram observados durante 24 h e em seguida sacrificados e seus cérebros removidos para as análises histopatológicas. O grupo P400, apresentou convulsões que progrediram para o estado epiléptico em 75 por cento dos animais. O pré-tratamento com OECL produziu uma redução de 25 por cento nesse índice. Os grupos P400 e OECL + P400 apresentaram 83,33 por cento e 25 por cento de animais com lesão cerebral no hipocampo, respectivamente. No corpo estriado dos animais do grupo P400 houve um comprometimento de 75 por cento. Por sua vez, na região estriatal dos animais do grupo OECL + P400 foi visto uma redução de 58,34 por cento nesse comprometimento. As convulsões induzidas pela pilocarpina são instaladas pelo sistema colinérgico e produzem dano cerebral. De acordo com nossos resultados podemos sugerir que o OECL pode modular a epileptogênese e promover ação neuroprotetora durante as convulsões no modelo investigado.

Neuronal damage and memory deficits after seizures are reversed by ascorbic acid? / O dano neuronal e o déficit de memória após convulsões são revertidos pelo ácido ascórbico?

The objective of the present study was to evaluate the neuroprotective effects of ascorbic acid (AA) in rats, against the neuronal damage and memory deficit caused by seizures. Wistar rats were treated with 0.9 percent saline (i.p., control group), ascorbic acid (500 mg/kg, i.p., AA group), pilocarpine (400 mg/kg, i.p., pilocarpine group), and the association of ascorbic acid (500 mg/kg, i.p.) plus pilocarpine (400 mg/kg, i.p.), 30 min before of administration of ascorbic acid (AA plus pilocarpine group). After the treatments all groups were observed for 24 h. Pilocarpine group presented seizures which progressed to status epilepticus in 75 percent of the animals. Pretreatment with AA led to a reduction of 50 percent of this rate. Results showed that pretreatment with AA did not alter reference memory when compared to a control group. In the working memory task, we observed a significant day's effect with important differences between control, pilocarpine and AA plus pilocarpine groups. Pilocarpine and AA plus pilocarpine groups had 81 and 16 percent of animals with brain injury, respectively. In the hippocampus of pilocarpine animals, it was detected an injury of 60 percent. As for the animals tested with AA plus pilocarpine, the hippocampal region of the group had a reduction of 43 percent in hippocampal lesion. Our findings suggest that seizures caused cognitive dysfunction and neuronal damage that might be related, at least in part, to the neurological problems presented by epileptic patients. AA can reverse cognitive dysfunction observed in rats with seizures as well as decrease neuronal injury in rat hippocampus.

O objetivo do presente estudo foi avaliar o efeito neuroprotetor do ácido ascórbico (AA), contra o dano neuronal e o déficit de memória em ratos causados pelas convulsões. Ratos Wistar foram tratados com solução salina a 0,9 por cento (i.p., grupo controle), ácido ascórbico (500 mg/kg, i.p., grupo AA), pilocarpina (400 mg/kg, i.p., grupo pilocarpina), e a associação de ácido ascórbico (500 mg/kg, i.p.) com pilocarpina (400 mg/kg, i.p.), 30 min após a administração de ácido ascórbico (AA + pilocarpina grupo). Após os tratamentos todos os grupos foram observados durante 24 h. O grupo pilocarpina apresentou crises convulsivas que evoluíram para o estado de mal epiléptico em 75 por cento dos animais. O pré-tratamento com AA produz uma redução de 50 por cento nesta taxa. Os resultados mostraram que o pré-tratamento com AA não alterou a memória em relação ao controle. No teste de memória, observou-se um efeito significativo nos dias avaliados entre os grupos controle, pilocarpina e AA + pilocarpina. 81 e 16 por cento dos animais dos grupos AA + pilocarpina e pilocarpina apresentaram danos cerebrais, respectivamente. No hipocampo dos animais do grupo pilocarpina, que foi detectada uma lesão de hipocampal de 60 por cento. Quanto aos animais do grupo AA + pilocarpina, a região do hipocampo apresentou uma redução de 43 por cento na extensão da lesão no hippocampo. Nosso resultados sugerem que as convulsões produzem disfunção cognitiva e dano neuronal que podem estar relacionados, pelo menos em parte, aos problemas neurológicos apresentados pelos pacientes epilépticos. O ácido ascórbico pode reverter essa disfunção cognitiva observado em ratos convulsivos, bem como reduz o desenvolvimento da lesão neuronal no hipocampo de ratos.