Palmatine antioxidant and anti-acetylcholinesterase activities: A pre-clinical assessment.

There is evidence that palmatine (PA), an alkaloid isolated from the Guatteria friesiana plant, has some important biological activities, including anti-inflammatory and antidepressant effects. In this study, the antioxidant and anti-acetylcholinesterase (AChE) effects of PA were assessed. The antioxidant capacity was evaluated in vitro and in vivo through 7 distinct assays, and the anti-AChE activity was determined in vitro. The standards, trolox and ascorbic acid were used for the in vitro antioxidant test, while hydrogen peroxide was selected as a stressor for the Saccharomyces cerevisiae test. Additionally, PA was also combined with trolox and ascorbic acid to determine the likelihood of synergistic effects occurrence to what concerns to antioxidant potential. PA exhibited a potent and concentration-dependent antioxidant potential, although a stronger antioxidant activity was stated using the PA + trolox combination. PA was also found to inhibit AChE activity when compared to the negative control. Thus, PA may be viewed as a promissory phytotherapeutic agent to manage oxidative stress-mediated neurological diseases, especially the Alzheimer's and Parkinson's diseases.

Toxicity, cytotoxicity, mutagenicity and in vitro antioxidant models of 2-oleyl-1,3-dipalmitoyl-glycerol isolated from the hexane extract of Platonia insignis MART seeds.

2-oleyl-1,3-dipalmitoyl-glycerol (ODG) was obtained from Platonia insignis (bacurizeiro) seeds. There are no studies on its toxicity and protective activities against oxidative stress. This study was aimed to evaluate antioxidant effects in vitro, as well as to evaluate the toxicological and mutagenic effects of the ODG. ODG showed a median lethal dose (LD50) greater than 1200 µg mL-1 in A. salina. In the assay of A. cepa (0.2-0.002 mg mL-1) the ODG compound at the highest concentration was slightly cytotoxic with decrease in the size of roots and mitotic indexes, but did not induce chromosomal alterations. ODG (8.75-140.00 µg mL-1) was found to reduce nitric oxide production by 41.6 %, while the antioxidant standard ascorbic acid (AA) reduced 54.14 %. ODG (15.625-250.00 µg mL-1) promoted removal of the hydroxyl radical by 35.69 % at the highest concentration and was able to prevent lipid peroxidation induced by 2,2'-azobis-2-amidinopropane (AAPH), inhibiting the amount of TBARS formed, up to 35.69 %, a result close to that obtained with AA. Thus, ODG moderately reduced the levels of hydroxyl radicals, nitric oxide, and TBARS in vitro and was nontoxic at low concentrations.

Determination by chromatography and cytotoxotoxic and oxidative effects of pyriproxyfen and pyridalyl.

Pyriproxyfen (PPF) is a larvicide, used to combat the proliferation of Aedes aegypti larvae. The objective of this study was to analyze the compounds of pyriproxyfen and pyridalyl (PYL) in a commercial larvicide to analyze the cytotoxic and oxidative effects of PPF and PYL. The toxic potential of PPF and PYL were assessed based on lethal concentration (LC50) in Artemia salina, cytotoxicity based on the mitotic index and the chromosomal alterations in Allium cepa and the oxidative damage in Saccharomyces cerevisiae. The PPF and PYL compounds were identified by HPLC-PDA based on their retention times and spectral data. The wavelengths λmax (258 nm) and (271 nm) of the UV spectrum of PYL and PPF and the retention times (RT) (3.38 min) and (4.03 min), respectively. The toxicological potentials of PPF and PYL were significant at concentrations (1, 10, 100 and 1000 ppm), with an LC50 of 48 h (0.5 ppm). PPF and PYL pointed out a cytotoxic effect in A. cepa at all concentrations (0.0001, 0.001, 0.01, 0.1, 1.0, 100 and 1000 ppm), genotoxic effect at concentrations only (0.0001; 0.1; 1; 100 and 1000 ppm), and mutagenic for concentrations (0.1, 100 and 1000 ppm). In relation S. cerevisiae, PPF e PYL prompted oxidative damage at concentrations (100 and 1000 ppm) in all strains (SODWT, Sod1, Sod2, Sod1Sod2, Cat1 and Sod1Cat1). Therefore, the PPF and PYL identificated in commercial larvicide by HPLC-PDA produced cytotoxic and oxidative effects that could cause health and ecosystem risks.

Determination of Parameters of Oxidative Stress in vitro Models of Neurodegenerative Diseases-A Review.

Oxidative stress is a major mechanism underlying the development of various neurodegenerative diseases (Alzheimer, Parkinson, Huntington and amyotrophic lateral sclerosis). Excessive formation of reactive oxygen species (ROS) and nitrogen (RNSs) can overburden the ability of the enzymatic antioxidant defense mechanisms (superoxide dismutase, catalase and glutathione reductase) and non-enzymatic (uric acid, ascorbic acid, α-tocopherol and reduced glutathione), causing the development of oxidative stress, and consequently, impairing the neuronal system cells by means of oxidative damage to a variety of important biological molecules such as lipids, DNA and proteins. Considering the importance of oxidative stress in neurodegenerative diseases, the present review aims to address the main parameters evaluated in in vitro studies on oxidative stress in different models of neurodegenerative diseases.The literary review was conducted through Pubmed, Science Direct, LILACS, Scielo and Google using following keywords: oxidative stress, neurodegenerative diseases and parameters of oxidative stress. We selected articles published between 2002 and 2017.The in vitro evaluation of the oxidative stress related parameters has provided a preliminary view about the pathogenesis of many neurodegenerative diseases (Alzheimer's, Parkinson's, Huntington's and Amyotrophic lateral sclerosis). In this way, it has demonstrated the mechanism of action of ROS/RNSs in these diseases by direct or indirect detection through several experimental procedures in vitro.

Non-clinical toxicity of ß-caryophyllene, a dietary cannabinoid: Absence of adverse effects in female Swiss mice.

ß-caryophyllene is a food additive that is found in food plants and has broad pharmacological potential. However, little toxicological information has been reported and its use is based on the fact that this bicyclic sesquiterpene is daily consumed as a plant food in much larger quantities than as a food additive. Thus, this study evaluated acute (14-day) and repeated-dose (28 days) oral ß-caryophyllene toxicity in female Swiss mice analyzing changes in body weight, food intake, water intake, hematological and biochemical parameters, organ weight after necropsy, oxidative stress markers and histopathology of various tissues. Acute (300 and 2000 mg/kg) and repeated-dose (300 and 2000 mg/kg) toxicity studies were performed according to the Organization for Economic Cooperation and Development (OECD) guideline 423 and 407, respectively. There was absence of adverse clinical signs and mortality in any animal subjected to acute and repeated-dose toxicity study. In addition, no significant changes in body weight, food and water intake, oxidative stress biomarkers, hematological and biochemical parameters were observed when compared to control group from single-dose and repeated-dose toxicity study. Therefore, the results of this study provide an understanding of the toxicity profile of ß-caryophyllene which can be considered a compound with toxicity at doses higher than 2000 mg/kg body weight.

A Brief Review on the Neuroprotective Mechanisms of Vitexin.

The neural dysfunction is triggered by cellular and molecular events that provoke neurotoxicity and neural death. Currently, neurodegenerative diseases are increasingly common, and available treatments are focused on relieving symptoms. Based on the above, in this review we describe the participation of vitexin in the main events involved in the neurotoxicity and cell death process, as well as the use of vitexin as a therapeutic approach to suppress or attenuate neurodegenerative progress. Vitexin contributes to increasing neuroprotective factors and pathways and counteract the targets that induce neurodegeneration, such as redox imbalance, neuroinflammation, abnormal protein aggregation, and reduction of cognitive and/or motor impairment. The results obtained provide substantial evidence to support the scientific exploration of vitexin in these pathologies, since their effects are still little explored for this direction.

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.

Antioxidant and antinociceptive effects of Citrus limon essential oil in mice.

The antioxidant and antinociceptive activities of Citrus limon essential oil (EO) were assessed in mice or in vitro tests. EO possesses a strong antioxidant potential according to the scavenging assays. Moreover, it presented scavenger activity against all in vitro tests. Orally, EO (50, 100, and 150 mg/kg) significantly reduced the number of writhes, and, at highest doses, it reduced the number of paw licks. Whereas naloxone antagonized the antinociceptive action of EO (highest doses), this suggested, at least, the participation of the opioid system. Further studies currently in progress will enable us to understand the action mechanisms of EO.

Antioxidant activity of Citrus limon essential oil in mouse hippocampus.

CONTEXT: Citrus limon (L.) Burms (Rutaceae) has been shown in previous studies to have various biological functions (anti-inflammatory, antiallergic, antiviral, antimutagenic, and anticarcinogenic). However, traditional uses in folk medicine suggest that C. limon may have an effect on the central nervous system (CNS). OBJECTIVE: This study investigated the effects of C. limon essential oil (EO) on lipid peroxidation level, nitrite content, glutathione reduced (GSH) concentration, and antioxidant enzymes [superoxide dismutase (SOD), catalase, and glutathione peroxidase (GPx)] activities in mice hippocampus. MATERIALS AND METHODS: Swiss mice were treated with the suspension of 0.5% Tween 80, in distilled water used as vehicle (i.p., control group) and with EO in three different doses (0.05, 0.1, or 0.15 g/kg, i.p., EO 50, EO 100, and EO 150 groups, respectively). After the treatments, all groups were observed for 24 h. The enzyme activities as well as the lipid peroxidation, nitrite, and GSH concentrations in mice hippocampus were measured using spectrophotometric methods and the results were compared with values obtained from control group. RESULTS: EO of C. limon treatment significantly reduced the lipid peroxidation level and nitrite content but increased the GSH levels and the SOD, catalase, and GPx activities in mice hippocampus. DISCUSSION AND CONCLUSION: Our findings strongly support the hypothesis that oxidative stress in hippocampus can occur during neurodegenerative diseases, proving that hippocampal damage induced by the oxidative process plays a crucial role in brain disorders, and also imply that a strong protective effect could be achieved using EO of C. limon as an antioxidant.

Lipoic acid effects on glutamate and taurine concentrations in rat hippocampus after pilocarpine-induced seizures.

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% 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%) and a decrease in taurine level (18%) in rat hippocampus, when compared to control group. Antioxidant pretreatment significantly reduced the glutamate level (28%) and augmented taurine content (32%) 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.

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.

Lipoic acid inhibits caspase-dependent and -independent cell death pathways and is neuroprotective against hippocampal damage after pilocarpine-induced seizures.

Alpha-lipoic acid has some neuroprotective properties, but this action has not been investigated in models of epilepsy. The aim of the present study was to investigate the protective efficacy of α-lipoic acid (lipoic acid) against pilocarpine-induced cell death through the caspase-dependent or -independent mitochondrial apoptotic pathways. Wistar rats were injected intraperitoneally with 0.9% saline (control group), pilocarpine (400 mg/kg, pilocarpine group) alone, or α-lipoic acid (20 mg/kg) in association with pilocarpine (400 mg/kg) 30 min before administration of α-lipoic acid. After the treatments all groups were observed for 24 h. Cell death was reduced in lipoic acid-treated rats. Cytosolic translocation of cytochrome c and subsequent activation of caspase-3 were reduced by lipoic acid treatment. AIF nuclear translocation and subsequent large-scale DNA fragmentation were also decreased in lipoic acid-treated rats. Our study suggests that lipoic acid inhibits both caspase-dependent and -independent apoptotic pathways and may be neuroprotective against hippocampal damage during pilocarpine-induced seizures.

Caffeic acid effects on oxidative stress in rat hippocampus after pilocarpine-induced seizures.

The objective of the study was to evaluate the caffeic acid (CA) effects against the oxidative stress (OS) observed during seizures. Wistar rats were intraperitoneally treated with either 0.9% saline (control), CA (4 mg/kg), pilocarpine (400 mg/kg, pilocarpine group), or the association of CA (4 mg/kg) plus pilocarpine (400 mg/kg). The thiobarbituric-acid-reacting substances and the hippocampal nitrite content were significantly increased (89 and 94%, respectively) in pilocarpine group when compared with control. There were marked decreases in lipid peroxidation level (43%) and nitrite content (45%) in CA group when compared with pilocarpine group. There were no marked alterations in superoxide dismutase (SOD) and catalase (CAT) activities in pilocarpine group; however, the SOD and CAT activities were significantly increased (35 and 51%, respectively) after CA pretreatment. Our findings strongly support the hypothesis that OS was indeed generated in hippocampus. CA pretreatment can reduces the OS produced by seizures.

Neuronal damage and memory deficits after seizures are reversed by ascorbic acid?

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% 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% of the animals. Pretreatment with AA led to a reduction of 50% 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% of animals with brain injury, respectively. In the hippocampus of pilocarpine animals, it was detected an injury of 60%. As for the animals tested with AA plus pilocarpine, the hippocampal region of the group had a reduction of 43% 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.

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.

Pilocarpine-induced seizures produce alterations on choline acetyltransferase and acetylcholinesterase activities and deficit memory in rats.

In the present study, we investigated the effect of seizures on rat performance in the Morris water maze task, as well as on choline acetyltransferase (ChAT) and acetylcholinesterase (AChE) activities in rat hippocampus. Wistar rats were treated with 0.9% saline (i.p., control group) and pilocarpine (400 mg/kg, i.p., pilocarpine group). After the treatments all groups were observed for 1 h. The changes on reference and working spatial memory caused by pilocarpine administration were observed in seized rats. The ChAT and AChE activities were measured using spectrophotometric methods and the results compared to values obtained from saline animals. Its activities were also determined after behavioral task. Results showed that seizures alter reference memory when compared to saline-treated animals. In the working memory task, we observed a significant day's effect with significant differences between control and pilocarpine-induced seizures. In pilocarpine group, it was observed a significant decreased in ChAT and AChE activities, when compared to control group. Our findings suggest that seizures caused cognitive dysfunction and a decrease of ChAT and AChE activities that might be related, at least in part, to the neurological problems presented by seizures induced by pilocarpine.

Lipoic acid blocks seizures induced by pilocarpine via increases in delta-aminolevulinic dehydratase and Na+, K+-ATPase activity in rat brain.

In the present study we investigated the effects of lipoic acid (LA) on delta-aminolevulinic dehydratase (delta-ALA-D) and Na(+), K(+)-ATPase activities in rat brain after seizures induction by pilocarpine. Wistar rats were treated with 0.9% saline (i.p., control group), lipoic acid (10mg/kg, i.p., LA group), pilocarpine (400mg/kg, i.p., pilocarpine group), or the combination of LA (10mg/kg, i.p.) with pilocarpine (400mg/kg, i.p.), 30 min before administration of LA (LA plus pilocarpine group). After the treatments all groups were observed for 1h. The enzyme activities (delta-ALA-D and Na(+), K(+)-ATPase) were measured using spectrophotometric methods, and the results were compared with that obtained from saline and pilocarpine-treated animals. Neuroprotective effects of LA against seizures were evaluated based on those enzyme activities. The pilocarpine group showed a reduction in delta-ALA-D and Na(+), K(+)-ATPase activities after seizures. In turn, LA plus pilocarpine abolished the appearance of seizures and reversed the decreased in delta-ALA-D and Na(+), K(+)-ATPase activities produced by seizures, when compared to the pilocarpine seizing group. The results from the present study demonstrate that preadministration of LA abolished seizure episodes induced by pilocarpine in rat, probably by increasing delta-ALA-D and Na(+), K(+)-ATPase activities in rat brain during seizures.