Repeated transcranial direct current stimulation reduces food craving in Wistar rats.

It has been suggested that food craving-an intense desire to consume a specific food (particularly foods high in sugar and fat)-can lead to obesity. This behavior has also been associated with abuse of other substances, such as drugs. Both drugs and food cause dependence by acting on brain circuitry involved in reward, motivation, and decision-making processes. The dorsolateral prefrontal cortex (DLPFC) can be activated following evocation and is implicated in alterations in food behavior and craving. Transcranial direct current stimulation (tDCS), a noninvasive brain stimulation technique capable of modulates brain activity significantly, has emerged as a promising treatment to inhibit craving. This technique is considered safe and inexpensive; however, there is scant research using animal models. Such studies could help elucidate the behavioral and molecular mechanisms of eating disorders, including food craving. The aim of our study was to evaluate palatable food consumption in rats receiving tDCS treatment (anode right/cathode left). Eighteen adult male Wistar rats were randomized by weight and divided into three groups (n = 6/group): control, with no stimulation; sham, receiving daily 30 s tDCS (500 µA) sessions for 8 consecutive days; and tDCS, receiving daily 20 min tDCS (500 µA) sessions for 8 consecutive days. All rats were evaluated for locomotor activity and anxiety-like behavior. A palatable food consumption test was performed at baseline and on treatment completion (24 h after the last tDCS session) under fasting and feeding conditions and showed that tDCS decreased food craving, thus corroborating human studies. This result confirms the important role of the prefrontal cortex in food behavior, which can be modulated by noninvasive brain stimulation.

Ethanolic extract of Casearia sylvestris Sw exhibits in vitro antioxidant and antimicrobial activities and in vivo hypolipidemic effect in rats / Extrato etanólico de Casearia sylvestris Sw apresenta atividade antioxidante e antimicrobiana in vitro e efeito hipolipemiante em ratos

ABSTRACT: The Casearia sylvestris Sw (Flacourtiaceae) is a shrub that occurs in forests of Southern Brazil; its leaves are widely used in folk medicine as a depurative, analgesic, anti-inflammatory and antiulcerogenic agent. The objective of this study was to perform the phytochemical description and to evaluate the pharmacological activities (antimicrobial, antifungal, antioxidant and toxicity) of the ethanolic extract (EE) of C. sylvestris Sw. In addition, we also evaluated the effect of the EE of C. sylvestris Sw on the glucose levels and lipid profile in blood serum of rats submitted to a model of streptozotocin-induced diabetes. Material and Methods: In vitro assay: the detection of chemical groups was done through chemical reactions with the development of color or precipitate and by chromatographic profile; the antioxidant activity was measured by the method of reduction of DPPH free radical (2,2-diphenyl-1-picrylhydrazyl); the Minimum Inhibitory Concentration was evaluated by the broth microdilution method, and the Minimum Bactericide Concentration and the Minimum Fungicide Concentration were performed in Petri dishes; the cytotoxic activity was measured by the Artemia salina test. In vivo assay: diabetic and non-diabetic rats were treated with EE of C. sylvestris Sw (300 mg/kg) for 45 days, and the glycaemia and lipid profile were analyzed. Results: The EE showed a Lethal Dose50 of 724.76 μg.mL-1 and important antioxidant, fungicide and fungistatic activities. The EE showed better antimicrobial activity regarding the microorganisms Staphylococcus aureus, Escherichia coli and Salmonella setubal. Conclusion: The EE of C. sylvestris Sw produces a significant decrease in triglycerides, total cholesterol and VLDL levels without any significant alteration in the glycaemia. The EE of C. sylvestris Sw presents antioxidant and antimicrobial activities and it exhibits a potent hypolipidemic effect.

RESUMO: Casearia sylvestris Sw (Flacourtiaceae) é uma planta comumente encontrada em florestas do sul do Brasil; suas folhas são amplamente utilizadas na medicina popular como depurativa, analgésica, anti-inflamatória e anti ulcerogênica. O objetivo deste estudo foi apresentar uma descrição fitoquímica e da atividade farmacológica (antimicrobiana, antifúngica, antioxidante e toxicidade) do extrato etanólico (EE) da C. Sylvestris Sw. Adicionalmente, procurou-se avaliar o efeito do EE da C. Sylvestris Sw sobre os níveis séricos de glicose e perfil lipídico de ratos submetidos a um modelo de diabetes induzida por estreptozotocina. A detecção de grupos químicos foi realizada por reações químicas de coloração ou precipitação, e também por cromatografia; a atividade antioxidante foi mensurada pelo método de redução do DPPH (2,2-difenil-1-picril-hidrazil); a concentração mínima inibitória foi realizada pela técnica de micro-diluição, e concentração mínima bactericida e concentração mínima fungicida foram realizadas em placa de Petri; enquanto a atividade citotóxica foi conduzida pelo teste da Artemia salina. Nos ensaios in vivo, ratos diabéticos e não-diabéticos foram tratado com EE da C. Sylvestris Sw (300mg/kg) por 45 dias, e os níveis glicêmico e perfil lipídico foram medidos. A dose Letal50 do EE foi de 724.76 μg.mL-1; mostrando importante atividades antioxidante, fungicida e fungistática e melhor atividade antimicrobiana contra Staphylococcus aureus, Escherichia coli e Salmonella setubal. O EE da C. Sylvestris Sw promoveu diminuição significativa nos níveis de triglicerídeos, colesterol total e VLDL; porém sem efeito significativo nos níveis glicêmicos. O EE da C. Sylvestris Sw, além de apresentar atividade antioxidante e antimicrobiana; possui também potente efeito hipolipidêmico.

Antioxidant activities of Ptychopetalum olacoides ("muirapuama") in mice brain.

Ptychopetalum olacoides (PO) roots are used by Amazonian peoples to prepare traditional remedies for treating various central nervous system conditions in which free radicals are likely to be implicated. Following the identification of PO ethanol extract (POEE) free-radical scavenging properties in vitro, the aim of this study was to verify the in vivo antioxidant effect of POEE. Aging mice (14 months) were treated (i.p.) with saline, DMSO (20%) or POEE (100mg/kg body wt.), and the hippocampi, cerebral cortex, striata, hypothalamus and cerebellum dissected out 60 min later to measure antioxidant enzyme activities, free-radical production and damage to macromolecules. POEE administration reduced free-radical production in the hypothalamus, lead to significant decrease in lipid peroxidation in the cerebral cortex, striatum and hypothalamus, as well as in the carbonyl content in cerebellum and striatum. In terms of antioxidant enzymes, catalase activity was increased in the cortex, striatum, cerebellum and hippocampus, while glutathione peroxidase activity was increased in the hippocampus. This study suggests that POEE contains compounds able to improve the cellular antioxidant network efficacy in the brain, ultimately reducing the damage caused by oxidative stress.