ABSTRACT
BACKGROUND: The mechanisms of the antinociceptive activity of (-) epicatechin (EPI), a compound isolated from the hydroalcoholic fraction of Combreum leprosum Mart & Eicher. METHODS: were assessed in the model of chemical nociception induced by glutamate (20 µmol/paw). To evaluate the mechanisms involved, the animals , male Swiss mice (25-30 g), received EPI (50 mg/kg p.o.) after pretreatment with naloxone (2 mg/kg s.c. opioid antagonist), glibenclamide (2 mg/kg s.c. antagonist K + channels sensitive to ATP), ketanserin (0.3 mg/kg s.c. antagonist of receptor 5-HT(2A)), yoimbine (0.15 mg/kg s.c. α2 adrenergic receptor antagonist), pindolol (1 mg/kg s.c. 5-HT1(a)/1(b) receptor antagonist), atropine (0.1 mg/kg s.c. muscarinic antagonist) and caffeine (3 mg/kg s.c. adenosine receptor antagonist), ondansetron (0.5 mg/kg s.c. for 5-HT(3) receptor) and L-arginine (600 mg/kg i.p.). RESULTS: The antinociceptive effect of EPI was reversed by pretreatment with naloxone and glibenclamide, ketanserin, yoimbine, atropine and pindolol, which demonstrates the involvement of opioid receptors and potassium channels sensitive to ATP, the serotoninergic (receptor 5HT(1A) and 5HT(2A)), adrenergic (receptor alpha 2) and cholinergic (muscarinic receptor) systems in the activities that were observed. The effects of EPI, however, were not reversed by pretreatment with caffeine, L-arginine or ondansetron, which shows that there is no involvement of 5HT(3) receptors or the purinergic and nitrergic systems in the antinociceptive effect of EPI. In the Open Field and Rotarod test, EPI had no significant effect, which shows that there was no central nervous system depressant or muscle relaxant effect on the results. CONCLUSIONS: This study demonstrates that the antinociceptive activity of EPI in the glutamate model involves the participation of the opioid system, serotonin, adrenergic and cholinergic.
Subject(s)
Analgesics/administration & dosage , Catechin/administration & dosage , Nociceptive Pain , Adenosine Triphosphate/metabolism , Animals , Catechin/chemistry , Combretum/chemistry , Dose-Response Relationship, Drug , Glutamic Acid/toxicity , Male , Mice , Nociceptive Pain/chemically induced , Nociceptive Pain/drug therapy , Potassium Channels/drug effects , Receptors, Adrenergic/drug effects , Receptors, Cholinergic/drug effects , Receptors, Opioid/drug effects , Receptors, Serotonin/drug effectsABSTRACT
Extratos etanólicos de Qualea grandiflora e Copernicia prunifera e extrato hexânico de Dipteryx lacunifera foram avaliados quanto a atividade antibacteriana, utilizando ensaios de difusão a partir de orifício e concentração inibitória mínima (CIM), frente a cepas Gram positivas e Gram-negativas, incluindo espécies multidroga resistentes. O extrato de Q. grandiflora apresentou atividade moderada para as cepas de Staphylococcus epidermidis (CIM = 500 µg/mL) e atividade fraca sobre as demais bactérias Gram-positivas testadas e inativo sobre bactérias Gram-negativas. Os resultados obtidos com S. epidermidis apesar de moderados são importantes, uma vez que este microorganismo é o principal causador de bacteremias e sepse associada com dispositivos médicos implantados. gama-Tocoferol e a mistura de sitosterol e estigmasterol foram isolados do extrato etanólico de raiz de C. prunifera e as estruturas destes compostos foram identificadas com base na análise dos dados espectrais de RMN e comparação com a literatura.
Ethanol extracts of Qualea grandiflora and Copernicia prunifera and hexane extract of Dipteryx lacunifera were evaluated by diffusion in agar and minimum inhibitory concentration (MIC) against Gram-positive and Gram-negative bacteria including multiresistant drug strains. The extract of Q. grandiflora presented moderate activity for Staphylococcus epidermidis (MIC = 500 µg/mL) and weak activity against other Gram-positive strains and inactive for Gram-negative species. The results obtained for S. epidermidis despite being moderate are important because this pathogen is often recovered from bacteremia and sepsis from infections of implanted devices. gamma-Tocopherol and the mixture of sitosterol and stigmasterol were isolated from the ethanol extract of the roots of C. prunifera. The structures of these compounds were identified by NMR spectroscopy and comparison with literature data.
