Document Type: Research article
Laboratory of Molecular Chemistry and Pharmacology, Regional University of Cariri Antonio Luis, Crato (CE), Brazil.
Laboratory of Research in Natural Products, Regional University of Cariri Antonio Luis, Crato (CE), Brazil.
Laboratory of Pharmacology and Biophysiology, Faculty of Medicine Estácio of Juazeiro do Norte, 515 Tenente Raimundo Rocha, Juazeiro do Norte (CE), Brazil.
Laboratory of Pharmacology and Experimental Biochemistry, Federal University of Paraíba, Cidade Universitária Pessoa (PB), Brazil.
Annona muricata Linnaeus (Annonaceae), popularly known as graviola, is used in folk medicine as both sedative and anticonvulsant. This study correlates the neurochemical profile with the behavioral effects of the hydroalcoholic extract from the leaves of Annona muricata (HLEAM) in mice, proposing to elucidate their mechanism of action on the central nervous system. Flavonoids and phenolic compounds were identified and quantified by High Performance Liquid Chromatography (HPLC) method. The acute toxicity (median lethal dose - LD50) was determined by probitos method using the percentage of mortality based on the Hippocratic screen. HLEAM (25, 50 and 100 mg/kg) was tested, intraperitoneally (i.p.), in models of sedation, anxiety, motor coordination and seizures. The endogenous levels of dopamine, norepinephrine and DOPAC were assayed by reverse-phase HPLC with electrochemical detection. The HPLC analysis of extract revealed the presence of flavonoids (quercetin, isoquercitrin, quercitrin, rutin and kaempferol) and phenolics acids (gallic, chlorogenic, ellagic and caffeic acids). The LD50 was 1091.7 mg/kg and Hippocratic screening indicated central nervous system depressant effect. HLEAM presented sedatives effects at doses 25, 50 and 100 mg/kg, and anxiolytic and anticonvulsant effects at a dose of 100 mg/kg. In addition, these effects were partially reversed by flumazenil. The monoamines analysis by HPLC showed that HLEAM decreased the level of norepinefrine and dopamine in the mouse brain striatum. Thus, the results indicate a possible interaction of HLEAM with the GABAergic and monoaminergic systems, adding medicinal value to the popular use of the plant for the treatment of behavioral and neurological disorders.