Antinociceptive activity of Syzygium cumini leaves ethanol extract on orofacial nociception protocols in rodents

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Context: Syzygium cumini (L.) Skeels (Myrtaceae) is a tree with dark purple fruits, popularly known as 'jambolao' or ' jambolan'. In folk medicine, this plant is used for the treatment of diabetes and inflammatory conditions. Objective: We investigated the antinociceptive effect of ethanol extract (EE) from S. cumini leaves on orofacial nociception. Material and methods: The antinociceptive effects of the EE obtained from the leaves of S. cumini were evaluated in mice using formalin-and glutamate-induced orofacial nociception. Results: ESI-MS/MS analyses demonstrated that major constituents in the analyzed samples coincided with the mass of the phenolic acids and flavonoids. In pharmacological approach, pre-treatment with EE (100, 200, or 400 mg/kg, p. o.) significantly reduced (p < 0.05 or p < 0.01) the percentage of paw licks time during phase 2 (43.2, 47.1, and 57.4%, respectively) of a formalin pain test when compared to control group animals. This effect was prevented by pretreatment with glibenclamide and N-G-nitro-L-arginine (L-NOARG). The extract, all doses, also caused a marked inhibition (p < 0.01 or p < 0.001) of glutamate-induced orofacial nociception (38.8, 51.7, and 54.7%) when compared with the control group. No effect was observed with the rota-rod model. Conclusions: We can suggest that the antinociceptive effect of the EE is mediated by peripheral mechanisms, possibly involving K-ATP channels and the nitric oxide pathways. These effects appear to be related to the presence of flavonoids compounds, such as quercetin.526762766Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP