Antinociceptive effect on mice of the hydroalcoholic fraction and (-) epicatechin obtained from Combretum leprosum Mart & Eich

Previous studies on Combretum leprosum, a tree growing in the Northeastern states of Brazil, have shown antinociceptive effects of the ethanol extract of its leaves and bark, but studies examining its constituents are rare. The objective of this study was to evaluate the antinociceptive effect of the hydroalcoholic fraction (HF) of one of its constituents, the flavonoid (-) epicatechin (EPI), administered orally to mice (20-30 g) in models of chemical nociception, and the possible mechanisms involved. Different doses of HF (62.5 to 500 mg/kg) and EPI (12.5 to 50 mg/kg) were evaluated in models of abdominal writhing, glutamate, capsaicin, and formalin in animals pretreated with different antagonists: naloxone, ondansetron, yohimbine, ketanserin, pindolol, atropine, and caffeine in the abdominal writhing test. To determine the role of nitric oxide, the animals were pretreated with L-arginine (600 mg/kg, ip) in the glutamate test. The HF was effective (P < 0.05) in all protocols at different doses and EPI was effective in the abdominal writhing, capsaicin and glutamate tests (P < 0.05) at doses of 25 and 50 mg/kg. However, in the formalin test it was only effective in the second phase at a dose of 25 mg/kg. The antinociceptive effect of HF was inhibited when HF was associated with yohimbine (0.15 mg/kg), ketanserine (0.03 mg/kg), and L-arginine (600 mg/kg), but not with the other antagonists. HF and EPI were effective in models of chemical nociception, with the suggested participation of the adrenergic, serotonergic and nitrergic systems in the antinociceptive effect of HF

A Highly Polar Phytocomplex Involving Rutin Is Responsible For The Neuromuscular Facilitation Caused By Casearia Sylvestris (guaçatonga)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Of the various biological activities ascribed to extracts from Casearia sylvestris (guaçatonga), its facilitatory activity, i.e., ability to increase skeletal muscle contractile amplitude, has promising therapeutic applications. In this work, we investigated the components responsible for the previously described neurofacilitation caused by C. sylvestris leaves. Methods: The methanolic fraction of C. sylvestris leaves was initially fractionated by column chromatography and partitioned in a MeOH:H2O gradient. The resulting fractions were analyzed by analytical HPLC and yielded fraction 5:5 (F55) that was subjected to solid phase extraction and preparative HPLC. Of the seven resulting subfractions, only F55-6 caused muscle facilitation. Subfractions F55-6 and F55-7 (similar in composition to F55-6 by TLC analysis, but inactive) were analyzed by 1H-NMR to identify their constituents. Results: This analysis identified a rutin-glycoside phytocomplex that caused neurofacilitation, a property that commercial rutin alone did not exhibit. Conclusion: F55-6 apparently caused neurofacilitation by the same mechanism (presynaptic action) as the methanolic fraction since its activity was also inhibited in tetrodotoxin-pretreated preparations. © 2016 Bentham Science Publishers.17151360136804/09705-8, FAPESP, Fundação de Amparo à Pesquisa do Estado de São Paulo07/53883-6, FAPESP, Fundação de Amparo à Pesquisa do Estado de São Paulo08/11005-5, FAPESP, Fundação de Amparo à Pesquisa do Estado de São Paulo08/50669-6, FAPESP, Fundação de Amparo à Pesquisa do Estado de São Paulo12/08271-0, FAPESP, Fundação de Amparo à Pesquisa do Estado de São PauloFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP