Caracterização química, avaliação da toxicidade oral aguda e da atividade antinociceptiva do extrato metanólico das folhas de Montrichardia linifera (Arruda) Schott

Abstract

Background: Montrichardia linifera (Arruda) Schott is popularly known as “aninga”, “aningaçu”, “aningaíba” and “aninga-do-igapó”. The compresses and plasters from the leaves of the medicinal plant are used to treat abscesses, tumors and pain caused by stingray stings. Aim of the study: The study aimed to investigate the antinociceptive potential of the methanolic extract of Montrichardia linifera leaves (MEMLL), as well as carry out chemical characterization and acute oral toxicity. Materials and methods: The leaves were collected during the rainy season and the methanolic extract was obtained after gradient extraction in different solvents. The MEMLL was analyzed using high performance liquid chromatography (HPLC) and Nuclear Magnetic Resonance (NMR). The evaluation of the acute oral toxicity test was used to observe the presence of toxic substances. Subsequently, acetic acid, hot plate and formalin tests were used to evaluate the analgesic effects. Results: The HPLC fingerprint analysis allowed the identification of rutin, quercetin and epicatechin. The analysis of NMR spectra identified rutin and quercetin, as well as the flavonoids luteolin and chrysoeriol. The MEMLL did not demonstrate effects considered toxic. In the acetic acid test, the MEMLL inhibited peripheral pain by 51.46% (p < 0.05) at a dose of 50 mg/kg and 75.08% (p < 0.001) at a dose of 100 mg/kg. The hot plate test evaluated the latency time of animals, demonstrating central activity at 30 and 60 min increasing by 164.43% (p < 0.01) and 122.95% (p < 0.05) at a dose of 50 mg /kg and 162.62% (p < 0.01) and 136.68% (p < 0.05) at a dose of 100 mg/kg. The formalin test evaluated the central and peripheral antinociceptive effect of the MEMLL. In the neurogenic phase, a reduction of 35.25% (p < 0.05) at a dose of 50 mg/kg and 52.30% (p < 0.01) at a dose of 100 mg/kg. In inflammatory pain, a reduction of 66.39% (p < 0.0001) and 72.15% (p < 0.0001) was observed. Conclusion: The antinociceptive activity supports its ethnopharmacological use. This analgesic effect is probably associated with the identified flavonoids, all of which have antioxidant, anti-inflammatory and antinociceptive properties. Furthermore, the MEMLL was non-toxic.