Isolamento, purificação, caracterização e avaliação antinociceptiva e anti-inflamatória da lectina de semente de canna limbata roscoe

Abstract

Lectins represent a group of proteins that are able to recognize specifically and reversibly bind to carbohydrates and glycoconjugates. The aim of this study was to purify, characterize and conduct the evaluation of antinociceptive and anti-inflammatory pharmacological activity of a lectin from seeds of Canna limbata. The protein extracts were obtained by powders the seeds and by salt extraction followed by precipitation with ammonium sulfate. The isolation and purification of lectin molecules have been performed by chitin affinity chromatography. The monitoring of the purification was performed by hemagglutination activity assays and electrophoresis (SDS-PAGE). The biochemical characterization of the molecule indicates a tetrameric protein (~ 50 kDa) composed by subunits consisting of monomers of 12 kDa. In order to evaluate the antinociceptive and anti-inflammatory activities of this lectin, murine models were used, such as acetic acid-induced writhing, nociception induced by formalin, hot plate and peritonitis induced by Zymosan A assays. In all assays, the doses tested were 0.1 mg/kg, 1 mg/kg, 5 mg/kg and 10 mg/kg (p. o.). In the writhing test, all doses induced significant inhibition of nociceptive response, resulting in 60.3 % (0.1 mg/kg), 52.1 % (1 mg/kg), 70.8 % (5 mg/kg) and 76.1 % (10 mg/Kg) of inhibition. In the first phase (neurogenic) of the formalin test, doses of the lectin did not reduce so significantly the licking of the paw by the mouse. Although, in the inflammatory phase, the doses of 1 mg/kg, 5 mg/kg and 10 mg/kg induced a statistically significant inhibition with 73.8 %, 57.6 % and 96.02 % of inhibition, respectively. In the hot plate test, treatment with all doses of the lectin was not able to increase statistically significantly the time the animal remained on the plate. The test of peritonitis induced by Zymosan A confirmed anti-inflammatory activity of the lectin, which were capable of inhibiting cell migration, with inhibition of 29.68 % (0.1 mg/kg) 41.74 % (1 mg/kg) 48.90 % (5 mg/kg) and 43.74 % (10 mg/kg).Thus, the present results showed that the lectin from Canna limbata have anti-inflammatory and peripheral antinociceptive activities and could be employed as pharmacological tools to study nociceptive and inflammatory conditions, assisting in drug discovery.