Antioxidant, anti-inflammatory and antinociceptive activities of methanolic extract of Justicia secunda Vahl leaf

Abstract

Background of studyPlants used for traditional medicine contain a wide range of substances which can be used to treat various infectious diseases. AimThe study evaluated the in vitro antioxidant, antinociceptive, and anti-inflammatory activities of the methanolic extract of Justicia secunda Vahl leaf. MethodsThe acute toxicity was performed with up and down method and the highest dose used was 2g/kg. The anti-inflammatory activity was evaluated using the carrageenan and formalin-induced paw edema models, and antinociceptive activity was evaluated using acetic acid-induced writhing reflex and tail flick test models while the antioxidant activity was evaluated using 2,2-diphenyl-2-picryl hydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) photometric assay. ResultsThe extract was well tolerated as no signs of toxicity or death were noticed during the period of observation. The extract produced a concentration dependent increase in antioxidant activities in both DPPH and FRAP models. The extract produced its optimum activity at 400μg/ml in both DPPH (54.07%) assay and FRAP (1.58μM) assay. The extract produced significant (P<0.05) dose-dependent increase in both anti-inflammatory and antinociceptive activities. The antinociceptive and anti-inflammatory activities of the extract (0.4g/kg) were comparable with the reference drugs (aspirin and pentazocine) used in the study. ConclusionThis study suggests that J. secunda possesses anti-inflammatory, antinociceptive and antioxidant activities and also provide the pharmacological basis for its uses in traditional medicine for these purposes.