Antiinflammatory, analgesic and antioxidant activities of Cyathula prostrata (Linn.) Blume (Amaranthaceae)

Ethnopharmacological relevance: Cyathula prostrata (Linn) Blume (Amaranthaceae) is an annual herb widely used traditionally in the treatment of various inflammatory and pain related health disorders in Nigeria. The aim of this study is to evaluate the anti-inflammatory, analgesic and antioxidant activities of the methanolic extract of Cyathula prostrata (Linn) Blume. Materials and methods: The anti-inflammatory (phorbol 12-myristate 13-acetate (PMA)-induced reactive oxygen species (ROS), lipopolysaccharide (LPS) induced nitric oxide production in U937 macrophages, LPS-induced COX-2 expression, carrageenan-induced rat paw oedema, arachidonic acid-induced ear oedema and xylene-induced ear oedema), analgesic (acetic acid-induced writhing and hot plate tests) and antioxidant activities (DPPH [1,1-diphenyl-2-picrylhydrazyl] and lipid peroxidation assays) activities of the plant extract were investigated. Results: The methanolic extract of Cyathula prostrata did not show inhibitory activity in the in vitro PMA-induced reactive oxygen species, LPS-induced nitric oxide production and LPS-induced COX-2 expression assays. In the in vivo anti-inflammatory assays, the extract (50, 100 and 200 mg/kg) showed a significant (P < 0.05) dose-dependent inhibition in the carrageenan, arachidonic acid and xylene-induced tests. Cyathula prostrata produced a significant (P < 0.05, 0.001) dose-dependent inhibition in the acetic acid and hot plate analgesic tests respectively. The plant extract did not exhibit any antioxidant activity in the DPPH and lipid peroxidation assays. Conclusion: The results suggest that the methanolic extract of Cyathula prostrata possesses anti-inflammatory and analgesic activities and this authenticates the use of the plant in the traditional treatment of ailments associated with inflammation and pain. © 2012 Elsevier Ireland Ltd. All rights reserved.