Evaluation of Anti-Inflammatory Mechanisms of Ethanol Extract of Hyptis suaveolens in Carrageenan-Induced Oedema Models and COX Enzyme Inhibition Assays

Hyptis suaveolens, commonly called Bush tea or efirin igbo across South Eastern and South Western Nigeria, is employed in traditional medicine for the management of inflammatory conditions, rheumatism, and pain. The scientific basis for its anti-inflammatory activity and the specific enzymatic targets involved remain insufficiently explored. This study evaluated the anti-inflammatory mechanisms of ethanol leaf extract of H. suaveolens in experimental models and enzyme inhibition assays at a research facility in Abeokuta, Ogun State. The extract was characterised phytochemically, and in vivo anti-inflammatory activity was assessed using carrageenan-induced paw oedema and xylene-induced ear oedema models in Wistar rats. In vitro inhibition of cyclooxygenase-1 and cyclooxygenase-2 enzymes was evaluated using commercial colorimetric assay kits. The extract inhibited carrageenan-induced paw oedema by 54.7% at 400 mg/kg, comparable to indomethacin at 10 mg/kg (58.3%). Ear oedema inhibition was 49.1% at the highest dose. In vitro COX-2 inhibition IC50 was 68.4 micrograms per millilitre, with selectivity index favouring COX-2 over COX-1. Flavonoids and triterpenoids isolated from the extract were identified as the likely mediators of COX-2 selective inhibition. These findings provide mechanistic evidence for the traditional anti-inflammatory use of H. suaveolens and identify it as a candidate for further isolation and lead optimisation for selective COX-2 inhibitor drug development. Keywords: Hyptis suaveolens, anti-inflammatory, COX inhibition, carrageenan oedema, Ogun State.