Abstract

The methanol:dichloromethane extract of Combretum calobotrys Engl & Diels (Combretaceae) leaves (CCE) was subjected to solvent-guided fractionation to yield the hexane (HF), dichloromethane (DF) and methanol (MF) fractions. The anti-inflammatory effects of the extract and fractions were evaluated in rodents using xylene-induced topical ear edema, carrageenan-induced pedal edema, formaldehyde-induced arthritis and cotton pellet granuloma tests, respectively. The extract and fractions were screened for analgesic activity using acetic acid induced writhing and formalin test in rodents. They were subjected to antimicrobial assay and also analysed for phytochemical constituents, while the CCE was subjected to acute toxicity (Lethal dosage, LD₅₀) test using standard procedures. The extract and fractions (200 and 400 mg/kg) significantly (P < 0.05) inhibited topical, systemic and chronic inflammation. The extracts and fractions (200 and 400 mg/kg) elicited significant (P < 0.05) and dose-related inhibition of acetic acid induced abdominal writhing, and also reduced the number and duration of paw licking in both early and late phases of formalin test, compared to control. They exhibited varying degrees of antimicrobial activity againstPseudomonas aeruginosa, Bacillus subtilis, Staphylococcus aureus, Aspergillus nigerand Candida albicans. The CCE and MF tested positive to alkaloids, resins, tannins, saponins, steroids, terpenoids and flavonoids. The HF contained alkaloids and resins, while the DF tested positive to resins and flavonoids. The oral LD₅₀ of CCE was estimated to be > 5,000 mg/kg. The results indicate that C. calobotrys leaf possess anti-inflammatory, analgesic and antimicrobial activities.

Key words: Combretum calobotrys, anti-inflammatory, analgesic, abdominal writhing, formalin test, agar dilution.