In vivo Pharmacological Evaluation of the Anti-inflammatory and Analgesic Effects of Cola hispida Methanol Leaf Extract and Its Fractions

Abstract

Cola hispida  Brenan & Keay (Sterculiaceae), a West African plant used in Nigerian Ethnomedicine for pain and inflammation, was evaluated for its anti-inflammatory and analgesic properties in Wistar rats. The methanol leaf extract (CHME) and its n-hexane (CHHF), ethyl acetate (CHEF), and n-butanol (CHBF) fractions were tested using egg albumin and formalin-induced paw oedema models for anti-inflammatory activity, and formalin-induced pain and acetic acid-induced writhing models for analgesic activity, with diclofenac sodium (50 mg/kg) as the positive control. The ethyl acetate fraction (CHEF) at 400 mg/kg exhibited the most potent anti-inflammatory effect, achieving up to 80% inhibition of paw oedema and significantly reducing white blood cell count and erythrocyte sedimentation rate (p < 0.01). CHME, CHBF, and CHHF also reduced oedema significantly (p < 0.05). Notably, CHBF (200 mg/kg) and CHHF (400 mg/kg) significantly decreased paw licking in the formalin test’s late phase by up to 36% (p < 0.05), while CHEF (200 mg/kg) and CHHF (400 mg/kg) reduced writhing by approximately 45% in the acetic acid test, demonstrating robust peripheral pain relief. CHME showed no toxicity up to 5000 mg/kg in mice. Flavonoids and phenolic acids, abundant in CHEF, likely mediate these effects. These findings validate Cola hispida ’s ethnomedicinal use and highlight its potential as a sustainable alternative to non-steroidal anti-inflammatory drugs, supporting Sustainable Development Goals for health (SDG 3) and biodiversity (SDG 15).