Antinociceptive and anti-inflammatory effects of Olax subscorpioidea Oliv. (Olacaceae) leaf extract in rodents: possible mechanisms of antinociceptive action
Ismail O. Ishola, Akinwumi Akinyede, Saheed M. Lawal, Temidayo D. Popoola, Abiodun M. Lawal
Department of Pharmacology, Therapeutics and Toxicology, Faculty of Basic Medical Sciences, College of Medicine, University of Lagos, PMB 12003, Lagos, Nigeria.
Corresponding author: Ismail Ishola
Email: oishola@cmul.edu.ng Phone: +2348033018908
ABSTRACT
Background: Olax subscorpioidea Oliv. (Olacaceae) is a medicinal plant commonly used in traditional medicine to relieve pain in inflammatory processes.
Objective: In the present study, the in vivo anti-inflammatory and antinociceptive effects of aqueous leaf extract of Olax subscorpioidea (OLS) and its possible mechanisms of action were investigated.
Methods: OLS (50, 100, 200, and 400 mg/kg, p.o.) was administered 1 h before injection of 0.6%v/v acetic v acid (10 ml/kg, i.p.), 1% / formalin (20 μl) or tail flick tests to evaluate antinociceptive effect while acute v anti-inflammatory effect was investigated using xylene-induced ear and carrageenan-induced paw edema models, chronic anti-inflammatory effect was investigated using the complete Freund’s adjuvant (CFA) test in rats.
Results: OLS (50-400 mg/kg) significantly (P<0.001) reduced acetic acid-induced writhes (68.28%, 50 mg/kg), duration of paw licking/biting by 73.10% (early phase) and 70.50% (late phase), 50 mg/kg) in formalin-test, while also increasing reaction latency by 79.73 and 92.47% at 150 and 180 min, respectively, in tail-flick test, at 400 mg/kg, in comparison to vehicle-treated, control. The antinociceptive effect elicited by the extract was prevented by pretreatment of mice with metergoline (5-HT receptor antagonist), 2 sulpiride (dopamine D receptor antagonist) and glibenclamide (K- sensitive channels blocker). The 2 ATP extract (400 mg/kg) or diclofenac (20 mg/kg) inhibited carrageenan-induced oedema by 73.08% and 80.77%, respectively, 5 h post-carrageenan injection. Moreover, OLS (400 mg/kg) significantly reduced CFA- induced chronic inflammation by 85.30%, on day 12 post-CFA injection which was similar to the effect of celecoxib (76.50% inhibition). Conversely, OLS failed to inhibit xylene-induced ear edema.
Conclusion: Olax subscorpioidea possesses antinociceptive effect through interaction with 5-HT , 2 dopamine D and sensitive potassium ATP channels as well anti-inflammatory effect. Thus confirm its 2 folkloric uses in the treatment of painful and inflammatory conditions.
Key words: Olax subscorpioidea; serotonergic; dopaminergic; potassium-ATP sensitive channel; complete Freund’s adjuvant