Antinociceptive Effect of Ethanolic Extract of Hybanthus enneaspermus Leaf in Rats
A. O. Afolabi
Department of Physiology, College of Health Sciences, Ladoke Akintola University of Technology, Ogbomoso, Oyo State, Nigeria.
E. T. Oluwakanmi
Department of Physiology, College of Health Sciences, Ladoke Akintola University of Technology, Ogbomoso, Oyo State, Nigeria.
H. M. Salahdeen
Department of Physiology, Lagos State University College of Medicine, Ikeja, Lagos State, Nigeria.
A. O. Oyekunle
Department of Physiology, College of Health Sciences, Ladoke Akintola University of Technology, Ogbomoso, Oyo State, Nigeria.
I. A. Alagbonsi
Department of Physiology, Faculty of Medicine, Kogi State University, P.M.B. 1008, Anyigba, Kogi State, Nigeria.
*Author to whom correspondence should be addressed.
Abstract
Aims: To test the hypothesis that Hybanthus enneaspermus leaf has an antinociceptive effect.
Methodology: Seventy-two male rats were randomly divided in a blinded fashion into 4 groups each for the tail immersion test (n=12 per group) and formalin test (n=6 per group). Group 1 (control) received 0.6 ml of distilled water. Group 2 received 100 mg/kg of acetaminophen (paracetamol). Group 3 and 4 received 500 mg/kg and 1000 mg/kg of ethanolic extract of Hybanthus enneaspermus leaf (EEHE) respectively.
Results: In the formalin test, oral administration of 500 mg/kg and 1000 mg/kg EEHE caused inhibitions of 62.48% and 72% in the early phase and 70.54% and 78.63% in the late phase respectively. The 1000 mg/kg dose significantly reduced the paw licking time when compared to the standard drug (acetaminophen) in the formalin test. The 500 mg/kg and 1000 mg/kg doses significantly increased the tail flick latency in a manner comparable to acetaminophen.
Conclusion: This study showed that the leaf has an anti-nociceptive effect.
Keywords: Acetaminophen, analgesic, formalin test, Hybanthus enneaspermus, pain, tail flick test