Analgesic and anti-inflammatory effects of the methanol root extracts of some selected Nigerian medicinal plants.
BACKGROUND
The roots of Alafia barteri Oliver (Apocynaceae), Combretum mucronatum Schumach (Combretaceae) and Capparis thonningii Schum (Capparaceae) are used in Traditional African Medicine to alleviate painful and inflammatory conditions.


OBJECTIVE
This study investigated the analgesic and anti-inflammatory effects of the methanol root extracts of Alafia barteri (MeAB), C. mucronatum (MeCM), and Capparis thonningii (MeCT).


METHODS
Analgesic activity of the extracts (50, 100, and 200 mg/kg, p.o. 1 h) was evaluated using acetic acid-, formalin- and hot plate-induced pain while anti-inflammatory actions (100 or 200 mg/kg) were investigated using the carrageenan- and xylene-induced edema tests.


RESULTS
MeAB, MeCM, and MeCT (200 mg/kg) inhibited acetic acid-induced abdominal constriction by 55.07, 46.67, and 47.25%, respectively. In the formalin test, the index of pain inhibition of early and late phases was, respectively, 47.83 and 81.98% for MeAB, 56.10 and 63.81% for MeCM, and 42.84 and 63.29% for MeCT (200 mg/kg). MeAB and MeCT pretreatments significantly increased the reaction time by 46.67 and 25.53%, respectively, 120 min post-treatment in the hot-plate test. Naloxone (5 mg/kg, s.c.) pretreatment 15 min before extract administration, significantly (p < 0.05) reversed the analgesic effect of MeAB and MeCT in the formalin test. MeAB, MeCM, and MeCT showed significant anti-inflammatory activity with 60.44 and 30.39%, 63.74 and 58.08%, and 50.55 and 77.84% (200 mg/kg, 4 h), respectively, inhibition of paw and ear edema.


CONCLUSIONS
The analgesic and anti-inflammatory effects of MeAB and MeCT involve an interaction with opioid pathway and/or inhibition of chemical mediators of pain and inflammation.
Department of Pharmacology, Faculty of Basic Medical Sciences, College of Medicine, University of Lagos , Lagos , Nigeria and.
Ismail O
IO
Ishola
Esther O
EO
Agbaje
Olufunmilayo O
OO
Adeyemi
Rakesh
R
Shukla
D000700:Analgesics / Q000008:administration & dosage / Q000302:isolation & purification / Q000494:pharmacology; D000818:Animals; D000893:Anti-Inflammatory Agents / Q000008:administration & dosage / Q000302:isolation & purification / Q000494:pharmacology; D029062:Apocynaceae / Q000737:chemistry*; D031484:Capparis / Q000737:chemistry*; D029765:Combretum / Q000737:chemistry*; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D004487:Edema / Q000188:drug therapy; D005260:Female; D007249:Inflammation / Q000188:drug therapy; D008297:Male; D016488:Medicine, African Traditional; D000432:Methanol / Q000737:chemistry; D051379:Mice; D009549:Nigeria; D010146:Pain / Q000188:drug therapy; D010936:Plant Extracts / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley
D000700:Analgesics; D000893:Anti-Inflammatory Agents; D010936:Plant Extracts; D000432:Methanol
Alafia barteri; Capparis thonningii; Combretum mucronatum; formalin; naloxone; opioid pathway; phospholipase A2; xylene