PROTECTIVE AND CURATIVE EFFECTS OF ETHANOL EXTRACT OF NAUCLEA LATIFOLIA ON ADJUVANT-INDUCED ARTHRITIS IN RATS
OKPO S.O.*, AMOO, S.O.
Department of Pharmacology & Toxicology, Faculty of Pharmacy
University of Benin, Benin City 300001, NIGERIA
Afr. J Pharm Res Dev; Volume 8(1): 32-41; June/July 2016
ABSTRACT
Nauclea latifolia Smith (Rubiaceae) is traditionally used in Nigeria in the management of various ailments such as abdominal pains, dysentery, diabetes, hepatitis, hypertension, rheumatism, yellow fever, jaundice and malaria. Its local use in the treatment of rheumatism has prompted the investigation into its anti-arthritic efficacy. The current study was therefore designed to evaluate the prophylactic and curative effects of ethanol root extract of Nauclea latifolia (ERENL) on development of adjuvant arthritis in rats. Arthritis was induced in Sprague-Dawley rats by a single injection of 0.1 ml complete Freund’s adjuvant (CFA) into the sub-plantar aponeurosis of the left hind paw. Rats were treated by once daily oral administration of ERENL (25, 50 and 100 mg/kg) on the same day of arthritis induction (prophylactic treatment) and day 12 post arthritis induction (curative treatment) till the 28th day. Indomethacin (2 mg/kg) and methotrexate (1 mg/kg) were used as the standard drugs and administered twice weekly. The effects of the extract and standard drugs were evaluated by changes in paw volume, ankle diameter, arthritis score, body weight, erythrocyte sedimentation rate (ESR), haemoglobin and leucocyte counts. Prophylactic and curative treatment with ERENL caused a dose-dependent and significant suppression of paw and ankle swelling, arthritis score, ESR and body weight loss but had no significant effects on spleen or liver weight indices, haemoglobin and leucocyte count compared to arthritic control rats. The ethanol root extract of Nauclea latifolia possesses anti-arthritic activity and was effective irrespective of whether it was administered alongside arthritis induction or after arthritis had already begun. Suppression of arthritis following administration of the extract before and after induction of arthritis demonstrates its ability to protect against development of arthritis as well as suppress an already established one.
*Corresponding Author: steveokpo@uniben.edu