Antinociceptive Properties of Methanolic Bark Extracts of Terminalia brownii in Wistar Rats

Abstract

Background: The barks of the medicinal plant, Terminalia brownii, are widely used in African folk medicine for the management of pain. However, this ethno-medicinal allegation has not been scientifically validated. This study was therefore designed to verify the antinociceptive potential of the methanolic bark extract of T. brownii in Wistar rats (Rattus novegicus). Methods: Fresh barks of T. brownii were obtained from Kitui County, Kenya with the guidance of a residential herbalist. The study used thirty 2-3 months old male Wistar rats, weighing 140-150 g. The rats were randomly divided into 6 groups; three control groups (normal, negative and positive) and three experimental groups (50, 100 and 150 mg/kg extract treatment). Each group had five rats. The analgesic properties of the extract were evaluated on formalin-induced pain and diclofenac was used as the standard drug. Results: The methanolic bark extracts of T. brownii demonstrated significant antinociceptive activity (p<0.05) by reducing the paw licking time by between 4.62%-44.96% in the early phase and 35.77%-58.89% in the late phase. Diclofenac reduced the paw licking time by 44.79% in the early phase and 55.33% in the late phase. Conclusion: Our study results strongly support the antinociceptive activity of the barks of T. brownii and rationalize the traditional use of the barks in management of pain.