Analgesic effect of the methanol extract of Garcinia kola stem bark

Abstract

This study sought to establish the analgesic properties of the methanol extract of the stem bark of Garcinia kola (Heckel) in mice 
using chemical and thermal test models of nociception. The hot plate, formalin, tail immersion and acetic acid-induced writhing tests were used to assess the analgesic effect of the extract in mice. Animals were pre-treated intraperitoneally with the extract in doses of 18, 36 and 72mg/kg. Acetylsalicylic acid was used as the reference drug; and one group of animal was given acetylsalicylic acid and 36mg/kg of the extract, in order to investigate the effect of the combination of the extract and the reference drug on nociception. The chemical models of analgesia showed significant inhibitions of acetic acid-induced writhing episodes, with percentage analgesic activity greater than acetylsalicylic acid; and significant decreases in formalin-induced sub-plantar licking time in the early and late phases. Furthermore, the extract produced significant increase in reaction time in the thermal models (tail immersion and hot plate tests). In all the models, the extent of analgesic activity in the group of animals where the extract was combined with acetylsalicylic acid was higher in magnitude than either acetylsalicylic acid or 36mg/kg of the extract given alone. The methanol extract of the stem bark of Garcinia kola (Heckel) markedly demonstrated analgesic action in mice. The result of this study scientifically justifies the rationale in the traditional use of this part of the plant to treat dysmenorrhoea.