In vivo inhibition of prostaglandin e2 production by crude aqueous extract of the root bark of zanthoxylumxanthoxyloides

Background: Crude aqueous extract of the root bark of Zanthoxylum xanthoxyloides is used in folklore medicine for its anti-inflammatory activity. Although it shares the analgesic and anti-inflammatory propertyof non-steroidal anti-inflammatory drugs (NSAIDs), its mechanism of action has not been well elucidated. Objective: To ascertain whether the extract decreases carrageenin-induced increase in plasma prostaglandinE2 (PGE2) concentration with the view to shed light on the mechanism of action.Methods: The extract was obtained by Soxhlet extraction and rotatory evaporation, followed by freezedrying. Forty Wistar rats (150g - 200g) were assigned to 8 groups of 5 rats each. The rats were given fourdifferent treatments orally: 0.9% saline (two groups of control); two groups received indomethacin, 20mg/kg and 40mg/kg respectively; another two groups received the extract, 2000mg/kg and 4000mg/kg respectively;and the remaining two groups, 50mg/kg and 100mg/kg nimesulide respectively. Inflammation was induced with carrageenin in one of the two groups of control. Enzyme-linked immunospecific assay was used tomeasure plasma PGE2 concentration in the control and treated groups of rats. Analysis of variance was used as the statistical test. Differences in means at