Inhibition of vascular response in inflammation by crude aqueous extract of the root bark of zanthoxylum xanthoxyloides

Abstract

Background: The root bark extract of Zanthoxylum xanthozyloides is used in folklore medicine in Ghana and Nigeria to treat inflammation. A previous pharmacological study confirmed the anti-inflammatory activity of the extract. Objective: To study the effect of the extract on vascular response in inflammation. Method: The extract was obtained by Soxhlet extraction and rotatory evaporation, followed by freezedrying. Groups of rats (with carrageenin-induced paw inflammation) and mice (with xylene-induced pinna inflammation) were, respectively, assigned randomly to treatment groups. The animals were given three different treatments orally: 0.9% saline (control), the extract (400mg/kg and 800mg/kg for mice; 1000mg/kg, 2000
mg/kg, and 4000mg/kg for rats), and indomethacin (5mg/kg and 10mg/kg for mice; 10mg/kg, 20mg/kg, and 40mg/kg for rats). In another set of experiment, each treatment group received phenylephrine subcutaneously (30μg/kg for rats and 20μg/kg for mice) in
addition to the specified treatment aforementioned. Inboth sets of experiments, each group of rats was rotated through the entire treatment groups such that each animal served as control as well as received all the treatments. Analysis of variance was used as the statistical test. Results: The extract and indomethacin both caused
dose-dependent reduction in the carrageenin-induced increase in paw volume in rats and also reduced xylene- induced increase in blood flow in mice pinna arteries. Phenylephrine enhanced the decrease in capillary permeability and vasodilatation caused by low dose extract but not that caused by high dose extract or both low and high dose indomethacin. Conclusion: The extract reduced vasodilatation and
decreased capillary permeability in inflammation.