Anti-Inflammatory Activity of Methanolic Extract of Vitex doniana Fruits in Wistar Rats

Abstract

Vitex doniana is used globally by different communities to treat various ailments including inflammation though without any scientific proof. Although some proven pharmacological properties are available for the leaves, roots, stems and barks; literatures reviewed depicts that there is yet to be an up-to-date information on the fruits. Thus, the aim is to validate this knowledge gap. Extraction was done using cold maceration method. Acute toxicity (LD50) test of methanolic extract of Vitex doniana fruits was determined by the method of Lorke while the phytochemical analyses was done using the method of Trease and Evans. Anti-inflammatory investigation was done using the method of egg albumen and formalin induced paw oedema models. Group I (positive control) received 10 mg/Kg of diclofenac sodium, Group II & III received 200 and 400 mg/Kg body weight of V. doniana fruits’ extract while Group IV (negative control) received 10 mL/Kg of sterile water. Oedema was induced in rats by injecting 0.2 mL of the edematogenic agents into the right hind paw 40 minutes after treatment. Paw oedema size was measured before and after induction of inflammation at 60, 120, 180, and 240 minutes for egg albumen model while at a fixed time for 7 consecutive days duration for the formalin model. The anti-inflammatory effect was calculated as percentage (%) inhibition of oedema in the animals treated groups in comparison to the control groups respectively. Statistical analysis was done using one-way ANOVA followed by a Dunnett’s post hoc analysis. Acute toxicity (LD50) test for Vitex doniana fruits’ extract revealed the absence of toxic symptoms or mortality at dose of 5000 mg/Kg. Phytochemical screening of methanolic extract of Vitex doniana fruits reveals the presence of flavonoids, steroids, carbohydrates, and reducing sugars. In both egg albumen and formalin models, the extract was significant in reducing paw oedema at P<0.05 when compared to the controls. This study has therefore provided some vital scientific information about the anti-inflammatory effect of Vitex doniana fruits that may possibly contribute to its use as a form of herbal therapy in the treatment and management of inflammatory conditions.