Abstract

The anti-inflammatory and analgesic activities of extract of leaves of Vitex donianaSweet (Verbenaceae) were investigated as well as the mechanisms of action. The extract significantly (P<0.05) inhibited the formation of paw edema induced by agar in rats and increased reaction latency to thermal pain in mice in a dose-dependent manner. The extract caused a significant (P<0.05) dose-dependent ulceration of the rat gastric mucosa and concentration-dependent inhibition of hypotonicity-induced haemolysis of red blood cells. Also, the extract significantly (P<0.05) inhibited the activities of phospholipase A₂ and prostaglandin synthase in a concentration-related manner. These suggest that the leaves possess anti-inflammatory and analgesic activities mediated through sequential inhibition of the enzymes responsible for prostaglandin synthesis from arachidonic acid. Phytochemical analysis of the extract revealed the presence of glycosides, tannins, alkaloids, flavonoids and saponins. Acute toxicity studies established an oral LD₅₀ greater than 3 000 mg/kg.

Key words: Vitex doniana, anti-inflammatory, analgesic, ulcerogenic activity.