Analgesic and Anti-Inflammatory Properties of Vitex doniana Stem Bark Extract: Preclinical Evaluation in Rodent Models

Background: Vitex doniana (black plum) is widely used in traditional medicine across Nigeria for the management of pain, fever, and inflammatory conditions. Despite its ethnopharmacological prominence, rigorous preclinical validation of its analgesic and anti-inflammatory activities is limited. This study evaluated the analgesic and anti-inflammatory effects of V. doniana methanolic stem bark extract using established rodent models. Methods: Phytochemical screening was conducted to characterise the extract composition. Analgesic activity was assessed using the acetic acid-induced writhing test and hot plate test in mice. Anti-inflammatory activity was evaluated using carrageenan-induced paw oedema and cotton pellet granuloma models in rats. Extract doses of 100, 250, and 500 mg/kg were compared against morphine, aspirin, and indomethacin as reference standards. Acute toxicity was assessed using the Lorke method. Results: The extract demonstrated significant dose-dependent analgesic activity (p less than 0.01) in both writhing and hot plate tests. Anti-inflammatory activity was significant from the second hour of carrageenan paw oedema, with maximum inhibition at 500 mg/kg (58%). Chronic granuloma inhibition was 42 percent at the highest dose. Phytochemical analysis confirmed flavonoids, terpenes, and tannins. LD50 exceeded 5000 mg/kg. Conclusion: V. doniana stem bark extract possesses significant analgesic and anti-inflammatory activities, lending scientific support to its traditional medicinal use. Bioguided fractionation is recommended to identify the active constituents. Keywords: Vitex doniana, analgesic, anti-inflammatory, ethnopharmacology, preclinical