Phytochemical and Antipyretic Activity of Aqueous Extracts of Nauclea latifolia Root Bark in Yeast-Induced Pyrexia in Rats

Nauclea latifolia, known as pin cushion tree or African peach, is distributed across the humid forest zones of South East and South South Nigeria, where its root bark is widely used by Igbo and Ibibio herbalists for fever, malaria, and pain management. This study evaluates the phytochemical composition and antipyretic activity of aqueous root bark extract of Nauclea latifolia in a yeast-induced pyrexia model. Plant material was collected from Akwa Ibom State, shade-dried, and extracted by hot maceration. Phytochemical screening detected alkaloids (including strictosamide and nauclefine), tannins, flavonoids, and saponins. Pyrexia was induced in Wistar rats by subcutaneous injection of Brewer's yeast (15% w/v in saline), and rectal temperature was recorded at baseline and hourly for five hours post-treatment. Rats were treated with extract doses of 100, 200, and 400 mg/kg, paracetamol (150 mg/kg) as the reference drug, or normal saline. All extract doses produced significant dose-dependent reductions in rectal temperature beginning one hour post-treatment. The 400 mg/kg dose achieved temperature reductions comparable to paracetamol by the third hour. Acute toxicity assessment showed an LD50 above 5000 mg/kg. These findings validate the traditional antipyretic use of Nauclea latifolia and support progression to further in vivo pharmacological studies. Keywords: Nauclea latifolia, antipyretic, yeast-induced pyrexia, Akwa Ibom, root bark