Phytochemical and Antimicrobial Evaluation of Piliostigma thonningii Bark Used in Traditional Medicine in Nassarawa State, North Central Nigeria

Piliostigma thonningii is a savannah tree found across the Guinea woodland zones of Nigeria, particularly in Nassarawa State, North Central Nigeria, where its bark is employed by the Eggon, Gbagyi, and Tiv peoples for the treatment of skin infections, wound sepsis, and gastrointestinal disorders. This study evaluates the phytochemical composition and antimicrobial properties of aqueous and ethanolic bark extracts of Piliostigma thonningii. Plant materials were collected from Akwanga and Lafia local government areas, shade-dried, and extracted by cold maceration. Phytochemical screening was conducted using standard procedures. Antibacterial and antifungal activities were assessed by the agar well diffusion method against Staphylococcus aureus, Escherichia coli, Salmonella typhi, and Candida albicans. MIC values were determined by serial broth dilution. Phytochemical analysis revealed tannins, flavonoids, phenolics, alkaloids, and terpenoids as the predominant constituents. The ethanolic extract demonstrated the highest antibacterial activity against S. aureus and S. typhi, with inhibition zones of 18 and 16 mm respectively. Antifungal activity against C. albicans was moderate. Physicochemical parameters of the bark drug material were also established. These findings provide a pharmacognostic basis for investigating Piliostigma thonningii as a source of lead antimicrobial compounds and support the development of standardised preparations from this species. Keywords: Piliostigma thonningii, antimicrobial, bark extract, Nassarawa State, phytochemical