BERNICE OHIORENUAN IMOOBE

Anthocleista vogelii Planch (Gentianaceae) root bark is employed in West African traditional medicine for managing infections and oxidative stress-related ailments. This study characterized the 70% ethanolic root bark extract using chromatographic techniques and evaluated its in-vitro antioxidant and antibacterial properties. Root bark was collected in Akoko Edo, Edo State, Nigeria, authenticated (voucher UBH- A258), and extracted by cold maceration with 70% ethanol. High-performance liquid chromatography (HPLC) employed a C-12 column with water-acetonitrile gradient and UV detection at 280 nm. Gas chromatography-mass spectrometry (GC-MS) used a DB-5MS column with helium carrier gas and NIST library matching. Antioxidant activity was assessed via (2,2-diphenyl-1-picrylhydrazyl) DPPH, (2,2’-azino-bis-3-ethybenzothiazoline-6-sulfonic acid) ABTS, Ferric Reducing Antioxidant Power FRAP, and Total Antioxidant Capacity (TAC) assays. Antibacterial effects were tested by agar well diffusion and dilution methods against Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, Staphylococcus aureus, and Enterobacter cloacae. HPLC identified 19 compounds, including ammodendrine (22.07 µg/mL), cyanogenic glycoside (20.19 µg/mL), and sparteine (15.98 µg/mL) with the higest concentrations. GC- MS detected 35 compounds, dominated by 2,8-decadiyne (18.0%), pentyl octanoate (9.7%), and elaidic acid (7.1%). The extract showed potent DPPH scavenging (91.92 % at 200 µg/ml), ABTS inhibition (93.24% at 200 µg/mL), FRAP (40.44 at 400 µg/ml),and TAC (89.15% at 1000 µg/ml). Inhibition zones ranged 13–18 mm; MICs were 25–100 mg/mL, with MBCs 100–200 mg/mL. The extract demonstrated bactericidal activity, particularly against S.aureus, P. aeruginosa and E. clocae. These results validate the ethnomedicinal use of A. vogelii root bark and highlight its potential as a natural source of antioxidants and antibacterials