In Vitro Antimicrobial Activity of Ethanolic Leaf Extracts of Hibiscus Asper Hook. F. and Hibiscus Sabdariffa L. on Some Pathogenic Bacteria

Purpose: The study aims to assess the antimicrobial activity of ethanolic leaf extracts of Hibiscus asper and Hibiscus sabdariffa against eight bacterial isolates. Materials and Methods: An in vitro Antimicrobial activity of ethanolic leaf extract of the two plants against eight nosocomical and pathogenic bacteria viz; Pseudomonas aeruginosa (PAE), Proteus vulgaris (PVU), Klebsiella aerogenes (KAE), Staphylococcus aureus (SAU), Bacillus cereus (BCE), Escherichia coli (ECO), Moraxella Catarrhalis (MCA) and Salmonella typhi (STY) was carried out using agar well diffusion assay with the concentration range of 3.13 – 100 mg/mL. Results: H. asper and H. sabdariffa showed significant difference (p< 0.05) in antimicrobial activity against BCE over the rest of the isolates. Inhibition zone diameters exhibited by the isolates to ethanolic leaf extract of H. asper was in descending order of BCE (15.00 ± 1.00a) >ECO (11.67 ± 0.58b) >SAU (7.67 ± 0.58c) >PAE (6.67 ± 0.58d) >STY (5.67 ± 0.58e) while that of H. sabdariffa was in the order BCE (15.33 ± 1.15a) > MCA (11.33 ± 1.15b) > SAU (11.00 ± 1.00bc) > KAE (9.67 ± 0.58c) > PAE (8.00 ± 1.00d) >PVU (7.67 ± 0.57e). PVU, KAE and MCA were resistant to the extract of H. asper while only STY was resistant to that of H. sabdariffa. Conclusion: H. sabdariffa extract demonstrated higher antimicrobial activity against the selected bacterial isolates than H. asper. However, the two extracts minimum inhibition concentrations (MICs) ranged from 25 mg/mL to 12.5 mg/mL. This is worthy of further exploration by pharmacological industries in the formulation of potent broad spectrum antibiotics for combating the present health challenge due to antimicrobial resistance