Antioxidant, antibacterial, antifungal activities and gas chromatographic fingerprint of fractions from the root bark of Afzelia africana

Bright Yaw Vigbedor; Clement Osei Akoto; Ralph Kwakye; Jonathan Osei-Owusu; David Neglo; Pius Kwashie

Antioxidant, antibacterial, antifungal activities and gas chromatographic fingerprint of fractions from the root bark of Afzelia africana

Int J Biochem Mol Biol. 2022 Dec 15;13(6):60-76. eCollection 2022.

Authors

Bright Yaw Vigbedor¹, Clement Osei Akoto², Ralph Kwakye¹, Jonathan Osei-Owusu³, David Neglo¹, Pius Kwashie¹

Affiliations

¹ Department of Basic Sciences, School of Basic and Biomedical Sciences, University of Health and Allied Sciences PMB 31, Ho, Ghana.
² Department of Chemistry, Kwame Nkrumah University of Science and Technology Kumasi, Ghana.
³ Department of Biological, Physical and Mathematical Sciences, University of Environment and Sustainable Development PMB, Somanya, Ghana.

PMID: 36721842
PMCID: PMC9884338

Abstract

Background: Afzelia africana is a tropical plant with numerous ethno-medicinal benefits. The plant has been used for the treatment of pain, hernia, fever, malaria, inflammation and microbial infections.

Objectives: To perform bioassay-guided fractionation, antioxidant and antimicrobial activities of the bark of Afzelia africana.

Methods: Column chromatography fractionation, antioxidant activity (% (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) and 1,1-diphenyl picrylhydrazyl (DPPH) scavenging activity))), antimicrobial activity (microbroth dilution: Minimum Inhibitory Concentration (MIC), Minimum Bactericidal Concentration (MBC), MBC/MIC ratio), and synergistic activities (Checkerboard assay: Fraction Inhibitory Concentration Index (FICI)).

Results: Bioassay-guided fractionation of A. africana produced four fractions that displayed promising free radical scavenging activities in the ABTS (54-93)% and the DPPH (35-76)% assays in the ranking order of F1(93-54)>F4(81-58)>F2(74-58)>F3(72-55) and F3(77-42)>F1(64-46)>F4(55-44)>F2(47-35) respectively at a concentration range of 1.0-0.01 mg/mL. The fraction F1 (MBC: 2.5-5.0 mg/mL) and F4 (MBC: 1.25-10.0 mg/mL) exhibited broad spectrum of superior bactericidal effects than F2 (MBC≥100.0 mg/mL) and F3 (MBC: 12.5-100.0 mg/mL) against Staphylococcus mutans, Staphylococcus aureus, Escherichia coli, fluconazole-resistant Candida albicans, methicillin-resistant S. aureus, Bacillus subtilis, Klebsiella pneumonia, Pseudomonas aeruginosa, Salmonella typhi, and Candida albicans (standard strain). The two most active fractions (F1 and F4) reported synergistic effects (FICI≤0.5) against S. typhi whilst the F4 reported additional synergism against E. coli, K. pneumonia, and S. typhi when combined with ciprofloxacin. Furthermore, the two fractions reported synergistic effects against Escherichia coli, Klebsiella pneumonia, Salmonella typhi, and Pseudomonas aeruginosa when combined with tetracycline whilst F1 reported antifungal synergism against fluconazole resistant Candida albicans when combined with fluconazole and ketoconazole.

Conclusion: The study has confirmed the antioxidant, antimicrobial and synergistic uses of A. africana for the treatment of both infectious and non-infectious disease.

Keywords: Afzelia africana; antimicrobial; antioxidant; bioassay-guided fractionation; fractional inhibitory concentration index (FICI); minimum bactericidal concentration (MBC).