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Author
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Kachisi, Micah K.
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Title
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Exploring the antibacterial effects of Kigella africana (mumvee/ umbvebe) extracts against Escherichia coli
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Abstract
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Escherichia coli is a gram negative bacterium which causes numerous infections, that includes urinary tract infections, gastrointestinal illnesses, and septicemia. The emergency of antibiotic-resistant strains, espacially those producing extended spectrum beta lactamases (ESBLs), has increased the requirement to search for alternative antimicrobial agents (O'Meara & Nesbit, 2013). Kigelia africana (locally known as Mumvee tree) is traditionally used in African ethnomedicine to treat infections, but its antibacterial efficacy against E. coli has not been fully explored (Iwu, 2014; Agyare et al., 2013).
This study investigated the antimicrobial potential of K. africana fruit extract obtained using methanol, ethanol, water, and hexane and tested against E. coli using broth microdilution for Minimum Inhibitory Concentration (MIC), Minimum Bactericidal Concentration (MBC), and disk diffusion assays. Ciprofloxacin served as the positive control. MIC results showed that ethanol and methanol extracts inhibited E. coli at 25% concentration, while ciprofloxacin inhibited at 5%. Water and hexane extracts required 50% and 75%, respectively. These differences were statistically significant (F (4,10) = ∞, p < 0.001), confirming that extract type significantly influenced MIC outcomes.
For MBC, ethanol and methanol extracts showed bactericidal activity at 50%, water at 75%, and hexane at 100%, compared to ciprofloxacin at 6.25% (control). ANOVA also revealed a significant difference in MBC across treatments (F (3,8) = 5.3, p < 0.021), indicating variable bactericidal potency depending on solvent type. In the disk diffusion assay, ciprofloxacin showed the largest mean inhibition zone (22.00 mm)as it was a control, followed by ethanol (15.67 mm), methanol (13.67 mm), water (10.67 mm), and hexane (9.33 mm). Tukey HSD post hoc tests showed ciprofloxacin was significantly more effective than all extracts (p < 0.001), and ethanol outperformed water and hexane extracts (p < 0.05), (Newman & Cragg, 2020; World Health Organization, 2020).
These results align with previous studies that found methanol and ethanol to be efficient solvents for extracting antimicrobial phytochemicals from K. africana (Eloff, 1998; Akinmoladun et al., 2020). The findings support the ethnomedicinal use of K. africana, especially ethanol and methanol extracts, as promising antimicrobial agents. However, ciprofloxacin remains significantly more potent. Further phytochemical screening, toxicity studies, and mode-of-action investigations are warranted to validate clinical applicability (Agyare et al., 2013; Irobi & Akinjogunla, 1994).
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Date
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June 2025
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Publisher
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BUSE
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Keywords
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Antibacterial
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Kigella africana
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Escherichia coli
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Supervisor
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I C. Siamayuwa
