Antioxidant, antibacterial and antidiarrhoeal properties of Combretum imberbe Wawra leaf extracts

Background: Bacterial diarrhoea affects people of all ages globally, and resistance of bacterial pathogens to commonly prescribed antibiotics is a major worldwide challenge. Aim: This study aimed at evaluating the antibacterial activities of Combretum imberbe leaf extracts against bacterial pathogens causing gastrointestinal infections. Setting: The study was conducted to provide a scientific basis for the antidiarrheal and antibacterial properties of C. imberbe. Methods: Acetone, ethanol and water extracts were prepared from C. imberbe leaves. Qualitative and quantitative phytochemical evaluation was conducted on the extracts. In vitro antioxidant activity of the extracts was also evaluated. The antibacterial ability was assayed using the minimum inhibition concentration (MIC) microdilution method against several bacterial pathogenic strains. Results: Phytochemical screening showed that the C. imberbe extracts contained flavonoids, saponins and tannins. The extracts demonstrated appreciable free radical-scavenging activities. The acetone and ethanol extracts of C. imberbe leaf were the most active against Staphylococcus aureus (MIC = 15.6 µg/mL), Enterococcus faecium (MIC = 31.2 µg/mL) and Enterococcus faecalis (MIC = 15.6 µg/mL). All the plant extracts showed low activity against Bacillus cereus and Escherichia coli bacteria, with MIC values in the range of 250 to ˃1000 µg/mL. Results showed that acetone and ethanol extracts were the most therapeutically relevant among the three extracts by showing considerable antibacterial activity and non-toxicity. Conclusion: This study underlines the antibacterial and antioxidant properties of the leaf extracts of C. imberbe. Contribution: This study plant can be considered in the treatment of treating diarrhoea because of enteric bacteria.