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Antimicrobial resistance to commercially available medications has become a global issue, yet there is still the possibility of developing new drugs from medicinal plants. As a result, the aims of the present study were to screen secondary metabolites and to evaluate in vitro antifungal activities of Brucea antidysenterica, Aloe vera, and Justicia schimperiana. After the plants were identified, their leaves were collected, washed, dried under the shade, pulverized, and extracted with methanol (99.8%) using the maceration technique. The presence of secondary metabolites in plant extracts was screened using various laboratory protocols. The antifungal activities of the plant extract against reference fungal strains of Candida albicans and Aspergillus niger at concentrations of 200, 100, and 50 mg/mL were assessed using the agar-well diffusion method. Ketoconazole (15 μg) was used as a positive control, while 5% dimethyl sulfoxide and/or 5% Tween 80 were used as negative controls. All tests were conducted in triplicate. Alkaloids, flavonoids, and phenols were secondary metabolites found in all plant extracts. The extract of leaves of B. antidysenterica and J. schimperiana formed a mean zone of inhibition of 15.5 ± 0.5 mm and 15.3 ± 0.58 mm, respectively, against Candida albicans at a concentration of 200 mg/mL, whereas extracts of A. vera leaves formed a 12.3 ± 0.58 mm inhibition zone only against Aspergillus niger at 200 mg/mL. In conclusion, the current study found that B. antidysenterica, A. vera, and J. schimperiana had antifungal activity. In addition, all these plants had a variety of secondary metabolites that possibly have antifungal activities. Studies on in vivo investigations and isolation of specific antifungal compounds from these medicinal plants are suggested.

Background: Although traditional healers in Ethiopia have a long history of using medicinal plants to treat diseases in animals and humans, studies on the antibacterial activities and potential bioactive ingredients of most medicinal plants have been insufficient. Therefore, this study aimed to evaluate the in-vitro antibacterial activities and to screen phytochemical constituents of selected medicinal plants against reference bacterial strains. Methods: The fresh and healthy roots of Echinops amplexicaulis, fruits of Ruta chalepensis, and leaves of Salix subserrata were collected from West Shewa Zone, Ethiopia. Agar well diffusion and agar dilution methods were used to evaluate antibacterial activities and minimum inhibitory concentrations (MIC). All the crude plant extracts were tested against Staphylococcus aureus, Streptococcus pneumoniae, Escherichia coli and Pseudomonas aeruginosa at concentrations of 100, 50, and 25 mg/mL in each triplet (3x). MIC of crude extracts ranging from 1.5625 to 12.50 mg/mL was applied to all bacterial strains. The positive control was ciprofloxacin disk (5 μg) and the negative control was 5% dimethyl sulfoxide. The presence of secondary metabolites of each crude extract was screened. The group means comparisons were done using one-way ANOVA and results were presented as mean ± standard deviation. Results: Although all selected plant extracts had shown antibacterial activities, methanol extracts had a greater zone of inhibition against all reference bacterial strains when compared to petroleum ether extracts. The growth of P. aeruginosa was inhibited at a minimum concentration of both methanol and petroleum extracts (1.5625 mg/mL) when compared to the remaining bacterial strains. Phytochemical screening showed that saponins and alkaloids were found in all crude plant extracts, while phytosterol was meager. Conclusion:This study revealed that all tested plants had significant secondary metabolites and antibacterial activities against reference bacterial strains.

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