Antimicrobial activity and phytochemical screening of ethanol extracts of six traditionally used medicinal plants in East Amhara, Ethiopia

Abstract Background: Antimicrobial resistance (AMR) poses a significant challenge to global health, necessitating the exploration of alternative treatments, particularly from natural sources. This study thus aimed to evaluate the antimicrobial activity and phytochemical profiles of six traditional medicinal plants from East Amhara in Ethiopia against Staphylococcus aureus and Salmonella typhi. Methods: Ethanol crude extracts of Myrtus communis, Ziziphus spina-christi, Euclea racemosa, Syzygium guineense, Carissa spinarum, and Senna singueanawere prepared using a 1:10 (w/v) ratio cold maceration extraction technique. Antibacterial activity was assessed via the agar disk diffusion assay method, whereas Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) were carried out by broth dilution method. Furthermore, phytochemical screenings of the extracts were conducted to identify secondary metabolites according to the respective protocols and operational manuals. Results: The findings indicated a dose-dependent antibacterial effect across all the tested plant species. M. communis exhibited the strongest antibacterial activity against S. aureus (22.33±1.2 mm inhibition zone) followed by C. spinarum (18.61± 0.33 mm). Regarding the antibacterial effects against S. typhi, M. communis, and C. spinarumagain produced the first and second highest activity; 17.01±0.58 mm and 16.62±0.33 mm zone of inhibition respectively. The lowest antibacterial activity against S. aureus was recorded by the extract of S. singueana (14.61±0.33 mm), whereas, the extract of E. racemosa (13.30±0.33 mm) produced the weakest activity against S. typhi. The lowest MIC values (6.25 mg/ml) were also noted for M. communisagainst both bacterial strains, indicating potent antibacterial properties. Furthermore, phytochemical screening revealed the presence of multiple bioactive compounds, such as alkaloids, flavonoids, tannins, phenolics, terpenoids, saponins, steroids, glycosides, and anthraquinones among the tested extracts. Conclusion: The study validates the antimicrobial potential of the selected medicinal plants, supported by their diverse phytochemical profiles. M. communis and C. spinarumwere found to cause potent antibacterial activity. The present study thus suggests that extracts of the leaves of these plant species may serve as valuable sources for developing new antimicrobial agents. Further investigation into their active compounds is also warranted to enhance therapeutic applications.