Phytochemical Screening and Antimicrobial Activity Evaluation of Selected Medicinal Plants in Ethiopia

Abstract

Background

The emergence and spread of resistant microbes continue to be a major public health concern. Effective treatment alternatives, particularly from traditionally used medicinal plants, are needed.

Objective

The main objective of this study was to conduct phytochemical screening and antimicrobial activity evaluation of selected traditionally used medicinal plants in Ethiopia.

Methods

The ethnomedicinal use value frequency index (FI) was used to select twelve medicinal plants. Phytochemical classes of compounds were screened using different standard methods. Anti-microbial activities of plant extracts were evaluated against Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, and Candida albicans. Minimum inhibitory concentrations were measured using the broth micro-dilution method. The data were analyzed using Statistical Package for the Social Sciences (SPSS) version 21.0 and the findings were presented descriptively and using non parametric one-way ANOVA analysis (Kruskal–Wallis/Ddunn’s test).

Results

The phytochemical constituents identified were flavonoids, alkaloids, glycosides, phenols, saponins, steroids, and terpenoids, with flavonoids, alkaloids, and phenols being the most abundant. The crude extracts and chloroform fractions of the extracts showed an activity against the tested strains. The crude extract of Thalictrum rhynchocarpum Quart.-Dill. and A.Rich root demonstrated superior activity against all the tested strains with the lowest minimum inhibitory concentrations of 0.48 μg/mL against Staphylococcus aureus and Escherichia coli; 0.98 μg/mL against Klebsiella pneumoniae, Pseudomonas aeruginosa; and 3.90 μg/mL against Candida albicans, which are even better than the reference drug, gentamicin and clotrimazole.

Conclusion

The majority of evaluated medicinal plants demonstrated remarkable activity against tested microbial strains, which can be attributed to the presence of secondary metabolites of different classes of compounds. The finding provided scientific evidence for the use of these traditionally used medicinal plants.

Keywords:

• traditional medicine
• medicinal plants
• phytochemical screening
• antimicrobial activity
• minimum inhibitory concentration

Abbreviations

ANOVA, Analysis of Variance; EPHI, Ethiopia Public Health Institution; DCM, Dichloro Methane; DMSO, Dimethyl Sulfoxide; IRB, Institutional Review Board; NTD, Neglected Tropical Infectious Diseases; MIC, Minimum Inhibitory Concentration; RF, Retention Factor; TLC, Thin Layer Chromatography; TMP, Traditional Medicine Practitioner; TM, Traditional Medicine; V/V, Volume by volume; WHO, World Health Organization.

Ethics Approval

The ethical clearance was obtained from the Jimma University Health Science Institutional Review Board (IRB) with approval letter reference number JHRPG/720/2020.

Acknowledgment

The authors would like to thank Jimma University for funding the study and providing reagents. Our gratitude also goes to the Ethiopian Public Health Institute (EPHI) for kindly providing us with the standard microbial strains.

Disclosure

All authors reported that there was no conflict of interest.