ANTIMICROBIAL ACTIVITIES OF SELECTED MEDICINAL PLANTS AGAINST PATHOGENS CAUSING CLINICAL MASTITIS IN DAIRY COWS IN GURSUM DISTRICT, OROMIA, ETHIOPIA

Abstract

The main objective of this study was to evaluate the antimicrobial activities of selected medicinal plants against bacterial and fungal pathogens isolated from clinical mastitis in dairy cows in Gursum District, Oromia, Ethiopia. Antimicrobial activities of Dolichos oliveri (D. oliveri), Mirabilis jalapa L. (M. jalapa L.), Euphorbia schimperiana (E. shimperiana), and Cyphostemma adenocaule (C. adenocaule) on Staphylococcus aureus, Enterobacter aerogenes, Candida albicans, and Aspergillus fumigatus was conducted by Methanol extraction and disc diffusion method measuring the mean zone of inhibition. The Minimum Inhibitory Concentration (MIC), Minimum Bactericidal Concentration (MBC), and Minimum Fungicidal Concentration (MFC)was determined by serial two-fold dilution using Tube Broth Dilution (broth macrodilution). Data analysis involved one-way ANOVA and Tukey post hoc tests using SPSS version 20. Phytochemical analysis identified active compounds, including alkaloids, phenols, saponins, and terpenoids, responsible for the antimicrobial properties. Dolichos oliveri exhibited the highest inhibition zone (13.33 ± 0.1 mm) against S. aureus standard strains at 125 mg/ml. D. oliveri and E. shimperiana showed significantly higher (P<0.05) activity against standard strains of S. aureus, E. aerogenes, C. albicans and A. fumigatus at 125 mg/ml than M. jalapa L. On the other hand, M. jalapa L.. had significantly higher activity against C. albicans (P<0.05) at the concentration of 125 mg/ml than all the tested plants. E. shimperiana and C. adenocaule showed significantly higher (p<0.05) activity against the clinical isolate of A. fumigatus at 125 mg/ml. Minimum Inhibitory Concentration (MIC) values ranged from 37.5 mg/ml (E. shimperiana, C. adenocaule, and M. jalapa L) against S. aureus and E. aerogenes to 125 mg/ml (D. oliveri) against S. aureus and C. albicans. Minimum Bactericidal Concentration (MBC) ranged from 100 mg/ml (D. oliveri) against S. aureus to 400 mg/ml (C. adenocaule and M. jalapa L.) against S. aureus and E. aerogenes. Minimum Fungicidal Concentration (MFC) was exhibited only at 200 mg/ml by M. jalapa L.. against A. fumigatus. M. jalapa was the only plant showing anti-fungal activity at MIC value (37.5 mg/ml) against A. fumigatus. It showed selective bacteriostatic and fungistatic effects on E. aerogenes and A. fumigatus. These findings justify the traditional use of the plants for the treatment of mastitis in dairy cows underscoring their promising potential as alternative antimicrobial agents for managing mastitis and other livestock diseases. Therefore, phytochemical isolation and analysis of individual bioactive compounds of plant extracts, their in vivo antimicrobial activities with different extraction solvents and their toxicity levels should be further studied to use them for the development of alternative sources of drugs.