Anti-salmonella activity of Ethanolic extracts of Eucalyptus globulus and Allium sativum

Abstract

Salmonella infections (typhoid fever) are among the leading public health threat in Uganda. Conventional drugs have been effectively used in the treatment of infections however, they are faced with many challenges which include; antimicrobial resistance, being expensive, inaccessibility to the people in remote areas and many side effects. Consequently, people have resorted to natural remedies such as Allium sativum and Eucalyptus globulus either singly or in combination. However, these have not been scientifically evaluated to be working effectively against typhoid fever. This study, therefore, sort to determine the Anti-salmonella activity of ethanolic extracts of Eucalyptus globulus, Allium sativum, and their combinations. A concentration of 70% ethanol was used to obtain the residues of Allium sativum and Eucalyptus globulus, the residues were then reconstituted to obtain five extracts of a stock solution 400mg/ml which included; A. sativum, E. globulus and their combinations of ratios 1:1 (A. sativum: E. globulus), 1:2 (A. sativum: E. globulus), and 2:1 (A. sativum: E. globulus). Clinical isolates of Salmonella typhi were used as the test organism. The study employed agar well diffusion assay to determine inhibition zone diameters and broth dilution assay was employed to determine the MIC and MBC. Eucalyptus globulus had a slightly higher percentage yield of 11.9% compared to that of A. sativum 11.3%. Allium sativum had the highest inhibition zone diameter (32.67±0.88) mm as compared to the rest including the positive control (Ciprofloxacin), minimum inhibition concentration (16.2mg/ml) and minimum bacterial concentration (12.4mg/ml). There was a statistically significant difference (P=0.01) between A. sativum and positive control. Therefore it can be concluded that Allium sativum had a higher antibacterial activity hence can be used in the management of S. typhi without combining it with E. globulus. However, further research should be carried comparing different types of solvents in the extraction, phytochemicals analysis, and more scientific evidence is required based on randomized clinical trials in order to investigate the antimicrobial activity of Allium sativum and Eucalyptus globulus against Salmonella typhi in vivo and its effect on prevention or reduction of typhoid fever.