Assessment of antibacterial properties of dried garlic and onion against common bacterial pathogens.

Thumbnail Image
Kalyati, Constance
Journal Title
Journal ISSN
Volume Title
The University of Zambia
According to the World Health Organization, the extensive and sometimes indiscriminate use of antibiotics for treatment and as growth promoters in the animal production industry has resulted in the widespread development of antibiotic resistance. As such, antimicrobial resistance cannot be overemphasized as the discovery trend of resistant strains has continued. Thus, the pursuit of new natural plant-based antibiotics is a call to action for scientists to save the world. Garlic and onions are traditional herbs that have been used since ancient times in the preparation of not only food but medicines as well. In this study, the aim was to assess if dried garlic, red, and yellow onions possess antibacterial properties and the effect evaporation procedures and temperatures used have on their activity. Cured Allium sativum (garlic) and Allium cepa (onion) were bought from the local market. The plants were dried, coarsely crushed, and macerated using solvents: ethyl acetate, ethanol, and water. To obtain the crude extracts, two evaporation procedures were used: water bath and oven evaporation; water bath evaporation was at a temperature of 95ºC, whereas oven evaporation was at 35ºC. To test for antibacterial activity, agar dilution method was used against standard American Type Culture Colony strains of Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli and Salmonella typhi all of which are of public health significance. The activity was then graded as susceptible, intermediate, or resistant. Among the extracting solvents used, water extracts had the highest yield potential, which was followed by ethanol and finally ethyl acetate in order of decreasing polarity. Results showed that extracts from the oven evaporating procedure were more efficacious compared to those of water bath evaporation procedure indicating that the active ingredient is heat labile to high temperatures and in this case 95ºC. The best antibacterial extracting solvent from the oven evaporating procedure was the water extracting solvent, which was effective against all four test organisms. The activity was followed by ethanol, with ethyl acetate being the least effective. Based on the water bath evaporating procedure, extracts obtained from ethanol were more efficacious compared to the two extracting solvents, which showed a higher percentage of bacteria resistance. Following the individual antibacterial assessment of garlic, red onion, and yellow onion with respect to the two evaporating procedures used, observations were made that the percentage of susceptible bacteria to the plant extracts subjected to oven evaporation was higher than the percentage susceptibility of the bacteria to the plant extracts subjected to water bath evaporation. Therefore, based on the findings, it can be said that dried garlic and onions do have antibacterial properties against bacterial pathogens under study and that the plants have a higher potency when exposed to a low evaporation temperature like 35ºC as opposed to a high temperature of 95ºC. However, evaporation at temperature 35ºC and below is recommended so as to minimize the exposure of these plants to heat, thereby raising their antibacterial activity.
Antibacterial Properties -- Dried Onion , Antibacterial Properties -- Dried Garlic , Common Bacterial Pathogens