Assessment of antibacterial properties of dried garlic and onion against common bacterial pathogens.
Date
2023
Authors
Kalyati, Constance
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Journal ISSN
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Publisher
The University of Zambia
Abstract
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.
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Keywords
Antibacterial Properties -- Dried Onion , Antibacterial Properties -- Dried Garlic , Common Bacterial Pathogens