Antibacterial Potential of Ethanolic and Aqueous Extracts of Carica papaya Leaves

Background: The search for newer sources of antibiotics is a global challenge pre-occupying
research institutions, pharmaceutical companies and academia, since many infectious agents are
becoming resistant to synthetic drugs.
Aim: This present study sought to investigate the antibacterial potential of ethanolic and aqueous
extracts of Carica papaya leaves.
Materials and Methods: Fresh and healthy leaves of C. papaya were harvested, air dried and
milled into powder. The powder was extracted using ethanol and water as solvents. The
antibacterial activities of both extracts were determined by diffusion method. Nutrient agar medium
was prepared using standard method. Pure cultures of Coliform bacillus, Staphylococcus
epidermidis, Streptococcus viridans, Salmonella typhi and Escherichia coli were obtained from the
Department of Veterinary Microbiology and Parasitology, Federal University of Agriculture,  Abeokuta, Nigeria. The extracts were serially diluted to obtain 1.0%, 0.5%, 0.25% and 0.125%

solutions in sterile test tubes. Sterilized 9 mm filter paper disc soaked in the diluted extracts were
placed on the plate and incubated for 24 hours at room temperature. The plates were examined for
clear zones of inhibition. Presence of zones of inhibition indicated activity.
Results: the results showed that both ethanolic and aqueous extracts of C. papaya leaves exhibit
antibacterial activities against C. bacillus, S. epidemidis, S. viridans and E. coli and also inhibited
their growth. The effect of the ethanolic extract was greater than that of the aqueous extract.
However, this activity was not observed with S. typhi.
Conclusion: The result of the present study showed that C. papaya leaves might effectively inhibit
the growth of C. bacillus, S. epidemidis, S. viridans and E. coli but not that of S. typhi. However,
the ethanolic extract is more potent than the aqueous extract.