Comparative Studies of Phytochemical and Antimicrobial Activity oc Carica papaya L. Extracts against Escherichia coli, Staphylococcus aureus and Candida albicans

Abstract

Carica papaya extracts are known for their traditional medicinal uses. The ability of its parts to control the
growth of common pathogens in the laboratory has been tested in different parts of the world using
different varieties of C. papaya. This study was initiated to compare the phytochemical and antimicrobial
activity of different plant parts extracts of C. papaya var. papayi GAV4 on Escherichia coli, Staphylococcus
aureus and Candida albicans. C. papaya plant parts were collected from a farm in Kiboswa (Kisumu):
coordinates 0.0245°S and 34.7474°E, and then were transported to Maseno University Botany Laboratory.
Seeds, green leaves and bark were washed thoroughly with tap water, rinsed in sterile water and dried after
which they were ground using a grinder. From each of the three plant parts, three types of extracts were
prepared using water, acetone and ethanol in the concentrations 25%, 50%, 75% and 100%. The
antimicrobial activity of the extracts was tested on microbes growing on agar plates by inoculation with the
different concentrations using diffusion method and replicated 3 times. Extracts were isolated using Soxhlet
apparatus and MIC determined by serial dilution, zone of inhibition was measured in millimeters. Means
from the measurements were separated and compared at significance level P = 0.05. Phytochemicals
present included alkaloids, flavonoids, tannins, phenols, saponins, glycosides, anthocyanins and terpenoids
while anthraquinones were absent. Ethanol bark extract on C. albicans showed higher inhibition and there
were significant differences in inhibition among the plant parts and extracts used. In concentrations used,
25% was significantly different from 50%, 75% and 100%. The results obtained in this study confirm that
C. papaya has antimicrobial activity on E. coli, S. aureus and C. albicans; and has also shown high potentials
for use as a potential source of antibiotics to treat diseases caused by these microorganisms.