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

Carica papaya extracts are known for their traditional medicinal uses. The ability of its parts to control thegrowth of common pathogens in the laboratory has been tested in different parts of the world usingdifferent varieties of C. papaya. This study was initiated to compare the phytochemical and antimicrobialactivity of different plant parts extracts of C. papaya var. papayi GAV4 on Escherichia coli, Staphylococcusaureus 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 afterwhich they were ground using a grinder. From each of the three plant parts, three types of extracts wereprepared using water, acetone and ethanol in the concentrations 25%, 50%, 75% and 100%. Theantimicrobial activity of the extracts was tested on microbes growing on agar plates by inoculation with thedifferent concentrations using diffusion method and replicated 3 times. Extracts were isolated using Soxhletapparatus and MIC determined by serial dilution, zone of inhibition was measured in millimeters. Meansfrom the measurements were separated and compared at significance level P = 0.05. Phytochemicalspresent included alkaloids, flavonoids, tannins, phenols, saponins, glycosides, anthocyanins and terpenoidswhile anthraquinones were absent. Ethanol bark extract on C. albicans showed higher inhibition and therewere 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 thatC. papaya has antimicrobial activity on E. coli, S. aureus and C. albicans; and has also shown high potentialsfor use as a potential source of antibiotics to treat diseases caused by these microorganisms.