Antibacterial Activities of the Aqueous and Ethanolic Extracts of the Male and Female Carica papaya Leaves on Some Pathogenic Bacteria

Abstract

The antibacterial activity of water and ethanol extracts of male and female Carica papaya leaves was carried out on pathogenic isolates. The leaf extracts were prepared by suspending the finely blended leaves separately in distilled water and ethanol. The mixtures were then agitated, decanted, filtered and finally, evaporated to dryness. The antibacterial activity was carried out using the disc diffusion method. The test organisms were Gram negative and Gram positive pathogenic bacteria organisms viz; Escherichia coli, Staphylococcus aureus, Proteus vulgaris, Klebsiella pneumoniae, Bacillus cereus, Salmonella typhi and Pseudomonas aeruginosa. The water extracts yielded no significant antibacterial activity against the test isolates. The ethanol extracts of both male and female papaya leaves demonstrated higher activities against all the Gram negative bacteria than Gram positive bacteria tested. The highest activities (18mm zone of inhibition) were demonstrated against Pseudomonas aeruginosa for the female leaf extract and (17mm zone of inhibition) for the male leaf extract. The Minimum Inhibitory Concentration ranged between 6.25-50μg/ml and Minimum Bacteriocidal Concentration ranged between 25μg/ml-50μg/ml for both male and female ethanol extracts. Demonstration of antimicrobial activity against the test isolates is an indication that there is possibility of sourcing alternative antibiotic substances in this plant for the development of newer antibacterial agents.