ABSTRACT

The antibacterial activity of the seed extract of Carica papaya on some human pathogens was carried out using the disc diffusion method. The bioactive compound of the seeds was extracted using water and 95%ethanol. These were investigated for antibacterial activity on Staphylococcus aureus, Shigella dysenteriae, Salmonella typhi, Pseudomonas aeruginosa and Escherichia coli. The aqueous and ethanol extract of the seeds were tested at 25, 50, and 100mg/ml concentrations on the bacterial isolates. Results showed that the ethanolic and aqueous extracts of the seeds were effective in inhibiting all the test organisms. The cthanolic cxtract gave a higher antibacterial activity on the test organism than the aqueous extract. S.aureus had the highest susceptibility to the ethanolic extract at I00mg/ml concentration with a zone or inhibition of 11.0mm. S.typhi had the least susceptibility to the ethanol extract at 25mg/ml concentration with a zone of inhibition of 2.9mm. The test organisms had a higher susceptibility to the standard antibiotics chloramphenicol (12.2-13.2mm) than the seed extract. Demonstration of antibacterial 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.