Studies on the antibacterial activity of root extracts of Carica papaya L.

The bioactive compounds of root extracts of Carica papaya L. were extracted, using water and organic solvents, and were investigated for antibacterial activity against some pathogenic bacteria using the cup plate agar diffusion method. The aqueous extracts did not show significant activity, but the organic extracts had significant activity with the methanol extracts demonstrating the highest activity against the test bacteria. The extracts demonstrated higher activities against all the gram-negative bacteria than the gram-positive bacteria tested, with the highest activity (14 mm zone of inhibition) demonstrated againstSalmonella typhi. Increase in temperature enhanced the activity of the extracts, while alkaline pH decreased the activity. The Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of the extracts ranged between 50-200 mg/ml. Preliminary phytochemical analyses showed that the extracts contain alkaloids, tannins, saponins, glycosides and phenols. Carica papaya may be used for the treatment of gastroenteritis, uretritis, otitis media, typhoid fever and wound infections.   Key words: Carica papaya L., antibacterial activity, phytochemical analysis, antibiotics.