Antibacterial effects of Carica papaya on common wound organisms [abstract]

ABSTRACT

OBJECTIVE: The objective was to investigate the antibacterial activity of the crude Carica papaya preparations as used by nurses, on gram negative and gram positive organisms; to determine which part and stage of maturity of the fruit yielded the best antibacterial activity, and determine the effects of storage conditions on the observed activity. METHODS: The pathogens commonly found in human wounds were obtained from the Microbiology Department, University of the West Indies, Biochemistry Section, The University of the West Indies and the Jamaican Bureau of Standards. Cultures were routinely maintained in nutrient agar slants at 4§c. Extracts were obtained by separately grinding fractions of the epicarp, endocarp and seeds of the immature, mature and ripe Carica papaya fruit and filtering them through guaze. Sensitivity tests were conducted by adding 0.06 ml. of agar wells (6 mm diameter) prepared from 20 ml agar seeded with 10 cells/ml suspension of one of the eight organisms per plate. The inoculated plates were allowed to equilibrate at 4§c for one hour then incubated at 37§c for 24 hours, after which zones of inhibition were measured in millimeters. Antibacterial activity was expressed in terms of the radius of the zone of inhibition calculated as the difference in radius of the observed zones and the edge of the agar wells. Daily sensitivity tests were carried out on extracts stored at 5§c, 25§c and 35§c for 7 days. RESULTS: The seed extracts from all three stages of the fruit showed an average order of inhibition in the following order B cereus> E coli> S faecalis> S aureus> P vulgaris> and X flexneri. There was no significant difference in bacterial sensitivity between the immature, mature and ripe fruits tested. The epicarp and endocarp did not produce any inhibition zone in any of the three stages of the fruit tested. There was a gradual reduction in antibiotic activity with increasing storage item. Also, a fall-off of activity was found to be more drastic at higher temperatures. CONCLUSION: The findings show that crude extracts of Carica papaya seed have antibacterial activity that inhibits the growth of both gram positive (B cereus, S aureus and S faecalis) and gram negative (E coli, P vulgaris and S flexneri) organisms. Observed activity was dependent on stage of maturity but tended to decrease with duration and conditions of storage. No antibacterial activity was observed from the epicarp and the endocarp of the fruit. (AU)