Evaluation of the Antibacterial ctivity of Ananas comosus (Pineapple) extract against selected gram-negative bacteria

Abstract

Pineapples are a tropical fruit that present with a wide array of health and beauty benefits. They are not only valued for their sweet taste, but have been used for centuries to treat digestion problems and inflammation. Studies have shown that bromelain, the enzyme found in pineapples, can reduce swellings, bruising, healing time, and pain associated with injury and surgical intervention. Bromelain is currently being used to treat and reduce inflammation from tendinitis, sprains, strains, and other minor muscle injuries as well as swelling related to ear, nose and throat surgeries or trauma. The present study was aimed at determining the antimicrobial activity of pineapple extract against selected gram-negative bacteria. The aim of the study was to evaluate the antibacterial activity of both stem and fruit pineapple crude extract against selected gram-negative bacterial pathogens notably Pseudomonas aeruginosa, Escherichia coli and Salmonella typhi. The antibacterial activity was carried out by agar well diffusion technique against the bacterial pathogens and the zone of inhibition were measured in mm diameter and the minimum inhibition concentration was calculated on every organism. In the study, pine apple extract was found to be effective against the all organisms tested when compared to control ( ciprofloxacin), the stem extract showed highest zone of inhibition in P. aeruginosa 22mm, S. typhi 17mm and E .coli 20mm and highest minimum inhibition concentration was 0.125g/ml, 0.25g/ml and 0.125g/ml for P. aeruginosa, S. typhi and E .coli respectively. For fruit crude extract, highest zone of inhibition in P. aeruginosa was 13mm, S. typhi 7mm and E. coli 12mm and highest minimum inhibition concentration was 0.25g/ml, 0.25g/ml and 0.125g/ml for P. aeruginosa, S. typhi and E. coli respectively. Generally, the stem crude extract has a high antimicrobial effect than the fruit crude extract on the organisms tested and it was found that E. coli and P. aeruginosa trended to be more susceptible than S. typhi. The finding that pineapple juice has antibacterial effect serves to suggest that there is a potential in discovering novel antimicrobial agents from the pineapple plant. This however needs further investigation.