Antibacterial Screening Of Ethanolic Pomegranate Peel Extract

Pomegranate ( Punica granatum L.) is reputed for its nutritional properties. This fruit is rich in antioxidants, vitamins, and minerals. The juice industry produces a high quantity of peel that is thrown away despite of its richness of bioactive compounds. The increased demand for environmentally friendly pharmaceutical agents brought attention to commercializing the use of fruit peel. Objectives This study aims to 1) evaluate the antibacterial activity of ethanolic pomegranate peel extract on six bacteria that cause food spoilage or are associated with human diseases., and to 2) determine the effect of temperature on the antimicrobial activity induced by the pomegranate peel ethanolic extract. Material and Methods The growth inhibition by the pomegranate peel extract was evaluated on Bacillus subtilis, Bacillus megaterium, Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, and Micrococcus luteus. Fresh pomegranate peel was dried, grinded into fine particles, and stirred in ethanol for 30 minutes either at room temperature or with gentle boiling. Both extract preparations were filtered, wrapped with aluminum foil to avoid photooxidation. The pH measurement was recorded immediately, then daily for at least 30 days. The crude (gummy) material is a concentrated extract which was tested on bacteria at a concentration of 40ug/μl. The antibacterial activity of was determined using agar well diffusion method. The bacterial were cultured into prepared nutrients broth and incubated at 37°C for 24 h and standardized to 0.5 Mc‐Farland Scale (108 cfu/mL) in a prepared normal saline. The cell suspensions were seeded into prepared nutrients agar plates, and wells of 8mm were bored into the agar. The screening was done by placing 100ul in a well of either the extract, or the crude that was prepared at 40ug/μl. Results The ethanolic extract and crude of pomegranate peel showed varying degree of antibacterial activity against the tested bacteria. The inhibition zone range was between 14–28 mm and it was sustained for up to 72hr. The high temperature preparations showed a minimum of 10% more antibacterial activity. The pH measurements showed stability for at least 30 days for all preparations kept in the refrigerator. Conclusion It appears that the pomegranate peel has the potential for use in food applications as a natural preservative, and also in pharmaceutical applications. Support or Funding Information NSF‐IPSRG, LSAMP Grant and Land Grant