The potential of Carica papaya peel and leaf extracts as antibacterial and antioxidant agent / Adreanna Syazana Mohd Sayuthi

Carica papaya which is also known as paw paw or papaya is one of the highly demanded fruits around the world. Traditionally used as a treatment for diseases like sinuses, eczema, constipation, and many more which has crowned papaya as one of the natural neutraceutical sources. This is due to high content of vitamin A, B, and C as well as proteolytic enzyme such as papain that have antibacterial and antioxidant properties. The purpose of the study was to determine antibacterial and antioxidant activity of papaya peel and leaf against Gram-negative and Gram-positive bacteria, Escherichia coli and Bacillus licheniformis. In this study, papaya peel and leaf were extracted through solvent extraction method by using acetone as the solvent. After extraction, the percentage yield of peel extract was 1.110% while leaf extract was 0.0005%. The low yield percentage were due to the improper extracts storage which indirectly impacted the constituents within the samples. The dried powdered form of papaya peel and leaf were extracted using acetone. The crude from both samples were obtained by drying in incubator shaker. Then, three concentrations, 400 μg/ml, 600 μg/ml, 800 μg/ml were prepared by diluting with 5% DMSO. Antioxidant test was done through DPPH Scavenging Assay by mixing 1 ml of DPPH solution with 100 μl for each sample of ascorbic acid (standard sample), peel extract (test sample 1), and leaf extract (test sample 2) respectively. Peel extract recorded the lowest IC50 value at 3.714 μg/ml, and highest percentage inhibition followed by ascorbic acid at 6.496 μg/ml and leaf extract at 7.766 μg/ml. Antibacterial activity was carried out through disc diffusion method and tested onto E. coli and B. licheniformis. Antibacterial activity was expressed in terms of diameter of bacterial inhibition zone surround the disc. The antibacterial test was done two times. However, only the first attempt showed inhibition surround the extracts discs. For the second attempt, no technical inhibition zone was produced due to technical error. Theoretically, papaya peel and leaf possessed alkaloids and flavonoids which are proven to express antibacterial activity. Papaya peel and leaf extracts exhibit good antioxidant reaction which could be useful in substituting synthetic antioxidant agent. As conclusion, peel and leaf extracts have the potential as antibacterial and antioxidant agent.