Phytochemical Screening and in Vitro Assessment of Antibacterial and Antioxidant Activities of Ananas Comosus (Pineapple) Peel Extracts

The agricultural by-product known as the peel of Ananas comosus (pineapple) is a considerable source of bioactive phytochemicals which are known for their antioxidant and antimicrobial properties. The aim of this study was to investigate the phytochemical composition, antimicrobial effectiveness, and antioxidant properties of pineapple peel extracts obtained by means of different solvents. Fresh pineapple peels were collected at Barasat Market in West Bengal, shade-dried, ground into a powder and then sequentially extracted with acetone, methanol and ethanol using a Soxhlet apparatus. A preliminary phytochemical analysis was carried out in order to identify the main phytochemical components. The antimicrobial activity against Escherichia coli was determined by means of the agar-well diffusion technique and the antioxidant capacity was assessed using the DPPH free-radical scavenging method, with ascorbic acid being used as the reference standard. The extraction yields for acetone, methanol and ethanol were found to be 1.417%, 2.032% and 3.529% respectively, ethanol giving the highest yield. The phytochemical analysis revealed the presence of carbohydrates, alkaloids, flavonoids and amino acids, but glycosides were not detected in any of the extracts. The methanolic extract displayed the greatest antimicrobial inhibition value of 28 at a concentration of 1.5 mg/mL. With regard to antioxidant activity, the methanolic extract had the highest inhibition rate of 82.16% at 0.75 mg/mL, followed by the ethanolic extract with 72.16% and the acetone extract at 64.56%. Ascorbic acid showed an inhibition rate of 91.27% at the same concentration. The results as a whole show that the pineapple peel extracts have significant antioxidant and antibacterial properties, particularly the methanolic extract. It is necessary to carry out further research in order to identify the active compounds, assess their safety, and determine their potential applications in pharmaceuticals and in the development of natural products.