Decoding the chemical repertoire, antimicrobial synergy, and antioxidant mastery of banana pulp and peel extracts

Abstract

This study investigates the antimicrobial, antioxidant, and phytochemical properties of banana extracts from both ripe and unripe pulp and peel, using various solvents, including ethanol, methanol, hexane, and aqueous solutions. Antimicrobial test reveals the effectiveness of unripe pulp aqueous extract against Staphylococcus aureus, while the unripe pulp ethanol extract against Bacillus subtilis among gram-positive bacteria. For gram negative bacteria, unripe pulp ethanol extract was most effective against Acinetobacter baumannii, and unripe pulp aqueous extract against Pseudomonas aeruginosa. In antifungal tests, ethanol extract of ripe banana pulp (1.8 ± 0.081) and aqueous extract of unripe pulp (2.5 ± 0.081) show effectiveness against Fusarium oxysporum. However, for Alternaria alternata, the aqueous extract of unripe pulp (1.8 ± 0.081) and methanolic extracts showed stronger inhibition compared to other samples. Phytochemical analysis detected secondary metabolites, including saponins, terpenoids, tannins and phytosterols. The highest polyphenol content was found in the ethanol extract of unripe peel (1.35 ± 0.01 mg GAE/g), and the highest flavonoid content in unripe peel ethanol extract (1.358 ± 0.03 mg QE/g). In contrast, carotenoid levels showed variation among extracts with no direct correlation to fruit maturity. Gas Chromatography–Mass Spectrometry analysis identified 14 bioactive compounds that were found to be common among all the solvent extracts of banana samples. Furthermore, the study reveals a decrease in free radical scavenging capacity with fruit maturity and solvent choice. The study suggests that both the banana fruit pulp and peel can result in a valuable source of natural antimicrobial and antioxidant agents for potential health and medicine applications.