Comparative evaluation of antibacterial activity of ethanolic extracts of peels of unripe, partially ripe, and fully ripe mangoes (Mangifera indica) against Escherichia coli and Staphylococcus aureus

Abstract

Amid rising concerns over antimicrobial resistance, plant derived bioactive compounds are increasingly studied for their therapeutic potential. This study evaluated the antibacterial activity of ethanolic extracts obtained from the peels of <i>Mangifera indica</i> (Carabao mango) at three distinct ripening stages: unripe, partially ripe, and fully ripe, against <i>Escherichia coli</i> and <i>Staphylococcus aureus.</i> Mango peels were processed through ethanol extraction and rotary evaporation, and their antibacterial efficacy was determined using agar well diffusion, minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC) assays. Results demonstrated a significant decline in antibacterial activity with increasing ripeness. Ethanolic extract of unripe mango peels exhibited the largest zones of inhibition (13.00 ± 1.00 mm against <i>E. coli</i> and 14.00 ± 2.52 mm against <i>S. aureus)</i> and the lowest MIC and MBC values, indicating the highest potency among the three stages. In contrast, ethanolic extract of peels of fully ripe mangoes showed the weakest antibacterial effect, with zones of inhibition of 11 mm, 12 mm, and 11 mm against <i>E. coli</i> and 5 mm, 13 mm, and 15 mm against <i>S. aureus,</i> with confluent bacterial growth at lower dilutions in MIC and MBC assays. The potent antimicrobial properties of the ethanolic extract of the unripe mango peel are attributed to its higher content of bioactive phytochemicals such as phenolics, flavonoids, and tannins, which decrease as the fruit matures. These findings suggest that unripe mango peels can serve as a valuable source of natural antibacterial agents and offer promising applications in the development of plant-based therapeutics, food preservatives, and bioactive packaging materials. Further studies are warranted to isolate the specific active constituents, elucidate their mechanisms of action, and assess their safety and efficacy in applied systems.