Antioxidant, Antimicrobial and Protease Inhibitory Activity of Potato Peel.

Background: Due to having health hazards of artificial preservatives, natural preservatives having anti-enzymatic, antimicrobial, and antioxidant properties are drawing the attention of food scientists. Objectives: Potato peel can be a cheap and available source of preservatives as it is considered a waste after processing its tuber. Methods: We evaluated the serine protease inhibitory activity, antibacterial activity by Disc diffusion assay, and antioxidant properties by DPPH free radical scavenging assay and Ferric-ion reducing antioxidant power assay (FRAP) of crude methanol and aqueous extract of potato peel. In addition, Total phenol, flavonoid, and tannin content were also quantified in both crude extracts. Results: Crude methanol extract was found more potential to have significant serine protease inhibition activity (IC50 = 534.87 μg/mL), DPPH free radical scavenging activity (IC50 = 183.56 μg/mL), and FRAP (ferric reducing antioxidant power) value of 351.81 µM Fe(II)/100µg of dried extract. Moreover, the total phenol, flavonoid and tannin content of the methanol extract were higher than the aqueous extract. Also, crude methanol extract showed maximum zone of inhibition (ZOI) against Vibrio cholera and Salmonella typhi (13.63 ± 0.53 and 13.25 ± 0.35 mm respectively). Later, column chromatography for the enrichment of total flavonoid content of methanol fractions exhibited elevated flavonoid content and serine protease inhibitory activity than crude methanol extract. Conclusion: This study showed, the methanol extract of potato peel is more potential than water extract.