Comparative Study of Total Phenolic Content, Antioxidant Activities, and Polyphenol Oxidase Enzyme Inhibition of Quince Leaf, Peel, and Seed Extracts

Quince (Cydonia oblonga Miller) is a widely consumed, safe, and low-cost natural source of different classes of interesting metabolites. Phenolic compounds in natural foods (especially fruits and vegetables) have application as preventive or therapeutic agents in the treatment of diseases caused by free radicals. This study focused on total phenolic content, DPPH and ABTS activities as antioxidant properties, and polyphenol oxidase (PPO) inhibitory activity of the total phenolic compounds extracted from quince leaf, peel, and seed. Quince leaf and peel extracts showed higher ABTS and DPPH activity than quince seed extract. Additionally, all quince extracts inhibited PPO, with IC50 values of 36.47 +/- 8.28 mu g/ml (leaf extract), 173.25 +/- 5.69 mu g/ml (peel extract), and 386.75 +/- 9.27 mu g/ml (seed extract). Moreover, the effects of extracts on enzymatic browning in apple were examined by measuring the color parameters.

Automated summary

This study investigated the antioxidant properties and polyphenol oxidase inhibitory activity of quince extracts. Quince leaf and peel extracts showed higher antioxidant activity, and all extracts inhibited polyphenol oxidase and affected enzymatic browning in apple.