Inhibitory Effect of Azamacrocyclic Ligands on Polyphenol Oxidase in Model and Food Systems

• Published in: Journal of agricultural and food chemistry Vol. 68; no. 30; pp. 7964 - 7973
• Main Authors: Muñoz-Pina, Sara, Ros-Lis, José V, Delgado-Pinar, Estefanı́a, Martı́nez-Camarena, Alvaro, Verdejo, Begoña, Garcı́a-España, Enrique, Argüelles, Ángel, Andrés, Ana
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 29.07.2020
• Subjects: Catechol Oxidase - antagonists & inhibitors; Catechol Oxidase - chemistry; Enzyme Inhibitors - chemistry; Food and Beverage Chemistry/Biochemistry; Fruit - chemistry; Fruit - enzymology; Fruit and Vegetable Juices - analysis; Kinetics; Ligands; Malus - chemistry; Malus - enzymology; Plant Proteins - antagonists & inhibitors; Plant Proteins - chemistry; macrocyclic polyamines; enzymatic activity; inhibition; PPO
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/acs.jafc.0c02407

Enzymatic browning is one of the main problems faced by the food industry due to the enzyme polyphenol oxidase (PPO) provoking an undesirable color change in the presence of oxygen. Here, we report the evaluation of 10 different azamacrocyclic compounds with diverse morphologies as potential inhibitors against the activity of PPO, both in model and real systems. An initial screening of 10 ligands shows that all azamacrocyclic compounds inhibit to some extent the enzymatic browning, but the molecular structure plays a crucial role on the power of inhibition. Kinetic studies of the most active ligand (L2) reveal a S-parabolic I-parabolic noncompetitive inhibition mechanism and a remarkable inhibition at micromolar concentration (IC50 = 10 μM). Furthermore, L2 action has been proven on apple juice to significantly reduce the enzymatic browning.