Phenolic compounds can delay the oxidation of polyunsaturated fatty acids and the growth of Listeria monocytogenes: structure-activity relationships.

BACKGROUND: Phenolic compounds present a potential solution to ensure food quality and safety. Indeed, they can limit oxidation reactions and bacterial growth in food products. Although their antioxidant mechanisms of action are well known, their antibacterial ones are less well understood, especially in light of their chemical structures. The aim of this study was first to quantify both aspects of a series of natural phenolic compounds and then link these activities to their chemical structure.
RESULTS: We evaluated antioxidant activity by measuring the capacity of phenolic compounds to delay free linoleic acid oxidation caused by the action of a hydrophilic azo-radical initiator (AAPH). We evaluated antibacterial activity by measuring the growth inhibition of Listeria monocytogenes and determining the non-inhibitory and minimum inhibitory concentrations for each compound. Compounds with ortho-diphenolic structures were the best antioxidants, whereas those belonging to the simple phenol category were the best antibacterial compounds.
CONCLUSION: The physico-chemical properties of the compounds influenced both activities but not in the same way. The chemical environment of the phenolic group and the presence of delocalization structures are the most important parameters for antioxidant activity, whereas the partition coefficient, logP, is one of the most important factors involved in antibacterial activity.