Natural and Bioinspired Polyphenols with Antioxidant Properties for Health and Food Applications

The search for novel antioxidants to be used to prevent/control food deterioration or as adjuvants in the treatment of oxidative stress based pathologies has recently spurred considerable interest. In this connection natural compounds and particularly polyphenols that can be easily obtained from accessible vegetable sources or even agricultural wastes are nowadays extensively investigated. The chemopreventive action exerted by polyphenols belonging to the hydroxycinnamate, catechol, catechin, and stilbene groups against the cellular damages brought about by reactive oxygen species (ROS), but also by the reactive nitrosating/nitrating species (RNS) generated in the acidic environment of the stomach from dietary and endogenous nitrite ions is largely documented. Along these lines the presentation will show: 1) how the most popular polyphenol antioxidants can efficiently act as antinitrosating agents and the trasformations they undergo further to reaction with RNS.1 2) how the potential antinitrosating/antioxidant potential of natural polyphenols may be enhanced by conjugation with biological thiols or by other bioinspired trasformations.2 Examples will also be provided of the uses of polymers obtained by biomimetic oxidation of natural phenols as stabilizing additives of polyethylene for packaging3 and as osteogenesis promoters in biocompatible polylactic acid biomaterials. Characterization of the reducing and free radical scavenging properties of a series of polymers from natural phenols (e.g. ferulic acid, caffeic acid and pyrogallol) provided a rationale to tailor the properties of these materials. The survey will include examples of natural polyphenolic pigments from food or wastes showing marked antioxidant properties and will illustrate the preliminary evaluation of their activity following simulated digestion processes