Natural and bioinspired phenol polymers with antioxidant properties for health and food applications

The search for novel phenol antioxidants in the prevention/control of food deterioration or as adjuvants in the treatment of oxidative stress-based pathologies has recently spurred considerable interest. In this frame, the presentation will show how natural polyphenol pigments from food or agricultural wastes including black sesame seeds, spent coffee grounds, and fermented pomegranate wastes, are endowed with antioxidant and radical scavenging properties that are remarkably potentiated following activation by hydrolytic treatment. Data of the activity following simulated digestion processes preliminary to the assessment of their potential as food supplement will be presented together with other possible uses related to these and other properties like heavy metals chelating abilities. Polymers synthetically obtained from natural polyphenols have so far received little attention as bioavailable, biocompatible antioxidant materials. Expected advantages with respect to the monomers include greater chemical stability under processing conditions, and lower tendency to be released into the contact medium (food, water, etc.) with reduced adverse effects. Examples of these polymers including those from caffeic ester (polyCAME) and tyrosol (polyTyr) will be provided with illustration of their preparation by oxidation of the phenol precursor under biomimetic conditions, structural characterization and uses as stabilizing additives of polyethylene (PE) for packaging and as osteogenesis promoters in biocompatible Polylactic acid polymers. The results of a systematic investigation of the reducing and free radical scavenging properties of a series of polymers from natural phenols (e.g. ferulic acid, caffeic acid and pyrogallol) and correlation with their structural features, and particularly the radical character as investigated by EPR techniques, allowed to draw a rationale to tailor the properties of these polymers as novel easily accessible materials for use in packaging and biomedical applications.