Abstract

The results of studies indicate that chemopreventive efficiency of isolated phytochemicals is lower than that of polyphenol-rich foods. This discrepancy has been ascribed to the food synergy concept that assumes additive or even synergistic influence of different food ingredients on human health. The results presented in the dissertation made it possible to propose an alternative and innovative explanation of these observations. The research carried out within the frame of PhD project has shown that properties of polyphenol mixtures are not just the combination of enhanced or weakened activities displayed by individual components. The study revealed the pronounced impact of interactions between polyphenols on redox-related biological activities. This was enabled owing to the wide range of methods used, including the assessment of cellular antioxidant activity, cytotoxicity, genotoxicity, epigenetic and nutrigenomic activity using a human colon adenocarcinoma cell line exposed to either pure compounds, model mixtures or natural extracts. These studies led to the formulation of the thesis that the activity of a mixture of polyphenols is dictated by interactions between the components, which creates a new substance displaying modified chemical and physicochemical properties resulting in unique biological effects.

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