Biomimetic Models for Radical Stress Investigation

Abstract

Free radicals are generated in the biological environment as a result of normal intracellular metabolism. Reactive oxygen species (ROS) function as physiological signalling molecules that participate in the modulation of apoptosis, stress responses and proliferation. ROS can also have a negative effect by causing damages to biomolecules. Therefore, the estimation of the type and extent of damages, as well as the efficiency of the protective and repair systems, is important subjects in life sciences. When studying free radical‐based chemical mechanisms, it is very important to establish biomimetic models, which allow the experiments to be performed in a simplified environment, but suitably designed to be in strict connection with cellular conditions. The biomimetic modelling approach has been coupled with physical organic chemistry methodologies and knowledge of free radical reactivity, in order to gather substantial knowledge on biological processes relevant to health, such as biological damages and repair, signalling and biomarkers, biotechnological applications and novel synthetic approaches. Key Concepts The overproduction of ROS/RNS has been linked with the aetiology of various diseases. Hydroxyl radicals (HO ⋅ ) can be generated by γ‐radiolysis of neutral water or by Fenton reaction of H 2 O 2 . 5′,8‐Cyclopurine lesions result from the chemistry of the C5′ radicals generated by the attack of HO ⋅ radicals to 2‐deoxyribose units of DNA. 5′,8‐Cyclopurine lesions can be exclusively repaired by nucleotide excision repair (NER) enzyme. Large unilamellar vesicles (LUV) are the closest models to membranes. Mono‐trans isomers of PUFA are biomarkers of endogenous formation by radical stress. Methionine or cysteine residues upon γ‐irradiation produce sulfur‐centred radicals. Bioinspired organic synthesis is based on the mechanism of naturally occurring processes.