Free Radicals and Antioxidants in Human Disease
Free radicals are species containing one or more unpaired electrons. Unpaired or free electrons are responsible for enhanced reactivity of free radicals with various biomolecules. Most frequently occurring radicals in biological systems are reactive oxygen species (ROS) and reactive nitrogen species (RNS). ROS and RNS are generated by the tightly regulated enzymes, nicotinamide adenine dinucleotide phosphate oxidase isoforms and nitric oxide synthases. Overproduction of ROS and RNS results in oxidative and nitrosative stress, a state which is responsible for the damage to cell macromolecules including lipids, proteins and DNA. Oxidative stress has been implicated in the aetiology of various disease states of an organism. In this chapter, we discuss the biochemistry of free radicals and their impact on the development of various diseases. Organs of biological systems are the principal targets of oxidant species, which are implicated in atherosclerosis, diabetes, carcinogenesis and neurodegeneration. Attention is focused on oxidative stress-induced cardiovascular disease, type 2 diabetes, cancer and Alzheimer’s disease. The roles of redox active metal-catalysed formation of ROS and antioxidants in protection against oxidative damage is also discussed.
KeywordsFree radicals Oxidative stress Antioxidants Human disease
This work was supported by the Scientific Grant Agency (VEGA Project 1/0686/17), Research and Development Support Agency (APVV-15-079), Grant Agency of Constantine Philosopher University in Nitra (UGA Project #VII/6/2014) and European Community under project #26220220180: Building Research Centre “AgroBioTech”. The authors would like to acknowledge the long-term development plan of FNHK and UHK.
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