EXPLORING ANTIOXIDANTS AND FREE REDICALS IN HEALTH AND DISEASES OF CHILDREN AND ADULTS
*Azikiwe C. C. A., Ifezulike C. C., Enye J. and Anowi C. F. and Ezeani M. C.
ABSTRACT
Living cells continually generate free radicals, reactive oxygen species (ROS) or reactive nitrogen species (RNS) through the respiratory chain during energetic metabolism leading to oxidative stress. Oxidative stress is defined as a disturbance in the equilibrium between free radicals (FR), reactive oxygen species (ROS) and the endogenous defense mechanism. It is the disturbance in the balance between oxidants and antioxidants in favour of the former that causes oxidative stress. Human body requires both oxidant and anti-oxidant species for normal mechanism, signal transduction and regulation of cellular functions. Therefore, each cell maintains a condition of homeostasis between the oxidant and anti-oxidant species. Oxidative stress may lead to injury to all the important cellular components such as proteins, DNA and membrane lipids which can cause death. Moderate production of free radicals can be beneficial to the body such as detoxification of xenobiotics, generation of ATP, killing of micro-organism and cancer cells and apoptosis of effete or defective cells. While high production of free radicals can cause a number of diseases such as diabetes mellitus, arthritis, arthrosclerosis, cancer, Alzheimer’s disease, Parkinson’s disease, cataract, aging and asthma. Anti-oxidants on the other hand can prevent and repair the deleterious effects of free radicals. Nature has bestowed the human body with a complex web of antioxidant defense system including enzymatic antioxidants like glutathione peroxidase, glutathione reductase, catalase and superoxide dismutase as well as non-enzymatic antioxidants such as thiol antioxidants, melatonin and metal chelating proteins, which are efficient enough to fight against excessive free radicals. Also, nutrient antioxidants such as vitamin C, vitamin E, carotenoids, polyphenols, trace elements, omega-3 and omega-6 fatty acids are known to have high antioxidant potency to assist in minimizing harmful effects of reactive species. Zinc also plays both anti oxidative stress as well as anti inflammatory cum anti infectious activities.
Keywords: Oxidants, Antioxidants, Free radicals, Oxidative stress, Carotenes, Zinc, Glutathione, vitamins A, C and E.
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