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The free radical theory of aging states that organisms age because cells accumulate free radical damage over time. [1] A free radical is any atom or molecule that has a single unpaired electron in an outer shell. [2] While a few free radicals such as melanin are not chemically reactive, most biologically relevant free radicals are highly ...
Hydroxyl radicals can attack the deoxyribose DNA backbone and bases, potentially causing a plethora of lesions that can be cytotoxic or mutagenic. Cells have developed complex and efficient repair mechanisms to fix the lesions. In the case of free radical attack on DNA, base-excision repair is the repair mechanism used. Hydroxyl radical ...
Oxidative stress mechanisms in tissue injury. Free radical toxicity induced by xenobiotics and the subsequent detoxification by cellular enzymes (termination).. Oxidative stress reflects an imbalance between the systemic manifestation of reactive oxygen species and a biological system's ability to readily detoxify the reactive intermediates or to repair the resulting damage. [1]
Free radicals, reactive chemicals that damage our cells, are believed to contribute to cancer development. Antioxidants protect the body from the harmful effects of free radicals by bolstering ...
Free radicals have an ominous name and a lot of people misunderstand them, their complex role in our bodies and how to manage them. Over the Counter: Connecting the dots on the role of free ...
The lipid hydroperoxyl radical (LOO•) can also undergo a variety of reactions to produce new radicals. [citation needed] The additional lipid radical (L•) continues the chain reaction, whilst the lipid hydroperoxide (LOOH) is the primary end product. [6] The formation of lipid radicals is sensitive to the kinetic isotope effect.
The primary factor in antioxidants causing or promoting the aforementioned health issues, is the attenuation or inactivation of reactive oxygen species (ROS), which immune system responders use to kill or destroy pathogens, mainly bacteria and fungi. ROS produce free-radicals as a by-product of the oxygen burst used to kill pathogens.
Some materials continue to weaken through aging, as the remaining free radicals react. [15] The resistance of these polymers to radiation damage can be improved by grafting or copolymerizing aromatic groups, which enhance stability and decrease reactivity, and by adding antioxidants and nanomaterials, which act as free radical scavengers. [19]