Potential applications of antioxidants -A Review

European Chemical Bulletin, 2017

Antioxidants were used to prevent oxidation process in foods which lead to rancidity and browning, DNA oxidation and have many positive physiological effects in human. The concentration and the absorption mechanism of natural antioxidants are important in obtaining the maximum beneficial effect. The sources of antioxidants must be carefully considered to maximize absorption and avoid the toxicity of higher concentration of synthetic groups. A general lack of information about antioxidants indicates by a survey of the general public. An organized effort to educate individuals about foods rich in natural antioxidants and the ability to recognize the major synthetic antioxidants on food labels would be highly beneficial, though more research needs to be done to fully understand their physiological effects.

All living organisms utilize oxygen to metabolize and use the dietary nutrients in order to produce energy for survival. Oxygen thus is a vital component for living. Oxygen meditates chemical reactions that metabolize fats, proteins, and carbohydrates to produce energy. While oxygen is one of the most essential components for living, it is also a double edged sword. Oxygen is a highly reactive atom that is capable of becoming part of potentially damaging molecules commonly called free radicals. These free radicals are capable of attacking the healthy cells of the body. This may lead to damage, disease and severe disorders. Antioxidants are substances that neutralize free radicals or their actions. Nature has endowed each cell with adequate protective mechanisms against any harmful effects of free radicals: superoxide dismutase (SOD), glutathione peroxidase, glutathione reductase, thioredoxin, thiols and disulfide bonding are buffering systems in every cell. α-Tocopherol (vitamin E) is an essential nutrient which functions as a chain-breaking antioxidant which prevents the propagation of free radical reactions in all cell membranes in the human body. Ascorbic acid (vitamin C) is also part of the normal protecting mechanism. Other non-enzymatic antioxidants include carotenoids, flavonoids and related polyphenols, α-lipoic acid, glutathione etc. This review article summarizes the functional role of reactive oxygen species (ROS), reactive nitrogen species, reactive halogen species and their pathological importance.

South Asian Research Journal of Medical Sciences

Incidence of premature aging, heart diseases and many other such disorders are on a rise and a matter of great concern worldwide. The environmental factors, consuming tobacco and smoking are the main causative factors of oral cancer. The effects of these can be reversed to a limit by consumption of antioxidants. This article gives detailed description about antioxidants, its mechanism of action and its role in different disorders. This will help educate the readers about the beneficial properties of antioxidants and how it may benefit the healthy and diseased individuals.

Chinese journal of integrative medicine, 2017

Antioxidants are the substances that are capable of counteracting the damaging effects of the physiological process of oxidation occur in animal tissues. These may be nutrients (vitamins and minerals) as well as enzymes (proteins) in our body that assist in chemical reactions. They are believed to play a role in preventing the development of chronic diseases like cancer, diabetes, heart disease, stroke, Alzheimer's disease, rheumatoid arthritis, and cataracts etc. The present review article emphasizes on the various aspects of oxidants and antioxidants viz. definition, types, causes, mechanism, functions, adverse effects along with various in vivo and in vitro models of evaluation of antioxidant activity of new molecule, compounds or any plant or plant part. This review is one of its kinds which will be of great importance for researchers working in this area in search of antioxidant moieties and their biological evaluation.

International Journal of Chemical Studies

Antioxidant is any substance that delays, prevents or removes oxidative damage to a target molecule. It can be found in many foods, including fruits and vegetables. The role of antioxidants in foods is to retard or control oxidation. The process of autoxidation and development of rancidity in foods involves a free radical chain mechanism via initiation, propagation and termination steps. While radicals are produced in the 'initiation' step, they react with unsaturated fatty acids by abstracting a hydrogen atom from a site which requires the least energy that is the allylic or diallylic position in the 'propagation' steps. The reactions in the propagation step make up a chain reaction until a 'termination' reaction occurs. Due to high stability and low volatility, it helps to maintain the level of nutrients, the texture, colour, taste, freshness, functionality, aroma, and appeal to consumers such as the older person. Various antioxidants found in food viz. natural antioxidants, synthetic antioxidants, dietary antioxidant, endogenous antioxidant play an important role in preservation of food. Vitamin C, Vitamin E, α-carotene, Lycopene, Polyphenol etc. is main sources of antioxidants. They may be present in foods as endogenous factors or may be added to preserve their lipid components from quality deterioration. The most widely used antioxidants in foods include butylated hydroxyl anisole (BHA), butylated hydroxyl toluene (BHT), propyl gallate (PG) and tertiary butyl hydroquinone (TBHQ). These antioxidants may be used at 200 ppm in bulk oils and at 200 ppm, based on the lipid content of other foods. The benefits of antioxidants include whole foods and beverages (e.g., acai berry, gogi berry, green tea) as well as isolated substances sold primarily as dietary supplements (e.g., vitamin C, lycopene, selenium) or added to foods (e.g., vitamin E). It reduces the risk of developing certain diseases such as; cancer, heart disease, stroke, and arthritis etc.

2017

Antioxidants are the substances that prevent the oxidation of other substances. These are found in many foods and other dietary supplements. Intake of high dose of antioxidants may cause some health risks. For example, intake of high doses of Beta Carotene may increase the risk of lung cancer in smokers. Intake of high doses of Vitamin E increases the risk of prostate cancer and stroke. The benefits of Antioxidants are very important to maintain good health, because if the free radicals released in the body are left without unchanged, these radicals may lead to wide range of chronic diseases and illness [5][8][9]. Antioxidants also help to slow down the process of aging, which can have immense effect on the skin. Antioxidants may be of lipid soluble or water soluble. Lipid soluble antioxidants protect the cell membrane from lipid peroxidation and are mostly located in the cell membrane whereas water soluble antioxidants are present in aqueous fluids like blood and cytosol. Some of the lipid soluble antioxidants include Vitamin A, E, Carotenoids, Lipoic acid. Water soluble antioxidants include Vitamin C, Polyphenols and Glutathione . There exists a need to be educated and to obtain knowledge on the dietary supplements that are to be taken inorder to prevent the onset of various diseases. People can gain awareness through literature, internet sources, nutritionists and dieticians. Open access journals provide more visibility and accessibility to the readers in gaining the required information.

2001

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The imbalance in homeostatic process between oxidants and antioxidants in the body caused by reactive oxygen and nitrogen species (free radicals) leads to oxidative stress. Cellular enzymes such as myeloperoxidase, nicotinamide adenine dinucleotide phosphate-oxidase (NADPH-oxidase) and nitric oxide synthase (NOS) produce these reactive oxygen and nitrogen species (RONS). Oxidative stress is considered to be the primary cause of aging and a wide variety of human diseases such as cancers, diabetes, neurodegenerative disorders (Alzheimer's disease, Parkinson's disease), rheumatoid arthritis etc. Invariably, to maintain a healthy biological system the balance between oxidation and antioxidation is a critical requirement. Antioxidants are any substances that significantly delay, prevent or inhibit oxidative damage to target molecules. They are widely distributed throughout plants and animals and are found to be at low concentrations compared with that of oxidizable substrates. Natural and synthetic antioxidants have been reported to prevent or treat various human diseases. This article presents a comprehensive account of free radical generation, oxidative stress and its consequences, antioxidants including sources, classification, chemical structures, mechanisms of action, physicochemical properties. The study also dealt with applications of antioxidants in pharmaceutical and food industries, their therapeutic properties and pharmacokinetic features.

African Journal of Pharmacy and Pharmacology

The human body uses an antioxidant defense system to neutralize the excessive levels of reactive oxygen species. This system consists of enzymatic and non enzymatic antioxidants, catalase, peroxidase, superoxide dismutase and gluatathion s-transferease as major defense enzymes. However, ascorbic acid, tocopherol, and phenolic compounds are considered as examples for non-enzymatic antioxidants. Increasing research on natural antioxidants in foods and development of new assays has prompted critical reflection on the field. It has been common practice to identify health benefits from antioxidant activity on the cellular level with antioxidant capacity of food measured in vitro. The use of antioxidants and their positive effects on food quality has been demonstrated in a large variety of foods and beverages using various methods for detection of lipid and protein oxidation or various assays based on electron transfer or hydrogen-atom transfer. There is a need for screening studies in order to identify the mode of action of different antioxidant compounds (enzymatic and non-enzymatic in addition, comparing between synthetic and natural antioxidant compounds) by different assays, in addition to highlighting the advantage and disadvantage of it. Some of these assays depend on hydrogen atom transfer methods or electron transfer methods in addition, metal chelating compounds and free radical scavenging activity.

Journal of Drug Delivery and Therapeutics, 2014

Free radicals induce damage mainly to biomembranes and DNA due to peroxidation, which lead to tissue damage resulting in number of degenerative diseases. Antioxidants can neutralise the effect of these free radicals through various ways and may protect the body from harmful alterations. Antioxidants may be of different types viz. enzymatic, non-enzymatic and also found from plant sources. Nowadays, numerous synthetic antioxidant supplements are also found in the market. The antioxidative potential of samples can be assayed by different in vitro and in vivo methods. The present review describes a brief account of the free radical generation, their role in aging and other diseases, classification of antioxidants, their n atural and synthetic sources, possible mechanism and several assay methods of free radical scavenging activity of different bioactive compounds.