Journal articles: 'Free radicals; Antioxidants'

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Kanter, Mitchell M. "Free Radicals, Exercise, and Antioxidant Supplementation." International Journal of Sport Nutrition 4, no. 3 (September 1994): 205–20. http://dx.doi.org/10.1123/ijsn.4.3.205.

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Free radicals have been implicated in the development of diverse diseases such as cancer, diabetes, and cataracts, and recent epidemic-logical data suggest an inverse relationship between antioxidant intake and cardiovascular disease risk. Data also suggest that antioxidants may delay aging, Research has indicated that free radical production and subsequent lipid peroxidation are normal sequelae to the rise in oxygen consumption with exercise. Consequently, antioxidant supplementation may detoxify the peroxides produced during exercise and diminish muscle damage and soreness. Vitamin E, beta carotene, and vitamin C have shown promise as protective antioxidants. Other ingestible products with antioxidant properties include selenium and coenzyme. The role (if any) that free radicals play in the development of exercise-induced tissue damage, or the protective role that antioxidants may play, remains to be elucidated. Current methods used to assess exercise-induced lipid peroxidation are not extremely specific or sensitive; research that utilizes more sophisticated methodologies should help to answer many questions regarding dietary antioxidants.

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Bisht, Rekha. "Antioxidants: a brief review." Journal of Drug Delivery and Therapeutics 8, no. 6-s (December 15, 2018): 373–76. http://dx.doi.org/10.22270/jddt.v8i6-s.2116.

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The field of free radical chemistry has gained a great deal of attention in recent years. Free radicals reactive oxygen species generated by our body by various endogenous systems leads to various pathological conditions. A balance between free radicals and antioxidants is prerequisite for proper physiological function. Oxidative stress caused by generation of free radicals adversely alters lipids, proteins, and DNA and provokes a number of human ailments. Oxidative stress can be managed by using external sources of antioxidants. Synthetic antioxidants such as butylated hydroxytoluene and butylated hydroxyanisole have recently been reported to be harmful for human health. Thus, the search for effective, nontoxic natural compounds with antioxidant activity has been escalated in recent years. The present review provides a brief overview on antioxidants and natural sources of antioxidants in the management of human diseases. Keywords: free radical, Oxidative stress, antioxidants,

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Dwimayasanti, Rany. "RUMPUT LAUT: ANTIOKSIDAN ALAMI PENANGKAL RADIKAL BEBAS." OSEANA 43, no. 2 (October 30, 2018): 13–23. http://dx.doi.org/10.14203/oseana.2018.vol.43no.2.17.

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SEAWEED: NATURAL ANTIOXIDANT FREE RADICAL ANTIDOTE. Free radicals are the result of various complex chemical processes in the body, in form of oxidation process, cell metabolism, UV irradiation, environmental pollution such as cigarette smoke, and other pollutants. The effects of free radicals can be prevented by addition of antioxidants endogenously from outside the body. Seaweed is one source of natural antioxidants that is safe for the body. Seaweed contains bioactive compounds that are able to prevent free radicals such as carotenoids, phenols, vitamins and minerals.

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Noor, Rana, Fatema Sayeed, Rizwana Mallick, Eram Perwez, and Shabina Sachdeva. "Effect of Free Radicals and Antioxidants in Periodontal Disease." Indian Journal of Dental Education 9, no. 3 (2016): 165–69. http://dx.doi.org/10.21088/ijde.0974.6099.9316.4.

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NEUBAUER, R. "Free radicals and antioxidants." Lancet 344, no. 8934 (November 1994): 1440–42. http://dx.doi.org/10.1016/s0140-6736(94)90612-2.

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Xu, Qing, Tian Zhong, and Hui Li Li. "Antioxidant and Free Radical Scavenging Activities of N-Modified Chitosans." Advanced Materials Research 1002 (August 2014): 91–98. http://dx.doi.org/10.4028/www.scientific.net/amr.1002.91.

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Recently, the search for effective natural antioxidants use in food and medicinal fields to replace synthetic ones has attracted the most attention. Chitosan, a natural nontoxic biopolymer, is known to possess antioxidant property, which is attributed that NH2 and OH attached in the pyranose ring react with unstable free radicals to form stable macromolecule radicals. It has been observed that the antioxidant activity of chitosan is closely related to the form of nitrogen atom in the molecules. This review focuses on the antioxidant and free radical scavenging activities of various nitrogen atom of chitosan, including N-acylated chitosans, Schiff bases of chitosan, N-alkyl chitosan, and N-quaternized chitosan. The free radical scavenging mechanisms are summarized and the effects on free radical scavenging activity of N-modified chitosan are discussed. This work may provide more insights into the antioxidant ability of N-modified chitosans and potentially enable them to be used as natural antioxidants for application in food, agriculture, cosmetic and biomedical science. Keywords: N-modified chitosan, Sythesis, Antioxidant, Free radical scavenging

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G, Savitha, Vishnupriya V, and Surapaneni Krishnamohan. "IN VITRO ANTIOXIDANT CAPACITY AND FREE RADICAL SCAVENGING ACTIVITIES OF CARDIOSPERMUM HALICACABUM LINN." Asian Journal of Pharmaceutical and Clinical Research 11, no. 7 (July 7, 2018): 421. http://dx.doi.org/10.22159/ajpcr.2018.v11i7.25044.

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Objective: Free radicals and oxidants are produced in the body during normal cellular metabolism and exposure to pollutions and ionizing radiations. They exert beneficial and harmful effects to the human body. Harmful effects of these radicals are destroyed by either antioxidants of our body in situ or antioxidants which are supplied through foods. Hence, the aim of this present study is to assess the antioxidant and free radical scavenging capacity of the easily available edible plant Cardiospermum halicacabum Linn. (Mudakathan keerai).Methods: Antioxidant and free radical scavenging activities of the aerial parts extract of C. halicacabum was determined by 2,2-diphenyl-1- picrylhydrazyl (DPPH) radical scavenging assay, 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging assay, ferrous ion chelating assay, nitric oxide (NO) radical scavenging assay, superoxide radical scavenging assay, hydroxyl radical scavenging assay, and lipid peroxidation assay.Results: Remarkable free radical scavenging potential was observed in the ethanolic extract of C. halicacabum with IC50 values on all tested radicals, namely DPPH (IC50=34.06 μg/ml), ABTS (IC50=21.45 μg/ml), ferrous ion chelating (IC50=19.56 μg/ml), NO (IC50=25.16 μg/ml), superoxide (IC50=35.16 μg/ml), hydroxyl (IC50=28.56 μg/ml), and lipid peroxidation (IC50=33.12 μg/ml). The results revealed that ethanolic extract of C. halicacabum Linn. has significant antioxidant activity.Conclusion: The present study suggested that the aerial part extract of C. halicacabum serves as a good source of natural antioxidants.

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Qiu, Song Shan, Zhi Hui Wang, and Cui Cui Jiang. "Free-Radical Scavenging Capacity of Sasanquasaponin from Camellia Oleifera Abel." Advanced Materials Research 236-238 (May 2011): 2367–70. http://dx.doi.org/10.4028/www.scientific.net/amr.236-238.2367.

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In this study, the antioxidant activity of sasanquasaponin fromCamellia oleifera Abel.was determined by various antioxidant assays. The results of reducing power of sample indicated sasanquasaponin were electron donors and could react with free radicals to convert them into more stable products, terminating the radical chain reactions.The results indicated that sasanquasaponin can clear active oxygen radicals producing in the chemical reactions and have stronger antioxidant ability. Therefore they could be used as natural antioxidant that are stable at high temperatures and can serve as substitutes for synthetic antioxidants.

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Buehler, Bruce A. "The Free Radical Theory of Aging and Antioxidant Supplements." Journal of Evidence-Based Complementary & Alternative Medicine 17, no. 3 (April 11, 2012): 218–20. http://dx.doi.org/10.1177/2156587212441939.

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Free radical excess occurs when cells are exposed to reactive oxygen species greater than the amount that can be neutralized by cellular produced antioxidants such as superoxide dismutase. This is termed oxidative stress, which can be caused by excessive energy intake or external pollutants. Excess free radicals are proposed to increase the rate of cell aging, injury, and mutations leading to a shortened cell life span. Vitamins A, C, and E and flavoproteins are supplements that function as free radical scavengers. Antioxidants are present in natural foods but added amounts beyond the diet may detoxify excess free radicals during “oxidative stress.” Antioxidant supplements decrease cellular damage from excess reactive oxygen species but they have not been proven to prolong life span.

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Gautam, Narayan. "Free radicals and vitamin antioxidants in health and lung diseases." Journal of Universal College of Medical Sciences 3, no. 3 (December 31, 2015): 43–52. http://dx.doi.org/10.3126/jucms.v3i3.24249.

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Several lung diseases have undergone oxidative stress due to free radical insult. Consequently, antioxidant vitamin C and vitamin E play important role in defense against cellular injury by scavenging free radicals. This article reviews the potential mechanism of free radicals generation and vitamin antioxidant defense to link amongst various lung diseases. One of the manifestations of free radical mediated process is lipid peroxidation subsequently producing malondialdehyde (MDA) in these patients. Supplementation of vitamin C and vitamin E as an adjuvant therapy as well as high intake of fresh fruits and vegetables appear to have a beneficial effect on lung health. Moreover, their consumption should be recommended on a daily basis. Further studies are needed to assess the impact of antioxidants as an adjuvant therapy in patients with lung diseases.

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Wattamwar, P. B., AMAR UMAKANT UPASE, S. B. Gholve, S. G. Zingade, and O. G. Bhusnure. "Formulation and Evaluation of Traditional Antioxidant Grape Seeds Extract in the Form of Tablets." Journal of Drug Delivery and Therapeutics 9, no. 5 (September 15, 2019): 110–13. http://dx.doi.org/10.22270/jddt.v9i5.3228.

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Oxygen uptake while breathing cause’s free radical production and in addition to that environmental factors such as pollutants, smoke and certain chemicals also contribute to their formation. Reactive oxygen species is a collective term that includes all reactive forms of oxygen, including both oxygen radicals and several non-radical oxidizing agents that participate in the initiation and/or propagation of chain reaction. Free radicals are atoms, molecules or ions with unpaired electrons that are highly unstable and active towards chemical reactions with other molecules. Antioxidant is any substance that when present at low concentrations compared to those of an oxidizable substrate significantly delays or prevents oxidation of that substrate. Antioxidants block the process of oxidation by neutralizing free radicals. Antioxidant power of proanthocyanidins is 20 times greater than vitamin E and 50 times greater than vitamin C. Proanthocyanidins in Grape seeds have been shown to exhibit strong antioxidant, antimutagenic, anti-inflammatory, anticarcinogenic and antiviral activity. Keywords- Antioxidants, Grape seed, Proanthocyanidins, DPPH activity.

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Raja*, G., Ivvala Anand Shaker, Inampudi Sailaja, R. Swaminathan, S. Saleem Basha, and Kondaveeti Sureshbabu. "Study of antioxidant potential in leaves, stems, nuts of Juglans regia L." International Journal of Bioassays 1, no. 10 (October 16, 2012): 79. http://dx.doi.org/10.21746/ijbio.2012.10.003.

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Natural antioxidants can protect the human body from free radicals and retard the progress of many chronic diseases as well as lipid oxidative rancidity in foods. The role of antioxidants has protected effect against free radical damage that may cause many diseases including cancer. Primary sources of naturally occurring antioxidants are known as whole grains, fruits, and vegetables. Several studies suggest that regular consumption of nuts, mostly walnuts, may have beneficial effects against oxidative stress mediated diseases such as cardiovascular disease and cancer. The role of antioxidants has attracted much interest with respect to their protective effect against free radical damage that may cause many diseases including cancer. Juglans regia L. (walnut) contains antioxidant compounds, which are thought to contribute to their biological properties. Polyphenols, flavonoids and flavonols concentrations and antioxidant activity of Leaves, Stems and Nuts extract of Juglans regia L. as evaluated using DPPH, ABTS, Nitric acid, hydroxyl and superoxide radical scavenging activity, lipid peroxidation and total oxidation activity were determined. The antioxidant activities of Leaves, Stems and Nuts extract of Juglans regia L. were concentration dependent in different experimental models and it was observed that free radicals were scavenged by the test compounds in all the models.

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Jamshidi-kia, Fatemeh, Joko Priyanto Wibowo, Mostafa Elachouri, Rohollah Masumi, Alizamen Salehifard-Jouneghani, Zohreh Abolhasanzadeh, and Zahra Lorigooini. "Battle between plants as antioxidants with free radicals in human body." Journal of Herbmed Pharmacology 9, no. 3 (March 29, 2020): 191–99. http://dx.doi.org/10.34172/jhp.2020.25.

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Free radicals are constructed by natural physiological activities in the human cells as well as in the environment. They may be produced as a result of diet, smoking, exercise, inflammation, exposure to sunlight, air pollutants, stress, alcohol and drugs. Imbalanced redox status may lead to cellular oxidative stress, which can damage the cells of the body, resulting in an incidence of various diseases. If the endogenous antioxidants do not stop the production of reactive metabolites, they will be needed to bring about a balance in redox status. Natural antioxidants, for example plants, play an important part in this context. This paper seeks to report the available evidence about oxidative stress and the application of plants as antioxidant agents to fight free radicals in the human body. For this purpose, to better understand oxidative stress, the principles of free radical production, the role of free radicals in diseases, antioxidant defense mechanisms, and the role of herbs and diet in oxidative stress are discussed.

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Goldfarb, Allan H. "Nutritional Antioxidants as Therapeutic and Preventive Modalities in Exercise-Induced Muscle Damage." Canadian Journal of Applied Physiology 24, no. 3 (June 1, 1999): 249–66. http://dx.doi.org/10.1139/h99-021.

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Several mechanisms have been forwarded to explain the etiology of exercise-induced muscle damage. Free-radical mediated processes appear to be an important component of the inflammatory mediated response. Free radicals have also been demonstrated to be a contributing factor in the loss of calcium homeostasis within the cell. Therefore, one of the proposed treatments for preventing or reducing the extent of this damage is the intervention of free-radical mediated processes. Antioxidants are agents that typically work to prevent free-radical mediated alterations within cells by quenching free radicals. The traditional dietary antioxidants most commonly investigated to inhibit free-radical damage are vitamin E, vitamin C, and beta carotene. Other nutritional agents have also been noted to posses antioxidant properties. Isoflavonoids and some phytochemicals have been proposed to contain antioxidant properties. This paper briefly reviews some aspects of these agents and their role, either proven or proposed, in the prevention of oxidative stress and muscle damage. Key words: vitamin E, vitamin C, beta carotene, genistein, oxidative stress

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Parcheta, Monika, Renata Świsłocka, Sylwia Orzechowska, Monika Akimowicz, Renata Choińska, and Włodzimierz Lewandowski. "Recent Developments in Effective Antioxidants: The Structure and Antioxidant Properties." Materials 14, no. 8 (April 15, 2021): 1984. http://dx.doi.org/10.3390/ma14081984.

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Since the last few years, the growing interest in the use of natural and synthetic antioxidants as functional food ingredients and dietary supplements, is observed. The imbalance between the number of antioxidants and free radicals is the cause of oxidative damages of proteins, lipids, and DNA. The aim of the study was the review of recent developments in antioxidants. One of the crucial issues in food technology, medicine, and biotechnology is the excess free radicals reduction to obtain healthy food. The major problem is receiving more effective antioxidants. The study aimed to analyze the properties of efficient antioxidants and a better understanding of the molecular mechanism of antioxidant processes. Our researches and sparing literature data prove that the ligand antioxidant properties complexed by selected metals may significantly affect the free radical neutralization. According to our preliminary observation, this efficiency is improved mainly by the metals of high ion potential, e.g., Fe(III), Cr(III), Ln(III), Y(III). The complexes of delocalized electronic charge are better antioxidants. Experimental literature results of antioxidant assays, such as diphenylpicrylhydrazyl (DPPH) and ferric reducing activity power assay (FRAP), were compared to thermodynamic parameters obtained with computational methods. The mechanisms of free radicals creation were described based on the experimental literature data. Changes in HOMO energy distribution in phenolic acids with an increasing number of hydroxyl groups were observed. The antioxidant properties of flavonoids are strongly dependent on the hydroxyl group position and the catechol moiety. The number of methoxy groups in the phenolic acid molecules influences antioxidant activity. The use of synchrotron techniques in the antioxidants electronic structure analysis was proposed.

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Rahman, Arif, Abd Malik, and Aktsar Roskiana Ahmad. "SKRINING FITOKIMIA DAN UJI AKTIVITAS ANTIOKSIDAN EKSTRAK ETANOLIK BUAH BUNI (Antidesma bunius (L.) SPRENG)." Jurnal Fitofarmaka Indonesia 3, no. 2 (July 5, 2016): 159–63. http://dx.doi.org/10.33096/jffi.v3i2.497.

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Free radicals play a role in the occurrence of various degenerative diseases that require free-radical scavengers or antioxidants. Buni fruit (Antidesma bunius (L.) Spreng) has the bioactive components are Anthocyanins (flavonoids) that serves to the free radicals. This study aimed to measure the antioxidant activity of theethanol extract contained 70% fruit Buni obtained by using the method of nitric oxide. Simplicia buni macerated dried fruit with 70% ethanol. Extracts were obtained in the test antioxidant activity against nitric oxide radicals. The antioxidant activity against free radical absorbance measured by means of UV-Vis spectrophotometry at a wavelength of 546 nm and calcul ated IC50 values. The results shows that the fruit buni has potential as a free radical with IC50 value of 2.28 µg/mL and a comparison of quercetin with IC50 value of 5.88 µg/mL.

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Cunnane, S. C. "Antioxidants, free radicals and PUFA." Prostaglandins, Leukotrienes and Essential Fatty Acids 50, no. 6 (June 1994): 363–64. http://dx.doi.org/10.1016/0952-3278(94)90248-8.

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Fang, Yun-Zhong, Sheng Yang, and Guoyao Wu. "Free radicals, antioxidants, and nutrition." Nutrition 18, no. 10 (October 2002): 872–79. http://dx.doi.org/10.1016/s0899-9007(02)00916-4.

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Conner, Elaine M., and Matthew B. Grisham. "Inflammation, free radicals, and antioxidants." Nutrition 12, no. 4 (April 1996): 274–77. http://dx.doi.org/10.1016/s0899-9007(96)00000-8.

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MCBRIDE, JEFFREY M., and WILLIAM J. KRAEMER. "Free Radicals, Exercise, and Antioxidants." Journal of Strength and Conditioning Research 13, no. 2 (May 1999): 175–83. http://dx.doi.org/10.1519/00124278-199905000-00013.

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Kuhn, Merrily A. "Oxygen Free Radicals and Antioxidants." AJN, American Journal of Nursing 103, no. 4 (April 2003): 58–62. http://dx.doi.org/10.1097/00000446-200304000-00022.

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MCBRIDE, JEFFREY M., and WILLIAM J. KRAEMER. "Free Radicals, Exercise, and Antioxidants." Journal of Strength and Conditioning Research 13, no. 2 (1999): 175. http://dx.doi.org/10.1519/1533-4287(1999)013<0175:freaa>2.0.co;2.

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Buettner, Garry R., and Freya Q. Schafer. "Free radicals, oxidants, and antioxidants." Teratology 62, no. 4 (2000): 234. http://dx.doi.org/10.1002/1096-9926(200010)62:4<234::aid-tera10>3.0.co;2-9.

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Furst, Arthur. "Oxidants, Antioxidants, and Free Radicals." International Journal of Toxicology 18, no. 2 (March 1999): 159. http://dx.doi.org/10.1080/109158199225738.

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Magun, A. M. "Free radicals, antioxidants, and bilirubin." Gastroenterology 94, no. 3 (March 1988): 852–53. http://dx.doi.org/10.1016/0016-5085(88)90269-7.

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Pilcher, Jobeth. "Free Radicals." Neonatal Network 21, no. 7 (January 2002): 33–37. http://dx.doi.org/10.1891/0730-0832.21.7.33.

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Free radicals may be the cause of many neonatal complications, such as chronic lung disease and brain injury. Treatment options for these complications using antioxidants are being evaluated through research. This article begins with a review of the basic science of free radicals. It then discusses neonatal complications potentially caused by free radicals. A brief description of research into potential treatment options is also included.

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AS, Shrikanth, and P. G. Jadar. "Anti-Oxidant effects of Swarnamakshika Bhasma : A Experimental Study." Journal of Ayurveda and Integrated Medical Sciences (JAIMS) 5, no. 04 (August 25, 2020): 92–101. http://dx.doi.org/10.21760/jaims.5.4.16.

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Shodhana of Swarnamakshika carried out by Bharjana in Eranda Tila. Marana of Swarnamakshika by finely powdered Shudda Swarnamakshika was taken in a Khalvayantra. Then equal quantity of Shudda Gandhaka was added and triturated together till they become homogenous. To this mixture 100ml of Jambhira Rasa was added triturated well till it becomes semisolid consistency. The paste were made into shape of Chakrikas weighing 25gm and 8cm uniformly and kept for drying. Subjecting into 5 required number of Varahaputas. The present day lifestyle and food habits have increased the production of free radicals. These cytotoxic free radicals not only raise the oxidative stress but also play an important role in the immune-system dysfunction due to which the mankind is prone to various major ailments and it is now proved that diseases like Prameha, Pandu, Vatavyadhi etc. are free radical mediated ones. To tackle these free radicals our body needs antioxidants. An antioxidant is a molecule which is capable of inhibiting the oxidation of other molecules. Oxidation reactions can produce free radicals which in turn start chain reactions that damage cells. Antioxidants terminate these chain reactions by removing free radical intermediates and inhibit other oxidation reactions. Many herbals drugs and compound herbal preparations have been screened for their antioxidant and immuno-modulatory properties but still there is a need for effective antioxidants. This dearth and also the fact that Swarnamakshika is being used in treating many of the free radical mediated diseases prompted us to take the present study which aims to validate the Antioxident effect of Swarnamakshika Bhasma scientifically and explain its probable mode of action at the cellular level.

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Tri Putri, Deby Kania, Beta Widya Oktiani, Candra Candra, and Rosihan Adhani. "ANTIOXIDANT ACTIVITY POTENCY OF CHITOSAN FROM HARUAN (CHANNA STRIATA) SCALES." Dentino : Jurnal Kedokteran Gigi 5, no. 2 (August 15, 2020): 139. http://dx.doi.org/10.20527/dentino.v5i2.8951.

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ABSTRACTBackground: Stimulation of inflammatory cells such as polymorphonuclear cells (PMN) will initiate to release free radicals in destroying bacteria. Excessive free radicals can damage cells in the body. Antioxidants as one of the body's defense systems will neutralize existing free radicals. Chitosan from Haruan scales in addition to being antimicrobial turned out to also be antioxidants. Objective: To know the antioxidant potential of chitosan from haruan (Channa striata) scales. Methods: This study is a pure experimental (true experimental design) with a post-test only with control group design using two treatment groups, with quantitative tests to calculate the amount of antioxidant activity of chitosan from fish scales using DPPH radical reduction method. The first treatment is 4, 6, 8 and 10 ppm standard ascorbic acid concentration with DPPH solution as positive control, and the second treatment is 200, 250, 300 and 350 ppm chitosan from Haruan scales concentration with DPPH solution. Results: The results showed that chitosan from Haruan fish scales have antioxidant activity with 50.513% percentage of inhibition at a maximum concentration of 350 ppm with an IC50 value of 356.98 ppm. The results of the independent T-test showed that there was a significant difference between the inhibition percentage of chitosan from haruan fish scales and the inhibition percentage of ascorbic acid (p = 0,000) (p <0.05). Conclusion: Chitosan from Haruan fish scales proved to have antioxidant activity.Keywords: Antioxidants, Chitosan, Haruan fish scalesABSTRACTBackground: Stimulation of inflammatory cells such as polymorphonuclear cells (PMN) will initiate to release free radicals in destroying bacteria. Excessive free radicals can damage cells in the body. Antioxidants as one of the body's defense systems will neutralize existing free radicals. Chitosan from Haruan scales in addition to being antimicrobial turned out to also be antioxidants. Objective: To know the antioxidant potential of chitosan from haruan (Channa striata) scales. Methods: This study is a pure experimental (true experimental design) with a post-test only with control group design using two treatment groups, with quantitative tests to calculate the amount of antioxidant activity of chitosan from fish scales using DPPH radical reduction method. The first treatment is 4, 6, 8 and 10 ppm standard ascorbic acid concentration with DPPH solution as positive control, and the second treatment is 200, 250, 300 and 350 ppm chitosan from Haruan scales concentration with DPPH solution. Results: The results showed that chitosan from Haruan fish scales have antioxidant activity with 50.513% percentage of inhibition at a maximum concentration of 350 ppm with an IC50 value of 356.98 ppm. The results of the independent T-test showed that there was a significant difference between the inhibition percentage of chitosan from haruan fish scales and the inhibition percentage of ascorbic acid (p = 0,000) (p <0.05). Conclusion: Chitosan from Haruan fish scales proved to have antioxidant activity. Keywords: Antioxidants, Chitosan, Haruan fish scales.

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Petrescu, Florian Ion Tiberiu, Relly Victoria Virgil Petrescu, and Eleni Mimi Buzea. "New natural antioxidants." Independent Journal of Management & Production 11, no. 3 (June 1, 2020): 967. http://dx.doi.org/10.14807/ijmp.v11i3.938.

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Antioxidants are, no doubt, an essential part of an optimal health and even traditional doctors support the importance of an appropriate contribution of antioxidants taken through food. Antioxidants are a category of molecules able to inhibit the oxidation of other molecules. The body distributes various nutrients in the body due to their antioxidant properties and also factory antioxidant enzymes to keep under control the reaction in the chain of free radicals. Some antioxidants are produced by the body, but others don't. In addition, the body's natural ability to produce antioxidants decreases with age. Antioxidants play a significant role for health as it may influence the aging by fighting free radicals. There are antioxidants which can’t be produced in the human body, and to be taken through antioxidant-rich foods, or supplements powerful antioxidant. The paper aims to present some natural sources of oxidants that can be obtained through diet.

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Andriantsitohaina, Ramaroson, Lucie Duluc, Julio C. García-Rodríguez, Lizette Gil-del Valle, Mariela Guevara-Garcia, Gilles Simard, Raffaella Soleti, et al. "Systems biology of antioxidants." Clinical Science 123, no. 3 (April 12, 2012): 173–92. http://dx.doi.org/10.1042/cs20110643.

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Understanding the role of oxidative injury will allow for therapy with agents that scavenge ROS (reactive oxygen species) and antioxidants in the management of several diseases related to free radical damage. The majority of free radicals are generated by mitochondria as a consequence of the mitochondrial cycle, whereas free radical accumulation is limited by the action of a variety of antioxidant processes that reside in every cell. In the present review, we provide an overview of the mitochondrial generation of ROS and discuss the role of ROS in the regulation of endothelial and adipocyte function. Moreover, we also discuss recent findings on the role of ROS in sepsis, cerebral ataxia and stroke. These results provide avenues for the therapeutic potential of antioxidants in a variety of diseases.

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Sari, Ayu Nirmala. "Berbagai Tanaman Rempah Sebagai Sumber Antioksidan Alami." Elkawnie 2, no. 2 (December 31, 2016): 203. http://dx.doi.org/10.22373/ekw.v2i2.2695.

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Radicals produced naturally in the body, can cause various diseases when present in large quantities. High levels of free radical compounds showed low antioxidant activity that leads to degeneration of the body cells, metabolic disorder, decreased immune response that trigger the emergence of a variety of degenerative diseases. Need extra antioxidants from outside the body in order to help prevent the adverse effects of free radicals, such as antioxidants derived from plants used as cooking ingredients or food ingredients. There are some herbal plants that are a source of natural antioxidants , which are also used as a spice, such as turmeric (Curcuma domestica), ginger (Zingiber offcinale), nutmeg (Myristica fragrans), paprika (Capsicum annum), lemongrass (Cymbopogon citratus), galangal (Alpinia galangal), onion (Allium cepa) and garlic (Allium sativum).

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Ácsová, Aneta, Silvia Martiniaková, and Jarmila Hojerová. "Selectedin vitro methods to determine antioxidant activity of hydrophilic/lipophilic substances." Acta Chimica Slovaca 12, no. 2 (October 1, 2019): 200–211. http://dx.doi.org/10.2478/acs-2019-0028.

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Abstract The topic of free radicals and related antioxidants is greatly discussed nowadays. Antioxidants help to neutralize free radicals before damaging cells. In the absence of antioxidants, a phenomenon called oxidative stress occurs. Oxidative stress can cause many diseases e.g. Alzheimer’s disease and cardiovascular diseases. Therefore, antioxidant activity of various compounds and the mechanism of their action have to be studied. Antioxidant activity and capacity are measured by in vitro and in vivo methods; in vitro methods are divided into two groups according to chemical reactions between free radicals and antioxidants. The first group is based on the transfer of hydrogen atoms (HAT), the second one on the transfer of electrons (ET). The most frequently used methods in the field of antioxidant power measurement are discussed in this work in terms of their principle, mechanism, methodology, the way of results evaluation and possible pitfalls.

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Zulaikhah, Siti Thomas. "The Role of Antioxidant to Prevent Free Radicals in The Body." Sains Medika 8, no. 1 (April 4, 2017): 39. http://dx.doi.org/10.26532/sainsmed.v8i1.1012.

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AbstractAntioxidants are compounds that can counteract or reduce the negative impact oxidants in the body. Antioxidants work by donating an electron to compounds that are oxidant so that the oxidant compound activity can be inhibited. Antioxidants are classified into two, namely antioxidant enzymes and non-enzyme. Antioxidant enzymes as enzyme superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx), a non-enzyme antioxidant found in many vegetables and fruits, which include reduced glutathione (GSH), vitamin C, E, β- carotene, flavonoids, isoflavones, flavones, antosionin, catechins, and isokatekin, and lipoic acid. Low antioxidant enzymes can be used as a marker of high levels of free radicals in the body. Following review aims to provide an overview of the role of antioxidants in preventing the formation of free radicals in the body.

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Gariballa, SE, and AJ Sinclair. "Cerebrovascular disease and oxidative stress." Reviews in Clinical Gerontology 9, no. 3 (August 1999): 197–206. http://dx.doi.org/10.1017/s0959259899009314.

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There is strong indirect evidence that free radical production appears to be an important mechanism of brain injury after exposure to ischaemia and reperfusion. Although significant brain damage occurs during an ischaemic episode, new cerebral damage can occur after reperfusion. One proposed mechanism for the brain damage that occurs during reperfusion involves generation of free radicals. Body defences against free radicals depends on the balance between free radical generation and the antioxidant protective defence system. Many of these protective antioxidants are essential nutrients or have essential nutrients as part of their molecule that has to be obtained from diet.

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Chahal, Anterpreet, Adesh K. Saini, Anil Kumar Chhillar, and Reena V. Saini. "NATURAL ANTIOXIDANTS AS DEFENSE SYSTEM AGAINST CANCER." Asian Journal of Pharmaceutical and Clinical Research 11, no. 5 (May 1, 2018): 38. http://dx.doi.org/10.22159/ajpcr.2018.v11i5.24119.

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In living cells, the production of free radicals that comprise both reactive oxygen species (ROS) and reactive nitrogen species is highly regulated that help the cells to sustain redox homeostasis. Overproduction of ROS from mitochondrial electron transport chain leakage or excessive stimulation of xanthine oxidase and other oxidative enzymes leads to the uncontrolled production of free radicals leading to oxidative stress that can mediate damage to cell structures. This damage can be repaired by the antioxidant defense system. Antioxidants are capable of stabilizing, or deactivating, free radicals before they attack cellular components such as DNA, proteins, and lipids. The use of antioxidants in cancer prevention is a rapidly evolving research area where antioxidants scavenge free radicals and thus, indirectly help in the prevention of cancer. A wide range of antioxidants such as glutathione, N-acetylcysteine, coenzyme Q10, lycopene, flavonoids, and isoflavones when used in combination with chemotherapy and radiotherapy, result in the reduction of drug toxicity and enhanced efficacy of anticancer agents. This review aims at the use of these exogenous antioxidants as disease-oriented therapy and elucidating the relation of antioxidant enzymes with different types of cancers to overcome the harmful effects of cancer treatment.

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Afifi, Mohamed, and Ali Alkaladi. "Antioxidant system in Uromastyx philbyi during hibernation and activity periods." Open Life Sciences 9, no. 9 (September 1, 2014): 864–68. http://dx.doi.org/10.2478/s11535-014-0318-x.

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AbstractHibernation is an extreme physiological state characterized by profound decreases in oxidative metabolism and body temperature during bouts of prolonged torpor, interrupted by brief periods of arousal with sudden increases in oxidative metabolism, with alterations in antioxidant defenses. We monitored the activities of antioxidant enzymes and oxidative stress during hibernation and activity in Uromastyx philbyi. 20 animals were used, 10 of which were collected in the hibernation season (group I) and the other 10 collected during the active period (group II). Blood, liver, brown adipose tissue (BAT) and brain samples were used to determine free radical and antioxidant levels. The results indicated a significant decrease of free radicals and increase of vitamin C, especially in serum during hibernation. In contrast, during the active period free radicals, enzymatic antioxidants as glutathione peroxidase (GPX), glutathione reductase (GR), superoxide dismutase (SOD) and catalase (CAT) and non-enzymatic antioxidants as reduce glutathione (GSH) and vitamin E increased in all studied tissues. It can be concluded that Uromastyx philbyi has a strong antioxidant defense system that protects it from the injurious effects of free radicals either at the periods of arousal or during activity periods.

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Burlakova, Elena, Elena Molochkina, and Grygoriy Nikiforov. "Hybrid antioxidants." Chemistry & Chemical Technology 2, no. 3 (September 15, 2008): 163–71. http://dx.doi.org/10.23939/chcht02.03.163.

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The article is a review of the data on synthesis and physiological activity of hybrid antioxidants. The introduction offers an explanation to the fact why, in some cases, it is necessary to add drug molecules with fragments responsible for various properties and aimed at various targets. A large group of hybrid antioxidants comprise stable nitroxyl radicals that behave as antioxidants in free-radical reactions of oxidation. Compounds of this type were synthesized extensively to form a group of antitumor agents. As a rule, the specific (antitumor) activity retained or even increased as compared with the initial compounds (without nitroxyl radicals); the toxicity decreased 5 to 10 times, which made it possible to apply the drug in considerably higher concentrations. There are reported data on nitroxyl derivatives of anthracycline antibiotics, antimetabolites, alkyl ting agents, and the recent results on platinum complexes with nitroxyl fragments. Much attention is given to hindered phenols with “buoyancy” properties, particularly, to biochemical effects, making them promising agents to treat Alzheimer’s disease.

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Mishra, Tulika, Ananda Kumar Kondepati, Shalini Devaprasad Pasumarthi, Gurmit Singh Chilana, Suresh Devabhaktuni, and Pratik Kumar Singh. "Phytotherapeutic antioxidants." Asian Journal of Medical Sciences 11, no. 2 (February 29, 2020): 96–100. http://dx.doi.org/10.3126/ajms.v11i2.26465.

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Plants have always been an integrated part of human life, whether we discuss about providing food or we about their medicinal value. Ethnomedicines have led to the discovery of many valuable drugs against various diseases. It has been postulated that most of the disease are related to immune system which is affected by imbalance balance between antioxidants and prooxidants or free radicals. Free radicals are the chemical entities capable of independent existence that contain one/more unpaired electrons and can be balanced by antioxidants. Antioxidants maintain the integrity and function of membrane lipids, cellular proteins, and nucleic acids and the control of signal transduction of gene expression in immune cells. For this reason, the immune cells are particularly sensitive to changes in their antioxidant status. Whenever there is imbalance between prooxidant and antioxidants they can lead to many diseases and even ameliorate the severity of disease like Alzheimer, cardiovascular disorder, cancer etc. There are evidences showing usage of plants as a potent source of antioxidants has provided a lot of support in combating various diseases, without any side effect. Various Bioflavonoids, Carotenoids, Hydroxycinnamates etc helps in scavenging the free radicals and thus proved to be immunostimulant. There are various mechanisms through which these Phyto antioxidants assisted against various disease. The present review is an attempt showing the relationship of free radicals with various diseases and immune system and the role of Phyto antioxidants against various health related conditions.

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Pokorný, J., Š. Schmidt, and H. T T Nguyen. "Functionality changes of natural antioxidants during food processing and storage." Czech Journal of Food Sciences 22, SI - Chem. Reactions in Foods V (January 1, 2004): S80—S83. http://dx.doi.org/10.17221/10617-cjfs.

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Food raw materials and products contain inhibitors of oxidation reactions, both in the lipidic phase and the aqueous phase. The most important inhibitors are phenolic antioxidants. During food processing and storage, concentrations of antioxidants in the two phases reach an equilibrium. Phenolics react with lipidic free radicals, being converted into antioxidant free radicals, quinones, polymers and copolymers. Some degradation products possess an antioxidant activity, too. The relative antioxidant activity decreases with decreasing concentration of oxygen in the system and with increasing temperature. Antioxidants are more rapidly decomposed in surface layers. Health aspects of antioxidant degradation products are often neglected as the safety of antioxidant degradation products is mostly unknown.

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Basaga, H. S. "Biochemical aspects of free radicals." Biochemistry and Cell Biology 68, no. 7-8 (July 1, 1990): 989–98. http://dx.doi.org/10.1139/o90-146.

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Toxic free radicals can be produced by many reactions required for the maintenance of normal metabolism and the production of energy in the cell. The reactivity of both primary and secondary radicals with biomolecules and in whole tissue systems is of interest, not only because of their importance in radiobiology but also because of the role these species play in toxicity and various disorders. Oxidant stress is known to increase the production of free radicals. In the presence of metals, especially iron, these radicals are converted into more damaging species. Trace elements play an important role in many systems that have evolved to deal with free radicals. The dietary status of the cell can affect the preventative antioxidant constituents of the cell. The chain-breaking antioxidant status can clearly be influenced by the dietary content of substances such as vitamins E and C.Key words: free radicals, oxidant stress, metal ions, antioxidants.

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Halliwell, Barry. "Free radicals and antioxidants – quo vadis?" Trends in Pharmacological Sciences 32, no. 3 (March 2011): 125–30. http://dx.doi.org/10.1016/j.tips.2010.12.002.

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Comporti, Mario. "FREE RADICALS, OXIDATIVE STRESS AND ANTIOXIDANTS." Journal of the Siena Academy of Sciences 2, no. 1 (April 27, 2012): 13. http://dx.doi.org/10.4081/jsas.2010.13.

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Seidman, Michael, Simon Melov, John Althaus, Russell Reiter, Jochen Schacht, Michael Angel, and Michael Seidman. "Free Radicals and Antioxidants in Otolaryngology." Otolaryngology–Head and Neck Surgery 115, no. 2 (August 1996): P157. http://dx.doi.org/10.1016/s0194-5998(96)80860-6.

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PhD, Okezie I. Aruoma. "Free radicals, antioxidants and international nutrition*." Asia Pacific Journal of Clinical Nutrition 8, no. 1 (March 1999): 53–63. http://dx.doi.org/10.1046/j.1440-6047.1999.00036.x.

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GOODE, HELEN F., and NIGEL R. WEBSTER. "Free radicals and antioxidants in sepsis." Critical Care Medicine 21, no. 11 (November 1993): 1770–76. http://dx.doi.org/10.1097/00003246-199311000-00029.

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Pryor, William A. "Free radicals and antioxidants in nutrition." Free Radical Biology and Medicine 18, no. 1 (January 1995): 130. http://dx.doi.org/10.1016/0891-5849(95)90080-2.

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Johnson, Kent J. "Free Radicals, Antioxidants, Aging & Disease." Archives of Pathology & Laboratory Medicine 125, no. 7 (July 1, 2001): 984. http://dx.doi.org/10.5858/2001-125-984-fraad.

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Bender, David A. "The antioxidant paradox: Damage and defence." Biochemist 28, no. 5 (October 1, 2006): 9–12. http://dx.doi.org/10.1042/bio02805009.

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Over the last three decades, a considerable body of evidence has accumulated to suggest that a key factor in the development of both cancer and coronary heart disease is damage to tissues or plasma lipoproteins caused by free radicals. The majority of radicals that damage tissues are reactive oxygen species, and compounds that can quench potentially damaging radical chain reactions are therefore generally referred to as antioxidants. Epidemiological studies have shown a negative correlation between intakes of antioxidants (especially vitamin E and -carotene) and the incidence of cancer and coronary heart disease, and a positive correlation between markers of radical damage and disease. At the molecular level, there are sound theories to explain how radical damage can lead to cancer and coronary heart disease, and how antioxidants may provide protection. However, the results of intervention trials of vitamin E and -carotene have been, at best, disappointing; indeed, many trials have shown increased death among people taking supposedly protective antioxidant supplements. This is the antioxidant paradox.

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Zhao, Lin, Yingmin Wang, and Yan Li. "Antioxidant Activity of Graphene Quantum Dots Prepared in Different Electrolyte Environments." Nanomaterials 9, no. 12 (November 29, 2019): 1708. http://dx.doi.org/10.3390/nano9121708.

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Antioxidants can reduce or inhibit damage such as oxidative decay caused by elevated levels of free radicals. Therefore, pursuing antioxidants with excellent properties has attracted more and more attention. Graphene quantum dots (GQDs) are considered a promising material because of their good free radical scavenging activity, low toxicity, and excellent water solubility. However, their scavenging efficiency, antioxidant mechanism, and effective control methods need to be improved. Herein, in order to further reveal the antioxidant mechanism of GQDs, the role of electrolytes in improving the antioxidant activity of GQDs is explored. In addition, 1,1-diphenyl-2-picrazine (DPPH∙), hydroxyl (∙OH), and superoxide (∙O2−) free radicals are used to evaluate the antioxidant activity of the as-prepared GQDs. Combined with transmission electron microscopy, Fourier-transform infrared spectroscopy, Raman spectroscopy, and cyclic volt–ampere characteristic curves, the effects of an electrolytic environment on the surface functional groups, charge transfer capability, and defect states of GQDs are obtained. The antioxidant mechanism of GQDs and how to improve their antioxidant activity are further elucidated.

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Chen, Alex F., Dan-Dan Chen, Andreas Daiber, Frank M. Faraci, Huige Li, Christopher M. Rembold, and Ismail Laher. "Free radical biology of the cardiovascular system." Clinical Science 123, no. 2 (March 23, 2012): 73–91. http://dx.doi.org/10.1042/cs20110562.

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Most cardiovascular diseases (CVDs), as well as age-related cardiovascular alterations, are accompanied by increases in oxidative stress, usually due to increased generation and/or decreased metabolism of ROS (reactive oxygen species; for example superoxide radicals) and RNS (reactive nitrogen species; for example peroxynitrite). The superoxide anion is generated by several enzymatic reactions, including a variety of NADPH oxidases and uncoupled eNOS (endothelial NO synthase). To relieve the burden caused by this generation of free radicals, which also occurs as part of normal physiological processes, such as mitochondrial respiratory chain activity, mammalian systems have developed endogenous antioxidant enzymes. There is an increased usage of exogenous antioxidants such as vitamins C and E by many patients and the general public, ostensibly in an attempt to supplement intrinsic antioxidant activity. Unfortunately, the results of large-scale trails do not generate much enthusiasm for the continued use of antioxidants to mitigate free-radical-induced changes in the cardiovascular system. In the present paper, we review the clinical use of antioxidants by providing the rationale for their use and describe the outcomes of several large-scale trails that largely display negative outcomes. We also describe the emerging understanding of the detailed regulation of superoxide generation by an uncoupled eNOS and efforts to reverse eNOS uncoupling. SIRT1 (sirtuin 1), which regulates the expression and activity of multiple pro- and anti-oxidant enzymes, could be considered a candidate molecule for a ‘molecular switch’.

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Journal articles on the topic 'Free radicals; Antioxidants'

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