Peroxyl Free Radicals: Biological Reactive Intermediates Produced during Lipid Oxidation

1991 ◽  
pp. 65-70 ◽  
Author(s):  
Lawrence J. Marnett
Keyword(s):  
Free Radicals ◽  
Lipid Oxidation ◽  
Reactive Intermediates

Laser-Induced Fluorescence Measurement of Free Radical Intermediates

1988 ◽  
Vol 117 ◽  
Author(s):  
David R. Crosley
Keyword(s):  
Free Radicals ◽  
Gas Phase ◽  
Spectroscopic Method ◽  
Simultaneous Detection ◽  
Reactive Intermediates ◽  
Laser Induced Fluorescence ◽  
Materials Processing ◽  
Fluorescence Measurement ◽  
Radical Intermediates ◽  
Quantitative Measurements

AbstractLaser-induced fluorescence (LIF) provides a means for sensitive, selective and nonintrusive measurements of reactive intermediates, often free radicals, which control the chemistry of combustion. The same approach can be used to detect in the gas phase, atoms, radicals and ions which are reactive intermediates in materials processing. This article briefly examines the use of LIF in combustion. It includes a description of the LIF spectroscopic method as employed for quantitative measurements, and the use of LIF in a semiquantitative manner with extension to the simultaneous detection of more than one species.

Free radical formation in freeze-dried raw milk in relation to its α-tocopherol level

1999 ◽  
Vol 66 (3) ◽  
pp. 461-466 ◽  
Author(s):  
HENRIK STAPELFELDT ◽  
KIRSTEN NYHOLM NIELSEN ◽  
SØREN KROGH JENSEN ◽  
LEIF H. SKIBSTED
Keyword(s):  
Free Radicals ◽  
Free Radical ◽  
Lipid Oxidation ◽  
Dairy Products ◽  
Raw Milk ◽  
Oxidation Products ◽  
Model Systems ◽  
Lipid Hydroperoxides ◽  
Lipid Oxidation Products ◽  
Esr Spectrometry

Lipid oxidation in milk and dairy products is a chain reaction initiated by formation of free radicals (Richardson & Korycka-Dahl, 1983). Thanks to intensive studies on both model systems and actual food, the autocatalytic process, including the formation of secondary lipid oxidation products from the lipid hydroperoxides formed initially, is fairly well understood. However, actually predicting the rate at which the first free radicals leading to spontaneous oxidation are formed in milk from different cows awaits the development of new analytical methods with higher specificity and sensitivity (Nicholson, 1993; Barrefors et al. 1995). Such methods would also be valuable for predicting the stability and shelf life of dried dairy products, which are determined by oxidative phenomena. Electron spin resonance (ESR) spectrometry has the potential for detecting the early events in lipid oxidation, as it is the only spectrometric method that will directly detect the unpaired electron characteristic of the free radical and it is, moreover, a highly sensitive method (Brudvig, 1995). ESR spectrometry has recently been shown to provide quantitative information on the level of free radicals in milk powder that correlates with the level of secondary oxidation products developed upon reconstitution and that also correlates with subsequent sensory evaluation (Nielsen et al. 1997; Stapelfeldt et al. 1997a, b, c). However, in order to explore further the potential of this method for raw milk, it was considered valuable to measure the tendency of milk to form free radicals in relation to its level of α-tocopherol, the most important lipophilic chain-breaking antioxidant (cf. Kamal-Eldin & Appelqvist, 1996).

scholarly journals Oilseeds as Functional Foods: Content and Composition of Many Phytochemicals and Therapeutic Alternatives

2021 ◽  
Author(s):  
Aicha O. Cherif
Keyword(s):  
Free Radicals ◽  
Cardiovascular Diseases ◽  
Lipid Oxidation ◽  
Human Health ◽  
Functional Foods ◽  
Cross Linking ◽  
Minor Components ◽  
Active Constituents ◽  
Dna Mutations ◽  
Therapeutic Alternatives

Oilseeds composition has been studied extensively, but recently it has been thoroughly investigated considering especially the phytochemicals representing the minor components. This interest is connected with the activity of such compounds against cardiovascular diseases, lipid oxidation, protein cross-linking and DNA mutations and hemostasis function, which prevent the attack of biomolecules by free radicals. This chapter book could aim to give an overview of the different uses of several oilseeds as bioactive foods, focusing on their active constituents (phytosterols, polyphenols, tocopherols, tocotrienols, and carotenoids) and their content in oilseeds. We will also focus on the beneficial aspects of theses nutraceuticals in human health.

scholarly journals DETERMINATION OF FLAVONOID LEVELS OF AlCl3 METHODE IN THE EXTRACT OF METANOL FLOWERS (Clitoria ternatea L.)

2020 ◽  
Vol 6 (2) ◽  
pp. 134-141
Author(s):  
Anita Agustina Styawan ◽  
Gandis Rohmanti
Keyword(s):  
Free Radicals ◽  
Immune System ◽  
Medicinal Plants ◽  
Lipid Oxidation ◽  
Secondary Metabolite ◽  
Methanol Extract ◽  
Degenerative Diseases ◽  
Clitoria Ternatea ◽  
Red Color

Telang flowers is one of the medicinal plants that can grow well in Indonesia, but have not been widely used. Previous research stated that methanol extract of telang flowers had secondary metabolite compounds such as tannin, saponin, flavonoid and alkaloid. Flavonoid are natural compounds that have the potential as antioxidants that can capture free radicals that play a role in the emergence of degenerative diseases throught the mechanisme of damage to the body’s immune system, lipid oxidation and protein.The purpose of this study was to determine whether telang flowers content was determined whether by the AlCl3 method and measured by using UV-Vis Spektrophotometry from the methanol extract of telang flowers.The results of this study indicate that the methanol extract of telang flowers contains flavonoid with red color. The level of flavonoids intended is 4.65%.  

Antioxidants, Carnitine, and Choline as Putative Ergogenic Aids

1995 ◽  
Vol 5 (s1) ◽  
pp. S120-S131 ◽  
Author(s):  
Mitchell M. Kanter ◽  
Melvin H. Williams
Keyword(s):  
Skeletal Muscle ◽  
Free Radicals ◽  
Lipid Oxidation ◽  
Physical Performance ◽  
Direct Effect ◽  
Mechanisms Of Action ◽  
Scientific Data ◽  
Antioxidant Vitamins ◽  
Plasma Lactate ◽  
Potential Efficacy

Three nutritional products that have very different mechanisms of action are antioxidant vitamins, carnitine, and choline. Antioxidant vitamins do not appear to have a direct effect on physical performance in well-fed people but have been touted for their ability to detoxify potentially damaging free radicals produced during exercise. Carnitine purportedly enhances lipid oxidation, increases VO2max, and decreases plasma lactate accumulation during exercise. However, studies of carnitine do not generally support its use for ergogenic purposes. Choline supplements have been advocated as a means of preventing the decline in acetylcholine production purported to occur during exercise; this decline may reduce the transmission of contraction-generating impulses across the skeletal muscle, an effect that could impair one’s ability to perform muscular work. However, there are no definitive studies in humans that justify choline supplementation. Much of the scientific data regarding the aforementioned nutrients are equivocal and contradictory. Their potential efficacy for improving physical performance remains largely theoretical.

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