Flavonoid as antioxidants

BORS w, HELLER w, MICHAEL c and SARAN M (1990) Flavonoids as antioxidants determination of radical scavenging efficiencies, Methods Enzymol, 186, 343-55. 

Jovanovic SV, Steenken S, Tosic M, Marjanovic B, Simic MG. 1994. Flavonoids as antioxidants. J Am Chem Soc 116 4846-4851. 

Saija A, Scalese M, Lanza M, Marzullo D, Castelli F. 1995. Flavonoids as antioxidant agents Importance of their interaction with biomembranes. Free Radic Biol Med 19 481-486. 

Bokkenheuse VD, Shacketon CHL, Winter J. 1987. Hydrolysis of dietaryflavonoide glycosides by strains of intestinal bacteroides from humans. Biochem J 248 953-956. Bors W, Heller W, Michel C, Saran M. 1990. Flavonoids as antioxidants Determination of radical-scavenging efficiencies. In Packer L, Glazer AN, Eds. Methods in Enzymology 186, San Diego Academic Press, pp. 343-355. 

Cos, P. Calomme, M. Pieters, L. Vlietinck, A.J. Vanden Berghe, D. 2000. Strueture-activity relationship of flavonoids as antioxidant and pro-oxidant eompounds. In Studies in Natural Produets Chemistry ( Atta ur, R., Ed.). Elsevier, pp. 307-341. 

Hernandez, I. Alegre, L. Van Breusegem, F. Muime-Bosch, S. 2009. How relevant are flavonoids as antioxidants in plants Trends Plant Sci. 14 125-132. 

Patil, J.R. Chidambara Murthy, K.N. Jayaprakasha, G.K. Chetti, M.B. Patil, B.S. 2009. Bioactive compounds from Mexican lime (Citrus aurantifolia) juice induce apoptosis in human pancreatic cells. J. Agric. Food Chem. 57 10933-10942. Pietta, P.G. 2000. Flavonoids as antioxidants. J. Nat. Prod. 63 1035-1042. 

Hakkinen and Auriola [54] studied the flavonoid contents of various types of Fiimish berries by a combination of LC-ESl-MS, LC-UV-DAD, and GC-MS for identification of the sugar residues. Quercetin was foimd in all berry species. In addition, myricetin and kaempferol were found in some species. Hexose-, deoxyhexose-hexose-, and pentose-flavonols were most abimdant. The presence of rhamnose, glucose, and galactose was identified GC-MS. The method was apphed to assess the health-promoting effects of the flavonoids as antioxidants and anticarcinogens... 

Herrmann, M.-E. 1999. [Sekundare Pflanzenunhaltsstoffe in Obst Carotenoids und Flavonoids als Antioxidantien], Phytochemicals in fruits Carotenoids and flavonoids as antioxidants. Erwerbsobstbau. 41 213-217. 

Flavonoids as antioxidants have been reviewed several times 45s including an outline of many claims to their beneficial health effects . Due to their complex structures and different classes (eight thousand different compounds are known ), researchers often resorted to qualitative screening methods to evaluate their antioxidant potentials in mixed aqueous/lipid phases. For example, the so-called Trolox equivalent antioxidant capacity (TEAC), the concentration of Trolox with equivalent antioxidant activity of a 1 mM concentration of the substrate, is frequently used in heterogeneous systems. Unfortunately, this can be an unreliable measure of the activity of the substance, especially if initiation is also carried out in the aqueous phase. Nevertheless, there have been some efforts made to evaluate antioxidant activities of specific flavonoids using more quantitative methods in heterogeneous systems in order to mimic natural environments. A few examples are cited below to illustrate some approaches to determine flavonoid activities in micelles or lipid membranes. 

STRUCTURE-ACTIVITY RELATIONSHIP OF FLAVONOIDS AS ANTIOXIDANT AND PRO-OXIDANT... 

Makris, D.R. and Rossiter, J.T., Comparison of quercetin and a non-orthohydroxy flavonoid as antioxidants by competing in vitro oxidation reactions, J. Agric. Food Chem., 49, 3370-3377, 2001. 

Much work has been published on evaluations of natural flavonoids in various lipid systems, but most evaluations were done either at elevated temperatures, under AOM or Rancimat conditions, or were based on the unspecific bleaching of )5-carotene by co-oxidation with linoleic acid. Unfortunately, from the results of these assays, the usefulness of flavonoids as antioxidants is difficult to predict for foods containing mainly triacylglycerols and stored under ambient or near ambient conditions (Chapter 8). 

Fraga CG, Mactino US, Ferraro GE et al (1987) Flavonoids as antioxidants evaluated by in vitro and in situ liver chemiluminescence. Biochem Syst Ecol 36 717-720... 

Pietta P (2000) Flavonoids as antioxidants. J Nat Prod 63 1035-1042 Bracke ME, Depypere HT, Boterberg T, Van Marck VL, Vennekens KM, Vanluchene E, Nuytinck M, Serreyn R, Marcel MM (1999) Influence of tangeretin on Tamoxifen s therapeutic benefit in mammary cancer. J Natl Cancer Inst 91 354—359... 

Pietta, P.G. (2000). Flavonoids as antioxidants. Journal of Natural Products, 63,1035-1042. 

Saija, A., Scalese, M., Lanza, M., MarzuUo, D., Bonina, F. CasteUi, F. (1995). Flavonoids as antioxidant agents importance of their interaction with biomembranes. Free Radical Biology and... 

Bors, W., Heller, W., Michel, C. Saran, M. (1990). Flavonoids as antioxidants Determination of... 

Terao, I (1999). Dietary flavonoids as antioxidants in vivo conjugated metaboHtes of (-)-epicatechin and quercetin participate in antioxidative defense in blood plasma. Journal of Medical Investigation, 46,159-168. 

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