Antioxidant activity of polyphenols

Sanchez-Morcno (2002) considered that this assay is an easy and accurate method for determining antioxidant capacity in fruit and vegetable samples. The DPPH assay has been used to determine the antioxidant activity of polyphenols (Sanchez-Moreno and others 1998 Bao and others 2004) flavonols (Jimenez and others 1998 1999 Choi and others 2002) anthocyanin-based natural colorants from berries (Espin and others... 

Siddhuraju, P. (2007) Antioxidant activity of polyphenolic compounds extracted from defatted raw and dry heated Famarindus indica seed coat. Food Science and Technology 40(6), 982-990. 

Montoro, P., Tuberoso, C. I. G., Piacente, S., Perrone, A., De Feo, V., Cabras, P., Pizza, C. Stability and antioxidant activity of polyphenols in extracts of Myrtus commtmis L. berries used for the preparation of myrtle liqueur. J. Pharmaceut. Biomed. Anal. 41(5), 1614-19, 2006. 

Kumazawa S, Taniguchi M, Suzuki Y, Shimura M, Kwon M-S, Nakayama T (2001) Antioxidant activity of polyphenols in carob pods. J Agric Food Chem 50 373-377... 

The potential health benefits of plant polyphenols, such as the flavonoids, have been addressed over the years in the framework of the oxidative stress concept. Oxidative stress, as initially formulated by Sies (1985), refers to an imbalance in the dynamic equilibrium between oxidants and antioxidants that favors the formers, potentially leading to damage. As several diseases are supposed to mechanistically involve oxidative stress, such as atherosclerosis, ischemia-reperfusion injury, cancer, and neurodegenerative disorders (Halliwell Gutteridge, 1999), an impressive number of studies on the in vitro antioxidant activity of polyphenols have spotted these compounds as putatively useful to counteract the deleterious oxidant imbalance associated with disease. However, as will be discussed later, because of limited bioavailability and recent updated concept of oxidative stress, the putative activity of polyphenols as global antioxidants is a limited and simplistic view of polyphenol activity in vivo that can be scarcely supported by experimental data. 

Lu Y, Foo LY (2001) Antioxidant activities of polyphenols from sage (Salvia officinalis). Food Chem 75 197-202... 

Chemical Antioxidant Systems. The antioxidant activity of tea extracts and tea polyphenols have been determined using in vitro model systems which are based on hydroxyl-, peroxyl-, superoxide-, hydrogen peroxide-, and oxygen-induced oxidation reactions (109—113). The effectiveness of purified tea polyphenols and cmde tea extracts as antioxidants against the autoxidation of fats has been studied using the standard Rancimat system, an assay based on air oxidation of fats or oils. A direct correlation between the antioxidant index of a tea extract and the concentration of epigallocatechin gallate in the extract was found (107). 

The total antioxidant activity of teas and tea polyphenols in aqueous phase oxidation reactions has been deterrnined using an assay based on oxidation of 2,2 -azinobis-(3-ethylbenzothiazoline-sulfonate) (ABTS) by peroxyl radicals (114—117). Black and green tea extracts (2500 ppm) were found to be 8—12 times more effective antioxidants than a 1-mAf solution of the water-soluble form of vitamin E, Trolox. The most potent antioxidants of the tea flavonoids were found to be epicatechin gallate and epigallocatechin gallate. A 1-mAf solution of these flavanols were found respectively to be 4.9 and 4.8 times more potent than a 1-mAf solution of Trolox in scavenging an ABT radical cation. 

WANG s M and zhao j f (1997) Antioxidant activities of tea polyphenol on edible oils . Western Cereal and Oil Technology, 11, 44-6. 

RICHELLE M, TAVAZZi I, OFFORD E (2001) Comparison of the antioxidant activity of commonly consumed polyphenolic beverages (coffee, cocoa, and tea) prepared per cup serving , J Agric Food Chem, 49 (7) 3438-42. 

Ruberto, G. et al.. Polyphenol constituents and antioxidant activity of grape pomace extracts from five Sicilian red grape cultivars. Food Chem., 100, 203, 2007. 

Alonso AM, Guillen DA, Barroso CG, Puertas B and Gracia A. 2002. Determination of antioxidant activity of wine byproducts and its correlation with polyphenolic content. J Agric Food Chem 50 5832-5836. Al-Saikhan MS, Howard LR and Miller JC Jr. 1995. Antioxidant activity and total phenolics in different genotypes of potato (Solarium tuberosum L). J Food Sci 60 341-343, 7. 

Wojdylo A, Oszmianski J and Laskowski P. 2008. Polyphenolic compounds and antioxidant activity of new and old apple varieties. J Agric Food Chem 56(15) 6520-6530. 

This method is relatively easy to use for anhydrous systems, but not for emulsions, foods, or biological media where the presence of water is detrimental. The method has been applied for determining antioxidant activity of both individual natural polyphenols and vegetable extracts. Methods based on this one have been used to evaluate the peroxide value in walnuts (Wilson-Kakashita and others 1995), mango seeds (Joseph 1995), almonds (Uthman and others 1998), and coconut cream powder (Yusof and others 2007). 

Cervellati R, Renzulli C, Guerra MC and Speroni E. 2002. Evaluation of antioxidant activity of some natural polyphenolic compounds using the Briggs-Rauscher reaction method. J Agric Food Chem 50(26) 7504-7509. 

Klimczak I, Malecka M, Szlachta M and Gliszczynska-Swiglo A. 2007. Effect of storage on the content of polyphenols, vitamin C and the antioxidant activity of orange juices. J Food Compos Anal 20(3 1) 313-322. 

Larrauri JA, Ruperez P and Saura-Calixto F. 1997. Effect of drying temperature on the stability of polyphenols and antioxidant activity of red grape pomace peels. J Agric Food Chem 45(4) 1390-1393. 

Pulido R, Bravo L and Saura-Calixto, F. 2000. Antioxidant activity of dietary polyphenols as determined by a modified ferric reducing/antioxidant power assay. J Agric Food Chem 48(8) 3396-3402. 

Thu NN, Sakurai C, Uto H, Van Chuyen N, Lien DTK, Yamamoto S, Ohmori R and Kondo K. 2004. The polyphenol content and antioxidant activities of the main edible vegetables in northern Vietnam. J Nutr Sci Vitaminol 50(3) 203-210. 

Antioxidant activity of flavonoids has already been shown about 40 years ago [90,91]. (Early data on antioxidant flavonoid activity are cited in Ref. [92].) Flavonoids are polyphenols, and therefore, their antioxidant activity depends on the reactivity of hydroxyl substituents in hydrogen atom abstraction reactions. As in the case of vitamins E and C, the most studied (and most important) reactions are the reactions with peroxyl radicals [14], hydroxyl radicals [15], and superoxide [16]. 

Frei B, Higdon JY. 2003. Antioxidant activity of tea polyphenols in vivo Evidence from animal studies. J Nutr 133 3275S-3284S. 

Rice-Evans, C.A. et al., The relative antioxidant activities of plant-derived polyphenolic flavonoids, Free Radio. Res., 22, 375, 1995. 

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