Procyanidins antioxidant activity

Liu L, Xie B, Cao S, Yang E, Xu X and Guo S. 2007. A-type procyanidins from Lit chi chinensis pericarp with antioxidant activity. Food Chem 105 1446—1451. 

Arteel and Sies (1999) examined procyanidin oligomers of different size, isolated from the seeds of Theobroma cacao, for their ability to protect against nitration of tyrosine. Serraino and others (2003) investigated antioxidant activity of the blackberry juice and cyanidin-3-O-glucoside on endothelial dysfunction in cells and in vascular rings exposed to peroxynitrite. However, more work is needed in this area, and the confounding effects of oxidized protein/amino acids in the diet need to be elucidated. 

Wood JE, Senthilmohan ST and Peskin AV. 2002. Antioxidant activity of procyanidin-containing plant extracts at different pHs. Food Chem 77(2) 155-161. 

Lotito SB, Actis-Goretta L, Renart ML, Caligiuri M, Rein D, Schmitz HH, Steinberg FM, Keen CL, Fraga CG. 2000. Influence of oligomer chain length on the antioxidant activity of procyanidins. Biochem Biophys Res Commun 276 945-951. 

Grape seed extract, which is another widely used plant extract similar to pycnogenol, contains procyanidins, which have a strong antioxidant activity. 

One of the earliest studies addressing the antioxidant activity of various procyanidins in vitro reported strong scavenging activity against free radicals such as the stable radical 1,1-diphenyl-2-picryl-hydrazyl (DPPH) and the oxygen free radicals O-2 and HO, as assessed by ESR spectroscopy. 

Packer, L., Rimbach, G., and Virgili, F. Antioxidant activity and biologic properties of a procyanidin-rich extract from pine (Pinus martima) bark, pycnogenol, Free Radic. Biol. Med., 27, 704—724, 1999. 

P., Diet enriched with procyanidins enhances antioxidant activity and reduces myocardial post-ischaemic damage in rats. Life Sci. 64,627—642 (1999). 

A variety of antioxidant phytochemicals in apples include catechin, procyanidins, hydroxyciimamates, flavonols, anthocyanins, and dihy-drochalcones. The consumption of apple contributes to the reduced risk of diseases such as cardiovascular disease and some forms of cancer (Boyer and Liu, 2004). In a recent study, the phenolic phytochemical composition and antioxidant activity of 67 varieties of apple cultivars were examined by Wojdylo et al. (2008). The total content of these phytochemicals varied from 0.5 to 2.7% of dry weight. In apple juice, the total phenolic content ranged from 0.02 to 0.1% of juice. Catechin and procyanidins are the major classes of apple phenolics, representing more than 80% of the total content. A small amount of anthocyanin was also found in red apples. The results of this study demonstrated that new varieties of apple, such as Ozark Gold, Julyred, and Jester, had the same... 

Stahl, L. Miller, K. Apgar, J. Sweigart, D. Stuart, D. McHale, N. Ou, B. Kondo, M. Flurst, W. 2009. Preservation of cocoa antioxidant activity, total polyphenols, flavan-3-ols, and procyanidin content in foods prepared with cocoa powder. J. Food Sci. 74 C456-C461. 

Animal studies using extracts of the seeds of Vitis vinifem have shown beneficial effects relevant to heart disease factors. These extracts generally contain up to 85% of procyanidins. Clinical trials have mainly concentrated on effects in peripheral vascular disease. One trial investigated the antioxidant potential of a commercial extract in healthy volunteers and found that serum antioxidant activity increased significantly for up to three hours after ingestion. 

The chemical stmctures of flavonols and procyanidins might be important for antioxidant activity because of free radical trapping and chelation of redox-active metals properties. Adamson et al. [32] indicated that polyphenol content positively correlated with antioxidant properties as measured by ORAC. AU polyphenols possess antioxidant properties in vitro but this activity is not well characterized in human. 

Several studies indicate that catechins and procyanidins are powerful scavengers of ROS. Some findings regarding the antioxidant activity of proanthocyanidins are listed in Ref. [100]. Other antioxidant mechanisms are the chelation of transition metals, as well as the mediation and inhibition of enzymes. The metal-chelating activity of proanthocyanidins is thought to be due to their capacity to reduce the concentration, and thus the oxidative activity, of hydroxyl radicals formed by Fenton reaction catalyzed by iron or copper. Flavanols also influence oxidative stress via enzyme modification and modulation of cell signaling pathways the extent of the effect relies greatly on flavanol structure-related protein reactivity [101]. 

Details about structure, biosynthesis, and classification of phenolics are described in the other chapters in this handbook. Plant phenolics have a distinctive ability to form non-covalent, intermolecular complexes with each other and with both large and small molecules. Recognition of the antioxidant activities of many polyphenols has established correlation with the health benefits by such compounds [34]. This leads to the development of commercial products containing free-radical-scavenging phytochemical mixtures, for example, Pycnogenol (procyanidin extracted from Pinus maritima). Table 82.2 represents a list of polyphenolic compounds used in nutraceuticals and their biologic effects on human health. 

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