Chemical characterization and antioxidant activities of oligomeric and polymeric procyanidin fractions from grape seeds

Abstract

Two procyanidin fractions, namely oligomers and polymers isolated from grape seed methanolic extract were characterized. Phenolic composition and procyanidin purity of these fractions were determined by normal-phase and reverse-phase HPLC, thioacidolysis-HPLC, ESI-MS analyses, formaldehyde-HCl precipitation and elemental analysis. Antioxidant activities of these fractions and other well-known antioxidants were measured using xanthine-xanthine oxidase system for generating superoxide radical ({O2(-)}), the DPPH (1,1-diphenyl-2-picrylhydrazyl) radical method and the Fenton system for generating hydroxyl radical (HO). The results showed that both oligomeric and polymeric procyanidin fractions were highly pure, with the degree of polymerization ranging from 2 to 17-18 and 12 to 32-37, respectively. On the basis of molar concentration, polymeric procyanidins appeared the highest antioxidant activities, followed by oligomeric procyanidins, whereas catechins presented a lower antioxidant activity than its oligomers and polymers. These results indicate that the antioxidant activities of grape seed procyanidins are positively related to their degree of polymerization. Moreover, grape seed procyanidins presented higher antioxidant activities than other well-known antioxidants such as vitamin C, suggesting that grape seed procyanidins might be of interest to be used as alternative antioxidants.

Protective action against chemical-induced genotoxicity and free radical scavenging activities of Stryphnodendron adstringens ("barbatimão") leaf extracts

“…In our study WFB, that had the highest content of proanthocyanidins, showed a similar radical scavenging activity to the extracts (AEB and EEB) with higher phenols and flavonoids content than WFB. Proanthocyanidins certainly contributed to the free radical scavenging activity of the extracts, as demonstrated by others (Kimura et al, 2008;Spranger et al, 2008). The extracts presented Fe 3+ reducing capacity similar to ascorbic acid and higher than BHT and it was also concentrationdependent.…”

Green and Efficient Extraction Method to Determine Polyphenols in Cocoa and Cocoa Products

“…The monomers presented higher antioxidant capacity than dimers (procyanidins B2 and B) and trimers (procyanidin C). It is not in agreement with data found in literature that showed that the antioxidant capacity of grape seed procyanidins was related to their degree of polymerization, for instance, the monomers were the compounds with less antioxidant power (Spranger et al 2008). However, to the best of our knowledge, there is no data that shows this statement in cocoa procyanidins.…”

Grape seeds proanthocyanidin extract as a hepatic-reno-protective agent against gibberellic acid induced oxidative stress and cellular alterations

“…Additionally, GSPE contains mainly flavonoids, all involved in ameliorating the oxidative stress in vitro and in vivo by increasing the endogenous antioxidant status (Martinez-Florez et al 2002). Besides, GSPE can clear off free radicals and protect the overoxidative damage caused by free radicals (Spranger et al 2008). Furthermore, the observed protective action of GSPE on the antioxidants may be due to the protection of SH groups in GSH from oxidative damages via free radical quenching action of the di-OH (catechol) structure in the B ring of GSPE (Ishige et al 2001).…”

“…Such products may increase lipid peroxidation, which can be harmful to different organs including liver and kidney (Soliman et al 2010). On the other hand, these free radicals, known to cause oxidative stress, can be prevented or reduced by dietary natural antioxidants through their capacity to scavenge these products (Spranger et al 2008;Wang et al 2008). The present study was undertaken to determine whether GSPE can prevent and/or reduce GA3-induced oxidative stress by examining different biochemical parameters of oxidative damage in the liver and kidney of male rats.…”