Proanthocyanidins in Health Care: Current and New Trends

Abstract

Polyphenolic compounds are widely distributed in higher plants and are an integral part of the human diet. Recent interest in these substances has been stimulated by their potential health benefits, which are believed to arise mainly from their antioxidant activity. In the past years, the antioxidant activity of flavonoids has been studied in detail. An important but often overlooked group of polyphenols is that of the proanthocyanidins. Therefore, the present review is focused mainly on the antioxidant activity of proanthocyanidins and its relevancy in vivo. The three most important mechanisms of their antioxidant action will be discussed, i.e. free radical scavenging activity, chelation of transition metals, and inhibition of enzymes. In addition, the protective role of proanthocyanidins against lipid peroxidation and peroxynitrite, as well as their antimicrobial properties will be discussed. To study the in vivo relevancy of the proanthocyanidin activities, the knowledge of their pharmacokinetic parameters is crucial. Although bioavailability and metabolism data on polyphenols in general and proanthocyanidins in particular are still largely unavailable, the first reports indicate that at least monomers and smaller oligomeric procyanidins are absorbed. There is also considerable scientific and public interest in the important role that antioxidants may play in health care, e.g. by acting as cancer chemopreventive and anti-inflammatory agents and by reducing risk of cardiovascular mortality. Each of these aspects will be discussed, with special attention to the role of proanthocyanidins on apoptosis, gene expression and transcription factors, such as NF-kappa B.

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

“…The antioxidant activity of plant compounds has been attributed to various mechanisms, including prevention of chain initiation, binding of transition metal ion catalysts, decomposition of peroxides, prevention of continued hydrogen abstraction, reductive capacity and radical scavenging (Cos et al, 2003). The results of the present work indicate that the extracts act as antioxidants.…”

Nutrition and cancer: A review of the evidence for an anti-cancer diet

“…Most of these substances are found in foods, but their effective doses for therapy are much higher than the normal concentration in the food. For example, grape seed extract contains proanthocyanidin, which shows anticarcinogenic properties (reviewed by Cos et al \ [157]. Also, green tea contains a flavanol, epigallocatechin-3-gallate (EGCG), which can inhibit metalloproteinases, among several possible other mechanisms [158].…”

Proanthocyanidin Synthesis and Expression of Genes Encoding Leucoanthocyanidin Reductase and Anthocyanidin Reductase in Developing Grape Berries and Grapevine Leaves

“…They occur in a wide range of plants and play an important role in defense against herbivores ( Harborne and Grayer, 1993;Peters and Constabel, 2002). PAs can protect ruminants against pasture bloat (McMahon et al, 2000) and act as antioxidants with beneficial effects for human health including protection against free radical-mediated injury and cardiovascular disease (Bagchi et al, 2000;Lin et al, 2002;Cos et al, 2004). PAs also contribute to the astringency and taste of many fruits and other plant products, such as fruit juices, tea (Camellia sinensis), and wine.…”