Wednesday, February 24, 2021

Oligomeric proanthocyanidins

Proanthocyanidins form a unique class of high-molecular weight oligomeric and polymeric secondary metabolites which are present in many fruits, nuts and berries, and also found in cocoa, tea, wine and beer.

Proanthocyanidins are present as a defence against biotic and abiotic stressors. Their astringency protects the plants from pathogens and predators.

Cocoa beans are a well-known source of antioxidant polyphenols. Especially individual oligomeric proanthocyanidins demonstrated a significant contribution to the total antioxidant activity of cocoa compared to monomeric compounds.

Chocolate contains flavonoids not found in tea, with high concentrations of oligomeric procyanidins.

Proanthocyanidins are shown to be highly effective inhibitors of radical chain reactions. In cocoa, they consist of oligomers or polymers of (+)- catechin and/or (-)-epicatechin units. The size of proanthocyanidins is specified by their degree of polymerization (DP).

Proanthocyanidin degree of polymerization can range between 3 and 11. Usually, proanthocyanidins with a lower degree of polymerization (two to four monomers) are named oligomeric proanthocyanidins, whereas those with more than five monomers are called polymeric proanthocyanidins.

Oligomeric proanthocyanidin complexes have been reported to demonstrate antioxidant, antibacterial, antiviral, anticarcinogenic, anti-inflammatory, anti-allergic, and vasodilatory actions. They can inhibit lipid peroxidation, platelet aggregation, and capillary hyperpermeability.
Oligomeric proanthocyanidins

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