What are proanthocyanidins?

Proanthocyanidins are chemical compounds. Proanthocyanidins are present in flowers, nuts, fruits, bark, and seeds of various plants, as a defense against biotic and abiotic stressors. They give the fruit or flowers of many plants their red, blue, or purple colors.

Proanthocyanidins are in a group of compounds called polyphenols. These belong to a subclass called flavonoids.

Proanthocyanidins, also called condensed tannins, are oligomeric and polymeric products of the flavonoid biosynthetic pathway. The building blocks of proanthocyanidins include catechin and epicatechin.

Proanthocyanidins may also be classified as type-A or -B according to the interflavanol linkage; type-B proanthocyanidins are found in a greater abundance and have only one C–C interflavan bond, while type-A are less common and are characterized by an additional ether linkage.

Berries and fruits are the best sources of proanthocyanidins, Lingonberry, cranberry, black elderberry, black chokeberry, black currant, blueberry are some of the edible berries with predominant of proanthocyanidin content. Proanthocyanidins have been identified in cereals (barley, rice, sorghum, and wheat), legumes (pinto beans), seeds (grape seeds and cocoa seeds), fruits (apples, pears), vegetables, and beverages such as red wine and tea.

As natural antioxidants, proanthocyanidins are used to stabilize food colors and to prevent rancidity due to oxidation of unsaturated fats as well as for chemoprevention of a variety of degenerative diseases.
What are proanthocyanidins?

Type-B proanthocyanidins