Oligomeric Proanthocyanidins: An Updated Review of Their Natural Sources, Synthesis, and Potentials

Abstract

Oligomeric Proanthocyanidins (OPCs), as a class of compounds widely found in plants, are particularly abundant in grapes and blueberries. It is a polymer comprising many different monomers, such as catechins and epicatechins. The monomers are usually linked to each other by two types of links, A-linkages (C-O-C) and B-linkages (C-C), to form the polymers. Numerous studies have shown that compared to high polymeric procyanidins, OPCs exhibit antioxidant properties due to the presence of multiple hydroxyl groups. This review describes the molecular structure and natural source of OPCs, their general synthesis pathway in plants, their antioxidant capacity, and potential applications, especially the anti-inflammatory, anti-aging, cardiovascular disease prevention, and antineoplastic functions. Currently, OPCs have attracted much attention, being non-toxic and natural antioxidants of plant origin that scavenge free radicals from the human body. This review would provide some references for further research on the biological functions of OPCs and their application in various fields.

Bioactive Compounds and Potential Health Benefits through Cosmetic Applications of Cherry Stem Extract

“…The presence of (epi)catechin and type A, B, and C procyanidins was tentatively detected. Proanthocyanidins are phenolic compounds found mainly in plant stems and seeds that have been characterized for their antioxidant and anti-inflammatory properties [28,29]. Epicatechin and proanthocyanidins have been previously described in cherry stems [27].…”

Research progress of procyanidins in repairing cartilage injury after anterior cruciate ligament tear

“…Procyanidins can decrease ER stress-related expression of peIF2α, ATF6α, and CHOP proteins, reducing the generation of superoxide radicals and ONOO in ER stress. They exhibit significant ER decompression potential, showing substantial anti-inflammatory effects [ 122 ].…”

“…Advanced glycation end products (AGEs) trigger oxidative stress, and procyanidins' ability to inhibit AGEs can mitigate oxidative stress [ 131 ]. Procyanidins activate antioxidant enzymes, augment antioxidant enzyme expression via the MAPK pathway, regulate the NF-κB pathway [ 132 ], induce Nrf2 expression to activate HO-1 and NQO-1 and enhance the body's antioxidant capacity [ 133 ]. Procyanidins can reduce ROS levels and diminish the expression of pertinent cytokines, such as interleukin-1β (IL-1β), IL-8, and tumor necrosis factor-α (TNF-α) [ 134 ].…”

Recent Advances in Visible Light Photoinitiating Systems Based on Flavonoids

“…Proanthocyanidins are flavonoids that can be found in black, red and purple rice, in other strongly colored fruits and vegetables and also in cereals such as blueberries, grapes, red cabbages and purple sweet potatoes [287][288][289][290][291][292][293]. Due to their high molar extinction coefficients, proanthocyanidins were thus ideal candidates for photopolymerization performed under visible light.…”