Proanthocyanidins (PAs), also known as condensed tannins, are a class of polyphenols found in a variety of plants. They are very Solidful antioxidants that remove harmful free oxygen radicals from cells.
In vitro
Proanthocyanidins have also been shown to inhibit lipid peroxidation, platelet aggregation, capillary permeability and fragility. They have been shown to modulate the activity of regulatory enzymes including cyclooxygenase, lipooxygenase, protein kinase C, angiotensin-converting enzyme, hyaluronidase enzyme and cytochrome P450 activities.
In vivo
Proanthocyanidins have been shown to play important roles in several biological processes resulting in health benefits. For instance, proanthocyanidins have been reported to have antioxidant, anti-inflammatory, antimicrobial, antiproliferative, cardioprotective, hypolipidemic and antidiabetic activities. Proanthocyanidins induce a strong hypotriglyceridemic effect in experimental animals, in part by inhibiting VLDL secretion by the liver. Animal studies demonstrate that proanthocyanidins reduce the plasma levels of atherogenic apolipoprotein B-triglyceride-rich lipoproteins and LDL-cholesterol but increase antiatherogenic HDL-cholesterol. Proanthocyanidins are thought to be poorly absorbable and highly metabolized by gut microflora before absorption. They affects lipid metabolism and has important positive consequences on cardiovascular diseases.