Oligomeric proanthocyanidins

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Oligomeric proanthocyanidins , also oligomeric procyanidins , OPC or PCO ( English oligomeric proanthocyanidins ) are naturally occurring substances in plants belonging to the group of flavanols includes the parent and polyphenols are attributable. OPC are mostly dimers or trimers of catechins .

Together with the polymeric proanthocyanidins, they are a group of condensed proanthocyanides ( tannins ).

Occurrence

OPC was discovered by Jacques Masquelier in 1948 during a study on the feedability of peanut skins. In animal experiments, he found that the membranes contain substances that are suitable for the treatment of venous diseases. During identification, he came across connections and called them OPC. They occur in many other plants and have always been part of human nutrition . These occur mainly in grape seeds ( grape seed flour ), the skin and the leaves of red grapes, in the red skins of peanuts, in coconuts, in ginkgo leaves , in apples, larch wood and in the bark of the maritime pine . The outer parts of the plant, such as the bark or shells, but also the kernels and kernels contain large amounts of OPC. Oligomeric proanthocyanidins are also found in different concentrations in red wine , depending on the location , much less in white wine .

OPC, like many other phytochemicals , are mainly used by plants to protect against UV radiation, climatic conditions and predators (e.g. parasites).

Biological effect

In addition to antioxidant and anti-inflammatory properties, a dose-dependent inhibition of the growth of colon cancer cells was also observed by OPC . OPCs are possibly catalysts that can enhance the beneficial effects of vitamins A , C and E. A group of experts from the Mount Sinai School of Medicine , New York , found out in animal experiments that polyphenols in grape seed extract could prevent or at least delay plaque formation as a precursor to Alzheimer's and thus the typical memory loss. The effect of OPC seems to be positively influenced by the presence of other substances in the sense of a synergism . These substances include ascorbic acid as well as taxifolin , rutin , hesperidin and quercetin as well as other bioflavonoids . Only about 80% pure taxifolin contains OPC in addition to other polyphenols and has a broad spectrum of activity on the human organism. In addition to the positive effects in cardiovascular diseases (vasodilator and vaso-stabilizing, lowering blood pressure), this includes the binding capacity of reactive oxygen species ROS , the antioxidant and anticarcinogenic properties.

OPC, depending on its composition, are absorbed to varying degrees, but after absorption are subject to partial metabolism , which means that not the entire amount of OPC supplied is available in an active form in the blood . The OPC found in the blood are therefore chemically different from those that were taken in with food. It has also been observed that the OPC are partially broken down by intestinal microorganisms before resorption. The effects of ingested OPC or OPC-rich foods observed in studies are not always limited to OPC itself. It has not yet been finally clarified whether possible metabolites, which arise through bacterial decomposition in the intestine or through human metabolism, are the actual active substances.

use

OPC (oligomeric procyanidins) are brought onto the market as a component of food supplements , whereby the advertising statements made in this context, in particular the claims about health and physiological effects, are often not tenable with regard to a certain scientific or medical knowledge.

The Federal Administrative Court ruled that OPC-containing agents should not generally be classified as functional medicinal products , as there are no reliable scientific studies on a significant effect on the human organism and therefore pharmacological efficacy can not be assumed. The classification of OPC as a food additive , which is important for assessing the marketability of OPC-containing food supplements (from a legal point of view, food supplements are food), was unclear for a long time. According to Section 2 (3) LFGB , substances that are neither consumed as food themselves nor used as a characteristic ingredient of a food are treated as additives. However, it is not defined which substance is considered “characteristic”. In 2007 the Federal Administrative Court came to the ruling that OPC can be regarded as a characteristic component of certain food supplements and are not treated as additives. Since there is no licensing requirement for OPC as is the case with food additives, OPC-containing food supplements are to be regarded as legally marketable.

Individual evidence

  1. ↑ Ernst Steinegger, Rudolf Hansel: Pharmakognosie. 5th edition, Springer, 1992, ISBN 978-3-662-09268-2 , p. 404, limited preview in the Google book search.
  2. ↑ YJ Kim et al. a .: Anticancer effects of oligomeric proanthocyanidins on human colorectal cancer cell line, SNU-C4. In: World J. Gastroenterol. 11 (30), 2005, pp. 4674-4678.
  3. ↑ Grape seeds protect against plaques. In: Focus online. June 18, 2008.
  4. ↑ P. Mladenka, L. Zatloukalová, T. Filipský, R. Hrdina: Cardiovascular effects of flavonoids are not only Caused by direct antioxidant activity. In: Free Radic Biol Med . 49 (6), 2010, pp. 963-975. PMID 20542108 .
  5. ↑ BVerwG, judgment of July 25, 2007-3 C21.06 ; OVG Münster