Polyphenol

Polyphenols are aromatic compounds containing two or more directly attached to an aromatic ring hydroxyl groups and are counted among the phytochemicals. Natural polyphenols occur in plants as bioactive substances such as dyes, flavors and tannins. They should protect the plant from predators ( predators ) or attract insects for pollination by their color. Due to their antioxidant effect and filtering high-energy UV -B radiation are polyphenols some plants as a protection of the photosynthetic apparatus. Furthermore, polyphenols are important building blocks of biopolymers such as lignin and suberin. In the group of polyphenols many plant substances are combined, as the dyes flavonoids and anthocyanins, procyanidins, benzoic acid derivatives (eg, the hydroxybenzoic acids such as vanillic acid Trihydroxybenzoesäuren such as gallic acid and dihydroxybenzoic acids such as protocatechuic acid ), cinnamic acid derivatives ( the hydroxycinnamic acids such as caffeic acid and p- coumaric acid ) and stilbene derivatives (such as resveratrol). The name of polyphenols derived from phenol.

Origin

Many polyphenols are considered to be beneficial to health. Plants with a high polyphenol content are for example the apple berries, leaves and grapes of the vine, also in red wine, the shell and the flesh of the mangosteen fruit ( Garcinia mangostana ), the juice of the pomegranate ( Punica granatum ), among others punicalagin, ellagic acid and gallic acid contains, Ginkgo, tea, cistus and the seeds of Perilla ( Perilla frutescens, also called " Perilla " or misleading "Wild sesame " called ). In addition, polyphenols (flavonoids ) are extracted from the bark of pine and larch for use in medicine.

Effect

Some polyphenols act like other antioxidants, anti-inflammatory and cancer-preventing, among other things. In various studies with pomegranate polyphenols stunted growth of cancer cells in the breast, lung, skin, intestine and prostate was observed. Flavonoids and anthocyanins protect body cells against free radicals and slow cell oxidation. They reduce the fatty deposits (plaques ) in the blood vessels and thus prevent atherosclerosis. Thus, the thickness of the inner vessel wall of the carotid artery in patients with reduced atherosclerosis after one year of consumption of pomegranate juice by 30 %, while it increased by 9% in the control group.

Furthermore, it was demonstrated in a study by Vanderbilt University Medical Center, that with regular fruit juice consumption can reduce the risk of Alzheimer's disease by up to 76 %, for which polyphenols also be held responsible. Other polyphenols, such as the larch extract Taxifolin be next to the Cancer Prevention frequently for the treatment of cerebral infarction ( ischemic stroke) and its sequelae, cerebral thrombosis, coronary heart disease and angina pectoris.

An in vivo study with female mice, the spontaneous hair loss had developed on the head, neck and back, revealed that in 33% of mice from group A, the polyphenol extract had obtained from green tea with their drinking water, a significant hair regrowth was observed during the six-month treatment. No hair growth was observed among the mice in the control group B, which received only water.

Polyphenols from grapes inhibit the bacterial species Streptococcus mutans, which contributes to the build-up of plaque (plaque ) and so-called biofilms on the teeth. Due to its bactericidal effect polyphenols inhibit the harmful effects of bacteria and act as well as preventive against dental caries.

At the same time polyphenols from plant foods can bind to digestive enzymes and thus reduce the absorption of nutrients in the intestine. In healthy people, the proline-rich proteins in saliva prevent this effect by forming a stable complex in the digestive tract with the polyphenols.

The polyphenols from tea and cocoa can be inhibited by the addition of milk in their effects, because the casein of the milk is also prolinreich.

Polyphenols can be detected with iron ( III ) chloride solutions. They react with iron (III ) ions to green to blue- colored complex compounds.

Toxicology

Many polyphenols have low dose, as they occur in plants, positive biological properties. In in vitro studies and in high doses it can also show toxic effects. If they are used in high doses or long- lasting, these effects are also possible in the organism, which is why this is not common. Apigenin, quercetin, kaempferol and taxifolin cytostatic effect. These and some other polyphenols such as catechol, genistein and gossypol are classified as hazardous to health substances, quercetin even as toxic. Polyphenols are absorbed not usually unchanged in the human body and show that depending on the chemical structure quite different pharmacokinetic behavior. Therefore, the results of in vitro experiments in polyphenols are limited transferable to humans. Addition, their effect is modulated even by the so-called matrix effect of other phytochemicals. For quercetin, for example, a mutagenic effect has been demonstrated. If quercetin in plant matrix, the other polyphenols, such as contains tannins, outweighs an antimutagenic effect of the plant extract.

Literature and additional sources

• Aviram et al.: Pomegranate juice consumption for 3 years by patients with carotid artery stenosis carotid intima -media Reduces common thickness, blood pressure and LDL oxidation. (PDF, 259 kB) In: Clinical Nutrition 23 pg116 (2004 ), pp. 423-433.
• Bonnie Tay Yen Ping: Chemical Constituents of Garcinia mangostana, G. parvifolia, G. griffiti, and G. diversifolia ( Guttifera s) and Their biological activities. Dissertation from University Putra Malaysia ( 1996)
• P. Chanarat, N. Chanarat, M. Fikojara, T Nagumo: Immunopharmacological activity of polysaccharide from the pericarp of mangosteen garcinia; phagocytic intracellular killing activities. In: J Med Assoc Thai, 1: pp. 149-154 (1997)
• S.X. Chen, M. Wan, BN Loh: Active Constituents against HIV -1 protease from Garcinia mangostana. In: Planta Med, 1996 August, 62 (4): pp. 381-382.
• Dahanukar et al.: Pharmacology of Medical Plants and Natural Products. In: Indian Journal of Pharmacology, 2000, p 96