Catechins

from Wikipedia, the free encyclopedia

Catechins are polyphenolic plant metabolites from the group of flavonoids and are therefore generally classified as secondary plant substances . They are of particular importance due to their high antioxidant potential .

Representative

Catechins
Surname (+) - catechin (-) - catechin (-) - epicatechin (+) - epicatechin
other names Flavan-3-ol
Structural formula (+) - catechin.svg (-) - Catechin.svg (+) - Epicatechin.svg (-) - Epicatechin.svg
CAS number
  • 154-23-4
  • 225937-10-0 (hydrate)
  • 18829-70-4
  • 88191-48-4 (hydrate)
 490-46-0 35323-91-2
abc-cas (mixture of isomers)
PubChem 9064 73160 72276 182232
Molecular formula C 15 H 14 O 6
Molar mass 290.27 g mol −1
Physical state firmly
Brief description
Melting point 240 ° C (decomposition)
GHS
labeling
07 - Warning
Caution
no GHS pictograms
07 - Warning
Caution
H and P phrases 315-319 no H-phrases 315-319-335
no EUH phrases no EUH phrases no EUH phrases
264-280-302 + 352-332-313
362-364-305 + 351 + 338-337 + 313 		no P-phrases 261-305 + 351 + 338

Catechins are to be understood as hydrogenated flavones or anthocyanidins and as derivatives of chroman . The four most common substances in the group can each be divided into two isomer pairs: (+) - catechin and (-) - epicatechin with the empirical formula C 15 H 14 O 6 and a molar mass of 290 g / mol and (+) - gallocatechin (CAS number: 970-73-0) and (-) - epigallocatechin with the empirical formula C 15 H 14 O 7 and a molar mass of 306 g / mol are found relatively frequently in various plant species. In addition, (-) - robinetinidol , (+) - fisetinidol , (-) - fisetinidol , (+) - afzelechin , (+) - epiafzelechin and (-) - epiafzelechin , mostly limited to a few plant species, occur.

Occurrence, properties and importance

Gerber acacia ( Acacia catechu )

Catechins occur as intermediate stages in the biosynthesis of other secondary plant substances ( flavonoids ) in many plant tissues together with other polyphenols (mostly epigallocatechin ). They form the monomeric building blocks of the condensed proanthocyanidins, a number of natural tannins, e.g. B. in black tea or cocoa , where they also contribute to the flavor development. Up to this degree of condensation, the catechin tannins are soluble in pure ethanol , which is particularly important for the manufacture of pharmaceuticals. The catechin tannins belong to the non-hydrolyzable tannins . Other names for catechin tannins are "condensed tannins" or "condensed anthocyanidins". The catechol (1,2-dihydroxybenzene) does not belong in this group of substances, however, is a structural component of catechins.

Catechins are also found in many other teas, including white tea , green tea ( epigallocatechin gallate , an ester of gallic acid with epigallocatechin ) and oolong . Here the levels are even relatively higher, as the polyphenol oxidase in black tea ferments a certain amount of the catechins to theaflavins . Catechins are also found in vegetables and wine as well as in the wood of the eponymous gerber acacia Acacia catechu . Many types of fruit - such as apples, apricots, pears, blackberries, strawberries, raspberries, black currants, peaches, plums, quinces, sour cherries, gooseberries, sweet cherries and grapes - also contain catechins.

Detection reactions

Qualitatively
  • Reaction of catechins with vanillin and HCl . This reaction produces a characteristic red color due to the condensation of catechin with vanillin.
  • Detection of phenols with iron (III) chloride: It turns green. This color indicates the structure of the catechol , because catechol itself produces a green color with iron (III) ions.
  • Detection with tungstophosphoric acid for phenols: These reduce tungstophosphoric acid to blue tungsten oxide , which can be easily recognized by its intense color.
  • Heating with mineral acids and the resulting red color.
Quantitatively

Physiological effect in humans

Plants containing catechins, for example the gerber acacia , were originally used for their astringent properties. Today there is evidence that catechin-containing plants and plant extracts, such as cocoa or green tea , can promote blood circulation through vasodilation . However, these statements are mainly based on short intervention studies and there are currently (2017) no data on long-term effects.

Differences in the metabolism of (-) - epicatechin between humans, mice and rats.

Catechins are metabolized in the jejunum and also in the liver when they are absorbed, mainly through glucuronidation, sulphation and methylation. Furthermore, catechins are metabolized by the intestinal flora , one of the specific main products being 5- (3 ', 4'-dihydroxyphenyl) -γ-valerolactone. 5- (3 ', 4'-dihydroxyphenyl) -γ-valerolactone is also metabolized in the liver . In terms of metabolism, there are great species-specific differences between humans, mice and rats .

Individual evidence

  1. ↑ a b Data sheet (-) - Epicatechin, ≥98% (HPLC), from green tea at Sigma-Aldrich , accessed on July 27, 2017 ( PDF ).
  2. ↑ Entry on (+) - Catechin Hydrate at TCI Europe, accessed on July 27, 2017.
  3. ↑ Data sheet (-) - Catechin, ≥97% (HPLC), from green tea at Sigma-Aldrich , accessed on July 27, 2017 ( PDF ).
  4. ↑ a b c Entry on catechins. In: Römpp Online . Georg Thieme Verlag, accessed on October 4, 2011.
  5. ^ Wissenschaft-Online-Lexika: Entry on "Catechins" in the Lexikon der Biochemie, accessed on October 4, 2011.
  6. ↑ Wissenschaft-Online-Lexika: Entry on “Acacia species” in the Lexicon of Medicinal Plants and Drugs, accessed on October 4, 2011.
  7. ^ Johann Schroeder: Pharmacopoeia medico-chymica: sive thesaurus pharmacologeus . Ed .: Johannis Gerlini. Ulmae Suevorum 1655.
  8. ↑ Lee Hooper, Colin Kay, Asmaa Abdelhamid, Paul A. Kroon, Jeffrey S. Cohn: Effects of chocolate, cocoa, and flavan-3-ols on cardiovascular health: a systematic review and meta-analysis of randomized trials . In: The American Journal of Clinical Nutrition . tape 95 , no. 3 , March 1, 2012, p. 740-751 , doi : 10.3945 / ajcn.111.023457 , PMID 22301923 ( nutrition.org [accessed September 12, 2017]).
  9. ^ Sabine Ellinger, Andreas Reusch, Peter Stehle, Hans-Peter Helfrich: Epicatechin ingested via cocoa products reduces blood pressure in humans: a nonlinear regression model with a Bayesian approach . In: The American Journal of Clinical Nutrition . tape 95 , no. 6 , June 1, 2012, p. 1365-1377 , doi : 10.3945 / ajcn.111.029330 , PMID 22552030 ( nutrition.org [accessed September 12, 2017]).
  10. ^ Gina Borges, Justin JJ van der Hooft, Alan Crozier: A comprehensive evaluation of the [2-14C] (-) - epicatechin metabolome in rats . In: Free Radical Biology and Medicine . tape 99 , p. 128–138 , doi : 10.1016 / j.freeradbiomed.2016.08.001 ( elsevier.com [accessed September 12, 2017]).
  11. ↑ Javier I. Ottaviani, Gina Borges, Tony Y. Momma, Jeremy PE Spencer, Carl L. Keen: The metabolome of [2-14C] ( -) - epicatechin in humans: implications for the assessment of efficacy, safety and mechanisms of action of polyphenolic bioactives . In: Scientific Reports . tape 6 , no. 1 , July 1, 2016, doi : 10.1038 / srep29034 ( nature.com [accessed September 12, 2017]).
  12. ↑ Lucas Actis-Goretta, Antoine Lévèques, Maarit Rein, Alexander Teml, Christian Schäfer: Intestinal absorption, metabolism, and excretion of (-) - epicatechin in healthy humans assessed by using an intestinal perfusion technique . In: The American Journal of Clinical Nutrition . tape 98 , no. 4 , October 1, 2013, p. 924-933 , doi : 10.3945 / ajcn.113.065789 , PMID 23864538 ( nutrition.org [accessed September 12, 2017]).
  13. ↑ Javier I. Ottaviani, Tony Y. Momma, Gunter K. Kuhnle, Carl L. Keen, Hagen Schroeter: Structurally related ( -) - epicatechin metabolites in humans: Assessment using de novo chemically synthesized authentic standards . In: Free Radical Biology and Medicine . tape 52 , no. 8 , p. 1403-1412 , doi : 10.1016 / j.freeradbiomed.2011.12.010 ( elsevier.com [accessed September 12, 2017]).
  14. ^ NP Das: Studies on flavonoid metabolism. Absorption and metabolism of (+) - catechin in man . In: Biochemical Pharmacology . tape 20 , no. December 12 , 1971, p. 3435-3445 , PMID 5132890 .
  15. ↑ Javier I. Ottaviani, Gina Borges, Tony Y. Momma, Jeremy PE Spencer, Carl L. Keen: The metabolome of [2-14C] ( -) - epicatechin in humans: implications for the assessment of efficacy, safety and mechanisms of action of polyphenolic bioactives . In: Scientific Reports . tape 6 , no. 1 , July 1, 2016, doi : 10.1038 / srep29034 ( nature.com [accessed September 12, 2017]).