Catechins - benefits of green tea – University of Copenhagen

NaToxAq > Toxin of the week > Catechins

29 April 2019

Catechins - benefits of green tea

Natural toxin

Catechins are well known as antioxidants and used traditionally to prevent several diseases.

Left: Green tea. Right: Cacao

The name comes from catechu family and more specifically from Mimosa catechu [1] Catechins can be found in cacao [2], green tea and grapevines, among other plants. Since its discovery around 3000 B.C in China, green tea has been a popular beverage consumed worldwide. Green tea (Camellia sinensis) contains various ingredients with beneficial health effects, the main ones being catechins.

Catechins are secondary metabolites produced by this kind of plants. They are chemically classified as flavonoids and comprise different isomers: catechin, catechin gallate (Cg), gallocatechin, gallocatechin gallate (GCg), epicatechin, epicatechin gallate (ECg), epigallocatechin, and epigallocatechin gallate (EGCg). Epigallocatechin gallate (EGCG) is the compound with the higher bioactivity.

Figure 1. Chemical structures of (+)-catechin and four major green tea catechins (From Isemura et al) [3]. Click image for interactive 3D-model of (+)-catechin.

These compounds show protective effects against diseases such as cancer, obesity, diabetes, arteriosclerosis, neurodegenerative diseases, and tooth decay. They also have antibacterial, antiviral, and hepatoprotective effects. Tea catechins are strong antioxidants and bind to proteins, lipids, nucleic acids, and metals. They also bind to the 67 kDa laminin receptor,8 B-cell lymphoma 2 (Bcl-2) proteins, vimentin, and peptidyl prolyl cis/trans isomerase, which are targets of EGCD and can be used in anticancer therapy. [4]

As any other phytotherapeutic compound, aside from their health benefits, a misuse of traditional herbal medicine can lead to severe adverse events. Exolise is an 80% ethanolic dry extract of green tea that has been available in France, Belgium, Spain and the United Kingdom since 1999, used in weight loss. A study reported a case of fulminant hepatitis during self-medication with Exolise, which ended in liver transplantation [6]. The European Food Safety Authority recommended a daily intake of maximum 800 to prevent risk of liver damage [7].

SMILES: C1C(C(OC2=CC(=CC(=C21)O)O)C3=CC(=C(C(=C3)O)O)O)OC(=O)C4=CC(=C(C(=C4)O)O)O

References:

  1. “Catechin,” Wikipedia. 21-Feb-2019.
  2. C. Kwik-Uribe and R. M. Bektash, “Cocoa flavanols - measurement, bioavailability and bioactivity,” Asia Pac. J. Clin. Nutr., vol. 17 Suppl 1, pp. 280–283, 2008.
  3. M. Isemura, N. Miyoshi, M. Pervin, T. Suzuki, K. Unno, and Y. Nakamura, “Green tea catechins for well-being and therapy: prospects and opportunities,” Bot. Targets Ther., vol. 2015, p. 85, Dec. 2015.
  4. C. S. Yang, G. Chen, and Q. Wu, “Recent Scientific Studies of a Traditional Chinese Medicine, Tea, on Prevention of Chronic Diseases,” J. Tradit. Complement. Med., vol. 4, no. 1, pp. 17–23, 2014.
  5. J. V. Higdon and B. Frei, “Tea Catechins and Polyphenols: Health Effects, Metabolism, and Antioxidant Functions,” Crit. Rev. Food Sci. Nutr., vol. 43, no. 1, pp. 89–143, Jan. 2003.
  6. R. Gloro et al., “Fulminant hepatitis during self-medication with hydroalcoholic extract of green tea,” Eur. J. Gastroenterol. Hepatol., vol. 17, no. 10, pp. 1135–1137, Oct. 2005.
  7. “Scientific opinion on the safety of green tea catechins - - 2018 - EFSA Journal - Wiley Online Library.” [Online]. Available: https://efsa.onlinelibrary.wiley.com/doi/full/10.2903/j.efsa.2018.5239. [Accessed: 23-Apr-2019].

Pictures:

  1. Green tea https://healthyeating.sfgate.com/foods-epicatechin-catechin-1310.html
  2. Cocoa https://detoxdiy.com/detox-tea-catechins