From Ergo Log
Green tea is a cortisol inhibitor, and it may well be a very effective one. Pharmacologists at University Medical School Schleswig-Holstein in Germany discovered this when they did an in-vitro study. Unfortunately it’s still too soon to say what the dosage should be.
The enzyme 11-beta-HSD-1 converts the inactive hormone cortisone into the stress hormone cortisol in the body. Another enzyme, 11-beta-HSD-2, converts cortisol back into cortisone.
If you reduce the action of 11-beta-HSD-1 in lab animals, they lose abdominal fat. Their cells become more insulin sensitive, their cholesterol level improves and their blood pressure goes down. 11-Beta-HSD-1 blockers might be interesting for medicines to treat type 2 diabetes for instance.
Green, black and white tea
In traditional Chinese medicine, tea is used to treat type 2 diabetes. So might tea be an 11-beta-HSD-1 inhibitor?
To try and answer this question the German researchers exposed liver cells to extracts of green, black and white tea, added cortisone to the liver cells and then measured how much cortisol was produced. All three types of tea inhibited the creation of cortisol considerably, but green tea worked best.
But green tea contains many, many substances. The researchers exposed liver cells to the most important substances found in green tea and then measured how well they inhibited the conversion of cortisone into cortisol.
Two substances, (-)-epigallocatechin gallate [EGCG] and (-)-gallocatechin [GC], turned out to be cortisol inhibitors.
The researchers used spatial models of 11-beta-HSD-1 to work out how EGCG deactivates the enzyme. The discovered that EGCG takes over the spot in the enzyme that is meant for cortisone. [Figure] As a result the conversion of cortisone into cortisol cannot take place.
“Our results decipher the mechanism by which catechins such as EGCG, or green tea in general, have been successfully consumed for thousand of years for general health benefits”, the researchers wrote. “These polyphenolic compounds may serve as model structures for the development of novel agents to treat the metabolic syndrome and related diseases.”
PLoS One. 2014 Jan 3;9(1):e84468.