Glucuronolactone
- D-glucuronic acid -3 ,6 -lactone
- D -glucuronic acid - γ -lactone
- (2R ) -2 - [ (2S, 3R, 4S ) -3,4 -dihydroxy-5 -oxo- oxolane -2-yl ] -2-hydroxy -acetaldehyde
Colorless, odorless solid
Fixed
0.67 g · cm -3
176-180 ° C
- Slightly soluble in water ( 257 g · L-1 at 21 ° C)
- Slightly soluble in ethanol
- > 20,000 mg · kg -1 ( LD50, mouse, oral)
- 10,700 mg · kg -1 ( LD50, rat, oral)
Template: Infobox chemical / molecular formula search available
Glucuronolactone (D -glucuronic acid - γ -lactone, also called glucuronolactone ) is a naturally occurring intramolecular ester ( lactone ) of the D - glucuronic acid. The latter is a product of the oxidation of D-glucose and one of the sugar acids. Of D- glucuronic acid, D- glucurono - δ -lactone can alternatively form, however, the D-glucuronic acid - γ -lactone is thermodynamically favored.
Occurrence and use
Glucuronolactone is an important component of connective tissue of many animals and vegetable fibers and mucilage. In the human body, the connection is formed as an oxidation product of UDP-glucose ( uridine -5 -diphosphate -D-glucose ). The foods with the highest natural content is wine with a share of about 20 mg / l Substance occurs in both an open-chain form with free aldehyde and as cyclic lactol form.
Glucuronolactone is a carbohydrate which, among other things in energy drinks - is used - often together with caffeine and taurine. In the European Union glucuronolactone is not considered a food additive, but as an ingredient. Manufacturers of energy drinks that wanted enforce the substance had been to obtain a license for each product. Since 2012, maximum levels of 2.400 mg / l for energy drinks in Germany are provided.
Effect in the human body
γ - glucuronolactone is readily soluble in water and is absorbed through the gastrointestinal tract. The lactone can cross the blood- brain barrier, as it is likely to be included on the glucose transporter GLUT -1 and GLUT -5. In the liver and brain of the fabric involved in equilibrium with glucuronic acid in the phase II reactions within the biotransformation of xenobiotics and of endogenous waste products; these processes are referred to as " conjugation ", referred to as " glucuronidation " in the particular case.
Safety
In animal studies with mice and rats γ - glucuronolactone showed a low toxicity; the oral LD50 values were> 20,000 mg / kg in the mouse and 10,700 mg / kg in rats.
Absorption through energy drinks, which contain an average of 2000-2400 mg / l of the lactone, is far higher than the natural absorption of organic food. BgVV looked around for an inquiry in 2002, unable to scientifically derive a maximum level for use in energy drinks. It was further found
" [ ... ] That in the common absorption of ethyl alcohol, caffeine, taurine and glucuronolactone in high concentrations, different interactions are to be considered, particularly because of the influence on the same organ system (eg, central nervous system, cardiovascular system in ethyl alcohol, caffeine and taurine ) and the similarity of toxicological effects could cause reproductive toxicity effects of ethyl alcohol, and caffeine ) of the individual components into a potentially toxicologically relevant effect gain compared to the use of the isolated substances (eg. "
In February 2009, the European Food Safety Authority fixed a NOAEL limit for glucuronolactone in energy drinks of 1000 mg per kilogram of body weight per day; so is a safety when shooting 350 ml ( ≈ 1.4 doses) per day stated. Negative health impacts - including deaths - occurred in young people, energy drinks sometimes in very high quantities (in one case has been recorded a lot of 1420 ml of an energy drink ), sometimes during physical exertion or frequently consumed with alcohol.