Glucuronolactone
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| Hemiacetal form (two diastereomers ) | ||||||||||||||||
| General | ||||||||||||||||
| Surname | Glucuronolactone | |||||||||||||||
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| Molecular formula | C 6 H 8 O 6 | |||||||||||||||
| Brief description |
colorless solid |
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| properties | ||||||||||||||||
| Molar mass | 176.13 g mol −1 | |||||||||||||||
| Physical state |
firmly |
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| density |
1.7 g cm −3 |
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| Melting point |
175 ° C (decomposition) |
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| As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . | ||||||||||||||||
Glucuronolactone or glucuronolactone ( D - glucuronic acid -γ-lactone, also called glucuron lactone) is a naturally occurring intramolecular ester ( lactone ) of D - glucuronic acid . The latter is an oxidation product of D- glucose and is one of the sugar acids . Alternatively, D- glucurono-δ-lactone can be formed from D- glucuronic acid , but D- glucuronic acid-γ-lactone is thermodynamically preferred.
Occurrence
Glucuronolactone is an important component of the connective tissue of many animals and vegetable fibers and mucilage . The compound is formed in the human body as an oxidation product of UDP-glucose ( uridine-5-diphosphate- D- glucose ). The food with the highest natural content is wine with a proportion of around 20 mg / l. The substance occurs both in an open-chain form with a free aldehyde function and as a cyclic lactol form.
Effect in the human organism
γ-glucuronolactone is readily soluble in water and is absorbed via the gastrointestinal tract. The lactone can cross the blood-brain barrier as it is probably taken up via the glucose transporters GLUT-1 and GLUT-5 . In the liver and brain , the substance, in equilibrium with glucuronic acid, is involved in the phase II reactions within the biotransformation of xenobiotics and also of the body's own waste products; these processes are called “conjugation reactions”, in the special case “ glucuronidation ”.
use
Glucuronolactone is a carbohydrate that is used in energy drinks , often together with caffeine and taurine . In the European Union, glucuronolactone is not considered a food additive , but an ingredient. Manufacturers of energy drinks who wanted to add this substance previously had to obtain approval for every product. Since 2012, maximum quantities of 2,400 mg / l have been planned for energy drinks in Germany.
safety instructions
In animal experiments with mice and rats, γ-glucuronolactone showed low toxicity; the oral LD 50 values were> 20,000 mg / kg in the mouse and 10,700 mg / kg in the rat.
The intake from energy drinks, which contain an average of 2000–2400 mg / l of the lactone, is far higher than the natural intake from organic foods. The BgVV looked after a request in 2002 unable scientifically derive a quantitative limit for use in energy drinks. It was further noted
" [...] that with the joint intake of ethyl alcohol, caffeine, taurine and glucuronolactone in high concentrations, different interactions have to be taken into account, especially because of the influence on the same organ system (e.g. CNS, cardiovascular system with ethyl alcohol, Caffeine and taurine) or the similarity of toxicological effects (e.g. reproductive toxicological effects of ethyl alcohol and caffeine) of the individual components could lead to a potentially toxicologically relevant increase in effectiveness compared to the use of the isolated substances. "
In February 2009 the European Food Safety Authority set a NOAEL limit value for glucuronolactone in energy drinks of 1000 mg per kilogram of body weight and day; this means that the intake of 350 ml (≈1.4 doses) per day is safe. Negative health consequences - including deaths - occurred in young people who consumed energy drinks, sometimes in very large quantities (in one case, 1420 ml of an energy drink was consumed), sometimes during physical exertion or more often with alcohol.
Individual evidence
- ↑ a b c d Data sheet D - (+) - Glucuronic acid γ-lactone from Sigma-Aldrich , accessed on February 7, 2019 ( PDF ).
- ^ Carl L. Yaws: Thermophysical Properties of Chemicals and Hydrocarbons . William Andrew, 2014, ISBN 978-0-323-29060-9 , pp. 280 ( limited preview in Google Book search).
- ↑ a b Entry on glucuronolactone. In: Römpp Online . Georg Thieme Verlag, accessed on June 7, 2014.
- ↑ a b c d Drugs in Japan , 1982, Vol. 6, p. 225.
- ^ Albert Gossauer: Structure and reactivity of biomolecules, Verlag Helvetica Chimica Acta, Zurich, 2006, pp. 335–336, ISBN 978-3-906390-29-1 .
- ↑ a b Patrick Pankert: Effect of glucuronolactone - proteome analyzes and transport studies at the blood-brain barrier. (PDF; 4.6 MB) Dissertation at the Technical University of Darmstadt , December 16, 2003.
- ↑ a b c BgVV : Health assessment of energy drinks. (PDF; 57 kB) Statement of March 18, 2002.
- ↑ Second ordinance amending the fruit juice ordinance and other food law regulations
- ↑ EFSA : EFSA accepts opinions on two ingredients that are often used in certain energy drinks. Press release from February 12, 2009.