Theanine
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| General | ||||||||||||||||||||||
| Surname | Theanine | |||||||||||||||||||||
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| Molecular formula | C 7 H 14 N 2 O 3 | |||||||||||||||||||||
| Brief description |
white solid |
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| Molar mass | 174.20 g mol −1 | |||||||||||||||||||||
| Physical state |
firmly |
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| Melting point |
214-215 ° C |
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| As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . | ||||||||||||||||||||||
L - Theanine (5- N -Ethyl- L -glutamine) is a non-proteinogenic amino acid found in the leaves of the tea plant ( Camellia sinensis ). L-theanine occurs in other species such as Camellia japonica and Camellia sasanqua , but also in Xerocomus badius ( chestnut boletus ).
In the fermentation of the tea a part of theanine is broken down so that green tea contains more than black.
Studies
Since green tea in particular is considered to be beneficial to health, numerous studies have been carried out to test the effects of the ingredients it contains. Theanine has also been studied several times, mainly in animal experiments. An influence on the central nervous system was found.
Oral administration of theanine to rats resulted in a decrease in the concentration of serotonin in the brain. The lethal dose determined in animal experiments with rats is above the highest value tested of 5 grams / kg body weight. No evidence of a carcinogenic effect of theanine was found and an Ames test also gave negative results.
Some studies also found effects on the central nervous system in humans . Theanine is said to have the ability to reduce mental and physical stress reactions. In one study, for example, an increased formation of alpha waves in the brain was measured after ingestion of 200 mg theanine, which arise in a state of relaxation.
L-theanine reaches its maximum plasma concentration between 32 and 50 minutes after oral ingestion; the plasma half-life is 58 to 74 minutes in humans.
criticism
Theanine is considered a nootropic . However, due to the action profile (reduction in beta and increase in alpha and delta waves in the EEG ), higher concentration performance is not to be expected. According to other studies, lower doses reduce the serotonin concentration in the brain in favor of an increasing catecholamine concentration ( dopamine , noradrenaline , adrenaline ), which has a concentration-promoting effect. Theanine seems to have a biphasic profile of action.
The isolated addition of the substance to beverages has not yet been approved in Germany after the rejection by the Federal Institute for Risk Assessment , but it is sold in capsule form as a dietary supplement . It is controversial whether this isolated intake in higher doses is beneficial or harmful to health.
The Federal Institute for Risk Assessment issued the following statement in 2001 (excerpt): “In isolated form, L-theanine shows various pharmacological effects in animal experiments. For example, higher doses of this amino acid lower blood pressure, influence the concentration of various messenger substances in the brain and counteract the effects of caffeine. L-theanine is therefore said to have a calming and relaxing (sedative) effect. However, it has not been clarified whether this is not also associated with other effects and B. the ability to react and alertness can be negatively influenced. It is also unclear whether these possible negative effects are exacerbated by the additional consumption of alcohol or medication. (...) Monopreparations that contain L-theanine in capsule form (...) may be used. a. advertised with anti-anxiety, mood-modulating, caffeine-antagonizing, antihypertensive, brain dopamine-increasing, PMS symptom-reducing effects ', and some of them carry the following warnings:' do not take this product if you are pregnant, breast-feeding or taking any prescription medications without prior medical consultation '(…) “(Eng .: Do not take this product if you are pregnant or breastfeeding. If you have been prescribed medication, do not take it until you have consulted a doctor).
Web links
- Information from the tea association on theanine (PDF file; 98 kB)
Individual evidence
- ↑ Entry on THEANINE in the CosIng database of the EU Commission, accessed on April 20, 2020.
- ↑ a b fda.gov: GRAS ASSESSMENT L-Theanine (> 98%) , accessed on August 18, 2014.
- ↑ a b L-Theanine data sheet from Sigma-Aldrich , accessed on April 24, 2011 ( PDF ).
- ↑ a b c Statement, August 2003 (PDF file; 52 kB) of the Federal Institute for Risk Assessment
- ↑ A. Kobayashi, Y. Nagato, N. Aoi, LR Juneja, M. Kim, T. Yamamoto, S. Sugimoto: Effects of L-Theanine on the Release of α-Brain Waves in Human Volunteers. In: Journal of the agricultural chemical society of Japan. 72, 1998, pp. 153-157, doi: 10.1271 / nogeikagaku1924.72.153 .
- ↑ Anna C. Nobre, Anling Rao, Gail N. Owen: L-theanine, a natural constituent in tea, and its effect on mental state . In: Asia Pacific Journal of Clinical Nutrition . 17 Suppl 1, 2008, ISSN 0964-7058 , p. 167-168 , PMID 18296328 .
- ↑ René Schneider, Teresa Lüdde, Sandra Töpper, Peter Imming: Tea against the noise of the world. In: Pharmaz. Ztg. 153 (17), 2008, pp. 1429-1436.
- ↑ Ai Yoto, Mao Motoki, Sato Murao, Hidehiko Yokogoshi: Effects of L-theanine or caffeine intake on changes in blood pressure under physical and psychological stresses . In: Journal of Physiological Anthropology . tape 31 , 2012, ISSN 1880-6805 , p. 28 , doi : 10.1186 / 1880-6805-31-28 , PMC 3518171 (free full text).
- ↑ T. Kukuda, A. Nozawa, T. Unno, N. Okamura, O. Okai: Inhibiting effect of theanine on caffeine stimulation evaluation by EEC in the rat. In: Biosci.Biotech.Biochem. 64, 2000, pp. 287-293.
