Theanine

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Not to be confused with theine, a seldom used name for caffeine.
Theanine
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Systematic (IUPAC) name
2-Amino-4-(ethylcarbamoyl)butyric acid
Clinical data
Routes of
administration		 oral
Legal status
Legal status
  • legal
Identifiers
CAS Number 3081-61-6
ATC code none
PubChem CID 228398
ChemSpider 388498
Synonyms L-theanine, N-ethyl-L-glutamine
Chemical data
Formula C7H14N2O3
Molar mass 174.20 g/mol[[Script error: No such module "String".]]
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Physical data
Melting point 117 °C (243 °F)
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Theanine (pronounced /ˈθiːəniːn/; gamma-glutamylethylamide, or 5-N-ethyl-glutamine) is a glutamic acid analog or amino acid derivative commonly found in tea (infusions of Camellia sinensis), and also in the basidiomycete mushroom Boletus badius.[1] In 1950 the Tea laboratory of Kyoto successfully separated theanine from Gyokuro leaf, which has the highest theanine content among all teas. Theanine is an analog to glutamine and glutamate, and can cross the blood-brain barrier.[2] It is sold in the US as a dietary supplement and is FDA confirmed as Generally recognized as safe (GRAS).[3] The Japanese Ministry of Health and Welfare approved the use of L-theanine (the levorotary enantiomer of theanine) for universal consumption in 1964.[4]

Effects on the brain

Able to cross the blood-brain barrier, theanine has psychoactive properties.[5] Theanine has been shown to reduce mental and physical stress[6], and improves cognition and mood in a synergistic manner with caffeine.[7]

While structurally related to the excitatory neurotransmitter glutamate, theanine only has weak affinity for the glutamate receptor on post-synaptic cells.[8] Rather, its primary effect seems to increase the overall level of the brain inhibitory transmitter GABA. Theanine also increases brain dopamine levels and has micromolar affinities for AMPA, kainate and NMDA receptors.[9] Its effect on serotonin is still a matter of debate in the scientific community, with studies showing increases and decreases in brain serotonin levels using similar experimental protocols.[10][11] It has also been found that injecting spontaneously hypertensive mice with theanine significantly lowered levels of 5-hydroxyindoles in the brain.[12] Researchers also speculate that it may inhibit glutamic acid excitotoxicity.[9] Theanine also promotes alpha wave production in the brain.[5]

Studies on test rats have shown that even repeated, extremely high doses of theanine cause little to no harmful psychological or physical effects.[13] Theanine showed neuroprotective effects in one rat study.[14]

Several beverage manufacturers are selling drinks containing theanine and are marketing them as drinks that help people focus and concentrate,[15] while other manufacturers claim relaxing and tranquillizing properties.[16]

Immune system benefits

L-Theanine may help the body's immune response to infection by boosting the disease-fighting capacity of gamma delta T cells. The study, published in 2003 by the Brigham and Women's Hospital, included a four-week trial with 11 coffee drinkers and 10 tea drinkers, who consumed 600 milliliters of coffee or black tea daily. Blood sample analysis found that the production of anti-bacterial proteins was up to five times higher in the tea-drinkers, an indicator of a stronger immune response.[17]

As a supplement

In 2003, the German Federal Institute for Risk Assessment (Bundesinstitut für Risikobewertung, BfR) objected to the addition of isolated theanine to beverages. The institute stated that the amount of theanine consumed by regular drinkers of tea or coffee is virtually impossible to determine. While it was estimated that the quantity of green tea consumed by the average Japanese tea drinker per day contains about 20 mg of the substance, there are no studies measuring the amount of theanine being extracted by typical preparation methods, or the percentage lost by discarding the first infusion. Therefore, with the Japanese being exposed to possibly much less than 20 mg per day, and Europeans presumably even less, pharmacological reactions to drinks typically containing 50 mg of theanine per 500 millilitres cannot be excluded in the opinion of the BfR. Such reactions could include impairment of psychomotor skills and amplification of the sedating effects of alcohol and hypnotics.[16]

In 2006 a study found no consistent, statistically significant treatment-related adverse effects on behavior, morbidity, mortality, body weight, food consumption and efficiency, clinical chemistry, hematology, or urinalysis in rats fed high doses of theanine for 13 weeks.[13] Large studies in humans are missing.

See also

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References

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de:Theanin

es:Teanina fr:Théanine ko:테아닌 it:Teanina mk:Теанин nl:Theanine ja:テアニン uz:Teanin pl:Teanina simple:Theanine fi:Teaniini sv:Teanin

zh:茶氨酸
  1. ↑ Casimir J, Jadot J, Renard M (1960). "[Separation and characterization of N-ethyl-gamma-glutamine from Xerocomus badius.]". Biochim Biophys Acta. 39: 462–8. doi:10.1016/0006-3002(60)90199-2. PMID 13808157. 
  2. ↑ Yokogoshi H, Kobayashi M, Mochizuki M, Terashima T (1998). "Effect of theanine, r-glutamylethylamide, on brain monoamines and striatal dopamine release in conscious rats". Neurochem Res. 23 (5): 667–73. doi:10.1023/A:1022490806093. PMID 9566605. 
  3. ↑ "FDA confirms GRAS status of Suntheanine". NutraIngredients-USA.com. March 22, 2007. 
  4. ↑ Perrini, Carolyn. "L-Theanine: How a Unique Anxiety Reducer and Mood Enhancer Increases Alpha Waves and Alertness" (PDF). Okinawa Tea Company. 
  5. ↑ 5.0 5.1 Gomez-Ramirez M; Higgins, BA; Rycroft, JA; Owen, GN; Mahoney, J; Shpaner, M; Foxe, JJ (2007). "The Deployment of Intersensory Selective Attention: A High-density Electrical Mapping Study of the Effects of Theanine". Clin Neuropharmacol. 30 (1): 25–38. doi:10.1097/01.WNF.0000240940.13876.17. PMID 17272967. 
  6. ↑ Kimura K, Ozeki M, Juneja L, Ohira H (2007). "L-Theanine reduces psychological and physiological stress responses". Biol Psychol. 74 (1): 39–45. doi:10.1016/j.biopsycho.2006.06.006. PMID 16930802. 
  7. ↑ Haskell CF, Kennedy DO, Milne AL, Wesnes KA, Scholey AB (2008). "The effects of l-theanine, caffeine and their combination on cognition and mood". Biol Psychol. 77 (2): 113–22. doi:10.1016/j.biopsycho.2007.09.008. PMID 18006208. 
  8. ↑ Kakuda T, Nozawa A, Sugimoto A, Niino H. Inhibition by theanine of binding of [3H] AMPA, [3H] kainate, and [3H]MDL 105,519 to glutamate receptors. Biosci Biotechnol Biochem. 2002;66(12):2683-6.
  9. ↑ 9.0 9.1 Nathan P, Lu K, Gray M, Oliver C (2006). "The neuropharmacology of L-theanine(N-ethyl-L-glutamine): a possible neuroprotective and cognitive enhancing agent". J Herb Pharmacother. 6 (2): 21–30. doi:10.1300/J157v06n02_02. PMID 17182482. 
  10. ↑ Yokogoshi H, Mochizuki M, Saitoh K. Theanine-induced reduction of brain serotonin concentration in rats. Biosci Biotechnol Biochem. 1998;62(4):816-7.
  11. ↑ Yokogoshi H, Kobayashi M, Mochizuki M, Terashima T. Effect of theanine, γ-glutamylethylamide, on brain monoamines and striatal dopamine release in conscious rats. Neurochem Res. 1998;23(5):667-73.
  12. ↑ Yokogoshi H, Kato Y, Sagesaka YM, Takihara-Matsuura T, Kakuda T, Takeuchi N (1995). "Reduction effect of theanine on blood pressure and brain 5-hydroxyindoles in spontaneously hypertensive rats". Biosci Biotechnol Biochem. 59 (4): 615–618. doi:10.1271/bbb.59.615. PMID 7539642. 
  13. ↑ 13.0 13.1 Borzelleca J, Peters D, Hall W (2006). "A 13-week dietary toxicity and toxicokinetic study with L-theanine in rats". Food Chem Toxicol. 44 (7): 1158–66. doi:10.1016/j.fct.2006.03.014. PMID 16759779. 
  14. ↑ Egashira N, Ishigami N, Pu F; et al. (2008). "Theanine prevents memory impairment induced by repeated cerebral ischemia in rats". Phytother Res. 22 (1): 65–8. doi:10.1002/ptr.2261. PMID 17705146. 
  15. ↑ Roan, Shari (May 17, 2009). "L-theanine: New drinks promise focus, but more research attention needed". Chicago Tribune. 
  16. ↑ 16.0 16.1 Lua error in package.lua at line 80: module 'Module:Citation/CS1/Suggestions' not found.
  17. ↑ Kamath A, Wang L, Das H, Li L, Reinhold V, Bukowski J (2003). "Antigens in tea-beverage prime human Vgamma 2Vdelta 2 T cells in vitro and in vivo for memory and nonmemory antibacterial cytokine responses". Proc Natl Acad Sci USA. 100 (10): 6009–14. doi:10.1073/pnas.1035603100. PMC 156317 Freely accessible. PMID 12719524. 
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