Theanine
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| Systematic (IUPAC) name | |
| 2-Amino-4-(ethylcarbamoyl)butyric acid | |
| Clinical data | |
| Pregnancy cat. | ? |
| Legal status | legal |
| Routes | oral |
| Identifiers | |
| CAS number | 3081-61-6  |
| ATC code | None |
| PubChem | CID 439378 |
| ChemSpider | 388498 |
| UNII | 8021PR16QO |
| KEGG | C01047 |
| ChEBI | CHEBI:58128 |
| Synonyms | L-theanine, N-ethyl-L-glutamine |
| Chemical data | |
| Formula | C7H14N2O3 |
| Mol. mass | 174.20 g/mol |
| SMILES | eMolecules & PubChem |
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| Physical data | |
| Melt. point | 117 °C (243 °F) |
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Theanine (
/ˈθiːəniːn/), also gamma-glutamylethylamide or 5-N-ethyl-glutamine, is an amino acid and a glutamic acid analog commonly found in tea (infusions of Camellia sinensis), primarily in green tea,[1] and also in the basidiomycete mushroom Boletus badius and in guayusa.[2] More specifically, this compound is called L-theanine, being the levorotatory enantiomer. In 1950, the tea laboratory of Kyoto successfully separated theanine from gyokuro leaf, which has high theanine content. Theanine is an analog to glutamine and glutamate, and can cross the blood-brain barrier.[3] It is sold in the US as a dietary supplement, and is FDA confirmed as Generally recognized as safe (GRAS).[4] The Japanese Ministry of Health and Welfare approved the use of theanine for universal consumption in 1964.[5]
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[edit] Effects on the brain
Able to cross the blood-brain barrier, theanine has psychoactive properties.[6] Theanine has been shown to reduce mental and physical stress,[7] and improves cognition[8] and mood in a synergistic manner with caffeine.[9][10]
While structurally related to the excitatory neurotransmitter glutamate, theanine only has weak affinity for the glutamate receptor on postsynaptic cells.[11] Rather, its primary effect seems to increase the overall level of the brain inhibitory transmitter GABA. Theanine also increases brain dopamine levels and has a low affinity for AMPA, kainate and NMDA receptors.[12] 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.[13][14] It has also been found that injecting spontaneously hypertensive mice with theanine significantly lowered levels of 5-hydroxyindoles in the brain.[15] Researchers also speculate it may inhibit glutamic acid excitotoxicity.[12] Theanine also promotes alpha wave production in the brain.[6]
Studies on test rats have shown even repeated, extremely high doses of theanine cause little to no harmful psychological or physical effects.[16] Theanine showed neuroprotective effects in one rat study.[17]
A placebo-controlled trial has shown adding theanine to ongoing antipsychotic medication is helpful in reducing some symptoms of schizophrenia.[18]
Several beverage manufacturers are selling drinks containing theanine and are marketing them as drinks to help people focus and concentrate,[19] while other manufacturers claim relaxing and tranquillizing properties.[18]
[edit] 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 the production of antibacterial proteins was up to five times higher in the tea drinkers, an indicator of a stronger immune response.[20]
[edit] 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 the amount of theanine consumed by regular drinkers of tea or coffee is virtually impossible to determine. While it was estimated 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.[18]
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.[16] Large studies in humans have not been undertaken.
[edit] See also
[edit] References
- ^ Juneja, LR; Chu, DC; Okubo, T; Nagato, Y; Yokogoshi, H. (1999). "L-Theanine - a unique amino acid of green tea and its relaxation effect in humans". Trends in Food Science & Technology 10 (2): 199–204. doi:10.1016/S0924-2244(99)00044-8.
- ^ 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.
- ^ 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.
- ^ "FDA confirms GRAS status of Suntheanine". NutraIngredients-USA.com. March 22, 2007. http://www.nutraingredients-usa.com/Industry/FDA-confirms-GRAS-status-of-Suntheanine.
- ^ Perrini, Carolyn. "L-Theanine: How a Unique Anxiety Reducer and Mood Enhancer Increases Alpha Waves and Alertness". Okinawa Tea Company. http://www.okinawateacompany.com/html/pdf/mood_3.pdf.
- ^ a b 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.
- ^ 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.
- ^ Park SK. Jung IC. Lee WK. Lee YS. Park HK. Go HJ. Kim K. Lim NK. Hong JT. Ly SY. Rho SS."A combination of green tea extract and l-theanine improves memory and attention in subjects with mild cognitive impairment: a double-blind placebo-controlled study."Journal of Medicinal Food. 14(4):334-43, 2011 Apr.
- ^ 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.
- ^ http://www.sciencenews.org/view/generic/id/8965/title/Distracted%3F_Tea_might_help_your_focus " John J. Foxe of the Nathan S. Kline Institute for Psychiatric Research in Orangeburg, N.Y., and his colleagues recruited 16 people for tests of attentiveness on four days. Before testing, each individual drank a glass of water. On 3 days, the drink was spiked with 100 milligrams of theanine, 60 mg of caffeine, or both. The theanine dose was equivalent to that in 4 to 5 cups of tea, and the caffeine translated to about 2.5 cups of tea. In the difficult tests, participants watched a computer screen and pressed a button when a designated shape appeared on the side of a busy visual field to which an arrow had previously pointed. Participants' accuracy differed little between days when they got water alone or with only one additive. Accuracy improved dramatically, however, on the day that they got the theanine-caffeine combination. The attention benefit lasted throughout the 3 hours of testing."
- ^ 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.
- ^ a b 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.
- ^ Yokogoshi H, Mochizuki M, Saitoh K. Theanine-induced reduction of brain serotonin concentration in rats. Biosci Biotechnol Biochem. 1998;62(4):816-7.
- ^ 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.
- ^ 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.
- ^ a b 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.
- ^ 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.
- ^ a b c Egashira N, Ishigami N, Pu F, et al., L-Theanine relieves positive, activation, and anxiety symptoms in patients with schizophrenia and schizoaffective disorder: an 8-week, randomized, double-blind, placebo-controlled, 2-center study, J Clin Psychiatry 2010;71:1-9., Stanley Research, http://www.stanleyresearch.org/Trial/Drug/awardedtrialdetail.aspx?id=252
- ^ Roan, Shari (May 17, 2009). "L-theanine: New drinks promise focus, but more research attention needed". Chicago Tribune. http://www.chicagotribune.com/features/lifestyle/chi-tc-health-theanine-0513may17,0,2196283.story.
- ^ 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. PMID 12719524. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=156317.
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