Theanine

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IUPAC_name = 2-Amino-4-(ethylcarbamoyl)butyric acid
CAS_number = 3081-61-6
PubChem = 228398
C=7 | H=14 | N=2 | O=3
molecular_weight = 174.20 g/mol
melting_point = 117
synonyms = L-Theanine, N-Ethyl-L-glutamine
smiles = OC( [C@@H] (N)CCC(NCC)=O)=O
metabolism =
excretion =
legal_status = Legal
routes_of_administration =

Theanine is an amino acid commonly found in tea (infusions of "Camellia sinensis"), and also in the basidiomycete mushroom "Boletus badius".cite journal |author=Casimir J, Jadot J, Renard M |title= [Separation and characterization of N-ethyl-gamma-glutamine from Xerocomus badius.] |journal=Biochim Biophys Acta |volume=39 |pages=462-8 |year=1960 |pmid=13808157] In 1950 the Tea laboratory of Kyoto successfully separated theanine from Gyokuro leaf, which has the highest theanine content among all teas. Theanine is related to glutamine, and can cross the blood-brain barrier.cite journal |author=Yokogoshi H, Kobayashi M, Mochizuki M, Terashima T |title=Effect of theanine, r-glutamylethylamide, on brain monoamines and striatal dopamine release in conscious rats |journal=Neurochem Res |volume=23 |issue=5 |pages=667–73 |year=1998 |pmid=9566605 |doi=10.1023/A:1022490806093] Because it can enter the brain, theanine has psychoactive properties.cite journal |author=Gomez-Ramirez M |title=The Deployment of Intersensory Selective Attention: A High-density Electrical Mapping Study of the Effects of Theanine |journal=Clin Neuropharmacol |volume=30 |issue=1 |pages=25–38 |year= |pmid=17272967] Theanine has been shown to reduce mental and physical stresscite journal |author=Kimura K, Ozeki M, Juneja L, Ohira H |title=L-Theanine reduces psychological and physiological stress responses |journal=Biol Psychol |volume=74 |issue=1 |pages=39–45 |year=2007 |pmid=16930802 |doi=10.1016/j.biopsycho.2006.06.006] , may produce feelings of relaxationcite journal |author=Lu K, Gray M, Oliver C, Liley D, Harrison B, Bartholomeusz C, Phan K, Nathan P |title=The acute effects of L-theanine in comparison with alprazolam on anticipatory anxiety in humans |journal=Hum Psychopharmacol |volume=19 |issue=7 |pages=457–65 |year=2004 |pmid=15378679 |doi=10.1002/hup.611] and improves cognition and mood when taken in combination with caffeine.cite journal |author=Haskell CF, Kennedy DO, Milne AL, Wesnes KA, Scholey AB |title=The effects of l-theanine, caffeine and their combination on cognition and mood |journal=Biol Psychol |volume=77 |issue=2 |pages=113–22 |year=2008 |pmid=18006208 |doi=10.1016/j.biopsycho.2007.09.008]

Theanine is speculated to produce these effects by increasing the level of gamma-aminobutyric acid (GABA) production. Theanine increases brain serotonin, dopamine, GABA levels and has micromolar affinities for AMPA, Kainate and NMDA receptors.cite journal |author=Nathan P, Lu K, Gray M, Oliver C |title=The neuropharmacology of L-theanine(N-ethyl-L-glutamine): a possible neuroprotective and cognitive enhancing agent |journal=J Herb Pharmacother |volume=6 |issue=2 |pages=21–30 |year=2006 |pmid=17182482] It has also been found that injecting spontaneously hypertensive mice with theanine significantly lowered levels of 5-hydroxyindoles in the brain.cite journal |author=Yokogoshi H, Kato Y, Sagesaka YM, Takihara-Matsuura T, Kakuda T, Takeuchi N |title=Reduction effect of theanine on blood pressure and brain 5-hydroxyindoles in spontaneously hypertensive rats. |journal=Biosci Biotechnol Biochem. |volume=59 |issue=4 |pages=615–618 |year=1995 |pmid=7539642] Researchers also speculate that it may inhibit glutamic acid excitotoxicity. Theanine also promotes alpha wave production in the brain.

Studies on test rats have shown that even repeated, extremely high doses of theanine cause little to no harmful psychological or physical effects.cite journal |author=Borzelleca J, Peters D, Hall W |title=A 13-week dietary toxicity and toxicokinetic study with L-theanine in rats |journal=Food Chem Toxicol |volume=44 |issue=7 |pages=1158–66 |year=2006 |pmid=16759779 |doi=10.1016/j.fct.2006.03.014] Theanine showed neuroprotective effects in one rat study.cite journal |author=Egashira N, Ishigami N, Pu F, "et al" |title=Theanine prevents memory impairment induced by repeated cerebral ischemia in rats |journal=Phytother Res |volume=22 |issue=1 |pages=65–8 |year=2008 |pmid=17705146 |doi=10.1002/ptr.2261]

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. [cite journal |author=Kamath A, Wang L, Das H, Li L, Reinhold V, Bukowski J |title=Antigens in tea-beverage prime human Vgamma 2Vdelta 2 T cells in vitro and in vivo for memory and nonmemory antibacterial cytokine responses |journal=Proc Natl Acad Sci U S A |volume=100 |issue=10 |pages=6009–14 |year=2003 |pmid=12719524 |doi=10.1073/pnas.1035603100]

ee also

* gamma-Glutamylmethylamide

References