3081-61-6

Basic information

• Product Name: L-Theanine
• Synonyms: H-GLU(NHET)-OH;H-GLN(ET)-OH;L-GLUTAMIC ACID GAMMA-(ETHYLAMIDE);L-GLUTAMIC ACID G-(ETHYLAMIDE);L-GAMMA-GLUTAMYLETHYLAMIDE;ETHYL-L-GLUTAMINE;N-GAMMA-ETHYL-L-GLUTAMINE;THEANINE, L-
• CAS NO: 3081-61-6
• Molecular Formula: C₇H₁₄N₂O₃
• Molecular Weight: 174.2
• EINECS: 221-379-0
• Product Categories: Amino ACIDS SERIES;Amino Acids 13C, 2H, 15N;Amino Acids;Biochemistry;non-Proteinorganic Amino Acids;Nutritional Supplements;Functional Products;Amino Acids & Derivatives;Chiral Reagents;amino acid;chemical reagent;pharmaceutical intermediate;phytochemical;reference standards from Chinese medicinal herbs (TCM).;standardized herbal extract;Inhibitors
• Mol File: 3081-61-6.mol
• Article Data: 25

Chemical Properties

• Melting Point: 207°C
• Boiling Point: 430.2 °C at 760 mmHg
• Flash Point: 214 °C
• Appearance: White crystalline solid
• Density: 1.171 g/cm³
• Vapor Pressure: 1.32E-08mmHg at 25°C
• Refractive Index: 8 ° (C=5, H2O)
• Storage Temp.: Store at?0-5°C
• Solubility: Soluble in Water (up to 20 mg/ml).
• PKA: 2.24±0.10(Predicted)
• Water Solubility: almost transparency
• Stability: Stable for 2 years from date of purchase as supplied. Solutions in distilled water may be stored at -20° for up to 2 months.
• CAS DataBase Reference: L-Theanine(CAS DataBase Reference)
• NIST Chemistry Reference: L-Theanine(3081-61-6)
• EPA Substance Registry System: L-Theanine(3081-61-6)

Safety Data

• Hazard Codes: Xi
• Statements: 43
• Safety Statements: 28-36/37
• Hazardous Substances Data: 3081-61-6(Hazardous Substances Data)

Usage

Physiochemical properties

Theanine, like the protein-based amino acids, exists as a zwitterionic species and is a colorless crystalline solid [needles, melting point 214–216 ?C][2]. Studies on the buffering capacity of green tea extracts suggest the pKa of the theanine amino group to be[10, 12]. The pKa of the carboxyl unit was not formally quantified due to interference from other acidic species. However, comparisons with close structural analogues such as glutamine suggest the value lies in the range 2.1–2.5[13]?Theanine is stable under acidic conditions but undergoes base hydrolysis to yield glutamic acid and ethylamine[2, 14]. During infusion, theanine does not react chemically with any of the other tea components. This is in contrast to catechins, which can precipitate from solution as a result of π stacking interactions with caffeine[15, 16]or can react with proteins and enzymes such as lipoxygenase, α-amylase, pepsin, trypsin and lipase[15]. Of the tea components, theanine exhibits a higher water solubility [385 g L?1 at 0 ?C, 556 g L?1 at 100 ?C]than caffeine [21.7 g L?1]and the catechins [e.g. epigallocatechin gallate, 5 g L?1]; this permits a very effective diffusion of theanine from tea during hot-water infusions [2, 17]. The relative insolubility of theanine in organic solvents such as methanol and chloroform allows for its easy separation from caffeine and the catechins, which possess a molecular rather than a zwitterionic structure[2]. Theanine has a complex umami taste[18-20].It also exhibits a synergism with the common umami flavouring agents monosodium glutamate and the purine nucleoside inosine 5’-monophosphate, which leads to an enhancement of the umami taste experience[18].The term umami is a Japanese-derived expression and it is classified as the fifth taste after sweet, salt, bitter and sour[19, 20]. Most of the typical umami substances are divided into two groups: L-α-amino acids, usually represented by monosodium glutamate and 5’-ribonucleotides and their derivatives, usually represented by inosine 5’-monophosphate or disodium 5’-guanylate[19, 20].

Sources and synthesis

Sources The tropical and temperate regions of Asian, African, South American countries are considered the main origin of tea plant [C. sinensis or Thea sinensis]. It is a member of Theaceae family. The majority members of Theaceae family are obtained from India, Sri Lanka, China, and Japan. The physiological properties and colour e.g. black, white, green, yellow or oolong tea strongly depends upon the degree of fermentation and processing conditions[20]. L-theanine is mainly derived from a non-edible mushroom of Xerocomus badius, and C. sinensis. It is an amino acid which accumulates in the leaves of tea like C. sasanqua and C. japonica[21]. In tea, L-theanine is responsible for a strong smell [aroma]in general and in particular it is linked with tea umami taste[22]. From the compositional viewpoint, L-theanine comprises approximately 50% of the tea contents. Whereas, the dry tea contains 1–3% of L-theanine only, this higher or lower ratio of L-theanine can vary depending on several factors i.e. cultivation zone, production season, processing techniques, class of tea, time and type of harvest, etc[27]. Additionally, the harvested tea at the beginning of summer is reported to have more theanine compared with tea harvested in late summer[27]. Moreover, L-theanine concentration also depends on the type/class of tea. According to one study, a specific type of C. sinensis var. Sinensis has more L-theanine contents as compared to the C. sinensis var. Assamica[23]. Besides natural L-theanine, the synthetic L-theanine [SuntheanineTM]is also available as a racemic mixture of Dand L-forms of ethylamine and L-glutamine. It is typically obtained from ethylamine and L-glutamine with the use of glutaminase enzyme[24]. Evidently, literature evidences that L-theanine is stable in acidic conditions[25, 26]. Synthesis Theanine was first chemically synthesised in 1942 by Lichtenstein[28]with a yield of 90 g kg?1 by treating pyrrolidone-5-carboxylic acid with aqueous ethylamine for 20 days at 37 ?C. A number of other synthetic approaches have since been developed including a large-scale production method involving the reaction of γ -benzyl glutamate in the presence of trityl chloride and ethylamine [339 g kg?1][29]and a two-step approach involving initial dehydration of L-glutamic acid to L-pyrrolidone carboxylic acid followed by ring opening in the presence of ethylamine to yield theanine [374 g kg?1][30]. More recently, theanine was produced in four steps starting from commercially available N-phthaloyl-L-glutamic acid, which was dehydrated to the corresponding cyclic anhydride by reaction with acetic anhydride and then the ring was opened by reaction with ethylamine. Subsequent de-protection of the amine unit with hydrazine hydrate gave theanine with a 700 g kg?1 overall yield[31]. In the tea plant, theanine is bio-synthesised from glutamic acid and ethylamine by the enzyme theanine synthetase. However, the enzyme is very labile and cannot be used to produce the amino acid in commercial quantities[32]. Therefore, other methods for the enzymatic synthesis of theanine have been developed using bacterial enzymes such as glutaminase, glutamine synthetase and γ-glutamyl-transpeptidase. The enzyme glutamine synthetase and related enzymes, originating from Escherichia coli[33], Pseudomonas taetrolens[34].Methylovorus mays [35], and Bacillus subtilis[35], have been utilized for the synthesis of theanine from glutamic acid and ethylamine. Unlike the glutaminase biosynthetic pathway discussed previously, this glutamic acid transformation, while using a cheaper and more stable starting material, requires a continuous supply of ATP to drive the reaction[34]. Another non-ATP-dependent biosynthetic pathway, involving γ -glutamyltranspeptidase from E. coli and glutamine as the starting substrate, has also been successfully developed but the reaction requires a high concentration of ethylamine to drive the conversion of glutamine to theanine[31, 36, 37].

Health effects

Green tea leaves have many beneficial health activities including anti-inflammatory, anti-carcinogenic, anti-mutagenic, antioxidative and antimicrobial and hypolipidemic effects[38, 39]. Those beneficial effects are largely originated from the biological effects from L-Theanine as below: Ingestion of theanine has been reported to facilitate the generation of alpha brain waves, which are associated with a relaxed but alert mental state[40]. In addition, theanine is reported to promote the release of the inhibitory neurotransmitterγ-aminobutyric acid [GABA], which in turn regulates dopamine and serotonin levels in the brain[41]. Thus, theanine consumption has been closely associated with relaxation and improved learning ability. A recent study found that ingestion of 50 mg of L-theanine dissolved in 100 mL of water could elicit a significant effect on the general state of mental alertness or arousal in subjects by increasing alpha-wave brain activity[42]. Another study also found a link between theanine consumption [200 mg]and the reduction of anxiety[43]. Other studies have shown that consumption of theanine in combination with caffeine could further improve concentration and learning ability. For example, the intake of a combination of 250 mg L-theanine and 150 mg caffeine was found to enhance rapid simple reaction time, fast numeric working memory reaction time and improve verification accuracy during reading tasks[44]. A separate study found that consuming a combination of 100 mg L-theanine and 50 mg caffeine improved both speed and accuracy performance during attention-switching tasks performed 60 min after ingestion and reduced susceptibility to distracting information in memory tasks at 60 and 90 min following ingestion[45]. Moreover, it is thought that theanine may provide effective prophylaxis and treatment for Alzheimer’s disease as it has been reported to exert neuro-protective effects through inhibition of the N-methyl-D-aspartate [NMDA]subtype of glutamate receptors and its related pathways in a transgenic neuronal cell model[46]. Theanine has also recently been linked to cancer prevention. Liu et al[47] found that theanine was linked to the inhibition of the in vivo and ex vivo growth of human non-small cell lung cancer and leukaemia cell lines. In another study, Friedman et al[47]found that theanine intake was associated with the induction of apoptosis in four cancer cell lines of breast, colon, hepatoma and prostate origin. In addition to enhanced antitumour activity, theanine can reduce the adverse effects of the cancer treatment drug, doxorubicin by providing protection against damage caused by doxorubicin to normal tissue[48]. It also acts as a biochemical modulator to improve the therapeutic efficacy of doxorubicin by suppressing the efflux of the drug from cancer cells, thereby increasing the effective doxorubicin concentration in the tumour[49]. Recent studies have also found that theanine was linked with regulation of blood pressure, promotion of weight loss and improvement of the immune system[51,53]. Injection of L-theanine at a dose rate of 2 g kg?1 was found to significantly reduce blood pressure in spontaneously hypertensive rats[50]. In humans, consumption of a single dose of 200 mg of theanine was also found to reduce blood pressure and, more importantly, theanine was found to antagonise the negative effect of caffeine increasing blood pressure, when the latter was consumed as a single 250 mg dose[51]. In addition, co-administration of L-theanine and L-cystine was reported to enhance antigen-specific immunoglobulin G [IgG]production, partly through augmentation of glutathione [GSH]levels and T-helper cell [Th2]-mediated responses[52]. Similarly, co-treatment of L-theanine with L-cystine was found to improve the immune response via an increase in GSH production, which significantly prevented weight loss associated with infection in aged mice[53].

Safety information

FDA classified L-theanine as “generally recognized as safe.” This classification means that they believe this additive to be safe when people use it as the packaging suggests.Women who are pregnant or breastfeeding should not use L-theanine.

Reference

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Nutr. 134 [12][2004]3431–3440. 7. ?R. Cooper, Green tea and theanine: health benefits, Int. J. Food Sci. Nutr. 6 [3][2012]90–97. 8. ?Juneja LR, ChuDC, Okubo T,Nagato Y and Yokogoshi H, L-Theanine – a unique amino acid of green tea and its relaxation effect in humans. Trends Food Sci Technol 10:199–204 [1999]. 9. ?Balentine DA, Harbowy ME and Graham HN, Tea: The plant and its manufacture; chemistry and consumption of the beverage, in Caffeine, ed. by Spiller GA. CRC Press, Boca Raton, pp. 35–72 [1998]. 10. Chu DC, Green tea – its cultivation, processing of the leaves for drinking materials, and kinds of green tea, in Chemistry and Applications of Green Tea, ed. by Yamamoto T, Juneja LR, Chu DC and Kim M. CRC Press, Boca Raton, pp. 1–11 [1997]. 11. Deng WW, Ogita S and Ashihara H, Biosynthesis of theanine [γ ethylamino-l-glutamic acid]in seedlings of Camellia sinensis. Phytochem Lett 1:115–119 [2008]. 12. Chu DC, Kobayashi K, Juneja LR and Yamamoto T, Theanine – its synthesis, isolation, and physiological activity, in Chemistry and Applications of Green Tea, ed. by Yamamoto T, Juneja LR, Chu DC and Kim M. CRC Press, Boca Raton, pp. 129–135 [1997]. 13. Yamano HandMiyagawa K,Buffer capacity curves of green tea extracts using a personal computer with numerically treated online software. Food Sci Technol Int Tokyo 3:69–73 [2009]. 14. Ekborg-Ott KH, Taylor A and Armstrong DW, Varietal differences in the total and enantiomeric composition of theanine in tea. J Agric Food Chem 45:353–363 [1997]. 15. Vuong VQ, Golding JB, Nguyen M and Roach PD, Extraction and isolation of catechins from tea. J Sep Sci 33:3415–3428 [2010]. 16. Ishizu T, Tsutsumi H and Sato T, Interaction between gallocatechin gallate and caffeine in crystal structure of 1 : 2 and 2 : 2 complexes. Tetrahedron Lett 50:4121–4124 [2009]. 17. Liang H, Liang Y, Dong J, Lu J, Xu H and Wang H, Decaffeination of fresh green tea leaf [Camellia sinensis]byhotwater treatment. Food Chem 101:1451–1456 [2007]. 18 Narukawa M, Morita K and Hayshi Y, L-Theanine elicits an umami taste with inosine 5’-monophosphate. Biosci Biotechnol Biochem 72:3015–3017 [2008]. 19 de Araujo IET, Kringelbach ML, Rolls ET and Hobden P, Representation of umami taste in the human brain. J Neurophysiol 90:313–319 [2003]. 20 Y. Kim, K.L. Goodnera, J.D. Parkb, J. Choib, S.T. Talcott, Changes in antioxidant phytochemicals and volatile composition of Camellia sinensis by oxidation during tea fermentation, Food Chem. 129 [4][2011]1331–1342. 21 W.W. Deng, S. Ogita, H. Ashihara, Biosynthesis of theanine [γ-ethylamino-l-glutamic acid]in seedlings of Camellia sinensis, Phytochem. Lett. 1 [2][2008]115–159. 22 M. Narukawa, Y. Toda, T. Nakagita, Y. Hayashi, T. Misaka, L-Theanine elicits umami taste via the T1R1 + T1R3 umami taste receptor, Amino Acids 46 [6][2014]1583–1587. 23 D.C. Chu, Green tea – its cultivation, processing of the leaves for drinking materials, and kinds of green tea, in: T. Yamamoto, J.R. Lekh, D.C. Chu, M. Kim [Eds.], Chemistry and Applications of Green Tea, CRC Press, Boca Raton, 1997, pp. 1–11. 24 L.R. Juneja, D.C. Chu, T. Okubo, Y. Nagato, H. Yokogoshi, L-theanine—a unique amino acid of green tea and its relaxation effect in humans, Trend Food Sci. Technol. 10 [12][1999]425. 25 K. Boros, N. Jedlinszki, D. Csupor, Theanine and caffeine content of infusions prepared from commercial tea samples, Pharmacogn. Mag. 12 [45][2016]75–79. 26 J. Williams, J. Kellett, P.D. Roach, A. McKune, D. Mellor, J. Thomas, N. Naumovski, L-theanine as a functional food additive: its role in disease prevention and health promotion, Beverages 2 [13][2016], http://dx.doi.org/10. 3390/beverages2020013. 27 Q.V. Vuong, M.C. Bowyer, P.D. Roach, L-theanine: properties, synthesis and isolation from tea, J. Sci. Food Agric. 91 [11][2011]1931–1939. 28 Lichtenstein N, Preparation of c-alkylamides of glutamic acid. J Am Chem Soc 64:1021–1022 [1942]. 29 Kawagishi H and Sugiyama K, Facile and large-scale synthesis of L-theanine. Biosci Biotechnol Biochem 56:689 [1992]. 30 Yan SH, Dufour JP and Meurens M, Synthesis and characterization of highly pure theanine. J Tea Sci 23:99–104 [2003]. 31. Gu H, Jiang Y and Wang J, A practical synthesis of ethyl L-glutamine [L-theanine]. Org Prep Proced Int 36:182–185 [2004]. 32. Zhang F, Zheng QZ, Jiao QC, Liu JZ and Zhao GH, Enzymatic synthesis of theanine from glutamic acid γ -methyl ester and ethylamine by immobilized Escherichia coli cells with γ –glutamyltranspeptidase activity. Amino Acids 39:1177–1182 [2010]. 33. Miyake K and Kakita S, A novel catalytic ability of γ –glutamylcysteine synthetase of Escherichia coli and its application in theanine production. Biosci Biotechnol Biochem 73:2677–2683 [2009]. 34. Yamamoto S, Wakayama M and Tachiki T, Cloning and expression of Methylovorus mays No. 9 gene encoding γ –glutamylmethylamide synthetase: An enzyme usable in theanine formation by coupling with the alcoholic fermentation system of baker’s yeast. Biosci Biotechnol Biochem 72:101–109 [2008]. 35. Zhou X, Zhang Z, Jia X, Wu Y, Luo L and Yin Z, Mn2+ enhances theanine-forming activity of recombinant glutamine synthetase from Bacillus subtilis in Escherichia coli. World J Microb Biotechnol 24:1267–1272 [2008]. 36. Suzuki H, Izuka S, Miyakawa N and Kumagai H, Enzymatic production of theanine, an ‘umami’ component of tea, from glutamine and ethylamine with bacterial γ -glutamyltranspeptidase. Enzyme Microb Technol 31:884–889 [2002]. 37. Zhang F, Zheng QZ, Jiao QC, Liu JZ and Zhao GH, Synthesis of theanine from glutamic acid γ -methyl ester and ethylamine catalyzed by Escherichia coli having γ –glutamyltranspeptidase activity. Biotechnol Lett 32:1147–1150 [2010]. 38. G.W. Varilek, F. Yang, E.Y. Lee, W.J.S. deVilliers, J. Zhong, H.S. Oz, K.F. Westberry, C.J. McClain, Green tea polyphenol extract attenuates inflammation in interleukin-2-difeicient mice, a model of autoimmunity, J. Nutr. 131 [7][2001]2034–2039. 39. S.M. Chacko, P.T. Thambi, R. Kuttan, I. Nishigaki, Beneficial effects of green tea: a literature review, Chin. Med. 5 [2010]13. 40 Cooper R, Morr′e DJ and Morr′e DM, Medicinal benefits of green tea: Part I. Review of noncancer health benefits. J Altern Complement Med 11:521–528 [2005]. 41 Mason R, 200 mg of Zen: L-theanine boosts alpha waves, promotes alert relaxation. Altern Complement Ther 7:91–95 [2001]. 42. Nobre AC, Rao A and Owen GN, L-theanine, a natural constituent in tea, and its effect on mental state. Asia Pac J Clin Nutr 17:167–168 [2008]. 43. Lu K, Gray MA, Oliver C, Liley DT, Harrison BJ, Bartholomeusz CF, et al, The acute effects of L-theanine in comparison with alprazolam on anticipatory anxiety in humans. Hum Psychopharmacol Clin 19:457–465 [2004]. 44. Haskell CF, Kennedy DO, Milne AL, Wesnes KA and Scholey AB, The effects of L-theanine, caffeine and their combination on cognition and mood. Biol Psychol 77:113–122 [2008]. 45 Owen GN, Parnell H, Bruin EAD and Rycroft JA, The combined effects of L-theanine and caffeine on cognitive performance and mood. Nutr Neurosci 11:193–198 [2008]. 46. Di X, Yan J, Zhao Y, Zhang J, Shi Z, Chang Y, et al, L-Theanine protects the APP [Swedish mutation]transgenic SH-SY5Y cell against glutamate-induced excitotoxicity via inhibition of the NMDA receptor pathway. Neuroscience 18:778–786 [2010]. 47. Liu Q, Duan H, Luan J, Yagasaki K and Zhang G, Effects of theanine on growth of human lung cancer and leukemia cells as well as migration and invasion of human lung cancer cells. Cytotechnology 59:211–217 [2009]. 47. Friedman M, Mackey BE, Kim HJ, Lee IS, Lee KR, Lee SU, et al, Structure–activity relationships of tea compounds against human cancer cells. J Agric Food Chem 55:243–253 [2007]. 48. Sugiyama T and Sadzuka Y, Theanine, a specific glutamate derivative in green tea, reduces the adverse reactions of doxorubicin by changing the glutathione level. Cancer Lett 212:177–184 [2004]. 49. Sadzuka Y, Sugiyama T, Suzuki T and Sonobe T, Enhancement of the activity of doxorubicin by inhibition of glutamate transporter. Toxicol Lett 123:159–167 [2001]. 50. Yokogoshi H and Kobayashi M, Hypotensive effect of γ -glutamylmethylamide in spontaneously hypertensive rats. Life Sci 62:1065–1068 [1998]. 51. Rogers PJ, Smith JE, Heatherley SV and Pleydell-Pearce CW, Time for tea: Mood, blood pressure and cognitive performance effects of caffeine and theanine administered alone and together. Psychopharmacology 195:569–577 [2007]. 52. Kurihara S, Shibahara S, Arisaka H and Akiyama Y, Enhancement of antigen-specific immunoglobulin G production in mice by co-administration of L-cystine and L-theanine. J Vet Med Sci 69:1263–1270 [2007]. 53. Takagi Y, Kurihara S, Higashi N, Morikawa S, Kase T, Maeda A, et al, Combined administration of L-cystine and L-theanine enhances immune functions and protects against influenza virus infection in aged mice. J VetMed Sci 72:157–165 [2010].

Description

L-Theanine is the major amino acid found in Camellia sinensis, the source of green tea. It is an analog of the excitatory neurotransmitter, glutamate, and thusly, binds to glutamate receptors. L-Theanine can antagonize various glutamate receptor subtypes as well as inhibit glutamine and glutamate transporters, which has been shown to be neuroprotective in animal models of focal cerebral ischemia. Further, L-theanine is reported to increase brain levels of dopamine, serotonin, GABA, nerve growth factor, and brain-derived neurotrophic factor.

Chemical Properties

White Crystalline Solid

Uses

Different sources of media describe the Uses of 3081-61-6 differently. You can refer to the following data:
1. L-Theanine is a safe and non-toxic photogenic food supplement.L-theanine has been studied as a food additive and functional food in relation to human nutrition. It has noticeable bioactivities including anti-cerebral ischemia-reperfusion injury, stress-reducing, antitumor, anti-aging, and anti-anxiety activities.
2. A non-protein amino acid mainly found naturally in the green tea plant. It may have activity in modulating the metabolism of cancer chemotherapeutics agents.

Definition

ChEBI: A N5-alkylglutamine where the alkyl group is ethyl. It has been isolated from green tea.

Biological Activity

Amino acid analog of glutamine and component of green tea. Shown to bind to AMPA, Kainate, NMDA and group I mGlu receptors. Displays neuroprotective effects in vivo . Promotes self-renewal of human embryonic stem cells (hESC).

Biochem/physiol Actions

Theanine is able to bind to AMPA, kainite, and NMDA glycine receptors in rat cortical neurons but with less affinity than glutamic acid. It has been studied as a glutamate transport inhibitor, preventing glutamate uptake by M5076 ovarian sarcoma-bearing mouse cells and increasing the effect of doxorubicin on tumor growth in M5076 mice.

InChI:InChI=1/C7H14N2O3/c1-2-9-6(10)4-3-5(8)7(11)12/h5H,2-4,8H2,1H3,(H,9,10)(H,11,12)/t5-/m0/s1

Upstream product

• 95082-77-2 Z-L-theanine 
• 73270-47-0 L-glutamic acid-5-ethyl ester; hydrochloride 
• 75-04-7 ethylamine 
• 56-85-9 L-glutamine 
• 70-18-8 GLUTATHIONE 
• 56-86-0 L-glutamic acid 
• 593-51-1 methylamine hydrochloride 
• 138036-14-3 2-(1,3-dioxo-1,3-dihydro-isoindol-2-yl)-pentanedioic acid 5-methyl ester 
• 10148-81-9 L-γ-glutamyl-L-glutamine 
• 15875-95-3 ethylamine monohydrate 
• 4652-65-7 (S)-2-Benzyloxycarbonylamino-pentanedioic acid 5-methyl ester 
• 142-47-2 monosodium glutamate 
• 56-85-9 GLUTAMINE 
• 557-66-4 ethanamine hydrochloride 

Downstream Products

• 56-86-0 L-glutamic acid 
• 75-04-7 ethylamine 
• 1437967-19-5 C₁₉H₃₄N₂O₁₃ 
• 1437967-23-1 C₁₉H₃₄N₂O₁₃ 
• 149-91-7 3,4,5-trihydroxybenzoic acid 
• 863-03-6 (-)-epicatechin gallate 
• 989-51-5 (+)-gallocatechin 3-O-gallate 
• 87-66-1 2-hydroxyresorcinol 
• 490-46-0 (2R,3R)-2-(3,4-dihydroxyphenyl)-3,4-dihydro-1[2H]-benzopyran-3,5,7-triol 
• 154-23-4 catechin 
• 970-73-0 epigallocatechin 
• 970-73-0 (+)-gallocatechin 

Relevant articles and documents

Preparation method of L-theanine

The invention relates to the technical field of organic chemical synthesis, in particular to a preparation method of L-theanine. The preparation method of the L-theanine comprises the following steps:(a) reacting L-glutamic acid with a copper salt in a solvent to obtain a chelate A; (b) carrying out an esterification reaction on the chelate A and methanol to obtain a compound B; and (c) after a reaction of the compound B with an aqueous ethylamine solution is finished, adding a decoppering reagent, carrying out stirring for a reaction, and removing a solvent to obtain a crude L-theanine product. According to the preparation method of the L-theanine, the L-glutamic acid is used as an initial raw material and is easy to obtain; in addition, residues in amino acid are protected by adopting acopper chelate manner, so the reaction process is green and environment-friendly. In the step (c), the safer aqueous ethylamine solution is used for the reaction, so the safety of the reaction is improved, requirements on equipment are reduced, production cost is greatly saved, and industrial production is easier.

Characterization of l -Theanine Excitatory Actions on Hippocampal Neurons: Toward the Generation of Novel N-Methyl- d -aspartate Receptor Modulators Based on Its Backbone

l-Theanine (or l-γ-N-ethyl-glutamine) is the major amino acid found in Camellia sinensis. It has received much attention because of its pleiotropic physiological and pharmacological activities leading to health benefits in humans, especially. We describe here a new, easy, efficient, and environmentally friendly chemical synthesis of l-theanine and l-γ-N-propyl-Gln and their corresponding d-isomers. l-Theanine, and its derivatives obtained so far, exhibited partial coagonistic action at N-methyl-d-aspartate (NMDA) receptors, with no detectable agonist effect at other glutamate receptors, on cultured hippocampal neurons. This activity was retained on NMDA receptors expressed in Xenopus oocytes. In addition, both GluN2A and GluN2B containing NMDA receptors were equally modulated by l-theanine. The stereochemical change from l-theanine to d-theanine along with the substitution of the ethyl for a propyl moiety in the γ-N position of l- and d-theanine significantly enhanced the biological efficacy, as measured on cultured hippocampal neurons. l-Theanine structure thus represents an interesting backbone to develop novel NMDA receptor modulators.

Synthesis of amino acid using a flow-type microreactor containing enzyme-mesoporous silica microsphere composites

A flow-type microreactor containing composite materials of a theanine synthetase (glutaminase) and mesoporous silica with 23.6 nm pore diameter (SBA-15 microsphere) was developed for the continuous synthesis of l-theanine, a unique amino acid. Enzyme-immobilisation ability and enzymatic activity in the SBA-15 microsphere with large mesopores were higher than those of SBA-15 with a 5.4 nm pore diameter. Moreover, the glutaminase-SBA-15 microsphere composites displayed higher selectivity in theanine production than the free enzyme did in a batch experiment. A direct visualization of composites of fluorescently labelled glutaminase and SBA-15 microsphere immobilised in the flow channel of the microreactor by a combination of differential interference contrast and fluorescence microscopy revealed that the enzymes were uniformly dispersed throughout the mesoporous silica particles, because of the successful encapsulation of the enzyme. The enzyme-encapsulated microreactor exhibited a high conversion of l-glutamine to l-theanine with local control of the reaction temperature. In addition to this advantage of the microreaction system, the microreactor enabled the on-off regulation of enzymatic activity during continuous theanine synthesis by controlling the reaction temperature or the pH of the substrate solution.