Theanine was first isolated from green tea in 1950. It is the characteristic amino acid of tea and also teaOdorantOne, it has strong quality with green teapositive correlation，correlation coefficientUp to 0.787~0.876.Among more than 20 kinds of amino acids in tea, theanine accounts for about 50%~60% of the total amino acids in tea;After research, it is found thatCamellia frutescens、Mushroom、oil-tea camelliaIt has not been found in other plants, except that trace amounts have been detected in other plants.[1]
The naturally occurring theanine isL-typeThe pure product is white acicular crystal, melting point 217 ℃~218 ℃,Specific rotation[α]Dtwenty=0.7 °, very soluble in water, insoluble inethanolandEtheretc.Organic solvent, aqueous solution slightly acidic, withCaramelized And similar monosodium glutamate, with a taste threshold of 0.06%.
Absorption metabolism
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Theanine is the same as otheramino acidIt is also absorbed in the small intestine. Three special carrier systems for amino acid transport have been identified on the small intestine wall, which transport neutral, acid andBasic amino acid。Some experiments have shown that theanine is effective for the same kind of amino acids, such asmethionine、leucine、isoleucineandvalineAntagonism is produced, so it is inferred that theanine may pass through methionineCarrier transportThe system is absorbed in the intestine.However, Kitaoka and other studies show that theanine absorption in the intestinal tract may be related toglutamateOne is shared by NacouplingOfCotransporterTheanine affinity is lower than glutamic acid.Unno et al. found that complete theanine, glutamic acid andEthylamineAnd these compounds are more or less related to theanine dosage.This indicates that theanine is absorbed into human body and hydrolyzed to glutamic acid and ethylamine by enzyme, and its metabolic site may be the kidney.Terashima et al. studied the metabolic dynamics of theanine in rats and found that one hour after oral administration of theanine,serum, liver, brainChinese teaThe concentration of theanine in serum and liver gradually decreased with time, while the concentration of theanine in brain reached the peak after 5 hours24 hoursTheanine disappeared completely in these tissues.
Function
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Hypotensive effect
Blood pressure is regulated mainly through the central andEndnervous systemcatecholamineand5-hydroxytryptamineRealized by increase or decrease.Yokogoshi et al. have proved through experiments that the administration of theanine to rats can reduce the content of 5-hydroxytryptamine, reduce the synthesis of 5-hydroxytryptamine in the brain and increase its decomposition in the brain.When givenSpontaneously hypertensive rats（SHR）The blood pressure decreased with the injection of different doses of theanine, and the degree of decline showed a dose-response relationship. In the high-dose group, the blood pressure decreased significantly;But even the highest dose of theanine will not change the normalRatBlood pressure;And theanineStructural similarityGlutamate was not found to reduce blood pressure.
Recent studies have shown that theanine itselfAntineoplastic activity, but can improve a variety of anti-tumorDrug efficacy。adriamycin(adriamycm) for some tumorsinhibitionTheanine can protect the concentration of doxorubicin in tumor tissue and reduce doxorubicin from Ehrlich ascitestumor cellTherefore, when theanine is used in combination with adriamycin, it can cause tumor in vivogrowth inhibitionIncrease by 2.1 times, adriamycin in tumor tissueConcentration increase2.9x.In addition, injectionAnticancer drugIdarubicin can reducewhite blood cellandmarrow cellsHowever, when used in combination with theanine, it can alleviate the toxicity of edacin and promote its anti-tumor effect, which indicates that theanine has a selective regulatory effect on the toxicity caused by edacin.When used in combination with theanine, the anticancer drug doxorubicin can inhibit M5076 ovarysarcomaMetastasis to the liver.Recently, Sa dzuka and others further studied the pathway of theanine to improve the anticancer activity of doxorubicin, pointing out that theanine can inhibit tumor cellsglutamateThe concentration of doxorubicin in tumor cells is increased by transmission, so as to improve its anti-cancer efficacy.Theanine paircancerClinical chemotherapy is very beneficial for patients. It not only promotes some anti-tumor activitiesDrug actionAnd also improve cancer patientsQuality of life。
Relax nervous tension, relaxation, etc
Terashima et al found that the main receptor of theanine is brain.After theanine enters the brain through the brain barrier, it makes the brain cells in the midline granuleNeurotransmitterdopamineSignificantly increased, while dopamine isadrenalineandNorepinephrinePrecursorIs to convey the brainnerve cellExcitement is an important substance. Its release will greatly affect people's emotions.In addition, Yokogoshi et al（5-hydroxytryptamine)Metabolic inhibitorStudies have found that theanine can affect the synthesis and decomposition of serotonin in the brain.After taking theanineTryptophanThe content of serum albumin increased obviously or tended to increase, but the content of serum albumin decreased.Theanine may reduce serotonin synthesis and increase its decomposition, or inhibit serotonin release.
caffeineIt has a refreshing and exciting effect. Tea also contains more caffeine, which is harmful to the human body if taken alone. However, after drinking tea, it will not produce the exciting effect of drinking the same amount of caffeine.Kimura and other researchers have proved that theanine stimulates caffeineAntagonismHe determined that caffeine induced central nervous spontaneityAmount of exerciseThe results showed that caffeine and theanine could significantly inhibit the excitability when administered simultaneously.Recently, some scholars usedElectroencephalographThe evaluation method further confirmed that theanine and caffeine are almost the sameMolar concentrationIn case of caffeineIrritant effectProduce antagonism.These fully indicate that theanine is caffeineAntagonistIt has obvious effects of calming nerves, reducing tension and relaxing nerves.
Generally speaking, animals and people always produce very weak pulse impulses on the surface of the brain, calledbrain waves。Under different mental conditions, the brain will produce differentCurrent frequencybrain waves.Brain waves are divided into α, β, δ andθ wave，Delta waveWhen you are asleep, theta wave is in the state of hitting tons,Alpha waveWhen it is quiet (relaxed),Beta waveIs onExcitatory stateAppears separately when.Someone artificially verified the mental impact of theanineHuman experimentLet the experimenter drink water and theanine solution, and determine after 60minelectroencephalogram；Results No change of EEG was found after drinking water, but significant α wave was produced after drinking theanine.Therefore, theanine has the effect of promoting the generation of alpha waves, thus causing a comfortable and pleasant feeling.And theanine did not causeSleep stateThe number of theta waves increases, so theanineEmotional stabilityAt the same time, it can also make people more focused.
Menstrual syndrome (PMS) is a condition in which womenChina JapanMental and physical discomfort.Juneja et al. investigated the improvement effect of theanine on PMS and asked 24 women to take theanine 200mg daily. Two months later, PMS symptoms improved significantly, such asheadache, low back pain, chestDistention pain, weakness, fatigue, inability to concentrate, irritability and other symptoms have been improved.Its mechanism needs further study, which may be related to the sedation of theanine.
Slimming effect
Feed with 0.028% theaninemiceAfter 16 weeks, their weight decreased significantly compared with the control group, and their abdominal fat decreased to 58% of the control group.Simultaneous bloodNeutral fatandcholesterolThe content of cholesterol in liver was reduced by 28%.Therefore, the weight loss effect of tea is the result of the joint action of various components in tea, including theanine, which is especially effective in reducing cholesterol in the body.
Anti fatigue effect
After 30 days of oral administration of theanine to mice, the weight bearing swimming test was used to observe and record the swimming of miceTime of death;The mice swam for a certain period of time and then collected blood for serum detectionUrea nitrogen、Blood lactic acid;Take the liver for detectionHepatic glycogen。Results After 30 days of oral administration of different doses of theanine, the swimming time of mice with load was significantly prolonged and the liver glycogen was reducedConsumptionReduce the level of serum urea nitrogen during exercise;It can obviously inhibit the increase of blood lactic acid in mice after exercise and promote the elimination of blood lactic acid after exercise. Therefore, theanine has an anti fatigue effect.Its mechanism may be related to theanine inhibiting s-hydroxyTryptamineSecretion, promoting catecholamine secretioncentral nervous systemIt has inhibitory effect, while catecholamine has excitatory effect).[2]
security information
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As early as 1985,US Food and Drug Administration（FDA）We hereby approve theanine and confirm that synthetic theanine is generally recognized as a safe substance（GRAS）There is no limit regulation during use.The safety test showed that theanine in ratsacute toxicityAbove 5g/kg;After taking theanine for 28 consecutive days (2g/kg per day)SubacuteIn the experiment, the rats did not see anyToxic reaction；stayMutagenicityNo mutagenic effect of theanine was found in the experiment;The bacterial recovery mutation experiment also proved that it did not causeGene variation。Good safety and stability, so that theanine has been used in beveragesBakingSnacks, frozen snacks and other foods are widely used;In addition, theanine has special properties andbiological activityIt also plays an important role in food.
application area
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Theanine, a kind of health food that does not have hypnosis, but also can relieve fatigue, lower blood pressure and improve learning and memory ability, is rare and eye-catching.For this reason, theanine won the research department award at the International Food Raw Materials Conference held in Germany in 1998.Theanine is the most abundant amino acid in tea, accounting for aboutfree amino acid More than 50% of the total amount, accounting for 1% - 2% of the dry weight of tea.Theanine is whiteAcicular body, soluble in water, with sweet and fresh taste, is a component of tea taste.[2]
Theanine can enhance the intensity of alpha waves in the brain, making people feel relaxed and improvememoryAnd has passedHuman body testconfirm.Therefore, it can be added to food as a functional ingredient to develop ways to relieve nervous tension and improve intelligenceFunctional food。If concentrated with black teaLixivium(Bx=20) 5%, filling sugar (Bx=7.5) 5%, granulated sugar 15%Gels1%, theanine 0.2%citric acid0.2%、Sodium citrate0.2%, add water to 100% to make black teajelly。Brain waves were measured 60 minutes after eating, once every 5 minutes. The results showed that the amount of alpha waves increased immediately after eating, and significantly increased after 30 minutes, up to 1.6 times.The study also confirmed that theanine was added tocandyAll kinds of drinks can achieve good sedative effect.Japan is actively carrying out research and development in this regard.
Improvement effect of theanine flavor
Theanine can not only be used asGreen TeaflavorImproverAnd can also inhibit the bitterness andAstringent taste, achieve improvementFood flavorPurpose.Cocoa drinks andWheat teaIt has a unique bitter or astringent taste. AddSweetenerThere will be an unpleasant taste. If 0.01% theanine is used instead of sweetener, the results show that the flavor of the beverage will be greatly improved after theanine is added.The study also confirmed that it is added to other foods (coffee, cocoa, ginseng drinksBeer）It also has a good effect of improving flavor, which indicates that theaninefood industryIt has broad application prospects.[2]
Japan is at the leading level in theanine research and application, and China is in this regardResearch and developmentNot yet in-depth.Theanine research, especially itspharmacological action The research has made great progress, but there are still many problems.It is believed that with the deepening of research, theanine will have a broader development and application prospect in food, medicine and other fields.
It is also known as L-Theanine Cas No.: 3081-61-6, molecular formula:C7H14N2O3quality standard: JP2000 content: 99% Min.Appearance: white or off white powder.Melting point: 202-215 ℃ pH value: 5.0-6.5
