Disease relevance of Theanine

• This action suggests that theanine leads the enhancement of the suppressive efficacy of doxorubicin on hepatic metastasis in vivo [1].
• In the present study, the effect of combination of theanine with doxorubicin against hepatic metastasis of M5076 ovarian sarcoma was investigated [1].
• Neuroprotective effect of gamma-glutamylethylamide (theanine) on cerebral infarction in mice [2].
• One microliter of theanine from each three concentrations (50, 125 and 500 microM) was administered through the lateral ventricle 30 min before ischemia [3].
• A 13-week dietary toxicity and toxicokinetic study with l-theanine in rats [4].

High impact information on Theanine

• Moreover, the liver weights and metastasis scores demonstrated that theanine enhanced the inhibition of hepatic metastasis induced by doxorubicin [1].
• Theanine, a naturally occurring non-proteinic amino acid found in tea leaves, has demonstrated wide-ranging physiological activity, from lowering blood pressure to enhancing the anti-tumor activity of chemotherapeutic drugs [5].
• Analysis of derivatized and underivatized theanine enantiomers by high-performance liquid chromatography/atmospheric pressure ionization-mass spectrometry [5].
• These findings indicate that group I mGluRs might be involved in neuroprotective effect of theanine by increasing the expression levels of PLC-beta1 and -gamma1 [6].
• In the present study, we examined the neuroprotective effect of gamma-glutamylethylamide (theanine) on the ischemic brain damage in a middle cerebral artery occlusion model in mice [2].

Chemical compound and disease context of Theanine

• Components, such as caffeine, theanine, (-)-epigallocatechin gallate (EGCG) and flavonoids have inhibitory effects on the DOX efflux from Ehrlich ascites carcinoma cells [7].
• We have examined the effect of theanine, a specific amino acid in green tea, on idarubicin (IDA)-induced antitumor activity and toxicity [8].

Biological context of Theanine

• With the use of flow rates compatible with each ionization source, native theanine standards achieved excellent sensitivity and detection limits (10 ng/mL) for both atmospheric pressure chemical ionization (APCI) and electrospray ionization (ESI) [5].
• In contrast, theanine did not affect the cerebral blood flow, brain temperature and physiological variables (pH, pCO(2), pO(2) and hematocrit) in this model [2].
• Pharmacokinetics of theanine enantiomers in rats [9].
• It is expected that theanine metabolism occurred by hydrolysis and rearrangement reaction by gamma-GTP in the liver [10].
• The results showed that l-Theanine intake resulted in a reduction in the heart rate (HR) and salivary immunoglobulin A (s-IgA) responses to an acute stress task relative to the placebo control condition [11].

Anatomical context of Theanine

• We examined the protective effect of gamma-glutamylethylamide (theanine) on ischemic delayed neuronal death in field CA1 of the gerbil hippocampus [3].
• Determination of amino acids in the brain after the intragastric administration of theanine showed that theanine was incorporated into brain through blood-brain barrier via leucine-preferring transport system [12].
• Because theanine is a glutamate analogue, we found that it is associated with a change in the drug transport system on the tumor cell membrane, in particular glutamate transporters [13].
• Compared to untreated controls, most catechins, theaflavins, theanine, and all tea extracts reduced the numbers of the following human cancer cell lines: breast (MCF-7), colon (HT-29), hepatoma (liver) (HepG2), and prostate (PC-3) as well as normal human liver cells (Chang) [14].
• Influence of alkylamides of glutamic acid and related compounds on the central nervous system. IV. Effect of theanine on adenosine 3',5'-monophosphate formation in rat cerebral cortex [15].

Associations of Theanine with other chemical compounds

• Under the optimized conditions (5 mM phosphate buffer (pH 5.5) containing 0.05 mM sodium dodecylsulfate as running buffer), the main amino acids contained in Japanese green tea were well separated within 2 min, and theanine (1475 mg/100 g tea leaf), Arg (408 mg/100 g tea leaf) and Gln (217 mg/100 g tea leaf) were detected in Japanese green tea [16].
• Electroencephalograms (EEG) were obtained after 3 tests on each volunteer as follows: intake only water, GABA, or L-theanine [17].
• To define relative anticarcinogenic potencies of tea compounds and teas, nine green tea catechins, three black tea theaflavins, and theanine as well as aqueous and 80% ethanol/water extracts of the same tea leaves were evaluated for their ability to induce cell death in human cancer and normal cells using a tetrazolium microculture (MTT) assay [14].
• Two liquid chromatographic methods that involve precolumn derivatization with o-phthaladehyde (OPA) and phenylisothiocyanate (PITC) with fluorescence and diode array UV detection for the determination of theanine have been developed [18].
• In this study, the inhibiting action of theanine on the excitation by caffeine at the concentration regularly associated with drinking tea was investigated using electroencephalography (EEG) in rats [19].

Gene context of Theanine

• Treatment with theanine or DHPG alone for 5-7 days resulted in increased expression of PLC-beta1 and -gamma1, and the action of theanine was completely abolished by group I mGluR antagonists [6].
• Theanine did not enhance, rather tended to normalize the increase of lipid peroxide level and reduction of glutathione peroxidase activity as indicators of the ADR-induced side toxicity [20].
• Namely, it is suggested that the metabolism of theanine mediated by glutaminase and gamma-GTP and the increase of glutamate mediated GSH is important for theanine-induced action [10].
• There was no change in the activity of any CYPs and the cytochrome P450 content by theanine treatment [10].
• Friedman Anova (p < 0.043) showed that effects on Omega-Complexity differed significantly between conditions and differences were maximal between gum base and theanine gum [21].

Analytical, diagnostic and therapeutic context of Theanine

• The effect of theanine on the efficacy of antitumor agents is expected to be applicable in clinical cancer chemotherapy [1].
• Microdialysis of brain with calcium-free Ringer buffer attenuated the theanine-induced DA release [12].
• Oral administration data indicated that gut absorption of d-theanine was far less than that of L-theanine [9].
• Furthermore, the decrease in tumor weight caused by IDA at 1.0 mg/kg per day x4 days (at this dose IDA exhibits antitumor activity) was significantly amplified by theanine [8].
• The content of the biologically active amino acid theanine in 15 commercial black, green, specialty, and herbal tea leaves was determined as the 2,4-dinitrophenyltheanine derivative (DNP-theanine) by a validated HPLC method [14].

References