ABSTRACT
L-theanine has been shown to have a therapeutic effect on depression.However,whether L-theanine has an excellent preventive effect on depression in children and adolescents and what its mechanism is have not been well explained.Given the complexity of the pathogenesis of depression,this study investigated the preventive effect and mechanism of L-theanine on depression in juvenile rats by combining serum and hippocampal metabolomic strategies.Behavioral tests,hippocampal tissue sections,and serum and hippocampal biochemical indexes were studied,and the results confirmed the preventive effect of L-theanine.Untargeted reversed-phase liquid chromatography-quadrupole-time-of-flight mass spec-trometry and targeted hydrophilic interaction liquid chromatography-triple quadrupole mass spec-trometry were developed to analyze the metabolism changes in the serum and hippocampus to screen for potential biomarkers related to L-theanine treatment.The results suggested that 28 abnormal me-tabolites in the serum and hippocampus that were considered as potential biomarkers returned to near-normal levels after L-theanine administration.These biomarkers were involved in various metabolic pathways,mainly including amino acid metabolism and lipid metabolism.The levels of amino acids and neurotransmitters in the phenylalanine,tryptophan,and glutamic acid pathways were significantly reduced after L-theanine administration compared with chronic unpredictable mild stress-induced rats.In summary,L-theanine had a significant preventive effect on depression and achieved its preventive results on depression by regulating various aspects of the body,such as amino acids,lipids,and inflammation.This research systematically analyzed the mechanism of L-theanine in preventing depression and laid the foundation for applying L-theanine to prevent depression in children and adolescents.
ABSTRACT
Sepsis induces lung injury and respiratory distress syndrome and is therefore potentially fatal. L-theanine (LT), an amino acid found in tea, is a bioactive compound with an important antioxidant, anti-inflammatory, and antifibrotic properties. The purpose of this study was to evaluates whether, LT exhibits protective effects against lung tissue damage by determining its effect on oxidative stress, inflammation and mineral levels in an experimental model of cecal ligation and perforation (CLP)-induced sepsis in rats. Rats were randomly divided into three groups (n=6): sham, CLP, and CLP+LT. LT was administered intraperitoneally (750 mg/kg) in two equal doses immediately and 12 h after surgery. Malondialdehyde (MDA), advanced protein oxidation product (AOPP), myeloperoxidase (MPO), total antioxidant status (TAS), total oxidant status (TOS), oxidative stress index (OSI), and ischemia modified albumin (IMA) values were determined spectrophotometrically. Serum elements (Na, K, Mg, Ca, and Fe), albumin, glucose, triglyceride, and lactate levels were determined using an autoanalyzer. Lung tissues were also examined histopathologically. Treatment of septic rats with LT significantly reduced oxidative stress and inflammation in lung tissues and serum. LT also increased albumin and Na levels and reduced triglyceride levels in serum. In conclusion, LT treatment may exhibit a preventive effect against sepsis-induced lung injury by reducing oxidative stress and inflammation, and by regulating osmotic balance.
ABSTRACT
Natural bioactive compounds from plants are of great importance in modem therapeutics,which are used to prepare antibiotics,growth supplements or some other therapeutics.L-theanine is such a bioactive amide amino acid presented in different plants and fungi,especially in tea.Theanine has influential effects on lifestyle associated diseases,such as diabetes,cardiovascular disorders,hypertension,stress relief,tumor suppression,menstruation and liver injury.This amino acid can maintain normal sleep and improve memory function and nullify effect of the neurotoxins.The rate of bioavailability and its medium of ingestion in the body is one of the great concerns for its additional antioxidant properties.Pharmacokinetics of the bioactive compound and its mode of action are described herewith.The biosynthesis and industrial synthesis are also reviewed to promote accelerated production of this bioactive compound in the pharmaceutical industries.
ABSTRACT
Natural bioactive compounds from plants are of great importance in modern therapeutics, which are used to prepare antibiotics, growth supplements or some other therapeutics. L-theanine is such a bioactive amide amino acid presented in different plants and fungi, especially in tea. Theanine has influential effects on lifestyle associated diseases, such as diabetes, cardiovascular disorders, hypertension, stress relief, tumor suppression, menstruation and liver injury. This amino acid can maintain normal sleep and improve memory function and nullify effect of the neurotoxins. The rate of bioavailability and its medium of ingestion in the body is one of the great concerns for its additional antioxidant properties. Pharmacokinetics of the bioactive compound and its mode of action are described herewith. The biosynthesis and industrial synthesis are also reviewed to promote accelerated production of this bioactive compound in the pharmaceutical industries.
ABSTRACT
Recombinant strains expressing enzymes for ATP regeneration and L-theanine production were constructed and used for the synthesis of L-theanine. The ppk gene encoding polyphosphate kinase (PPK) from Rhodobacter sphaeroides and gmas gene encoding γ-glutamylmethylamide synthetase (GMAS) from Methylovorus mays were synthesized, and two recombinant plasmids, pETDuet-ppk+gmas and pET21a-ppk+gmas were constructed for co-expression of PPK and GMAS in Escherichia coli BL21(DE3). SDS-PAGE analysis showed that PPK and GMAS were overexpressed in soluble form in both recombinant strains. GMAS-PPK obtained from the recombinant strain containing pET21a-ppk+gmas was more efficient to synthesize L-theanine. After 24 h at 37 ℃ and pH at 7.0, 86.0% yield of L-theanine was achieved with catalytic amount of ATP. This study extends the application of enzymatic ATP regeneration system. In addition, it provides an efficient method for the biosynthesis of L-theanine.
Subject(s)
Carbon-Nitrogen Ligases , Genetics , Electrophoresis, Polyacrylamide Gel , Escherichia coli , Genetics , Glutamates , Ligases , Phosphotransferases (Phosphate Group Acceptor) , GeneticsABSTRACT
Zinc and its compounds with insulin-like effects have been found to own such properties as strong bio-compatibility,good stability and remarkable hypoglycemic effect. Since the discovery of their insulin-like function,zinc compounds and their anti-diabetic effects have been a geobal focus of research. Zinc ion is involved in physiological and biochemical processes in vivo,such as in carbohy-drate and lipid metabolism. The mechanism of zinc and zinc complexes in anti-diabetic activity are sum-marized in this article,including direct participation in insulin synthesis,antioxidation,involvement in the regulation of tyrosine protein phosphatase,and improving immunity. Zinc complexes with Zn(N2 O2 )have remarkable insulin-like effects. Particularly,the L-theanine-zinc compound,which is a class of zinc com-plexes with natural ligands,has also been found to show significant hypoglycemic effect in an in vivo experiment on KK-Ay mice,have stable chemical properties,be absorbed fast in vivoand be non-toxic with oral administration during model animal experiments. This paper reviews the progress in research on relationships between zinc and its complexes and the anti-diabetic effect.
ABSTRACT
The purpose of this study is to investigate whether the combination of green tea extract (GTE) and L-theanine has an anxiolytic effect by oral administration through behavioral tests and neurtransmitters (or hormone) anaylses. Four week oral administration of GTE (24 mg/kg), L-theanine (4 mg/kg) or their combination showed anxiety-reducing effects determined by increasing numbers of head-dips in a hole board test and reducing retention time in a rota-rod test without changing spontaneous locomotor activity. Biochemical analyses indicated that the test materials decreased dopamine (DA), noradrenaline (NA), corticosterone (CS) and increased serotonin (5-HT) levels in brain cortex, hippocampus, and striatum, which suggests a possible mechanism of previous behavioral tests. Although the synergistic effects of GTE and L-theanine combination were not observed on the behavioral test, its effects on neurotransmitters (NA, CS) were synergistic and comparable to diazepam (2 mg/kg i.p.) with much less muscle relaxation side effect. Therefore, a combination of GTE and L-theanine may be useful as a functional food ingredient having an anxiolytic effect.
Subject(s)
Administration, Oral , Anti-Anxiety Agents , Brain , Corticosterone , Diazepam , Dopamine , Functional Food , Hippocampus , Motor Activity , Muscle Relaxation , Neurotransmitter Agents , Norepinephrine , Retention, Psychology , Serotonin , TeaABSTRACT
L-theanine (γ-glutamylethylamide) is the main free amino acid component of tea and its favorable physiological effects on mammals have been reported. An enzymatic method for optically pure L-theanine production with a new L-aminoacylases-production fungi Cunnighamella echinulata 9980 was developed. The optimum conditions for enzymatic catalysis were at pH 6.5 with 50 mmol/L N-Acyl-DLtheanine and 40 mmol/L CoCl2. After 12-h incubation at 50℃,22.5 mmol/L L-theanine was obtained, the conversion rate against N-Acyl-L-theanine being 90%. Cunnighamella echinulata and the aminoacylase were applied in preparation of L-theanine.
ABSTRACT
L-theanine (γ-glutamylethylamide) is the main free amino acid component of tea and its favorable physiological effects on mammals have been reported. An enzymatic method for optically pure L-theanine production with a new L-aminoacylases-production fungi Cunnighamella echinulata 9980 was developed. The optimum conditions for enzymatic catalysis were at pH 6.5 with 50 mmol/L N-Acyl-DLtheanine and 40 mmol/L CoCl2. After 12-h incubation at 50℃,22.5 mmol/L L-theanine was obtained, the conversion rate against N-Acyl-L-theanine being 90%. Cunnighamella echinulata and the aminoacylase were applied in preparation of L-theanine.
ABSTRACT
L-theanine (γ-glutamylethylamide) is the main free amino acid component of tea and its favorable physiological effects on mammals have been reported. An enzymatic method for optically pure L-theanine production with a new L-aminoacylases-production fungi Cunnighamella echinulata 9980 was developed. The optimum conditions for enzymatic catalysis were at pH 6.5 with 50 mmol/L N-Acyl-DLtheanine and 40 mmol/L CoCl2. After 12-h incubation at 50℃,22.5 mmol/L L-theanine was obtained, the conversion rate against N-Acyl-L-theanine being 90%. Cunnighamella echinulata and the aminoacylase were applied in preparation of L-theanine.
ABSTRACT
BACKGROUND: L-theanine is one of the most popular amino acids in green tea and has been known to produce mental relaxation, lower blood pressure and improve learning ability in human beings. But, few studies on these effects for human beings have been conducted so far. This study was conducted to evaluate the effect of L-theanine containing functional beverage on mental relaxation and fatigue perception. METHODS: Twenty healthy volunteers aged 30 to 55 years those who has had persistent fatigue for more than 1 month without any specific disease were recruited through written advertisement. All the subjects gave their informed consent, and the study was approved by Institutional Review Board of St. Mary's Hospital. This study was performed in a randomized placebo controlled double blind cross over fashion. Pathologic fatigue due to disease state was screened through medical history, physical examination, laboratory tests and questionnaires. alpha to beta power value of EEG as a surrogate marker of mental relaxation was measured in frontal and occipital regions for an hour after administration of placebo or test (200 mg L-theanine) solutions and crossed over at 7-day intervals. We analyzed average alpha to beta power value of EEG in frontal and occipital regions at 10 minute intervals for each 5 minutes. The baseline and 7-day follow-up scores of fatigue severity scale (FSS) were also evaluated. RESULTS: Repeated ANOVA revealed that there were significant differences of frontal alpha to beta power value between placebo and test in high anxiety group (P0.05). Fatigue score was significantly decreased in test (P0.05) after 7-day administration of placebo or test solutions. The mean differences from baseline in placebo and test were 0.42, and 0.80, respectively. CONCLUSIONS:The results of this study suggest that L-theanine containing functional beverage should promote alpha to beta power value in relation to mental relaxation, and also have the effect of reducing the fatigue perception.