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Mika Takeshima, Ikuko Miyazaki, Shinki Murakami, Taizo Kita, Masato Asanuma
l-Theanine (γ-glutamylethylamide), a component of green tea, is considered to have regulatory and neuroprotective roles in the brain. The present study was designed to determine the effect of l-theanine on excess dopamine-induced neurotoxicity in both cell culture and animal experiments. The primary cultured mesencephalic neurons or co-cultures of mesencephalic neurons and striatal astrocytes were pretreated with l-theanine for 72 h, and then treated with excess dopamine for further 24 h. The cell viability of dopamine neurons and levels of glutathione were evaluated...
September 2016: Journal of Clinical Biochemistry and Nutrition
Huajun Zheng, Dejiang Ni, Zhi Yu, Pei Liang
A kind of graphene oxide/silver (GO/Ag) nanocomposites with high Surface enhanced Raman scattering (SERS) activity were fabricated via a facile and green liquid phase reduction method. The synthesized materials were characterized in detail using various microscopic and spectroscopic techniques. In this method, the GO sheets worked as a holder which makes silver nanoparticles (AgNPs) aggregate to a particular morphology, and under a suitable dosage of silver ions, well-dispersed AgNPs on the surface of GO were obtained, which could generate more "hot spots" of SERS...
February 15, 2017: Food Chemistry
Peiling Ben, Zhengping Zhang, Yanyan Zhu, Aiying Xiong, Yanhong Gao, Jianyun Mu, Zhimin Yin, Lan Luo
Cadmium (Cd) has long been known to induce neurological degenerative disorders. We studied effects of l-theanine, one of the major amino acid components in green tea, on Cd-induced brain injury in mice. Male ICR mice were intraperitoneally injected with l-theanine (100 or 200mg/kg/day) or saline and after one hour these mice were orally administrated with CdCl2 (3.75-6mg/kg). The treatment was conducted for 8 weeks. l-Theanine significantly reduced Cd level in the mouse brain and plasma. Cd-induced neuronal cell death in the mouse cortex and hippocampus were apparently inhibited by l-theanine treatment...
September 17, 2016: Neurotoxicology
Rubia C G Corrêa, Rosane M Peralta, Charles W I Haminiuk, Giselle Maria Maciel, Adelar Bracht, Isabel C F R Ferreira
Aging is an inevitable process influenced by genetic, lifestyle and environmental factors. Indirect evidence shows that several phytochemicals can have anti-aging capabilities, although direct evidence in this field is still limited. This report aims to provide a critical review on aspects related to the use of novel phytochemicals as anti-aging agents, to discuss the obstacles found when performing most anti-aging study protocols in humans, and to analyze future perspectives. In addition to the extensively studied resveratrol, epicatechin, quercetin and curcumin, new phytochemicals have been reported to act as anti-aging agents, such as the amino acid L-theanine isolated from green tea, and the lignans arctigenin and matairesinol isolated from Arctium lappa seeds...
September 13, 2016: Critical Reviews in Food Science and Nutrition
Jiannan Liu, Yuping Sun, Huarong Zhang, Dexin Ji, Fei Wu, Huihui Tian, Kun Liu, Ying Zhang, Benhao Wu, Guoying Zhang
Cervical cancer is the third most prevalent cancer among women worldwide. Theanine from tea and its derivatives show some anticancer activities. However, the role of theanine and its derivatives against human cervical cancer and the molecular mechanisms of action remain unclear. Thus, in this study, we aim to investigate the anticancer activities and underlying mechanisms of theanine and a theanine derivative, ethyl 6-bromocoumarin-3- carboxylyl L-theanine (TBrC), against human cervical cancer. In vitro and in vivo assays for cancer cell growth and migration have confirmed the inhibition of the cell growth and migration by TBrC and theanine in highly-metastatic human cervical cancer...
September 6, 2016: European Journal of Pharmacology
Shinsuke Hidese, Miho Ota, Chisato Wakabayashi, Takamasa Noda, Hayato Ozawa, Tsutomu Okubo, Hiroshi Kunugi
OBJECTIVE: l-theanine, an amino acid uniquely contained in green tea (Camellia sinensis), has been suggested to have various psychotropic effects. This study aimed to examine whether l-theanine is effective for patients with major depressive disorder (MDD) in an open-label clinical trial. METHODS: Subjects were 20 patients with MDD (four males; mean age: 41.0±14.1 years, 16 females; 42.9±12.0 years). l-theanine (250 mg/day) was added to the current medication of each participant for 8 weeks...
July 11, 2016: Acta Neuropsychiatrica
Klára Boros, Nikoletta Jedlinszki, Dezső Csupor
BACKGROUND: Caffeine and L-theanine are pharmacologically important constituents of tea, especially due to their effects on the central nervous system. The effects of these two compounds are opposite: While caffeine is a well-known stimulant, theanine has a relaxing effect. Tea processing may influence the caffeine and theanine content of tea leaves. OBJECTIVE: The aim of our work was to quantify these constituents from a set of commercial products to reveal the possible correlations of caffeine and theanine content and processing methods...
January 2016: Pharmacognosy Magazine
Sumit Jamwal, Puneet Kumar
L-theanine is unique amino acid which readily crosses blood brain barrier and possesses neuroprotective potential against neurodegenerative disorders including Huntington disease (HD). HD is characterized by selective loss of GABAergic medium spiny neurons. 3-nitropropionic acid (3-NP) induces a spectrum of HD-like neuropathology in rat striatum and widely used as experimental tool to study HD. Therefore, the present study was intended to investigate the effect of L-theanine against 3-NP-induced striatal toxicity and to explore its possible mechanism...
March 9, 2016: Molecular Neurobiology
Chengjian Li, Haiou Tong, Qiongxian Yan, Shaoxun Tang, Xuefeng Han, Wenjun Xiao, Zhiliang Tan
BACKGROUND This study aimed to investigate the regulatory effects of L-theanine on secretion of immune cytokines, hormones, and neurotransmitters, and mRNA expression of phospholipase C (PLC) in rats, and to explore its regulatory mechanism in immune function. MATERIAL AND METHODS Sixty-four Sprague-Dawley rats received daily intragastric infusion of different doses of L-theanine solution [0, 50 (LT), 200 (MT), and 400 (HT) mg/kg BW]. Cytokines, immunoglobulins, and hormones in the serum, neurotransmitters, and mRNA expression of PLC in the relevant tissues were assayed...
2016: Medical Science Monitor: International Medical Journal of Experimental and Clinical Research
Tânia R Dias, Marco G Alves, Susana Casal, Branca M Silva, Pedro F Oliveira
Caffeine, epigallocatechin-3-gallate (EGCG) and L-theanine are the major components of tea (Camellia sinensis L.) and the main representatives of the classes of methylxanthines, catechins and free amino acids present in this beverage. There are many studies reporting tea's health benefits, however it is not clear if those effects are mediated by a single component or a synergistic action. This study aimed to evaluate the individual and synergistic effects of tea's major components on rat epididymal spermatozoa survival and oxidative profile during 3-day storage at room temperature (RT)...
March 2016: Food & Function
Chanaka N Kahathuduwa, Tharaka L Dassanayake, A M Tissa Amarakoon, Vajira S Weerasinghe
Objective l-theanine is a constituent of tea which is claimed to enhance cognitive functions. We aimed to determine whether theanine and theanine-caffeine combination have acute positive effects on cognitive and neurophysiological measures of attention, compared to caffeine (a positive control) and a placebo in healthy individuals. Design In a placebo-controlled, five-way crossover trial in 20 healthy male volunteers, we compared the effects of l-theanine (200 mg), caffeine (160 mg), their combination, black tea (one cup) and a placebo (distilled water) on cognitive (simple [SVRT] and recognition visual reaction time [RVRT]) and neurophysiological (event-related potentials [ERPs]) measures of attention...
February 11, 2016: Nutritional Neuroscience
Wen-Hsin Tsai, Chung-Hsin Wu, Hong-Jeng Yu, Chiang-Ting Chien
AIMS: Upregulation of substance P (SP) and neurokinin-1 receptor (NK1R) activation induces pro-inflammatory bladder hyperactivity through the PKC/ERK/NF-κB/ICAM-1/IL-33 signaling pathways to increase the leukocyte infiltration and adhesion leading to reactive oxygen species (ROS) production, autophagy, and apoptosis. l-Theanine is a unique non-protein-forming amino acid present in tea (Camellia sinensis [L.] O. Kuntze) with its antioxidant, anti-inflammatory, and relaxation effects to improve cognition, mood, gastric ulcer injury, and cerebral ischemia/reperfusion injury, and posttraumatic stress disorder...
February 1, 2016: Neurourology and Urodynamics
Thangarajan Sumathi, Deivasigamani Asha, Ganesan Nagarajan, Arivazhagan Sreenivas, Rajendran Nivedha
The present study is aimed at evaluating the protective role of L-theanine on aroclor 1254-induced oxidative stress in rat brain. Intraperitoneal administration of Aroclor 1254 (2 mg/kg b.wt. for 30 days) caused oxidative stress in rat brain and also caused neurobehavioral changes. Oxidative stress was assessed by determining the levels of lipid peroxide (LPO), protein carbonyl content, and changes in activities of creatine kinase (CK), acetylcholinesterase (AchE), and ATPases in the hippocampus, cerebellum and cerebral cortex of control and experimental rats...
March 2016: Environmental Toxicology and Pharmacology
David J White, Suzanne de Klerk, William Woods, Shakuntla Gondalia, Chris Noonan, Andrew B Scholey
L-theanine (γ-glutamylethylamide) is an amino acid found primarily in the green tea plant. This study explored the effects of an L-theanine-based nutrient drink on mood responses to a cognitive stressor. Additional measures included an assessment of cognitive performance and resting state alpha oscillatory activity using magnetoencephalography (MEG). Thirty-four healthy adults aged 18-40 participated in this double-blind, placebo-controlled, balanced crossover study. The primary outcome measure, subjective stress response to a multitasking cognitive stressor, was significantly reduced one hour after administration of the L-theanine drink when compared to placebo...
January 2016: Nutrients
Jianchang Jin, Hao Ying, Meirong Huang, Qizhen Du
The Chinese commonly believe that tea helps maintain clear vision. This viewpoint has been recorded in Chinese medical books also. The key bioactive compounds in green tea leaves, (-)-epigallocatechin gallate (EGCG), L-theanine (theanine) and caffeine, were investigated for their abilities to attenuate the injury of retinal ganglion cells (RGC-5) induced by H2O2 and ultraviolet radiation. Theanine and caffeine promoted cell growth while concentrations of EGCG greater than 10μg/ml inhibited cell growth. The nine and caffeine both protected RGC-5 cells from injury as well as enhanced their recovery, while EGCG only protected the cells from injury and did not help them to recover...
November 2015: Pakistan Journal of Pharmaceutical Sciences
Adasa Kardashev, Yael Ratner, Michael S Ritsner
AIMS: Pregnenolone (PREG) and L-Theanine (LT) have shown ameliorative effects on various schizophrenia symptoms. This is the first study to evaluate the efficacy and safety of augmentation of antipsychotic treatment among patients with chronic schizophrenia or schizoaffective disorder with PREG - LT. METHODS: Double-blind, placebo-controlled trial of PREG - LT or placebo augmentation was conducted for 8 weeks with 40 chronic DSM-IV schizophrenia and schizoaffective disorder patients with suboptimal response to antipsychotics...
July 28, 2015: Clinical Schizophrenia & related Psychoses
Duygu Türközü, Nevin Şanlier
Tea has been a very popular beverage around the world for centuries. The reason that it is delicious, enabling hydration, showing warming and relaxing effect can be mentioned why it is consumed so much in addition to its prominent health effects. Although the catechins and caffeine are the primary bioactive components that are related with the health effects of the tea, the health effects of theanine amino acid, which is a non-proteinic amino acid special to tea, has become prominent in recent years. It has been known that the theanine amino acid in tea has positive effects especially on relaxing, cognitive performance, emotional status, sleep quality, cancer, cardiovascular diseases, obesity and common cold...
July 20, 2015: Critical Reviews in Food Science and Nutrition
Peiling Ben, Zhengping Zhang, Chunxia Xuan, Shasha Sun, Lei Shen, Yanhong Gao, Xiang Cao, Yi Zhou, Lei Lan, Zhimin Yin, Lan Luo
L-Theanine is an amino acid derivative from green tea. The present work was aimed at the effect of L-theanine on neuron-like rat pheochromocytoma (PC12) cells stimulated with cadmium chloride. Treatment with L-theanine before cadmium exposure increased cell viability; the experiments of Annexin V/PI staining indicated that L-theanine inhibited cadmium-induced cell apoptosis. Meanwhile, L-theanine decreased ROS production and protected from cadmium-induced disruption of mitochondrial transmembrane potential...
August 2015: Neurochemical Research
Alemu Tadesse, Ariaya Hymete, Adnan A Bekhit, Salahuddin Farooq Mohammed
OBJECTIVE: In this study four tea samples Gumero black, Wushwush black and Wushwush green from Agri- Ceft Plc and East Africa black tea leaves from East African Agribusiness Plc were investigated for total polyphenols, caffeine, catechin and L-theanine content. MATERIALS AND METHODS: The aqueous extracts were investigated for their antioxidant and antileishmanial property and effect on amphotericin B, miltefocine and sodium stibogluconate, the commonly used antileishmanial drugs...
June 2015: Pharmacognosy Research
Hiroshi Ashihara
Theanine (γ-glutamyl-L-ethylamide) is the most abundant non-protein amino acid in tea leaves. In addition to Camellia sinensis, theanine occurs in several plants belonging to the Ericales. Biosynthesis of theanine from glutamic acid and ethylamine by theanine synthetase is present in all organs of tea seedlings, but roots are the major site of theanine biosynthesis in adult tea trees. Theanine is transported from roots to young leaves via the xylem sap. Theanine is hydrolysed to glutamic acid and ethylamine in leaves...
May 2015: Natural Product Communications
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