Article

Effects of theanine on the release of brain alpha wave in adult males

Authors:
To read the full-text of this research, you can request a copy directly from the authors.

No full-text available

Request Full-text Paper PDF

To read the full-text of this research,
you can request a copy directly from the authors.

... In humans, L-theanine has been shown to facilitate the generation of alpha waves in the brain that are indicative of a relaxed, awake and alert state, without promoting drowsiness [2,[7][8][9]. L-theanine would also help regulate the physiological parameters usually increased during stressful events (e.g. blood pressure, heart rate, cortisol secretion), which further contributes to the stress-reducing effects [9][10][11][12]. ...
... The main reasons for inclusion were stress-related behavioural signs (hypervigilance, nervousness, fear) in 79% of the cases and inappropriate elimination (45% of the cases) while aggressiveness (24% of the cases) and stress-induced functional/organic signs (mainly changes in feeding or drinking behaviour; 21% of the cases) occurred less often ( Table 1). The median (range) age of onset of undesirable behaviours/signs was 1 (0. [2][3][4][5][6][7][8][9][10][11][12] year with 67% and 15% of the cats starting to show issues before the age of 1 and from adoption, respectively. In 42% of the cats, such behaviours had been stable since their onset, but had worsened over time in another 58% of the cats. ...
... Shivering was the parameter most reduced in frequency since it was detected in 11/ 33 cats (33%) at the beginning of the trial and in only 3/ 33 cats (9%) by the end of the study. The median (IQR) global score significantly decreased from D0: 18 (13-23) to D15: 11 (8)(9)(10)(11)(12)(13) and D30: 5 (3-12); p < 0.0001 (Friedman test); Fig. 1. Improvement between D15 and D30 was also statistically significant; (p < 0.05); Fig. 1.The median (IQR) relative reduction of the global score from D0 to D30 was 62% (39-75%). ...
Article
Full-text available
Background L-theanine is an aminoacid found in tea leaves which has relaxing effects in humans and animals. It is a structural analogue of glutamate which can bind glutamate receptors. Although the relaxing action of L-theanine has been shown in humans, laboratory animals and dogs, it has never been published in cats. The goal of this open-label, multicentre and prospective trial was to determine whether an L-theanine based oral supplement (Anxitane®, Virbac, France) could attenuate manifestations of stress in cats under field conditions. Case presentation Thirty-three privately owned cats presenting signs associated with stress or fear (inappropriate urination/defecation, fear-induced aggressiveness, hypervigilance/tenseness or physical/functional manifestations of stress) for at least 1 month, were included in the study. They were given L-theanine (Anxitane®, 25 mg twice a day) for 30 days and 20 stress-related parameters were scored at Days 0, 15 and 30. The evolution of some parameters was also rated relative to Day 0. All median scores of the 20 parameters were significantly reduced at D30, and 30/33 cats (91%) had a reduced global score at the end of the study, including 21/33 with ≥50% score reduction. The median (IQR) global scores went from 18 (13–23) at D0 to 11 (8–13) at D15 and 5 (3–12) at D30 (p < 0.0001; Friedman test; significant reduction starting from D15). All the stress-related signs were significantly improved compared to D0, according to the owners, especially inappropriate elimination. Tablet palatability was judged good or very good in 94% of cases with spontaneous intake by cats when given by hand or in food. Tolerance was satisfactory as well, and no side effects were reported, so that most owners (27/33; 82%) were satisfied with the product. Conclusions Despite the lack of a placebo group, it can be concluded that L-theanine (Anxitane®) helped to improve the undesirable manifestations of stress in cats in as soon as 15 days, though better results could be seen after 30 days of administration. These encouraging results show that L-theanine can help manage stress-related behaviour, but additional trials with a placebo group should be run to confirm this effect.
... However, recently it has been stated that, like caffeine and catechin, L-theanine amino acid is responsible of an important part of health effects of tea as well (da Silva Pinto, 2013). The studies conducted in that direction state that L-theanine amino acid is related with the physiologic and illness situations shown in Fig. 1 (Yokozawa et al., 1995;Song et al., 2003;Kelly et al., 2008;Yamada et al., 2008;Liu et al., 2009;Lyon et al., 2011;Matsumoto et al., 2011). ...
... It is stated that, 40 minutes after orally taking L-theanine (50-200 mg) a waves occur on the occipital and parietal areas of the brain and that causes relaxation without causing a state of sleep (Kobayashi et al., 1998). Song et al. (2003) found out that 200 mg L-theanine increased the alpha (a) activity in the frontal and occipital areas 40 minutes after it was taken by individuals with high anxiety levels (Song et al., 2003). However, the measurements made by Gomez-Ramirez et al. (2007) for the performances require high level of attention, it was reported that 250 mg L-theanine caused decreases in alpha (a) activity of the brain. ...
... It is stated that, 40 minutes after orally taking L-theanine (50-200 mg) a waves occur on the occipital and parietal areas of the brain and that causes relaxation without causing a state of sleep (Kobayashi et al., 1998). Song et al. (2003) found out that 200 mg L-theanine increased the alpha (a) activity in the frontal and occipital areas 40 minutes after it was taken by individuals with high anxiety levels (Song et al., 2003). However, the measurements made by Gomez-Ramirez et al. (2007) for the performances require high level of attention, it was reported that 250 mg L-theanine caused decreases in alpha (a) activity of the brain. ...
Article
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. The results of acute and chronic toxicity tests conducted on the safety of theanine express that L-theanine is reliable in general even if it is consumed too much with diet. However, it is not revealed a clear evidence based result yet regarding theanine metabolism, health effects and its safety. Within this frame, chemical structure of theanine, its bio-synthesis, dietary sources, metabolism, health effects, and safety are discussed in present study.
... This study failed to observe a concomitant change in subjective anxiety associated with this effect on alpha oscillatory activity. Significantly increased alpha activity has also been described 45-105 min after up to 50 mg of L-theanine, consumed as part of a tea infusion, in a parallel group design compared to placebo in healthy participants [29], as well as in high anxiety participants one hour after administration [30]. These findings are typically interpreted in line with the proposed relaxant properties of L-theanine when recordings are taken at rest; however, while research has linked lower resting state alpha activity with states of autonomic arousal associated with caffeine [31,32], no study to date has explored the association between these changes in resting state alpha activity and potential anti-stress benefits of L-theanine administration. ...
... The outcomes of resting state MEG recordings demonstrated increased alpha oscillatory activity across posterior brain regions after treatment with the L-theanine-based nutrient drink. Consistent with previous research [24,28,30], this effect was apparent only for those higher in trait anxiety. Trait anxiety scores in the high anxiety group ranged from 60th-90th percentile ranks based on Australian adult population norms [67]; as such, this higher anxiety group represents moderate to high levels of trait anxiety. ...
Article
Full-text available
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. The salivary cortisol response to the stressor was reduced three hours post-dose following active treatment. No treatment-related cognitive performance changes were observed. Resting state alpha oscillatory activity was significantly greater in posterior MEG sensors after active treatment compared to placebo two hours post-dose; however, this effect was only apparent for those higher in trait anxiety. This change in resting state alpha oscillatory activity was not correlated with the change in subjective stress response or the cortisol response, suggesting further research is required to assess the functional relevance of these treatment-related changes in resting alpha activity. These findings further support the anti-stress effects of L-theanine.
... Ltheanine enhanced the power in the alpha-1 frequency band, replicating previous reports. 7,10 In the current experiment, the power in the alpha band increased linearly with time and this linear increase was significantly enhanced by L-theanine. This increase in alpha-band activity supports a role for L-theanine in achieving a relaxed but alert mental state via a direct influence on the central nervous system. ...
Article
Tea is the most widely consumed beverage in the world after water. Tea is known to be a rich source of flavonoid antioxidants. However tea also contains a unique amino acid, L-theanine that may modulate aspects of brain function in humans. Evidence from human electroencephalograph (EEG) studies show that it has a direct effect on the brain (Juneja et al. Trends in Food Science & Tech 1999;10;199-204). L-theanine significantly increases activity in the alpha frequency band which indicates that it relaxes the mind without inducing drowsiness. However, this effect has only been established at higher doses than that typically found in a cup of black tea (approximately 20mg). The aim of the current research was to establish this effect at more realistic dietary levels. EEG was measured in healthy, young participants at baseline and 45, 60, 75, 90 and 105 minutes after ingestion of 50mg L-theanine (n=16) or placebo (n=19). Participants were resting with their eyes closed during EEG recording. There was a greater increase in alpha activity across time in the L-theanine condition (relative to placebo (p+0.05). A second study replicated this effect in participants engaged in passive activity. These data indicate that L-theanine, at realistic dietary levels, has a significant effect on the general state of mental alertness or arousal. Furthermore, alpha activity is known to play an important role in critical aspects of attention, and further research is therefore focussed on understanding the effect of L-theanine on attentional processes.
... 567 It has been shown in the rat that theanine inhibits the 568 effects of caffeine and other methylxanthine stimulants 569 found in tea, as measured by EEG (Kakuda et al., 570 2000a). Theanine also influences brain activity in humans 571 by stimulating the production of alpha waves, which indi-572 cates a relaxed state (Song et al., 2003). In human volun-573 teers, alpha waves were generated within 15 min after 574 oral administration of 200 mg of theanine. ...
Article
Full-text available
This study was conducted to evaluate the safety of l-theanine (Suntheanine) when administered as a dietary admixture to male and female Crl:CD (SD)GS BR rats at concentrations providing doses of 0, 1500, 3000 or 4000 mg/kg bw/day for 13 weeks. The study design was consistent with OECD Guideline 408 and USFDA Redbook II (1993) and GLP. There were no consistent, statistically significant treatment-related adverse effects on behavior, morbidity, mortality, body weight, food consumption and efficiency, clinical chemistry, hematology, or urinalysis. There were no consistent treatment-related adverse effects in gross pathology, organ weights or ratios or histopathology. The increased incidence of renal tubular cell adenomas in high-dose females only were not consistent with the characteristics of a renal carcinogen (due to early onset and low number of animals affected) but were more consistent with a genetic predisposition than with direct organ toxicity. The no-observed-adverse-effect-level (NOAEL) was 4000 mg/kg bw/day, the highest dose tested.
... Theanine has been found to affect neurotransmitters serotonin and gamma-aminobutyric acid (GABA), and may modulate and ''tone down'' central nervous system (CNS) responses and regulate anxiety (Kimura & Murata, 1986a,b;Nathan, Lu, Gray, & Oliver, 2006). Furthermore, theanine has been found to increase alpha brain wave activity during rest, which is indicative of a state of wakeful relaxation, especially among those reporting higher levels of anxiety (Ito et al., 1998;Nobre, Rao, & Owen, 2008;Song, Jung, Oh, & Kim, 2003). Reduced subjective ratings of anxiety and other 0195-6663/$ -see front matter Ó 2011 Elsevier Ltd. ...
Article
The aim of this research was to examine relationships between tea, coffee and other beverage consumption and associates of work performance and mood among individuals in relatively stressful and cognitively demanding work-place settings. Using a naturalistic, cross-sectional study design, 95 professional and academic staff logged their beverage intake and completed self-reports of associates of work performance (fatigue/exhaustion, mindfulness, work engagement), subjective work performance, mood, work-related strain and recovery four times daily during ten working days. Data were analysed using multilevel modelling in keeping with the hierarchical structure of the data. Tea consumption was associated with increased perceived work performance and reduced tiredness, especially when consumed without milk or sugar. Consumption of non-caffeinated beverages was associated with increased relaxation and recovery from work. In contrast, tea and other caffeinated beverages were found to enhance the negative effects of evening recovery and morning mood on mindfulness during the day. The findings suggest that beverage intake may have a role in optimising work-related psychological states and performance.
... Both electroencephalographic [EEG] and behavioural studies indicate that L-theanine influences brain functioning. During rest, L-theanine increases a activity in the EEG (Palva and Palva, 2007), indicating greater relaxation as measured in different periods between 40 and 105 min following consumption in three studies (Kobayashi et al., 1998; Nobre et al., 2008; Song et al., 2003). During performance of a task that requires attention, L-theanine induced changes in a activity that indicated increased attentional processing measured 0–75 min (Gomez-Ramirez et al., 2007) and 30– 100 min after consumption of L-theanine (Gomez-Ramirez et al., 2008). ...
Article
After consumption of tea, L-theanine enters systemic circulation and is assumed to enter the brain. Several human studies indicate that L-theanine influences brain functioning. Knowledge about the pharmacokinetics of L-theanine facilitates further study of this health effect. Volunteers received 25–100 mg of L-theanine as tea, as L-theanine-enriched tea, and as biosynthetic L-theanine in aqueous solutions. Plasma was analysed for L-thea-nine content after which data were fitted with a 1-compartment model. For all interven-tions, the lag time was approximately 10 min and half-lives of absorption and elimination were approximately 15 and 65 min respectively. After approximately 50 min, maximum plasma concentrations of between 1.0 and 4.4 mg/L were achieved. Maximum plasma concentration and area under the plasma-concentration–time curve were dose-proportional. This knowledge allows prediction of plasma concentrations for various dose regimens supporting further study of a health benefit of L-theanine.
... 1996). Theanine has recently received much attention due to its health benefits such as promoting relaxation, reducing stress and anxiety, improving memory and learning ability, as well as suppressing high blood pressure (Yokogoshi et al., 1995;Juneja et al., 1999;Kakuda, 2002;Kim et al., 2004;Zhang et al., 2007). Owing to its special quality and healthy potential, good tea products prepared from the albino tea cultivars are in great demand. ...
Article
Full-text available
White young shoots from albino tea cultivars have high level of amino acids and are rare and valuable materials for processing green tea. The effects of temperature on leaf colour, accumulation of chlorophylls and leaf ultrastructures of an albino tea cultivar 'Xiaxueya' were investigated. The study showed that the shoot albino phenomenon of 'Xiaoxueya' was controlled by temperature. The development of chloroplast from etioplast and the accumulation of chlorophylls a and b were blocked and albino shoots were observed at 15˚C. However, the albino phenomenon was reversed when the plant was grown at 20˚C or above. The authors recommended that the albino tea cultivars should be grown at high altitude or high latitude areas so as to prolong the production season of albino tea shoots.
... L-Theanine is a unique non-proteinic amino acid that has been reported with predominant therapeutic values. It has been shown to regulate oscillatory brain activities in humans with an ability to pass through the blood-brain barrier during cognitive task execution and electroencephalographic (EEG) transcriptions and is believed to cause a relaxation effect (Song, Jung, & Oh, 2003;Yokogoshi, Kobayashi, Mochizuki, & Terashima, 1998). Kobayashi et al. (1998) reported that activity within the brain's neurotransmission rhythm of alpha frequency band (8)(9)(10)(11)(12)(13)(14) increased in reaction to 200 mg L-theanine ingestion when measured during a state of rest. ...
Article
Previous human studies revealed that l-theanine influences brain function. The current study was designed to evaluate the affect of l-theanine (Suntheanine®) on attention and reaction time response in 18 normal healthy University student volunteers. In accordance with preliminary analysis of the manifest anxiety scale (MAS), the subjects were divided into two groups referred to as high anxiety propensity group and the minimal anxiety propensity group. Both groups received l-theanine (200mg/100ml water) and placebo (100ml water) in a double blind repeated measurement design protocol. Assessments were performed for 15–60min after consumption under a relaxed condition upon exerting an experimentally induced visual attentional task as well as audio response tests. Self-reports of anxiety as State-Trait Anxiety Inventory (STAI) was characterized at post experiments. Alpha bands electroencephalographic activity and heart rate were recorded throughout the trial. The results demonstrate the significant enhanced activity of alpha bands, descending heart rate, elevated visual attentional performance, and improved reaction time response among high anxiety propensity subjects compared to a placebo. However, no significant differences were noticed among subjects with a minimal anxiety propensity. Results evidently demonstrated that l-theanine clearly has a pronounced effect on attention performance and reaction time response in normal healthy subjects prone to have high anxiety.
... Amino acids are important in the sensory quality of green tea [32]. Theanine, which was first discovered in tea leaves, is the most abundant free amino acid in tea plants and is beneficial for human health [33][34][35][36][37]. The theanine and total free amino acids contents in the shoots (two leaves and one bud) of LJ43 and ZH2 were analyzed. ...
Article
Full-text available
Background: The tea plant (Camellia sinensis (L.) O. Kuntze) is one of the most economically important woody crops. Recently, many leaf color genotypes have been developed during tea plant breeding and have become valuable materials in the processing of green tea. Although the physiological characteristics of some leaf color mutants of tea plants have been partially revealed, little is known about the molecular mechanisms leading to the chlorina phenotype in tea plants. Results: The yellow-leaf tea cultivar Zhonghuang 2 (ZH2) was selected during tea plant breeding. In comparison with Longjing 43 (LJ43), a widely planted green tea cultivar, ZH2 exhibited the chlorina phenotype and displayed significantly decreased chlorophyll contents. Transmission electron microscopy analysis revealed that the ultrastructure of the chloroplasts was disrupted, and the grana were poorly stacked in ZH2. Moreover, the contents of theanine and free amino acids were significantly higher, whereas the contents of carotenoids, catechins and anthocyanin were lower in ZH2 than in LJ43. Microarray analysis showed that the expression of 259 genes related to amino acid metabolism, photosynthesis and pigment metabolism was significantly altered in ZH2 shoots compared with those of LJ43 plants. Pathway analysis of 4,902 differentially expressed genes identified 24 pathways as being significantly regulated, including 'cysteine and methionine metabolism', 'glycine, serine and threonine metabolism', 'flavonoid biosynthesis', 'porphyrin and chlorophyll metabolism' and 'carotenoid biosynthesis'. Furthermore, a number of differentially expressed genes could be mapped to the 'theanine biosynthesis', 'chlorophyll biosynthesis' and 'flavonoid biosynthesis' pathways. Changes in the expression of genes involved in these pathways might be responsible for the different phenotype of ZH2. Conclusion: A novel chlorophyll-deficient chlorina tea plant cultivar was identified. Biochemical characteristics were analyzed and gene expression profiling was performed using a custom oligonucleotide-based microarray. This study provides further insights into the molecular mechanisms underlying the phenotype of the chlorina cultivar of Camellia sinensis.
... A convincing body of evidence supports that this substance has several pharmacological functions, including reducing blood pressure in spontaneously hypertensive rats [38] and antagonizing caffeine-induced convulsions [39][40][41] and sleep disturbances [42]. Moreover, this compound has been shown to decrease physical stress in men [43,44] and to suppress anxiety and stress during the premenstrual period in women [45] and anxiety levels in both men and women [46][47][48][49]. The structural similarity of L-theanine to glutamic acid, a neurotransmitter in the brain, has also prompted researchers to investigate its competitive action on the nervous system as a glutaminergic antagonist [50]. ...
Article
Sleep deprivation is associated with an elevated risk of various diseases and leads to a poor quality of life and negative socioeconomic consequences. Sleep inducers such as drugs and herbal medicines may often lead to dependence and other side effects. l-Theanine (γ-glutamylethylamide), an amino acid naturally found abundant in tea leaves, has anxiolytic effects via the induction of α brain waves without additive and other side effects associated with conventional sleep inducers. Anxiolysis is required for the initiation of high-quality sleep. In this study, we review the mechanism(s), safety, and efficacy of l-theanine. Collectively, sleep studies based on an actigraph, the obstructive sleep apnea (OSA) sleep inventory questionnaire, wakeup after sleep onset (WASO) and automatic nervous system (ANS) assessment, sympathetic and parasympathetic nerve activities, and a pediatric sleep questionnaire (PSQ) suggest that the administration of 200 mg of l-theanine before bed may support improved sleep quality not by sedation but through anxiolysis. Because l-theanine does not induce daytime drowsiness, it may be useful at any time of the day. The no observable adverse effect level (NOAEL) for the oral administration of l-theanine was determined to be above 2000 mg/kg bw/day. Key teaching points: Sleep deprivation-associated morbidity is an increasing public health concern posing a substantial socioeconomic burden. Chronic sleep disorders may seriously affect quality of life and may be etiological factors in a number of chronic diseases such as depression, obesity, diabetes, and cardiovascular diseases. Most sleep inducers are sedatives and are often associated with addiction and other side effects. l-Theanine promotes relaxation without drowsiness. Unlike conventional sleep inducers, l-theanine is not a sedative but promotes good quality of sleep through anxiolysis. This review suggests that l-theanine is a safe natural sleep aid.
... Die Aktivität der Gehirnwellen gibt Aufschluss über das Bewusstsein eines Menschen: Alpha-Wellen werden vermehrt in entspannenden Situationen (Schlaf-Wach Übergang) ausgeschüttet, Beta-Wellen (13 -über 100 Hz) im wachen und gespannten Zustand, Theta-Wellen (4 -7 Hz) entstehen überlicherweise im Schlaf und Deltawellen (1 -3 Hz) treten hauptsächlich im Tiefschlaf auf. Sowohl die regenerativen, als auch die anregenden Eigenschaften von Theanin können durch die die Modulierung des Stresslevels erklärt werden.127,128 Kaum verwunderlich also, dass Theanin entspannend wirkt.• ...
Article
Full-text available
Die hier vorgestellten Produkte mit Schwerpunkt Nachhaltigkeit und Evidenz-basierten Inhaltsstoffen (Energy-Drink & Protein-Riegel) erhalten im Verbrauchermarkt aufsteigendes Interesse. Dies liegt unter anderem daran, dass Nahrungsmittel mit gesundheits- und leistungsfördernden Eigenschaften benötigt werden, um der steigenden Anzahl an Krankheiten präventiv entgegenzuwirken. Besonders wichtig ist die adäquate Zufuhr von Proteinen und sekundären Pflanzenstoffe, um langfristig gesund zu bleiben. Im Gegensatz zu anderen bereits bestehenden Unternehmen liegt der Fokus dieses Konzepts auf der wissenschaftlichen Bestätigung zur Wirksamkeit der einzelnen Inhaltsstoffe. Damit soll dem Käufer ein optimales Preis-Leistungsverhältnis, auch in Bezug auf den Geschmack, geboten werden. Zusätzlich steht der Ressourcen-schonende Umgang mit Rohstoffen und Verpackungsmaterialien im Vordergrund, sodass zukunftsfähiges Handeln ermöglicht wird. Gerade in einer Zeit von hohen menschengemachten Umweltbelastungen, wie beispielsweise durch Plastikaufkommen in den Meeren, ist eine moralische Firmenpolitik notwendiger denn je.
... It has been reported that after administration to rats, EGCG "significantly reduced food intake, body weight, blood levels of testosterone, estradiol, leptin, insulin, insulin-like growth factor I, glucose, cholesterol and triglyceride" (Kao et al, 2000). L-Theanine, a neurologically active non protein amino acid, originally derived from the leaves of the tea plant quells anxiety and stress without negative side effects (Juneja et al, 1999) and promotes a sense of relaxation and well being without causing drowsiness (Kobayashi, 1998;Song, 2003). ...
Article
Full-text available
Effect of chronic treatment of standardized hot water extract of Camellia sinensis (BTE) for 14 days on stress and hypertensive models of rat, behavioural (learning and memory) testing (Shuttle box avoidance test), brain EEG activity and serum neurotransmitter (NE, 5-HT, DA) was studied in male Charles Foster strain rats. The result revealed that oral pretreatment with BTE (5ml/kg) markedly increase in the performance of active avoidance learning in the Shuttle box avoidance test. Electroencephalographic recording showed that BTE pretreatment to experimental animals elicited significant decrease in β-waves and increase in α-waves. It also resulted in the elevation of serum serotonin (5-HT) level and significant decrease in norepinephrine (NE) level. The present study suggests that chronic administration of BTE helps in combating stress and hypertension possibly by altering serum monoamine level.
... As it is a natural analog of glutamate and glutamine, it has been shown to have a strong affinity for the glutamine transporter inhibiting glutamine uptake, thereby inhibiting excitatory neurotransmission release [102]. Electroencephalography data following intake of 50-250 mg of L-THE shows an increase in alpha waves in the brain, which indicates a state of relaxation [103,104]. Additionally, L-THE has been shown to be effective in reducing blood pressure increases following a mental task or from the effects of caffeine consumption [105,106]. ...
Article
Full-text available
Functional beverages can be a valuable component of the human diet with the ability to not only provide essential hydration but to deliver important bioactive compounds that can contribute to chronic disease treatment and prevention. One area of the functional beverage market that has seen an increase in demand in recent years are beverages that promote relaxation and sleep. Sleep is an essential biological process, with optimal sleep being defined as one of adequate duration, quality and timing. It is regulated by a number of neurotransmitters which are, in turn, regulated by dietary intake of essential bioactive compounds. This narrative review aimed to evaluate the latest evidence of the sleep promoting properties of a selection of bioactive compounds (such as L-theanine and L-tryptophan) for the development of a functional beverage to improve sleep quality; and the effectiveness of traditional sleep promoting beverages (such as milk and chamomile). Overall, the bioactive compounds identified in this review, play essential roles in the synthesis and regulation of important neurotransmitters involved in the sleep-wake cycle. There is also significant potential for their inclusion in a number of functional beverages as the main ingredient on their own or in combination. Future studies should consider dosage; interactions with the beverage matrix, medications and other nutraceuticals; bioavailability during storage and following ingestion; as well as the sensory profile of the developed beverages, among others, when determining their effectiveness in a functional beverage to improve sleep quality.
... 1996). Theanine has recently received much attention due to its health benefits such as promoting relaxation, reducing stress and anxiety, improving memory and learning ability, as well as suppressing high blood pressure (Yokogoshi et al., 1995;Juneja et al., 1999;Kakuda, 2002;Kim et al., 2004;Zhang et al., 2007). Owing to its special quality and healthy potential, good tea products prepared from the albino tea cultivars are in great demand. ...
Article
White young shoots from albino tea cultivars have high level of amino acids and are rare and valuable materials for processing green tea. The effects of temperature on leaf colour, accumulation of chlorophylls and leaf ultrastructures of an albino tea cultivar ‘Xiaxueya’ were investigated. The study showed that the shoot albino phenomenon of ‘Xiaoxueya’ was controlled by temperature. The development of chloroplast from etioplast and the accumulation of chlorophylls a and b were blocked and albino shoots were observed at 15°C. However, the albino phenomenon was reversed when the plant was grown at 20°C or above. The authors recommended that the albino tea cultivars should be grown at high altitude or high latitude areas so as to prolong the production season of albino tea shoots.
... It has been shown in the rat that theanine inhibits the effects of caffeine and other methylxanthine stimulants found in tea, as measured by EEG (Kakuda et al., 2000a). Theanine also influences brain activity in humans by stimulating the production of alpha waves, which indicates a relaxed state (Song et al., 2003). In human volunteers, alpha waves were generated within 15 min after oral administration of 200 mg of theanine. ...
... Several studies directly support that in individuals at rest, L-theanine increases alpha-brain waves, which are associated with a relaxed but alert mental state (Song et al., 2003;Nobre, 2008). Activity in the alpha-band has been linked with general attention processes and recent research has shown that oscillations in the alpha band are a key component in selective attention (Klimesch, 1999). ...
Article
Tea is the most widely consumed beverage after water around the globe with consumer-base of both young and old, while energy drinks are popular primarily among young adults. Among the different varieties available black tea is the most commonly used and contains L-Theanine, theobromine, theophylline and the highest amount of caffeine. Energy drinks on the other hand contain taurine, herbs, B vitamins and stimulant drugs chiefly caffeine. The purpose of the study conducted was to evaluate the effect of regular tea and energy drinks on attention. A survey was conducted and subjects were given a task that was designed to test the above mentioned parameter and time taken to solve each part of the task was accurately noted. Results of the energy drink group and the tea group were compared to the control group. Gender based differences were also analyzed. Our results lead us to conclude that the most widely taken beverages enhance attention in both genders, with women outperforming men.
... Tea roots are rich in l-theanine, a unique non-protein amino acid synthesized in the roots, but accumulates in the leaves of tea plants. Recently l-theanine has been researched due to its beneficial effects on reducing anxiety, suppressing high blood pressure, improving learning ability, as well as promoting relaxation [4][5][6][7][8]. Tea leaves are rich in polyphenols, which exhibit anticancer, antiallergic, antiviral, anti-inflammatory, antibacterial and immunostimulant effects [9]. ...
Article
Full-text available
Background: Camellia sinensis var. sinensis is widely grown for tea beverages that possess signifcant health promoting efects. Studies on tea plant genetics and breeding are hindered due to its recalcitrance to Agrobacterium-mediated genetic transformation. Among the possible reasons, oxidation of phenolics released from explant tissues and bactericidal efects of tea polyphenols during the process of transformation play a role in the plant recalcitrance. The aim of the present study was to alleviate the harmful efects of phenolic compounds using in-planta transformation. Results: Two-month old seedlings of tea cultivar “Nong Kangzao” were infected at the hypocotyl with wild type Agrobacterium rhizogenes and maintained in an environment of high humidity. 88.3% of infected plants developed hairy roots at the wounded site after 2 months of infection. Our data indicated that transgenic hairy root induction of tea can be achieved using A. rhizogenes following the optimized protocol. Conclusion: With this method, composite tea plants containing wild-type shoots with transgenic roots can be generated for “in root” gene functional characterization and root-shoot interaction studies. Moreover, this method can be applied to improve the root system of composite tea plants for a better resistance to abiotic and biotic stresses.
... Tea roots are rich in l-theanine, a unique non-protein amino acid synthesized in the roots, but accumulates in the leaves of tea plants. Recently l-theanine has been researched due to its beneficial effects on reducing anxiety, suppressing high blood pressure, improving learning ability, as well as promoting relaxation [4][5][6][7][8]. Tea leaves are rich in polyphenols, which exhibit anticancer, antiallergic, antiviral, anti-inflammatory, antibacterial and immunostimulant effects [9]. ...
... Tea roots are rich in l-theanine, a unique non-protein amino acid synthesized in the roots, but accumulates in the leaves of tea plants. Recently l-theanine has been researched due to its beneficial effects on reducing anxiety, suppressing high blood pressure, improving learning ability, as well as promoting relaxation [4][5][6][7][8]. Tea leaves are rich in polyphenols, which exhibit anticancer, antiallergic, antiviral, anti-inflammatory, antibacterial and immunostimulant effects [9]. ...
Article
Full-text available
Background: Camellia sinensis var. sinensis is widely grown for tea beverages that possess significant health promoting effects. Studies on tea plant genetics and breeding are hindered due to its recalcitrance to Agrobacterium-mediated genetic transformation. Among the possible reasons, oxidation of phenolics released from explant tissues and bactericidal effects of tea polyphenols during the process of transformation play a role in the plant recalcitrance. The aim of the present study was to alleviate the harmful effects of phenolic compounds using in-planta transformation. Results: Two-month old seedlings of tea cultivar “Nong Kangzao” were infected at the hypocotyl with wild type Agrobacterium rhizogenes and maintained in an environment of high humidity. 88.3% of infected plants developed hairy roots at the wounded site after 2 months of infection. Our data indicated that transgenic hairy root induction of tea can be achieved using A. rhizogenes following the optimized protocol. Conclusion: With this method, composite tea plants containing wild-type shoots with transgenic roots can be generated for “in root” gene functional characterization and root-shoot interaction studies. Moreover, this method can be applied to improve the root system of composite tea plants for a better resistance to abiotic and biotic stresses.
... 13,14 Studies using L-theanine at typical serving doses of tea (20 mg) or higher doses have reported that tea consumption promotes relaxation by stimulating the alpha brainwave activity that is normally associated with a wakeful relaxation state. 15,16 However, two other studies measuring electroencephalogram (EEG) after L-theanine consumption demonstrated that L-theanine may increase attention and plays a positive role in learning and concentration, but not relaxation. 17,18 It has been demonstrated that green tea has a beneficial role in cognitive functions, specifically in alertness, attention, and memory retention. ...
Article
Background and objectives: Green tea is reported to have wide benefits on psychological states and cognitive functions. Studies that focus on the underlying neural mechanisms of green tea are limited to its single composition while people usually benefit from green tea water that contains various composition. In this study, we examined the human brain activity changes after drinking natural green tea by using regional homogeneity and functional connectivity based on the resting-state functional MRI technique. Methods and study design: Fifteen healthy volunteers participated in two imaging sessions: a control (water) session and a green tea session, each session comprised a predrinking, drinking, and postdrinking section, during the drinking section, the subject consumed 200 mL of green tea infusion or water in 3 to 5 minutes. Then the post-tea and post-water imaging data were selected for regional homogeneity and functional connectivity analysis. Results: Our results revealed that, compared with the control group, the green tea group exhibited an increased regional homogeneity in the frontal, parietal, and occipital areas of the brain, decreased regional homogeneity values in the left cuneus and left lingual gyrus, mainly a decreased functional connectivity in the default mode network, somatosensory, visual cortex, and parieto-frontal areas and enhanced functional connectivity in brain regions associated with memory. Conclusions: This result indicates that green tea consumption impacts the brain activity during resting state.
Article
Objectives: Tea has been associated with many mental benefits, such as attention enhancement, clarity of mind, and relaxation. These psychosomatic states can be measured in terms of brain activity using an electroencephalogram (EEG). Brain activity can be assessed either during a state of passive activity or when performing attention tasks and it can provide useful information about the brain's state. This study investigated the effects of green and black consumption on brain activity as measured by a simplified EEG, during passive activity. Methods: Eight healthy volunteers participated in the study. The EEG measurements were performed using a two channel EEG brain mapping instrument - HeadCoach™. Fast Fourier transform algorithm and EEGLAB toolbox using the Matlab software were used for data processing and analysis. Results: Alpha, theta, and beta wave activities were all found to increase after 1 hour of green and black tea consumption, albeit, with very considerable inter-individual variations. Discussion: Our findings provide further evidence for the putative beneficial effects of tea. The highly significant increase in theta waves (P < 0.004) between 30 minutes and 1 hour post-consumption of green tea may be an indication of its putative role in cognitive function, specifically alertness and attention. There were considerable inter-individual variations in response to the two teas which may be due genetic polymorphisms in metabolism and/or influence of variety/blend, dose and content of the selected products whose chemistry and therefore efficacy will have been influenced by 'from field to shelf practices'.
Article
Full-text available
Theanine (n-ethylglutamic acid), a non-proteinaceous amino acid component of green and black teas, has received growing attention in recent years due to its reported effects on the central nervous system. It readily crosses the blood-brain barrier where it exerts a variety of neurophysiological and pharmacological effects. Its most well-documented effect has been its apparent anxiolytic and calming effect due to its up-regulation of inhibitory neurotransmitters and possible modulation of serotonin and dopamine in selected areas. It has also recently been shown to increase levels of brain-derived neurotrophic factor. An increasing number of studies demonstrate a neuroprotective effects following cerebral infarct and injury, although the exact molecular mechanisms remain to be fully elucidated. Theanine also elicits improvements in cognitive function including learning and memory, in human and animal studies, possibly via a decrease in NMDA-dependent CA1 long-term potentiation (LTP) and increase in NMDA-independent CA1-LTP. Furthermore, theanine administration elicits selective changes in alpha brain wave activity with concomitant increases in selective attention during the execution of mental tasks. Emerging studies also demonstrate a promising role for theanine in augmentation therapy for schizophrenia, while animal models of depression report positive improvements following theanine administration. A handful of studies are beginning to examine a putative role in attention deficit hyperactivity disorder, and theoretical extrapolations to a therapeutic role for theanine in other psychiatric disorders such as anxiety disorders, panic disorder, obsessive compulsive disorder (OCD), and bipolar disorder are discussed.
Article
L‐theanine, originally found in green tea, elicits various physiological effects, such as promoting relaxation, improving concentration and learning ability, and providing antianxiety‐like and antidepressant‐like properties. This study aims to investigate the effects of L‐theanine (2 mg/kg) on monoamine levels in an animal model of depression. The effect of l‐theanine on the symptoms of depression was examined through the open‐field test, sucrose preference test, and forced swim test. The monoamine neurotransmitters that involve serotonin (5‐HT), norepinephrine (NE), and dopamine (DA) were measured in the limbic–cortical–striatal–pallidal–thalamic (LCSPT)‐circuit related brain regions, including the prefrontal cortex (PFC), nucleus accumbens (NAC), striatum (ST), amygdala, and hippocampus (HIP). L‐theanine ameliorated the depressive‐like behaviors in the chronic unpredictable mild stress (CUMS) rat model. In the PFC, NAC, and HIP, L‐theanine administration significantly increased the levels of 5‐HT, NE, and DA. In the ST, the levels of 5‐HT and DA were increased after the administration of L‐theanine. However, in the HIP, only the level of DA significantly changed after the treatment of L‐theanine. Taken together, these results indicated that L‐theanine has possibly antidepressant‐like effects in the CUMS rat model, which could be mediated by the monoamine neurotransmitters in the LCSPT‐circuit related brain regions.
Article
Full-text available
The non-proteinic amino acid L-theanine and caffeine, a methylxanthine derivative, are naturally occurring ingredients in tea. The present study investigated the effect of a combination of 97 mg L-theanine and 40 mg caffeine as compared to placebo treatment on cognitive performance, alertness, blood pressure, and heart rate in a sample of young adults (n = 44). Cognitive performance, self-reported mood, blood pressure, and heart rate were measured before L-theanine and caffeine administration (i.e. at baseline) and 20 min and 70 min thereafter. The combination of moderate levels of L-theanine and caffeine significantly improved accuracy during task switching and self-reported alertness (both P < 0.01) and reduced self-reported tiredness (P < 0.05). There were no significant effects on other cognitive tasks, such as visual search, choice reaction times, or mental rotation. The present results suggest that 97 mg of L-theanine in combination with 40 mg of caffeine helps to focus attention during a demanding cognitive task.
Article
The aim of this study was to compare 50 mg caffeine, with and without 100 mg L-theanine, on cognition and mood in healthy volunteers. The effects of these treatments on word recognition, rapid visual information processing, critical flicker fusion threshold, attention switching and mood were compared to placebo in 27 participants. Performance was measured at baseline and again 60 min and 90 min after each treatment (separated by a 7-day washout). Caffeine improved subjective alertness at 60 min and accuracy on the attention-switching task at 90 min. The L-theanine and caffeine combination improved both speed and accuracy of performance of the attention-switching task at 60 min, and reduced susceptibility to distracting information in the memory task at both 60 min and 90 min. These results replicate previous evidence which suggests that L-theanine and caffeine in combination are beneficial for improving performance on cognitively demanding tasks.
Chapter
Plant-derived drugs represent a significant proportion of the pharmaceutical market. Plant in vitro culture has emerged as a useful platform for producing secondary metabolites due to its multiple advantages: production under controlled culture conditions; independence from geographic, seasonal or weather conditions; and since it avoids the use of land and the extraction from the natural source, it has a low environmental impact. Since the production of secondary metabolites in plant in vitro cultures can be low, there are several strategies that can be applied to enhance the production of these compounds. Elicitation has been widely used to increase secondary metabolite production in plant in vitro cultures. This phenomenon involves the treatment of plant cultures with different agents (physical, chemical or biological) that triggers a defence response, which generally involves the production of secondary metabolites. Anthraquinones are secondary metabolites traditionally used as dyes that exhibit interesting therapeutic applications, such as antiviral (against hepatitis C virus), and as photosensitizers of cancer cells. In this chapter, we will present an approach for the establishment of hairy root cultures of Rubia tinctorum and a protocol for elicitation with methyl jasmonate. We will also discuss the possibility of combining elicitation with other strategies, such as in situ removal with Miglyol® 812.
Article
This review summarizes the literature on the association between two dietary components of tea, caffeine and L-theanine, and the psychological outcomes of consumption; it also identifies areas for future research. The studies reviewed suggest that caffeinated tea, when ingested at regular intervals, may maintain alertness, focused attention, and accuracy and may modulate the more acute effects of higher doses of caffeine. These findings concur with the neurochemical effects of L-theanine on the brain. L-theanine may interact with caffeine to enhance performance in terms of attention switching and the ability to ignore distraction; this is likely to be reflective of higher-level cognitive activity and may be sensitive to the detrimental effects of overstimulation. Further research should investigate the interactive effects of caffeine, L-theanine, and task complexity, utilize a range of ecologically valid psychological outcomes, and assess the neuroprotective effects of L-theanine using epidemiological or longer-term intervention studies among individuals at risk of neurodegenerative disease.
Chapter
Tea is a widely consumed nonalcoholic beverage, made from tender tea leaves, which contain extraordinarily high amount of specialized metabolites. These specialized metabolites are beneficial to human health and crucial in tea brisk, umami taste, and pleasant scent. Agrobacterium-assisted genetic transformation studies on tea plant are largely limited due to recalcitrant nature of tea plant. Release of oxidation phenolics that are dominant from explant tissues and the antibacterial nature of polyphenols during the transformation are among the possible reasons for tea plant recalcitrance. Our main objective in this study was to create an in vitro system for selection of transgenic roots from composite plants for possible production of specialized metabolites. Three-week-old in vitro-germinated seedlings were used in generating composite plants. The hypocotyl and the stems were wounded using a sonicator and a sterilized needle and infected with Agrobacterium rhizogenes harboring pBI121 plasmid and maintained in aseptic conditions. Molecular assay of roots from antibiotic selected plants showed amplification of rol B C and gus confirming the integration of Agrobacterium rhizogenes T-DNA region into the root system. From our data, it was clear that hairy root generation in tea can be achieved using A. rhizogenes. With this method, composite tea plants containing wild-type shoots with transgenic roots can be developed for gene functional characterization as well as specialized metabolite production and root-shoot interaction research in plants.
Article
Previously, we revealed that theanine, a green tea component, induced phospholipase C (PLC)-beta1 and -gamma1, stress-responsible molecules, in primary cultured rat cerebral cortical neurons, suggesting its protective effect on oxidative stress in neurons. In this study, we investigated whether the same favorable effect occurs in vivo. On the oral administration of theanine (10 mmol (1.74 g)/kg, once a day) to rats via gastric intubation for 2 weeks, there was no change in the weight of the body or the cerebral cortex (Cx), cerebellum (Cb), or hippocampus (Hip) in the brain. On assessment of oxidation levels in the brain with thiobarbiturate reactive substances as a marker, the levels were found to be 20% lower in the Cx of theanine-treated rats than in that of control ones. The protein expression levels of PLC-beta1 and -gamma1 were significantly increased in the Cx on theanine administration and the same tendency was observed in the Cb, but not the Hip. In addition, the protein expression level of PLC-delta1, which plays an opposite role to the other two isozymes, was not affected in any brain regions on theanine administration. Overall, it was demonstrated that theanine is a safe compound and its repeated oral administration reduces oxidation levels in the brain, especially the Cx, by increasing PLC-beta1 and -gamma1 protein expression, suggesting its favorable effect on the brain in vivo.
ResearchGate has not been able to resolve any references for this publication.