• Asian-Australasian Journal of Animal Sciences
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• v.21 no.12
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• pp.1753-1759
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• 2008

Forty weanling piglets ($5.6{\pm}0.5kg$ and 26 to 30 d of age) were used in a 28-d experiment to determine the effects of ${\beta}$-glucan from Paenibacillus polymyxa and L-theanine on growth performance. Piglets were randomly allotted to four groups (n = 10, 2 animals per pen) provided with the basal feed (control), ${\beta}$-glucan 400 mg/kg feed, L-theanine 80 mg/kg feed or ${\beta}$-glucan plus l-theanine (combination of the above-mentioned concentrations). Body weight and feed consumption were recorded during four weeks. Subsequently, the immunomodulatory effects of ${\beta}$-glucan and L-theanine were investigated for lipopolysaccharide (LPS)-induced cytokine production in vitro and in vivo on day 28. Although there were no significant differences in the growth performances among the treatment groups, ${\beta}$-glucan plus L-theanine had 5.6% greater ADG (p = 0.074) on day 21 to 28. ${\beta}$-Glucan alone or plus L-theanine increased interleukin (IL)-10 levels and decreased interferon (IFN)-$\gamma$ and tumor necrosis factor (TNF)-${\alpha}$ levels in cultured medium by LPS treatment (p<0.05). Plasma IL-10 levels were also increased in the piglets fed with ${\beta}$-glucan alone or plus L-theanine after LPS challenge ($25{\mu}g/kg$, i.p.), whereas plasma IFN-$\gamma$ and TNF-${\alpha}$ levels were decreased (p<0.05). The levels of IFN$\gamma$ in piglets fed with ${\beta}$-glucan plus L-theanine showed the greatest inhibition after LPS challenges. In conclusion, treatment of ${\beta}$-glucan alone or plus L-theanine might lessen inflammatory responses against Gram-negative bacterial infection via the inhibition of pro-inflammatory cytokine production and enhancement of anti-inflammatory cytokine production. Further studies are needed to determine an optimal concentration of ${\beta}$-glucan and L-theanine for improved growth performance.

• Korean Journal of Food Science and Technology
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• v.53 no.5
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• pp.553-560
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• 2021

Theanine, the major amino acid and a sweet umami component of green tea, has anti-stress effects in humans. From green tea, theanine was extracted at 80℃ for 2 h using a low temperature, high pressure extractor, and caffeine was removed using an HP-20 column with 80% ethanol. Theanine extracts were applied to produce functional jelly using three kinds of gelling agents (I, II, and III) or various concentrations of theanine extracts (10-50%). Theanine jelly was characterized with respect to its physical properties, product stability, and physiological function. Gelling agent III (tamarind gum, xanthan gum, and locust bean gum=2:3:5, w/w/w) and S3 (35% theanine extracts) jelly exhibited the optimum textural properties with lower hardness and high springiness. Among theanine jellies, S3 exhibited optimum product stability, high 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging, and acetylcholinesterase inhibitory activity. These results indicate that the anine extracts could be used as a neuroprotective source in the food industry.

• YAKHAK HOEJI
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• v.53 no.5
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• pp.241-249
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• 2009

Various neurotransmitters are involved in regulating stress systems. In this study, we investigated the combination relieving effect of green tea extract(GTE) and L-theanine on the stress induced by electric foot shock. Four week oral administration of GTE (24 mg/kg), L-theanine (4 mg/kg) or their combination reduced the levels of dopamine, noradrenaline and corticosterone in blood, brain cortex, hippocampus, and striatum, wherease increased serotonin level. The combination of GTE and L-theanine showed much greater effects than single treatment of each component, and the effects are comparable to diazepam (2 mg/kg). Therefore, this study suggests that the combination of GTE and L-theanine may act effective and be useful for stress relieving treatment.

• YAKHAK HOEJI
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• v.52 no.5
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• pp.384-393
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• 2008

We examined the effect of green tea extract (GTE) and L-theanine combination on the $A{\beta}_{1-42}$-induced memory dysfunction. GTE and combination were administrated into mice for 3 weeks followed by injection of $A{\beta}_{1-42}$ to induce memory impairment. GTE and L-theanine administration significantly improved cognitive ability and reduced $A{\beta}_{1-42}$ level accompanied with the inhibition of neuronal cell death and activities of secretase. These results suggest that GTE and L-theanine combination may be a useful for preventing for the development or progression of Alzheimer's disease.

• YAKHAK HOEJI
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• v.51 no.6
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• pp.409-414
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• 2007

Acetylcholinesterase (AChE) plays a role in the progression of Alzheimer's disease (AD). In this study, we examined the improving effect of L-theanine, a major amino acid in Japanese green tea (Camellia sinensis) on the scopolamine (1 mg/kg/mouse)-induced memory dysfunction in mice. Treatment with L-theanine (2, 4 mg/kg/mouse p.o.) in the drinking water for 7 days reversed the scopolamine-induced latency time and distance in the water maze test, latency time in the passive avoidance test, and inhibited AChE activity. This study suggests that L-theanine may be a useful agent for prevention of progression of AD.

• Biomolecules & Therapeutics
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• v.19 no.3
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• pp.288-295
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• 2011

Amyloid beta ($A{\beta}$)-induced neurotoxicity is a major pathological mechanism of Alzheimer's disease (AD). In this study, we investigated the inhibitory effect of L-theanine, a component of green tea (Camellia sinensis) on $A{\beta}_{1-42}$-induced neurotoxicity and oxidative damages of macromolecules. L-theanine inhibited $A{\beta}_{1-42}$-induced generation of reactive oxygen species, and activation of extracellular signal-regulated kinase and p38 mitogenic activated protein kinase as well as the activity of nuclear factor kappa-B. L-theanine also signifi cantly reduced oxidative protein and lipid damage, and elevated glutathione level. Consistent with the reduced neurotoxic signals, L-theanine (10-50 ${\mu}g$/ml) concomitantly attenuated $A{\beta}_{1-42}$ (5 ${\mu}M$)-induced neurotoxicity in SK-N-MC and SK-N-SH human neuroblastoma cells. These data indicate that L-theanine on $A{\beta}$-induced neurotoxicity prevented oxidative damages of neuronal cells, and may be useful in the prevention and treatment of neurodegenerative disease like AD.

• Korean Journal of Veterinary Service
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• v.35 no.4
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• pp.347-350
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• 2012

L-theanine was examined for its effects on the generation of superoxide anion, lysozyme and anti-protease in the plasma of catfish (Silurus asotus) by a single intraperitoneal injection with five different concentrations (0, 3, 6, 9 and 12 mg/kg). When compared with the mock-injected group (0 mg/kg), both groups injected with 6 and 9 mg/kg were significantly enhanced in levels of superoxide anion in leukocytes, lysozyme and anti-protease in plasma. Based on the results, L-theanine is thought to function as an immunostimulant and/or immunomodulator on non-specific immune responses in catfish.

• Journal of Nutrition and Health
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• v.36 no.9
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• pp.918-923
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• 2003

L-theanine Is an amino acid in green tea and has been known to decrease serotonin and increase norepinephrine in rat brains, and also reported 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 on the release of brain alpha waves known to be related with mental relaxation and concentration. Twenty healthy male volunteers aged 18 to 30 years without any Physical and Psychological diseases were recruited through written advertisement. Alpha power values of EEG as a surrogate marker of mental relaxation and concentration were measured in frontal and occipital regions for 40 minutes after administration of four placebo or test tablets and 20 minute resting period. The same procedure crossed over at 7-day intervals. We analyzed average alpha power values in frontal and occipital regions at 10 minute intervals. Repeated ANOVA revealed that there were significant differences of occipital alpha power values between placebo and test groups with high anxiety (p < 0.05). The mean values at 20,30,40,50 and 60 minute intervals were 0.23, 024, 0.28, 0.25 and 0.34 in placebo, respectively and 0.23, 0.29, 0.40, 0.34, and 0.45 in test, respectively. But there were no significant differences of frontal and occipital alpha power values between placebo and test groups with low anxiety (p > 0.05) . The results of this study suggest that L-theanine containing tablets promote the release of alpha waves related to mental relaxation and concentration in young adult males.

• Journal of Microbiology and Biotechnology
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• v.30 no.5
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• pp.785-792
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• 2020

ʟ-Theanine, found in green tea leaves has been shown to positively affect immunity and relaxation in humans. There have been many attempts to produce ʟ-theanine through enzymatic synthesis to overcome the limitations of traditional methods. Among the many genes coding for enzymes in the ʟ-theanine biosynthesis, glutamylmethylamide synthetase (GMAS) exhibits the greatest possibility of producing large amounts of production. Thus, GMAS from Methylovorus mays No. 9 was overexpressed in several strains including vectors with different copy numbers. BW25113(DE3) cells containing the pET24ma::gmas was selected for strains. The optimal temperature, pH, and metal ion concentration were 50℃, 7, and 5 mM MnCl₂, respectively. Additionally, ATP was found to be an important factor for producing high concentration of ʟ-theanine so several strains were tested during the reaction for ATP regeneration. Baker's yeast was found to decrease the demand for ATP most effectively. Addition of potassium phosphate source was demonstrated by producing 4-fold higher ʟ-theanine. To enhance the conversion yield, GMAS was additionally overexpressed in the system. A maximum of 198 mM ʟ-theanine was produced with 16.5 mmol/l/h productivity. The whole-cell reaction involving GMAS has greatest potential for scale-up production of ʟ-theanine.

• Proceedings of the Korean Society of Food Science and Nutrition Conference
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• 2001.12a
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• pp.38-47
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• 2001

L-theanine is a unique amino acid, found almost solely in tea plants. It is the main component responsible for the exotic taste of green tea. In our studies of L-theanine, we have found a variety of biological activities including relaxation and the alleviation of PMS. In general, animals generate very weak electric pulses on the surface of the brain, called brain waves. Brain waves are classified into four types, namely $\alpha$, $\beta$, $\delta$ and $\theta$-waves, based on their frequency. Brain waves correlate with individual mental conditions. For example, generation of $\alpha$-waves is considered an index of relaxation. In human volunteers, $\alpha$-waves were generated on the occipital and parietal regions of the brain surface within 40 minutes after the oral administration of 50 or 200 mg Suntheanine$^{TM}$ without causing drowsiness. Premenstrual Syndrome (PMS) is a symptom unique to women which appears in the luteal phase from the ovulation period through the first day of menstruation. It possesses characteristics of having a peak just prior to menstruation and disappearing 1 - 2 days following the start of menstruation. Symptoms of PMS are generally categorized as mental, physical and social symptoms. When comparing the reported Symptoms of PMS by the methods of MDQ score, the Suntheanine$^{TM}$ group was found to have a lower incidence of PMS symptoms, including physical, mental and social symptoms. Overall, a significant alleviation of PMS symptoms by the administration of 200 mg Suntheanine$^{TM}$ was observed. With the successful industrial production of L-theanine, we are now able to supply Suntheanine$^{TM}$, offering a tremendous opportunity for designing functional foods targeting relaxation and the alleviation of PMS.