Psychotropic effects of L-theanine and its clinical properties: From the management of anxiety and stress to a potential use in schizophrenia

Abstract

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Tea and tea drinking: China’s outstanding contributions to the mankind

“…The beneficial effects of tea on human health are obtained through three ways. (1) Constituent-associated way, such as the anxiolytic effects of theanine [ 164 , 165 ] and antiviral activity of tea polyphenols [ 166 ]; (2) Culture-associated way, drinking tea has rich cultural connotation, as people have cultural needs and dependence; (3) Constituent/culture-associated way, as man is a heteroion of material and spirit, both of which have impacts on human health [ 167 ]. Drinking tea may produce positive influences on both the material and spirit parts.…”

“…The beneficial effects of tea on human health are obtained through three ways. (1) Constituentassociated way, such as the anxiolytic effects of theanine [164,165] and antiviral activity of tea polyphenols [166];…”

Green tea might be effective in alleviating COVID-19 associated psychiatric complications: preliminary results from a pilot randomized controlled trial

“…Besides, the other component of green tea, which is also believed to have neuroprotective effects and might play a significant role in alleviating psychiatric symptoms such as fatigue, depression, stress, anxiety cognition and sleep disorders, is a major amino acid of green tea, L-theanine, known as a likely analog of glutamate, and thus it might be able to affect the neuroexcitatory because of glutamatergic activation. A recent systematic review on nine RCT revealed that orally administered L-theanine for 200–400 mg/day up to eight weeks could help decrease the levels of stress and anxiety among the subjects exposed to stressful situations (Williams et al , 2020; Lopes Sakamoto et al , 2019; Hidese et al , 2017). It is worth noting that compared to other types of teas, the L-theanine content of green tea as an unfermented tea seems to be higher (Lopes Sakamoto et al , 2019).…”

“…A recent systematic review on nine RCT revealed that orally administered L-theanine for 200–400 mg/day up to eight weeks could help decrease the levels of stress and anxiety among the subjects exposed to stressful situations (Williams et al , 2020; Lopes Sakamoto et al , 2019; Hidese et al , 2017). It is worth noting that compared to other types of teas, the L-theanine content of green tea as an unfermented tea seems to be higher (Lopes Sakamoto et al , 2019). It is suggested that the modulatory effects of theanine on the release and activity of several neurotransmitters, for example, promoting the brain levels of norepinephrine, serotonin and dopamine, contribute to its neuroprotective function stress-reducing and antidepressant influences (Kim and Kim, 2018; Williams et al , 2019; Shen et al , 2019; Niu et al , 2009; Pham et al , 2014).…”

Novel Therapeutic Approach for the Management of Mood Disorders: In Vivo and In Vitro Effect of a Combination of L-Theanine, Melissa officinalis L. and Magnolia officinalis Rehder & E.H. Wilson

“…Recently, it was found that 4 weeks of administration of TEA (200 mg/day) was also able to reduce stress-related symptoms and improve cognitive functions in healthy adults [ 50 ]. Moreover, TEA was reported to possess beneficial effects in the treatment of anxiety and sleep disturbance [ 51 , 52 , 53 ]. Its activity seems to involve the inhibition of presynaptic glutamate release [ 11 ] and antagonism at the N-metyl-D-aspartate (NMDA) and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) glutamate receptors [ 54 ], leading to a reduction in over-activated glutamatergic neurotransmission.…”