L-Theanine: A Unique Functional Amino Acid in Tea (Camellia sinensis L.) With Multiple Health Benefits and Food Applications

Li, Mingyue; Liu, Hongyan; Wu, Ding‐Tao; Kenaan, Ahmad; Geng, Fang; Li, Hua-Bin; Gunaratne, Anil; Li, Hang; Gan, Ren‐You

doi:10.3389/fnut.2022.853846

Cited by 37 publications

(38 citation statements)

References 108 publications

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“…12 L-Theanine has a broad range of uses due to its taste and different health advantages, such as being utilized as a beverage component or nutritional supplement. 4 Furthermore, green tea infusion has been reported to effectively prevent CPinduced reproductive dysfunction in male mice. 13 However, whether L-theanine affects testis toxicity induced by CP and its potential mechanisms remain unclear.…”

Section: Introductionmentioning

confidence: 99%

Protective Effect of l-Theanine on Cyclophosphamide-Induced Testicular Toxicity in Mice

Fang

et al. 2023

J. Agric. Food Chem.

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L-Theanine is the most abundant free amino acid present in tea. Several tea components have been studied for their impact on male fertility, but little is known about the effects of L-theanine. Cyclophosphamide (CP) is an antineoplastic and immunosuppressive agent that reduces fertility in males. In the present study, we evaluated the effect of L-theanine on CP-induced testicular toxicity in male mice. A single dosage of 50 mg/kg saline or CP was administered intraperitoneally over the course of 5 days. Mice were administered L-theanine (80 mg/kg) or saline by gavage for 30 days. Animals were euthanized 24 h after the last Ltheanine administration, and the testes were removed for histopathological and transmission electron microscopy analysis. Histological evaluation and transmission electron microscopy showed that administration of L-theanine alleviated CP-induced damage to the testicles, including spermatogonial cells, epithelial cells, seminiferous tubules, and basement membrane. An integrated proteomics and metabolomics investigation of testes revealed that L-theanine therapy substantially affected the quantity of 719 proteins (395 upregulated and 324 downregulated) and 196 metabolites (75 upregulated and 111 downregulated). The top three enriched Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways for these proteins and metabolites were purine metabolism, choline metabolism in cancer, and arachidonic acid metabolism. This is the first study to reveal the protective effect of L-theanine on CP-induced testicular toxicity. L-Theanine could be a potential natural active substance for resistance to the testis toxicity induced by CP.

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Section: Introductionmentioning

confidence: 99%

Protective Effect of l-Theanine on Cyclophosphamide-Induced Testicular Toxicity in Mice

Fang

et al. 2023

J. Agric. Food Chem.

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“…L-theanine (LT) is a molecule with a similar structure to glutamate and glutamine, accounting for 0.5–2% of the dry weight of tea leaves. LT consists of ethylamine and glutamate and is rapidly absorbed into the circulation of the gastrointestinal system and subsequently distributed to various organs, including the brain, via cotransport with Na + [ 9 ]. LT was reported to have taste-enhancing properties and health benefits and has been widely utilized in the food and pharmaceutical industries, as it does not produce any toxic effects in animals or humans according to toxicological and technical reports [ 9 , 10 ].…”

Section: Introductionmentioning

confidence: 99%

“…LT consists of ethylamine and glutamate and is rapidly absorbed into the circulation of the gastrointestinal system and subsequently distributed to various organs, including the brain, via cotransport with Na + [ 9 ]. LT was reported to have taste-enhancing properties and health benefits and has been widely utilized in the food and pharmaceutical industries, as it does not produce any toxic effects in animals or humans according to toxicological and technical reports [ 9 , 10 ]. Additionally, LT was shown to possess sedative, hypotensive, anti-obesogenic, and anti-inflammatory properties [ 9 , 10 , 11 ], as well as the ability to scavenge reactive radicals and mitigate peroxidative conditions.…”

Section: Introductionmentioning

confidence: 99%

“…LT was reported to have taste-enhancing properties and health benefits and has been widely utilized in the food and pharmaceutical industries, as it does not produce any toxic effects in animals or humans according to toxicological and technical reports [ 9 , 10 ]. Additionally, LT was shown to possess sedative, hypotensive, anti-obesogenic, and anti-inflammatory properties [ 9 , 10 , 11 ], as well as the ability to scavenge reactive radicals and mitigate peroxidative conditions. LT was proposed to have neuroprotective properties against behavioral deficits resulting from toxins, stress, and spinal cord nerve injury [ 12 , 13 , 14 , 15 ].…”

Section: Introductionmentioning

confidence: 99%

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Through Its Powerful Antioxidative Properties, L-Theanine Ameliorates Vincristine-Induced Neuropathy in Rats

et al. 2023

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L-theanine (LT), which is a major amino acid found in green tea, was shown to alleviate Vincristine (VCR)-induced peripheral neuropathy and associated neuronal functional changes in rats. To induce peripheral neuropathy, rats were administered VCR at a dose of 100 mg/kg/day intraperitoneally on days 1–5 and 8–12, while control rats received LT at doses of 30, 100, and 300 mg/kg/day intraperitoneally for 21 days or saline solution. Electrophysiological measurements were taken to evaluate the nerve functional loss and recovery through motor and sensory nerve conduction velocities. The sciatic nerve was examined for several biomarkers, including nitric oxide (NO), malondialdehyde (MDA), glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), total calcium, IL-6, IL-10, MPO, and caspase-3. The results showed that VCR caused significant hyperalgesia and allodynia in rats; decreased nerve conduction velocity; increased NO and MDA levels; and decreased GSH, SOD, CAT, and IL-10 levels. LT was found to significantly reduce VCR-induced nociceptive pain thresholds, decrease oxidative stress levels (NO, MDA), increase antioxidative strength (GSH, SOD, CAT), and reduce neuroinflammatory activity and apoptosis markers (caspase-3). LT’s antioxidant, calcium homeostasis, anti-inflammatory, anti-apoptotic, and neuroprotective properties make it a potential adjuvant to conventional treatment in VCR-induced neuropathy in rats.

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“…In addition, EGCG can also promote axonal growth in PC12 cells ( 20 ). L -theanine, a non-protein water-soluble amino acid, is characteristically found in tea plants ( 21 ). L -theanine content accounts for about 1–2% of the dry weight of tea leaves, and the content of L -theanine in high-theanine tea tree varieties is about 4% or more ( 22 ).…”

Section: Introductionmentioning

confidence: 99%

Synergistic effects of epigallocatechin gallate and l-theanine in nerve repair and regeneration by anti-amyloid damage, promoting metabolism, and nourishing nerve cells

et al. 2022

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Green tea has significant protective activity on nerve cells, but the mechanism of action is unclear. Epigallocatechin gallate (EGCG) and N-ethyl-L-glutamine (L-theanine) are the representative functional components of green tea (Camellia sinensis). In this study, an AD model of Aβ25–35-induced differentiated neural cell line PC12 cells was established to study the synergistic effect of EGCG and L-theanine in protecting neural cells. The results showed that under Aβ25–35 stress conditions, mitochondria and axons degenerated, and the expression of cyclins was up-regulated, showing the gene and protein characteristics of cellular hyperfunction. EGCG + L-theanine inhibited inflammation and aggregate formation pathways, significantly increased the percentage of G0/G1 in the cell cycle, downregulated the expression of proteins such as p-mTOR, Cyclin D1, and Cyclin B1, upregulated the expression of GAP43, Klotho, p-AMPK, and other proteins, promoted mitochondrial activity and energy metabolism, and had repair and regeneration effects on differentiated nerve cells. The synergistic mechanism study showed that under the premise that EGCG inhibits amyloid stress and inflammation and promotes metabolism, L-theanine could play a nourish nerve effect. EGCG + L-theanine keeps differentiated nerve cells in a quiescent state, which is beneficial to the repair and regeneration of nerve cells. In addition, EGCG + L-theanine maintains the high-fidelity structure of cellular proteins. This study revealed for the first time that the synergistic effect of EGCG with L-theanine may be an effective way to promote nerve cell repair and regeneration and slow down the progression of AD. Our findings provide a new scientific basis for the relationship between tea drinking and brain protection.

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L-Theanine: A Unique Functional Amino Acid in Tea (Camellia sinensis L.) With Multiple Health Benefits and Food Applications

Cited by 37 publications

References 108 publications

Protective Effect of l-Theanine on Cyclophosphamide-Induced Testicular Toxicity in Mice

Protective Effect of l-Theanine on Cyclophosphamide-Induced Testicular Toxicity in Mice

Through Its Powerful Antioxidative Properties, L-Theanine Ameliorates Vincristine-Induced Neuropathy in Rats

Synergistic effects of epigallocatechin gallate and l-theanine in nerve repair and regeneration by anti-amyloid damage, promoting metabolism, and nourishing nerve cells

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