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Review
. 2022 Apr 4:9:853846.
doi: 10.3389/fnut.2022.853846. eCollection 2022.

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

Ming-Yue Li  1   2 , Hong-Yan Liu  2 , Ding-Tao Wu  1 , Ahmad Kenaan  3 , Fang Geng  1 , Hua-Bin Li  4 , Anil Gunaratne  5 , Hang Li  2 , Ren-You Gan  1   2
Affiliations
Review

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

Ming-Yue Li et al. Front Nutr. .

Abstract

Tea (Camellia sinensis L.) is a very popular health drink and has attracted increasing attention in recent years due to its various bioactive substances. Among them, L-theanine, a unique free amino acid, is one of the most important substances in tea and endows tea with a special flavor. Moreover, L-theanine is also a bioactive compound with plenty of health benefits, including antioxidant, anti-inflammatory, neuroprotective, anticancer, metabolic regulatory, cardiovascular protective, liver and kidney protective, immune regulatory, and anti-obesity effects. Due to the unique characteristics and beneficial functions, L-theanine has potential applications in the development of functional foods. This review summarized the influencing factors of L-theanine content in teas, the main health benefits and related molecular mechanisms of L-theanine, and its applications in food, understanding of which can provide updated information for the further research of L-theanine.

Keywords: L-theanine; food applications; health benefits; mechanisms of action; tea.

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Conflict of interest statement

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Figures

FIGURE 1
FIGURE 1
Influencing factors of L-theanine content in tea leaves.
FIGURE 2
FIGURE 2
The health benefits of L-theanine. AMPK, adenosine 5′-monophosphate-activated protein kinase; CPT1, carnitine palmitoyltransferase 1; IR, insulin receptor; IRS, insulin receptor substrate; LKB1, liver kinase B1; PFK, phosphofructokinase.
FIGURE 3
FIGURE 3
Food applications of L-theanine. AGEs, advanced glycation end products.
See this image and copyright information in PMC

References

    1. Guo YJ, Sun LQ, Yu BY, Qi J. An integrated antioxidant activity fingerprint for commercial teas based on their capacities to scavenge reactive oxygen species. Food Chem. (2017) 237:645–53. 10.1016/j.foodchem.2017.05.024 - DOI - PubMed
    1. Zhu YM, Dong JJ, Jin J, Liu JH, Zheng XQ, Lu JL, et al. Roasting process shaping the chemical profile of roasted green tea and the association with aroma features. Food Chem. (2021) 353:129428. 10.1016/j.foodchem.2021.129428 - DOI - PubMed
    1. Lin FJ, Wei XL, Liu HY, Li H, Xia Y, Wu DT, et al. State-of-the-art review of dark tea: from chemistry to health benefits. Trends Food Sci Technol. (2021) 109:126–38. 10.1016/j.tifs.2021.01.030 - DOI
    1. Tang GY, Meng X, Gan RY, Zhao CN, Liu Q, Feng YB, et al. Health functions and related molecular mechanisms of tea components: an update review. Int J Mol Sci. (2019) 20:6196. 10.3390/ijms20246196 - DOI - PMC - PubMed
    1. Bi W, He C, Ma Y, Shen J, Zhang LH, Peng Y, et al. Investigation of free amino acid, total phenolics, antioxidant activity and purine alkaloids to assess the health properties of non-Camellia tea. Acta Pharm Sin B. (2016) 6:170–81. 10.1016/j.apsb.2015.11.003 - DOI - PMC - PubMed

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