L-Theanine is a free amino acid unique to tea, and the following is a detailed description of it:
1. Basic Information
Chinese name: L-Theanine
Foreign name: L-Theanine; N-gamma-ethyl-L-glutamine; N-ethyl-L-glutamine
Chemical formula: C7H14N2O3
Molecular weight: 174.1977 (or 174.198)
CAS No.: 3081-61-6
EINECS No.: 221-379-0
2. Physical and Chemical Properties
Appearance: white crystalline powder, odorless, with sweet and sour taste.
Solubility: soluble in water, insoluble in ethanol, ether.
3. Natural existence and synthesis
Natural existence: L-Theanine natural product mainly exists in green tea, which is the main component of tea to produce flavor and sweetness. Among the 26 kinds of amino acids in tea (6 kinds of non-protein amino acids), theanine accounts for about 50%60% of the total amino acids in tea, accounting for 1%2% of the dry weight of tea. Theanine is synthesized in the roots of the tea tree, converted from glutamic acid and ethylamine by the enzyme theanine synthase, which is then transferred through the branches to the leaves for accumulation. Theanine is converted to catechic acid under sunlight, so L-theanine is found in higher levels in high grade green tea cultivated under shade, and in lower levels in general coarse tea leaves. It is also present in trace amounts in a few plants such as tea plums, mushrooms and oil tea.
Artificial synthesis: It can be produced by heating L-glutamic acid under high pressure to make pyrrolidone carboxylic acid, adding anhydrous monoethylamine, and heating under high pressure again.
4. Physiological functions and applications
Food additives: L-Theanine has a fresh flavor and can be used as a food additive to enhance the taste of products. For example, it is used in some energy drinks and tea drinks to enhance the function of relieving fatigue and improving mood.
Neuromodulation: L-Theanine is able to cross the blood-brain barrier into the brain and affect neurotransmitter levels. It increases the synthesis and release of the neurotransmitter gamma-aminobutyric acid (GABA) in the brain, while promoting the synthesis of the intralinear neurotransmitter dopamine as well as norepinephrine in brain cells. These effects help to relieve stress and tension, improve mental health, and also help to improve sleep quality. In addition, theanine may have a beneficial effect on the brain’s learning and memory functions, enhancing attention and cognitive flexibility.
Cardiovascular protection: L-Theanine is known to lower blood lipids and cholesterol, helping to prevent cardiovascular disease. It promotes vasodilation by regulating the function of vascular endothelial cells, thus helping to lower blood pressure.
Antioxidant and anti-inflammatory: L-Theanine is rich in phenolic hydroxyl groups, which can effectively scavenge free radicals in the body, preventing free radicals from damaging the body’s cells, and acting as an antioxidant and anti-aging agent. At the same time, it can also inhibit some key enzymes in the inflammatory response and reduce the generation of inflammatory factors, thus relieving inflammation.
Antibacterial and antiviral: L-Theanine has an inhibitory effect on some common pathogenic bacteria, such as Staphylococcus aureus and Escherichia coli, which helps to protect the human body from microorganisms. In addition, it can inhibit the reproduction of viruses and reduce the symptoms of edema caused by viral infections.
Liver protection: L-Theanine can be converted to acetic acid in the human liver, which plays an inhibitory role on pyruvate kinase in the liver, thus reducing the damage of pyruvate kinase and protecting the health of the liver.