L-Theanine

L-Theanine (L-Glutamic Acid γ-ethyl amide) is a non-protein amino acid contained in green tea leaves, which blocks the binding of L-glutamic acid to glutamate receptors in the brain, and with neuroprotective, anticancer and anti-oxidative activities. L-Theanine can pass through the blood–brain barrier and is orally active^[1][2][3]. In Vitro: L-Theanine (L-Glutamic Acid γ-ethyl amide) inhibits the incorporation of extracellular glutamine into neurons, resulting in the suppression of exocytotic release of glutamate^[3].
L-Theanine (500 μM; 72 h) protects against excess Dopamine (HY-B0451)-induced neuronal death in presence of astrocytes and increases glutathione level in astrocytes^[3].
L-Theanine (0-5 mM; 72 h) is involved in glutathione synthesis^[3].
L-Theanine (0.1-5 mM; 24 h) dose-dependently inhibits the viability of melanoma but not normal epidermal melanocytes^[4].
L-Theanine (1-5 mM; 24 h) arrests cell cycle at G0/G1 phase, suppresses cell migration, induces apoptosis in A375 cells^[4].
L-Theanine (1-5 mM; 24 h) also affects the proliferation, migration, and apoptosis of B16–F10 melanoma cells^[4].
L-Theanine shows protective effect on cadmium-induced apoptosis in PC12 cells by inhibiting the mitochondria-mediated pathway and decreased ROS production^[5]. In Vivo: L-Theanine (4.0 mg/kg; p.o.; daily for 14 days) upregulates glutathione contents in striata of normal mice^[3].