L-Theanine (Suntheanine, L-γ-glutamylethylamide)

Theanine /ˈθiːəniːn/, also known as L-γ-glutamylethylamide and N5-ethyl-L-glutamine, is an amino acid analogue of the proteinogenic amino acids L-glutamate and L-glutamine and is found primarily in particular plant and fungal species. It was discovered as a constituent of green tea in 1949 and in 1950 was isolated from gyokuro leaves, which have high theanine content. Appearance of the name "theanine" without a prefix is understood to imply the L-enantiomer, which is the form found in fresh teas.

Studies

L-Theanine extends lifespan of adult Caenorhabditis elegans
http://www.ncbi.nlm.nih.gov/pubmed/22422488