Anthranilic acid (vitamin L)

Anthranilic acid (vitamin L) is an intermediate in the biosynthesis of tryptophan. Vitamin L1 is anthranilic acid or ortho-aminobenzoic acid, a vitamin required for lactation in human females. Vitamin L2 is adenyl thiomethylpentose, an alternate form of vitamin L. Vitamin L is thought to be necessary for lactation -- the reason for the "L" -- although it is not officially recognized as a vitamin and dietary sources have not been identified.

L2 was isolated and seems to be related to adenosine. It has been referred to as LT but LT is a much more complex substance and is sometimes erroneously included with the B vitamin complex. Anthranilic acid is an aromatic amine which occurs physiologically as a metabolite of the amino acid tryptophan. It is used commercially as an intermediate in dye synthesis.