Folic acid (also known as folate, vitamin M, vitamin B9, vitamin Bc, pteroyl-L-glutamic acid, pteroyl-L-glutamate, and pteroylmonoglutamic acid) are forms of the water-soluble vitamin B9. Folate is composed of the aromatic pteridine ring linked to para-aminobenzoic acid and one or more glutamate residues. Folic acid is itself not biologically active, but its biological importance is due to tetrahydrofolate and other derivatives after its conversion to dihydrofolic acid in the liver.