S-Adenosyl-L-methionine tosylate (S-Adenosyl methionine tosylate) is produced endogenously from methionine and ATP by action of the enzyme methionine adenosyltransferase and is an important orally active methyl group donor. S-Adenosyl-L-methionine tosylate is a dietary supplement with potent antidepressant and analgesic effects, and has the potential for liver disease and osteoarthritis research[1][2][3].

S-Adenosyl-L-methionine (Ademetionine) is involved in three main metabolic pathways: 1) methylation, as the principal source of methyl groups in the body; 2) transsulfuration, S-Adenosyl-L-methionine forms S-Adenosylhomocysteine (SAH) and then converted to homocysteine (Hcy) which can be converted to cystathionine then to cysteine and the sulfate (SO4) donated to other metabolic intermediates; and 3) aminopropylation, as S-Adenosyl-L-methionine plays an important role in the synthesis of polyamines which can eventually form and recycle methionine[2].In vitro studies using human articular chondrocytes have shown S-Adenosyl-L-methionine-induced increases in proteoglycan synthesis and proliferation rates in rabbits[2].

Mice lacking methionine adenosyltransferase 1a (Mat1a) have reduced hepatic S-Adenosyl-L-methionine levels and develop oxidative stress, steatohepatitis, and hepatocellular carcinoma (HCC). However, injury and HCC also occur if hepatic S-Adenosyl-L-methionine level is excessive chronically. Thus a normal hepatic S-Adenosyl-L-methionine level is necessary to maintain liver health and prevent injury and HCC[3].

[1]. G M Bressa. et al. S-adenosyl-l-methionine (SAMe) as antidepressant: meta-analysis of clinical studies. Acta Neurol Scand Suppl. 1994;154:7-14. [2]. Wadie I Najm, et al. S-adenosyl methionine (SAMe) versus celecoxib for the treatment of osteoarthritis symptoms: a double-blind cross-over trial. [ISRCTN36233495]. BMC Musculoskelet Disord. 2004 Feb 26;5:6. [3]. Shelly C Lu, et al. S-adenosylmethionine in liver health, injury, and cancer. Physiol Rev. 2012 Oct;92(4):1515-42.