Se-methyl selenocysteine (MSC) is a naturally occurring selenium compoundwith favourable pharmacokinetic properties andth high peroral bioavailability in humans. MSC is synthesized by plants such as garlic, astragalus, onions and broccoli. Se-methylselenocysteine has been proven to have a chemo-preventive property, which is shown by several authors via various cell culture models and animal models. It has also been shown to have anti-carcinogenic properties by inducing cell cycle arrest and apoptotic cell death. It is considered a pro-drug because the compound per se is not toxic unless it is metabolized by the enzymes Kynurenine aminotransferase 1 (KYAT1), Kynurenine aminotransferase 3 (KYAT3) and cystathionine γ-lyase (CTH). Of these, KYAT1 plays a vital role in MSC metabolism.
