(S)-Sulindac is the (S)-enantiomer of nonsteroidal anti-inflammatory drug (NSAID) Sulindac, that is marketed in the U.S. by Merck as Clinoril. Sulindac is a prodrug, derived from sulfinyl-indene, that is converted in vivo to an active sulfide compound by liver methionine sulfoxide reductases (Msr). The (Msr) family of enzymes includes two major classes, MsrA and MsrB, that specifically reduce the S- and R-epimers of Sulindac. Reduction of (S)-Sulindac to Sulindac Sulfide catalyzed by methionine sulfoxide reductase (Msr)-A. The oxidation of both epimers to sulindac sulfone is catalyzed primarily by the microsomal cytochrome P450 (P450) system. (S)-Sulindac increases the activity of the P450 system better than (R)-sulindac, but both epimers increase primarily the enzymes that oxidize (R)-sulindac. Both epimers can protect normal lung cells against oxidative damage and enhance the killing of lung cancer cells exposed to oxidative stress.

(R)-Sulindac is the (R)-enantiomer of nonsteroidal anti-inflammatory drug (NSAID) Sulindac, that is marketed in the U.S. by Merck as Clinoril. Sulindac is a prodrug, derived from sulfinylindene, that is converted in vivo to an active sulfide compound by liver methionine sulfoxide reductases (Msr). The (Msr) family of enzymes includes two major classes, MsrA and MsrB, that specifically reduce the S- and R-epimers of Sulindac. Reduction of (R)-Sulindac to Sulindac Sulfide catalyzed by methionine sulfoxide reductase (Msr)-B. The oxidation of both epimers to sulindac sulfone is catalyzed primarily by the microsomal cytochrome P450 (P450) system. (S)-Sulindac increases the activity of the P450 system better than (R)-sulindac, but both epimers increase primarily the enzymes that oxidize (R)-sulindac. Both epimers can protect normal lung cells against oxidative damage and enhance the killing of lung cancer cells exposed to oxidative stress.