摘要Mitochondrial superoxide overproduction is believed to be responsible for the neurotoxicity associated with neurodegeneration.Mitochondria-targeted antioxidants,such as MitoQ,have emerged as potentially effective antioxidant therapies.Methionine sulfoxide reductase A(MsrA)is a key mitochondrial-localized endogenous antioxidative enzyme and it can scavenge oxidizing species by catalyzing the methionine(Met)-centered redox cycle(MCRC).In this study,we observed that the natural L-Met acted as a good scavenger for antimycin A-induced mitochondrial superoxide overproduction in PC12 cells.This antioxidation was largely dependent on the Met oxidase activity of MsrA.S-methyl-L-cysteine(SMLC),a natural analogue of Met that is abundantly found in garlic and cabbage,could activate the Met oxidase activity of MsrA to scavenge free radicals.Furthermore,SMLC protected against antimycin A-induced mitochondrial membrane depolarization and alleviated 1-methyl-4-phenylpyridinium(MPP+)-induced neurotoxicity.Thus,our data highlighted the possibility for SMLC supplement in the detoxication of mitochondrial damage by activating the Met oxidase activity of MsrA.