3-MA: 3-methylademine; ACTB/β-actin: actin, beta; ATG: autophagy related; ATG16L1: autophagy related 16-like 1 (S. cerevisiae); BECN1: beclin 1, autophagy related; CNR2: cannabinoid receptor 2 (macrophage); CNS: central nervous system; CQ: chloroquine; EAE: experimental autoimmune encephalomyelitis; FOXO3: forkhead box O3; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; H&E: hematoxylin and eosin; ITGAM: integrin alpha M; LPS: lipoplysaccharide; MAP1LC3/LC3: microtubule-associated protein 1 light chain 3; miRNAs: microRNAs; MS: multiple sclerosis; PPARG: peroxisome proliferator activated receptor gamma; PTPRC: protein tyrosine phosphatase, receptor type, C; RA: rheumatoid arthritis; SQSTM1: sequestosome 1; TB: tuberculosis; TIMM23: translocase of inner mitochondrial membrane 23; TLR: toll-like receptor.

Muscle redox disturbances and oxidative stress have emerged as a common pathogenetic mechanism and potential therapeutic intervention in some muscle diseases. Parthenolide (PTL), a sesquiterpene lactone found in large amounts in the leaves of feverfew, possesses anti‐inflammatory, anti‐migraine, and anticancer properties. Although PTL was reported to alleviate cancer cachexia and improve skeletal muscle characteristics in a cancer cachexia model, its actions on oxidative stress‐induced damage in C2C12 myoblasts have not been reported and the regulatory mechanisms have not yet been defined. In our study, PTL attenuated H2O2‐induced growth inhibition and morphological changes. Furthermore, PTL exhibited scavenging activity against reactive oxygen species and protected C2C12 cells from apoptosis in response to H2O2. Meanwhile, PTL suppressed collapse of the mitochondrial membrane potential, thereby contributing to normalizing H2O2‐induced autophagy flux and mitophagy, correlating with inhibiting degradation of mitochondrial marker protein TIM23, the increase in LC3‐II expression and the reduction of mitochondria DNA. Besides its protective effect on mitochondria, PTL also prevented H2O2‐induced lysosomes damage in C2C12 cells. In addition, the phosphorylation of p53, cathepsin B, and Bax/Bcl‐2 protein levels, and the translocation of Bax from the cytosol to mitochondria induced by H2O2 in C2C12 cells was significantly reduced by PTL. In conclusion, PTL modulates oxidative stress‐induced mitophagy and protects C2C12 myoblasts against apoptosis, suggesting a potential protective effect against oxidative stress‐associated skeletal muscle diseases.