Skeletal muscle is an organ that regulates biological metabolic energy. Its dysfunction causes decline of body functions and disability, thus deteriorating the overall quality of life. Various materials are being developed with an anti-sarcolytic effect. However, anti-sarcolytic effect of Sinomenium acutum rhizomes extract (SAE) remains unclear. Therefore, this study aimed to investigate anti-muscle atrophy effects of SAE and its alkaloids, including sinomenine (SIN), magnoflorine (MF), acutumine (ACU), and N-ferultyramine (NFT) isolated from SAE, on dexamethasone (Dex)-induced myotubules. C2C12 myogenic cells differentiated for 6 days were treated with 1 mM Dex for 24 hours. Induction of muscular atrophy was confirmed by a decrease in myogenin expression. We found that Dex increased expression levels of muscle-specific ubiquitin ligases MuRF1 and MAFbx/atrogin-1. However, mRNA and protein levels of these muscle-specific ubiquitin ligases were significantly reduced by cotreatment with SIN, MF, and NFT in myotubes. Glucose uptake reduced by Dex in myotubules were also restored by SIN, MF, and NFT treatments. These results suggest that SIN, MF, and NFT can reduce muscle wasting and enhance glucose uptake in Dex-treated myotubes, highlighting their potential as therapeutic agents to prevent muscle atrophy.

Alpha-linolenic acid is an important polyunsaturated fatty acid that exhibits anticancer, anti-inflammatory, and antioxidative effects. In this study, we investigated the protective effects of alpha-linolenic acid on the cell proliferation and differentiation of C2C12 cells under essential amino acid-deficient conditions. Different concentrations of alpha-linolenic acid and essential amino acids were added to the growth and differentiation media. The concentrations of 10 μM of alphalinolenic acid and 2% essential amino acid were chosen for subsequent experiments. Supplementation with alpha-linolenic acid and essential amino acids improved the proliferation and differentiation of C2C12 cells and significantly increased the mRNA levels of catalase, superoxide dismutase, B-cell lymphoma-2, and beclin-1 as well as the protein levels of PPARγ coactivator-1α compared to those in the controls. Moreover, supplementation with alpha-linolenic acid and essential amino acids reduced the levels of phosphorylated H2A.X variant histone, Bcl-2-associated X, p53, and light chain 3 during C2C12 cell proliferation, and increased the expression levels of myogenic factors 4 (myogenin) and 5 during C2C12 cell differentiation. Overall, we determined that alpha-linolenic acid and essential amino acids maintained the cell proliferation and differentiation of C2C12 cells via their anti-oxidative, anti-apoptotic, and anti-autophagic effects.