ETAS®, a Standardized Extract of Asparagus officinalis Stem, Alleviates Sarcopenia via Regulating Protein Turnover and Mitochondrial Quality

Background: ETAS®, a standardized extract of Asparagus officinalis stem, has been found to alleviate cognitive impairment in senescence-accelerated mice prone 8 (SAMP8) and is now considered a functional food in aging. The present study aimed to investigate the impacts of ETAS® on relieving aging-related muscle atrophy in SAMP8 mice. Methods: The SAMP8 mice were fed a regular diet supplemented with 200 or 1000 mg/kg BW ETAS®50 for 12 weeks. Grip strength, muscle mass, and molecular markers of protein synthesis, degradation, and mitochondrial quality were assessed. Results: We found that ETAS® significantly increased grip strength and muscle mass in SAMP8 mice. At the molecular level, ETAS® significantly upregulated protein synthesis via PI3K/Akt/mTOR/p70S6K and downregulated protein degradation via FoxO1a/atrogin-1 and MuRF-1 and myostatin via NFκB expression. In addition, ETAS® improved mitochondrial quality via promoting mitochondrial biogenesis genes, oxidative respiration genes, fusion/fission genes, PGC1α, and PINK1 proteins and maintained the autophagic flux via reducing ATG13, LC3-II/LC3-I, and p62. Conclusions: ETAS® exerts beneficial effects on sarcopenia by modulating the positive protein turnover and improving mitochondrial quality in aging.