Catalpa ovata fruit extract promotes muscular differentiation and exercise performance: In vitro and in vivo study

Objective: To investigate the effect of Catalpa ovata fruit extract (COFE) on muscle growth and exercise performance in C2C12 myoblasts and mice. Methods: Cell viability was determined through a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Myogenic differentiation was observed using Giemsa staining. COFE was administered to mice orally at 50 and 200 mg/kg for 10 weeks. Muscular strength was evaluated using the whole-limb grip strength assay. The expression levels of myogenesis- and energy metabolism-related proteins in vitro and in vivo were determined using Western blotting. Results: COFE significantly improved myoblast-to-myotube differentiation in C2C12 myoblasts. It also increased the expression of myogenesis determination protein 1 and myogenin compared with the control group. Moreover, the expression levels of glucose transporter type 4 (Glut4) and peroxisome proliferator-activated receptor-gamma coactivator 1-alpha (PGC-1α) were significantly elevated in the presence of COFE in C2C12 myoblasts. COFE also markedly increased phosphorylation of AMP-activated protein kinase, which regulates Glut4 and POC-1α expression levels in C2C12 myoblasts. Mice treated with COFE showed improved grip strength. Myogenesis- and energy metabolism-related protein levels in muscle tissue were significantly increased in COFE-administered mice. Conclusions: COFE treatment improves exercise performance by controlling myogenesis and energy metabolism in skeletal muscle. COFE has the potential to be used as an effective natural agent for enhancing muscular strength.