Examination of the anabolic activity and mechanisms of action of the combination of Diosgenin and Ecdysterone in C2C12 myotubes

Plant steroids such as ecdysterone (ECDY) or diosgenin (DIO) have been associated with anabolic and performance-enhancing effects for years. However, the molecular mechanisms have not yet been extensively studied in skeletal muscle cells. Consequently, the anabolic activity and associated molecular mechanisms of ECDY and DIO alone and in combination were investigated in C2C12 myotubes. Dose-dependent effects of both compounds on myotube diameter, mRNA expression of IGF-1 and PI3KR1 as well as expression of myosin heavy chain (MHC) proteins were analyzed in differentiated C2C12 cells. In addition, the binding affinities to androgen and estrogen receptors were analyzed. Treatment with ECDY and DIO significantly induced hypertrophy of C2C12 myotubes. Partially additive effects were observed. This is supported by the mRNA expression of IGF-1 and PI3KR1 as well as in the expression of MHC. However, no clear statement can be made regarding which combination has the strongest additive effects. Besides the results suggest that, in contrast to ECDY, DIO has antiandrogenic effects and bind on AR. Consequently, it indicate that two different mechanisms of action are activated in ECDY and DIO combinations. However, this must be confirmed in further cell cultures studies and human interventions concerning anti-doping regulations.