Ethanol extract of Cyclolepis genistoides D. Don (palo azul) induces formation of myotubes, which involves differentiation of C2C12 myoblast cells

In this study, we examined the cell differentiation effect of an ethanol extract of Cyclolepis genistoides D. Don, a herbaceous perennial belonging to the family Asteraceae (vernacular name: palo azul). Palo azul has numerous physiological effects that contribute to the prevention of metabolic syndromes, although the mechanism remains unclear. We previously suggested that palo azul has antidiabetic activity via an adipose differentiation effect. Here, we focused on whether palo azul promoted the differentiation of myoblasts. The mouse muscle myoblast cell line C2C12 was cultured and differentiated using horse serum with or without an ethanol extract of palo azul (12.5-200 μg/mL). Quantitative real-time polymerase chain reaction was performed to evaluate differentiation markers, including insulin-like growth factor-1 and myogenin. To evaluate myotube formation, myosin heavy-chain (MHC) expression and localization were detected by immunohistochemistry. Palo azul increased the expression of the differentiation markers. Furthermore, immunohistochemistry analysis revealed increased formation of MHC myotubes after palo azul treatment along with increased diameter and fusion indices of the myotubes. The expression level of MHC was also increased. In conclusion, palo azul may increase muscle mass in the body and improve insulin resistance conditions by facilitating the formation of myotubes by promoting myocyte differentiation.