Effect of pinoresinol and vanillic acid isolated from Catalpa bignonioides on mouse myoblast proliferation via the Akt/mTOR signaling pathway

Abstract Sarcopenia is a disease in which skeletal muscle decreases with age. Stimulating the proliferation and differentiation of muscle cells may help prevent sarcopenia. To discover effective natural substances enabling to treat muscle loss without side effects, we evaluated muscle growth with several compounds extracted from Catalpa bignonioides Walt. Among these compounds, pinoresinol and vanillic acid increased C2C12, a mouse myoblast cell line, proliferation the most without cytotoxicity. These substances activated the Akt/mammalian target of rapamycin (mTOR) pathway, which positively regulates the proliferation of muscle cells. In addition, they strongly bound to insulin-like growth factor 1 receptor (IGF-1R), which is an upstream of the Akt/mTOR pathway, indicating that both pinoresinol and vanillic acid stimulate myoblast proliferation through direct interaction with IGF-1R. These results suggest that pinoresinol and vanillic acid may improve the proliferation of skeletal muscle via IGF-1R/Akt/mTOR signaling and thus alleviate diseases such as sarcopenia.