RT-PCR assay for induction of follistatin expression. (A) Assays of S. Persicae extract and liquid-liquid extraction products. HepG2 cells were treated with S. Persicae extract at the indicated concentrations and S. Persicae-derived fractions for 24 h, and the expression of follistatin mRNA was detected by RT-PCR. S/N, supernatant; EA, ethyl acetate. (B) HPLC separation of the n-butanol extract. The n-butanol extract was separated by semi-preparative RP-HPLC on a C18 column into 11 fractions. (C) Assays of HPLC fractions. The HPLC fractions were assayed for induction of follistatin mRNA expression.