Expression of cell apoptosis-associated proteins regulated by steviol. (A) Bcl-2, Bax, Caspase 3, Survivin; (B) Relative expression levels of the apoptosis-associated proteins, calculated using densitometric analysis. β-actin was used as an internal control. *P<0.05 and **P<0.01 vs. untreated cells. Bcl-2, B-cell lymphoma 2; Bax, Bcl-associated X protein.