Objective: To evaluate the mechanism of licochalcone B induce mouse melanoma B16F0 cells apoptosis. Method: Effect of licochalcone B on proliferation of B16F0 cells was determined by MTT. Hoechst 33258 fluorescent staining were used to observe the morphological changes of apoptotic cell. Apoptosis was determined by staining cells with annexin V fluorescein isothiocyanate (FITC) and propidium iodide (PI) labeling.The mRNA expression levels of B cell lymphoma/lewkmia-2(Bcl-2) associated X protein(Bax) and Bcl-2 were detected using RT-PCR analysis. Changes of Caspase-9 and Caspase-3 were measured with fluorescence assay. Result: Licochalcone B(5-15 mg·L-1) can effectively inhibit B16F0 cell proliferation in a dose-dependent manner. IC50 was 11.3 mg·L-1

and cell obviously appeared apoptosis characteristics

with the concentration of licochalcone B increased

the apoptosis rate was increased

licochalcone B(10

12.5 mg·L-1) significantly lowered the mRNA expression levels of Bcl-2/Bax

and raised the expression of caspase-9 and caspase-3

licochaleone B(7.5 mg·L-1) cause the activation degree of Caspase-9 and Caspase-3 higher than 12.5 mg·L-1. Conclusion: Licochalcone B induce B16F0 cell apoptosis through mitochondria-dependent pathway.