The effect of BBR on cell viability in A549 cells. (A) Chemical structure of berberine hydrochloride. A549 cells (B) and nomal human bronchial epithelial cells (C) were treated with 0, 20, 40, 80 and 160 μM BBR for 48h and 72h. Cell viability was measured using MTT assay. Values are expressed as mean±SD of three experiments. *P<0.05, **P<0.01, as compared with control.