Methanol extracts of Asarum sieboldii Miq. induces apoptosis via the caspase pathway in human FaDu hypopharynx squamous carcinoma cells

Asarum sieboldii Miq. (Aristolochiaceae) is a perennial herbaceous plant and has been used as traditional medicine for treating diseases, cold, fever, phlegm, allergies, chronic gastritis, and acute toothaches. Also, it has various biological activities, such as antiallergic, antiinflammatory, antinociceptive, and antifungal. However, the anticancer effect of A. sieboldii have been rarely reported, except anticancer effect on lung cancer cell (A549) of water extracts of A. sieboldii. This study investigated the anticancer activity of methanol extracts of A. sieboldii (MeAS) and the underlying mechanism in human FaDu hypopharyngeal squamous carcinoma cells. MeAS inhibited FaDu cells grown dose-dependently without affecting normal cells (L929), as determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide and live and dead assay. In addition, concentration of MeAS without cytotoxicity (0.05 and 0.1 mg/mL) inhibited migration and colony formation. Moreover, MeAS treatment significantly induced apoptosis through the proteolytic cleavage of caspase-3, -7, -9, poly (ADP-ribose) polymerase, and downregulation of Bcl-2 and upregulation of Bax in FaDu cells, as determined by fluorescence-activated cell sorting analysis, 4'6-diamidino-2-phenylindole stain, and western blotting. Altogether, these results suggest that MeAS exhibits strong anticancer effects by suppressing the growth of oral cancer cells and the migration and colony formation via caspase- and mitochondrial-dependent apoptotic pathways in human FaDu hypopharyngeal squamous carcinoma cells. Therefore, MeAS can serve as a natural chemotherapeutic for human oral cancer.