The antitumor effects of osthol were evaluated using the murine P-388 D1 leukemia in vivo model. P-388 D1 cells were transplanted intraperitoneally into 5-week-old CDF1 female mice on day zero. Osthol was dissolved in 10% soybean oil and administered orally once per day on days 0 - 8 at a dose of 30 mg/kg. The life-span of tumor-bearing mice receiving osthol was increased by more than 37.5% compared to solvent control mice.

Human cervical carcinoma (HeLa) were maintained in DMEM supplemented with 10% FBS, 100 mg/L streptomycin, and 100 IU/mL penicillin and incubated at 37 deg-C in a 5% CO2 atmosphere. Cell cultures were prepared in a 96 well plate and incubated for 24 and 48 hours with a range of Osthol concentrations. The surviving cells were counted using the tetrazolium assay. Osthol inhibited the growth of HeLa cells in a time and concentration-dependent manner, with IC50 values of 77.96 and 64.94 microM for 24 and 48 hours respectively.