Figure 2. Naringin inhibits the proliferation of osteosarcoma cells. (A) Results of MTT proliferation assays in hFOB1.19, MG63, and U2OS cells cultured with various concentrations of naringin for different times. Results represent the mean ± SD of three experiments done in triplicate. **P < 0.05, compared with NaCl. (B) Proliferation inhibition rates induced by naringin on MG63 and U2OS cells. IC50 values were calculated through linear regression. (C, D) Flow cytometric analysis of cell cycle distribution in MG63 and U2OS cells pre-incubated with or without naringin for 24 h and stained with PI. The experiment was repeated three times. **P < 0.05, compared with NaCl. (E, F) Flow cytometric assay of apoptosis in MG63 and U2OS cells pre-incubated with or without naringin for 24 h and stained with Annexin V-FITC/PI. The experiment was repeated three times. **P < 0.05, compared with NaCl. (G-J) Expression of Cyclin D1 and bcl-2 detected by Western blot and real-time PCR in MG63 and U2OS cells treated with NaCl or naringin for 24 h. **P < 0.05, compared with NaCl.