Anticancer activity of Phloretin against the human oral cancer cells is due to G0/G1 cell cycle arrest and ROS mediated cell death.

Phloretin is one of the important polyphenolics abundantly present across the plant kingdom. Studies have reported the anticancer effects of Phloretin against different human cancer cells. Nonetheless, the anticancer effects of Phloretin have not been explored against the human oral cancer cells. Therefore this study was designed to investigate the anticancer effects of Phloretin against the human oral cancer cells.CCK-8 assay was used for the determination of cell viability. Annexin V/propidium iodide (PI) staining and flow cytometry were used for necrosis detection and cell cycle analysis, respectively. Wound healing assay was used for cell migration analysis. Western blot analysis was used for protein expression analysis.The results showed that Phloretin suppressed the proliferation rate of the human SCC-1 oral cancer cells and showed an IC50 of 12.5 µM. Nonetheless, Phloretin had negligible effects on the proliferation rate of the EBTr normal oral cells. DAPI staining showed that Phloretin did not induce apoptosis and western blot showed that it had no apparent effects on the Bax and Bcl-2 expression. Nonetheless annexin V/PI staining showed that Phloretin caused cell death in SCC-1 oral cancer cells. Flow cytometric analysis showed that Phloretin caused increase in the reactive oxygen species (ROS) levels of the SCC-1 cells in a time and dose-dependent manner. Cell cycle analysis showed that Phloretin caused increase in the percentage of the SCC-1 cells in the G0/G1 phase of the cell cycle leading to G0/G1 cell cycle arrest. The G0/G1 arrest of SCC-1 cells was also associated with depletion of cyclin D1, CDK4 and CDK6 expression. Wound healing assay was also performed which showed that Phloretin suppressed the migration of the SCC-1 oral cancer cells, indicative of the anti-metastatic potential of Phloretin.Phloretin exhibits significant growth inhibitory effects on the human oral cancer cells and may prove beneficial in oral cancer treatment.