Plumbagin suppresses tumor cell growth in oral squamous cell carcinoma cell lines

Objectives Plumbagin ( PL ), a naturally occurring quinoid, exerts antitumoral effects in diverse types of cancer cells. However, the effect of PL on tumor cell proliferation in oral squamous cell carcinoma ( OSCC ) remains poorly understood. In this study, we assessed the efficacy of PL , in human OSCC cells. Methods The effect of PL on the cell growth and apoptosis of OSCC cell lines was evaluated using MTT and Annexin V assays, respectively. The effect of PL on mitochondrial membrane potential loss and reactive oxygen species ( ROS ) generation was evaluated using flow cytometry analysis. Results MTT assay showed that PL dose‐dependently suppressed OSCC cell growth, with IC 50 values ranging from 3.87 to 14.6  μ M. Flow cytometry analysis revealed that PL treatment resulted in a significant decrease in mitochondrial membrane potential and an increase in the number of apoptotic cells. Notably, ROS generation was significantly elevated after PL treatment. Furthermore, a ROS scavenger, N ‐acetylcysteine ( NAC ), clearly suppressed the decrease in mitochondrial membrane potential, increase of caspase‐3/7 activity, and apoptosis after PL treatment. Conclusion This study provides the considerable evidence of the tumor‐suppressive effect of PL , thereby highlighting its therapeutic potential for OSCC treatment.