The Apoptotic Activity of Curcumin Against Oral Cancer Cells Without Affecting Normal Cells in Comparison to Paclitaxel Activity.

Until now, chemotherapy, which has a series of side effects, has been the most widely employed treatment for different types of cancer. However, bioactive products have been utilized as alternative medicines for tumors due to their bioactivities with low or no side effects in normal cells. This research reported for the first time that curcumin (CUR) and paclitaxel (PTX) have significant anti-cancer activity against normal human gingival fibroblast (HGF) and tongue squamous cell carcinoma fibroblast (TSCCF) cell lines. The results showed that CUR (13.85 microg mL(-1)) and PTX (8.17 microg mL(-1)) significantly inhibited TSCCF cell viability, with no significant effect on normal HGF cells. SEM showed morphological changes in cells treated with CUR and PTX, especially with TSCCF cells, compared to HGF normal cells. For TSCCF, the results showed the highest necrosis was achieved with CUR (58.8%) and PTX (39%) as compared to the control (2.99%). For normal HGF cells, the highest early and late apoptosis was achieved with PTX. Further, DCFH-DA analyses showed no significant ROS stimulation in TSCCF and HGF cell lines treated with CUR and PTX. The (1)H NMR analysis results show the presence of methoxy and hydroxyl groups and aromatic hydrogens in the CUR structure. In conclusion, the results confirmed that CUR is more specific to the oral cancer cells but not normal cells by inducing apoptosis in a dose- and time-dependent manner, with decreased TSCCF cell viability, and the cytotoxicity of CUR and PTX is not through the ROS pathway.