Abstract

The oropharyngeal cancer is the popular medicinal uses of Curcuma caesia Roxb. (C. caesia) include the treatment of cancer. We aimed to evaluate the cytotoxic potential of C. caesia extract in oropharyngeal cancer cells. Total phenolic compounds and secondary metabolites of C. caesia extracts were determined by the Folin-Ciocalteu and UPLC-QToF-MS methods, respectively. Cellular analyses were carried out in an oropharynx cancer cell line (FaDu) and in a control keratinocyte cell line (Hacat). The cytotoxicity assay was carried out by reduction of 3-[4,5-dimethylthiazole-2-yl]-2,5-diphenyltetrazolium bromide (MTT). Flow cytometry was conducted to evaluate cell cycle progression, and cell morphology was evaluated using Giemsa-May-Grunwald stain. Analysis of the intracellular Reactive Oxygen Species (ROS), Mitochondrial Membrane Potential (MMP), and the expression of p21, Bax and cytochrome c were conducted. The extract demonstrated dose-dependent cytotoxic activity in both cell lines. Increased retention was seen in the early stages of the cell cycle (G0/G1) in FaDu cells. Moreover, FaDu cells showed strong alterations in their morphology that suggested cellular apoptosis and there was increased expression of p21 in that line. The treatment with C. caesia extract shows no significant differences in ROS, cytochrome c or Bax in both cell lines. C. caesia extract reduces cell viability and induces apoptosis in FaDu cells without deleterious effects in Hacat cells. To our best knowledge, there has been no other study that described such effect in cancer cells due to the treatment of organic C. caesia extract.

Keywords: Cell viability; Oropharyngeal cancer; p21 expression; Apoptosis; Zingiberaceae; Phenolic compounds