Paradol Induces Cell Cycle Arrest and Apoptosis in Glioblastoma Cells

Despite being the most common primary malignant tumor of the central nervous system, the prognosis of glioblastoma (GBM) is still remarkably poor. Paradol is a flavor phenolic constituent found in pepper and ginger, with anti-tumor, anti-inflammatory, and antioxidant activities. However, the effects of paradol on GBM cells remain unknown. In this study, we investigated the cytotoxicity of paradol on U-87 and U-251 GBM cells. Cell viability and Transwell assays revealed that paradol treatment markedly inhibited the viability and migration of GBM cells. Flow cytometry analysis showed G0/G1 cell cycle arrest, which was verified by the downregulation of CCNA and CCNB expression using western blotting. Paradol-induced cell apoptosis was confirmed by annexin V-FITC/PI staining and nuclear morphology. Furthermore, the phosphorylation of extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein kinase (MAPK) was determined by western blotting. Collectively, our data revealed that paradol inhibited cell viability and migration of GBM cells by inducing G0/G1 phase arrest and apoptosis, and activating ERK and p38 MAPK signaling.