Metabolomics reveals that Curcuma longa and demethoxycurcumin inhibit HCT116 human colon cancer cell growth

Studies on the use of natural products to treat cancer are ongoing, and turmeric (Curcuma longa L.), a medicinal crop, is known for various effects including anticancer activity. In this study, the inhibitory effect of C. longa and demethoxycurcumin on cancer cell growth in a colorectal cancer cell line (HCT116) was investigated by using nuclear magnetic resonance (NMR) spectroscopy-based metabolomics. For this analysis, HCT116 cells were treated with doxorubicin (positive control), C. longa extract, or demethoxycurcumin (20, 40, and 60 μM). In the NMR spectra of the HCT116 cell extract, 45 metabolites were identified and quantified. The quantified metabolites were analyzed by biomarker analysis, and significantly changed metabolites were filtered by the area under the curve (AUC) of the receiver operator characteristic (ROC) curve. Multivariate statistical analysis of NMR spectra was conducted to confirm the distribution among groups. Through an S-line plot, it was possible to identify metabolites that contributed to the differences seen in the OPLS-DA score plot. Taken together, the results reveal that C. longa extract induces oxidative stress and changes the energy metabolism in HCT116 cells, and that demethoxycurcumin inhibits the energy metabolism strategy for the survival of cancer cells, escape from immune cells, and cancer cell proliferation, thereby enabling the survival of HCT116 cells.