Aims: Sesamol lignan is a phenolic compound found in sesame seeds. We investigated the effect of different concentrations of sesamol on oxidative stress in colorectal carcinoma cells (HCT116).
Main methods: Antioxidation in vitro was determined from elimination of the DPPH radical, ferric reducing-antioxidant power (FRAP), O2(-), and peroxyl radical scavenging activity. Intracellular O2(-), H2O2 and GSH levels were determined by DHE, DCFH-DA, and CMF-DA assay, respectively. Cell viability was detected by neutral red assay. Cell cycle proportion and mode of apoptotic HCT116 cells death was analyzed by flow cytometry. Apoptosis in sesamol-treated HCT116 cells was confirmed by morphological changes in the nuclei using DAPI staining and changes in mitochondrial membrane potential using the DiOC6(3) assay.
Key findings: Sesamol at both low (0.05 and 0.25mM) and high (0.5, 2, 5, and 10mM) concentrations concurrently reduced FRAP reagent and scavenged DPPH, and O2(-). Sesamol at low concentrations scavenged ROO, but ROO-scavenging was decreased at higher concentrations. Sesamol suppressed cell viability via disruption of cell cycle progression at high concentrations (0.5, 1, 2, and 5mM), thereby causing S-phase arrest and inducing apoptosis-through the production of intracellular O2(-), mitochondrial dysfunction, and DNA fragmentation.
Significance: High concentrations of sesamol induced the mitochondrial apoptosis pathway in human colon cancer HCT116 cells via a pro-oxidant effect.
Keywords: Apoptosis; Chemopreventive effect; Human colon cell line; Reactive oxygen species; Sesame; Sesamol.
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