Cytoprotective and Cytotoxic Effects of Curcumin: Dual Action on H₂O₂-Induced Oxidative Cell Damage in NG108-15 Cells

抄録

The ability of curcumin, a natural antioxidant isolated from Curcuma longa, to inhibit hydrogen peroxide (H₂O₂)-induced cell damage in NG108-15 cells was examined. When added simultaneously with 500 μM H₂O₂, curcumin (25—100 μM) effectively protected cells from oxidative damage. However, when the cells were pretreated with curcumin (25—100 μM) for 1.5 h before H₂O₂ exposure, curcumin was unable to inhibit H₂O₂-induced cell damage. Instead, it caused a significant concentration-dependent decrease in cell viability after H₂O₂ exposure. This dual action of curcumin suggests that pretreatment with curcumin by itself did not have any significant effect on the viability of the NG108-15 cells, but it sensitized them to oxidative damage induced by H₂O₂ under our experimental conditions. It appears that these events may not relate to the antioxidant and free radical scavenging activities of curcumin.