Effects of curcumin and its derivatives on a glioma cell line

Glioblastomas are highly invasive brain tumors associated with oxidative stress (OS) and chronic inflammation. Curcumin (CUR), the principal bioactive compound of Curcuma longa, as well as its natural analogues demethoxycurcumin (DMC) and bisdemethoxycurcumin (BDMC), exhibit promising therapeutic properties. The aim of this study was to evaluate the antioxidant effects of CUR, DMC, and BDMC in an in vitro model using the LN229 glioma cell line. LN229 glioblastoma cells and MO3.13 cells as a non-tumor control were cultured in Dulbecco’s Modified Eagle Medium (DMEM) under standard conditions. Cells were treated with CUR, DMC, and BDMC for 24 h and 48 h at concentrations selected based on MTT assay results. Antioxidant capacity was assessed using the ferric reducing antioxidant power (FRAP) assay, while lipid peroxidation and protein oxidation were evaluated by measuring malondialdehyde (MDA) and protein carbonyl group levels, respectively, in cell lysates. Curcumin, demethoxycurcumin, and bisdemethoxycurcumin reduced LN229 cell viability in a time- and dose-dependent manner. Curcumin exhibited the strongest antioxidant activity, significantly decreasing MDA levels and protein carbonyl content (p < 0.001). Demethoxycurcumin was the most effective compound in reducing protein oxidation after 48 h, whereas bisdemethoxycurcumin increased MDA levels, suggesting a potential pro-oxidative effect. The FRAP assay confirmed a sustained antioxidant capacity of all compounds, particularly at higher concentrations. In conclusion, curcumin and its derivatives demonstrated both antioxidant and cytotoxic activities in a time- and dose-dependent manner. Among the tested compounds, curcumin showed the most stable and long-lasting antioxidant and cytotoxic effects, indicating its potential therapeutic value in mitigating oxidative stress–related damage in glioma cells.