MTS

Human neuroblastoma SH-SY5Y cells (ATCC CRL-2266) were maintained in DMEM and grown to confluence in 96-well plates as previously described⁶⁴. Cells (≈10,000 cells /well) were treated with 2.0 µM tau oligomers and 2.0 µM tau oligomers incubated with 5 µM of curcumin or curcumin derivatives for 24 hours. The dose-response curve was used to calculate the concentration of the compound required for 50% inhibition of cell viability (IC₅₀).

Primary neurons were treated with 0.5 µM tau oligomers or 0.5 µM tau oligomers pre-incubated with 5 µM of curcumin derivatives for 2 hours. Primary neurons were also treated with 5 µM of curcumin derivatives and cell viability was assessed over the time at 2, 12 and 24 hours by evaluating LDH release of the cells.

Cell viability was corrected by the vehicle background. All measurements were performed in triplicate. The cytotoxic effect was determined using MTS assay (G3582, Promega) for assessing cell viability following the manufacturers’ instructions. Optical density (OD) was measured at 490 nm with POLARstar OMEGA plate reader (BMG Labtechnologies). Cell viability was calculated as the percentage of the OD value of treated cells compared to untreated controls, according to the following equation: Viability = (OD SAMPLE/OD CONTROL) × 100%.