Viability of Differentiated Neuronal Cells

The viability of cells was determined by MTT assay. SH-SY5Y cells were plated in 96-well plates (2 × 10⁴ cells/well), cultures for 24 h at 37 °C in 5% CO₂ and were differentiated for 5 days with 10 µM RA. The differentiated neurons were treated with serially diluted concentration of catechin (cat), epicatechin (epi), cyanidin (cy) (50–0.1 µM in EtOH/DMSO (1:5 v/v) and red fruit extract (final concentration: 1, 0.5, 0.25, 0.125, 0.62 and 0 mg/mL) dissolved in serum-free DMEM. After 3 and 18 h of incubation 20 µL of a MTT solution (5 mg/mL in PBS) was added to each well and incubated for an additional 2 h at 37 °C in 5% CO₂. Formazan crystals formed in the wells were solubilized in 200 µL of DMSO (Dimethyl sulfoxide). Absorbance was measured at 570 nm wavelength employing a microplate reader PowerWaveTM XS (BioTek Instruments, Inc., Winooski, VT, USA).
The assay was repeated with three independent experiments. The viability was calculated in comparison to control experiments in which a solvent control was added in place of polyphenols and that was used as 100% viable reference [53 (link)].