*4.6. MTS-Assay*

For the cell viability and protection assays after 24 h a commercially proliferation assay named "CellTiter 96® AQueous One Solution Cell Proliferation Assay" from Promega Corporation (Mannheim, Germany) was applied as described in the instructions of the supplier. Twenty μL of the MTS solution was added to each treated well of a 96 well plates for 1 h. For the prior treatment of cells, media without phenol red was used.
