Then, 400 μm of freshly prepared solution was added and
diluted to the final volume of 4.1 mL with deionized water. This procedure was repeated for 400 μL,
300 μL, 200 μL, 100 μL and 50 μL addition of freshly prepared solutions of the tested compounds.
The prepared solutions mixed and incubated at room temperature for 30 minutes. After the incubation,
200 μL of solution from each tube was transferred to the 96 well plate. The absorbance at 450 nm was
determined against a reagent blank by Beckman Coulter DTX 880 spectrometer.