Hello all

I used the below protocol to identify the antioxidant activity

But frankly, I did not understand well the mechanism and what exactly happens and the role of each compound in the used method

So can anybody please help me and explain this with chemical equations?

Thank you so much

used Protocol:

Superoxide radical scavenging activity (SOD):

The superoxide anion scavenging activity can be measured as described by Robak and Gryglewski (1988). The superoxide anion radicals are generated in 3.0 mL of Tris–HCl buffer (16 mM, pH 8.0), containing 0.5 mL of nitroblue tetrazolium (NBT) (0.3 mM), 0.5 mL NADH (0.936 mM) solution, 1.0 mL extract and 0.5 mL Tris–HCl buffer (16 mM, pH 8.0). The reaction is initiated by adding 0.5 mL phenazine methosulfate (PMS) solution (0.12 mM) to the mixture, incubated at 25 C for 5 min and then the absorbance is measured at 560 nm against a blank sample.