Superoxide dismutase (SOD) activity was measured with 50%
inhibitor rate about the reduction reaction of WST-1 using SOD
Assay kit (Dojindo Molecular Technologies, Inc.). One unit of SOD is
defined as the amount of the enzyme in 20 ml of sample solution
that inhibits the reduction reaction of WST-1 (2-(4-lodophenyl)-3-
(4-nitrophenyl)-5-(2,4-disulfophenyl)- 2H -tetrazolium, monosodium
salt) with superoxide anion by 50%. SOD activity was
expressed as unit mg protein