highly significantp<0.01
However, the highly significant (p<0.01) inhibition of GST activity was also recorded at the highest concentration (0.012%) of ZnO NPs, while at lower concentrations (0.004% & 0.008%) of ZnO NPs, an insignificant increase of GST activity was observed, thus showing transition phase from active antioxidant defense mechanism (ADM) to exhausted ADM ( Fig 2B ).