2.7. Detoxification Enzyme Activity 
SOD activity was assessed using an assay that utilizes a tetrazolium salt for detection of superoxide radicals generated by xanthine oxidase and hypoxanthine using a superoxide dismutase assay kit colorimetrically at 450 nm (Cayman, Ann Arbor, MI, USA). One unit of SOD was defined as the amount of enzyme needed to exhibit 50% dismutation of the superoxide radical. Total GST activity was measured by quantifying the conjugation of 1-chloro-2,4-dinitrobenzene (CDNB) with reduced glutathione using a glutathione S-transferase assay kit colorimetrically at 340 nm (Cayman). 