Finally, the early indicators of oxidative-stress-associated chronic kidney disease (CDK) [127] after CCl4-induced intoxication and its prevention by EOs were investigated by monitoring the catalytic activities of renal toxicity markers, such as xanthine oxidase (rXO) [126] and NADPH oxidase (rNOX) [127], as well as the protectors of the kidneys, nitric oxidase (rNO) [128] and glutathione peroxidase (rGPx) [48]. This evidence concerns the gene FMO5 and chronic kidney disease.