Fig. 2. Effect of cinnamon essential oil administration on oxidative stress markers in liver among groups. Levels of SOD (A), GPx (C), and CAT (D) were found to be decreased due to FA treatment, as a result of oxidative stress. CEO administration at the dose of 100 mg/kg ameliorated these abnormal elevations. MDA (B) and NO (E) activities which were increased in response to FA treatment, were significantly decreased following 100 mg/kg CEO administration. C, control; FA, formaldehyde 10 mg/kg; V, FA 10 mg/kg+solvent; CEO_10,20,100, FA 10 mg/kg+cinnamon essential oil 10,20,100 mg/kg; SOD, superoxide dismutase; GPx, glutathione peroxidase; CAT, catalase; MDA, malondialdehyde; NO, nitric oxide. ^*P<0.05, ^**P<0.01, ^***P<0.001, ^****P<0.0001.