Abstract: Objective: To evaluate the effect of ferulic acid and its analogues, curcumin and oryzanol, on oxidative stress in mice. Methods: Ninety male ICR mice were randomly divided into six groups: normal, model, ferulic acid, curcumin, oryzanol and positive control (coenzyme Q10) groups. The mice in the normal group were intramuscularly injected with normal saline, while those in the other groups were injected with 40 mg/kg mb of prednisone once every three days for eight weeks to induce oxidative stress. The mice in the normal and model groups were fed a normal diet, and 40 mg of ferulic acid, curcumin, oryzanol and coenzyme Q10 were added to 1 kg of the normal diet for the other four groups, respectively. After feeding for four weeks, behavioral experiments were started: sucrose preference and forced swimming. After feeding for eight weeks, all the mice were sacrificed to collect plasma and liver, heart and muscle tissues and extract mitochondria from heart, liver, and leg muscle tissues for measurement of oxidative stress-related parameters. Results: 1) The body mass of the mice in the ferulic acid group decreased significantly compared with that before being injected with prednisone. The sucrose preference of the mice in the coenzyme Q10 group was significantly higher than that in the model and ferulic acid groups (P < 0.05). The cumulative time of the desperate state for the mice in the curcumin, oryzanol and coenzyme Q10 groups during the forced swimming experiment was significantly shorter than that in the model group (P < 0.05). 2) The contents of hypothalamic corticotropin-releasing hormone (CRH) and pituitary adrenocorticotropic hormone (ACTH) in the ferulic acid, curcumin, oryzanol and coenzyme Q10 groups were significantly lower than those in the model group (P < 0.05). Plasma corticosterone (CROT) levels in the oryzanol and coenzyme Q10 groups were significantly lower than those in the model group (P < 0.05). 3) The contents of malondialdehyde (MDA) in plasma and the tested tissues in the oryzanol and coenzyme Q10 groups were significantly lower than those in the model group (P < 0.05), and the activity of catalase (CAT) was significantly higher than that in the model group (P < 0.05). 4) The total superoxide dismutase (SOD) activity in the tissues and the Mn-SOD activity in muscle mitochondria in the oryzanol and coenzyme Q10 groups were significantly higher than their respective counterparts the model group (P < 0.05). 5) The mitochondrial membrane potential in the oryzanol and coenzyme Q10 groups was significantly higher than that in the model group (P < 0.05). The mitochondrial NADH/NAD+ ratio and acetyl-CoA content in the coenzyme Q10 group were significantly higher than those in the model group (P < 0.05). The above results indicated that under the experimental conditions employed in this study, the anti-oxidative stress and mitochondrial antioxidant capacities of the four drugs increased in the following order: ferulic acid < curcumin < oryzanol < coenzyme Q10. Oryzanol and coenzyme Q10 were significantly more effective in improvinf the activity of antioxidant enzymes in tissues and rescuing the mitochondrial dysfunction caused by oxidative stress. Among these, ferulic acid had the lowest antioxidant capacity and coenzyme Q10 possessed the strongest antioxidant capacity, which was slightly stronger than that of oryzanol. The antioxidant capacity of ferulic acid and its two analogues may be associated with their lipophilicity.

Key words: ferulic acid analogues; oxidative stress; antioxidant capacity; mitochondria