Quercetin and Curcumin Effects in Experimental Hemithyroidectomy.

Background. Thyroid gland is susceptible to oxidative stress. It uses hydrogen peroxide for hormone synthesis and the removal of thyroid tissue may trigger the increase of pro-oxidant processes. Aims. We investigated the antioxidant effects of quercetin and curcumin on the oxidative stress parameters in rats with hemithyroidectomy. Methods. Male albino Wistar rats with hemithyroidectomy were used. The animals were randomly allocated in the following groups: group CMC -received carboxymethyl cellulose (CMC) 1%; Que 20 group -quercetin 20 mg/kg/day; Que 40 group-quercetin 40 mg/kg/day; group Euthyrox -1.3 μg/kg/day of sodium levothyroxine; Curcumin 15 group -15 mg/kg/day of curcumin; Curcumin 30 group -revived 30 mg/kg/day of curcumin. The parameters of the oxidative stress were investigated in serum and thyroid homogenate. Thyroxine (T4) and TSH levels were also evaluated. Results. Quercetin 40 mg/kg/day or Curcumin 30 mg/kg/day administration produced significant modifications: in serum, decreased malondialdehyde (MDA) and increased catalase level; in thyroid gland, decreased MDA, increased glutathione (GSH) and catalase levels. Thyroxine and TSH levels were not modified significantly. Conclusions. Quercetin and curcumin protected against oxidative stress by decreasing the lipid peroxidation and increasing the antioxidant protection. Curcumin presented the best effects. [ABSTRACT FROM AUTHOR]