Effects of curcumin on brain-derived neurotrophic factor levels and oxidative damage in obesity and diabetes

We evaluated the effects of curcumin treatment on protein oxidation (PO), lipid peroxidation (LP) and brain-derived neurotrophic factor (BDNF) levels in the hippocampus and frontal cortex (FC) of diabetic db/db mice (DM) and in sera of obese humans. Thus, DM were treated daily with 50 mg/kg of curcumin during an 8-week period. Obese human were treated daily with 500 and 750 mg of curcumin that was administered orally for 12 weeks; BDNF, PO and LP levels in sera were determined at in weeks 0, 2, 6 and 12 of treatment. BDNF levels decreased in hippocampus and FC of DM as compared with untreated wild-type mice. Curcumin improved or restored BDNF levels to normal levels in DM, but curcumin did not have any effect on BDNF levels in sera of obese humans. In hippocampus and FC of DM, hyperglycaemia and curcumin did not have effect on LP levels. Hyperglycaemia increased PO levels in hippocampus and FC, whereas curcumin decreased these levels in hippocampus but not in FC. In sera of obese humans, the 500-mg dose decreased LP levels in weeks 6 and 12 when compared with basal levels, but the 750-mg dose did not have any effect; both doses of curcumin decreased PO levels in weeks 2, 6 and 12 of treatment when compared with basal levels. Present results suggest a therapeutic potential of curcumin to decrease oxidation caused by obesity in humans and also show that curcumin restores BDNF levels in DM.