Luteolin protects against high fat diet-induced cognitive deficits in obesity mice

• Luteolin ameliorated high fat diet-induced cognitive dysfunction.
• Luteolin inhibited obesity-induced oxidative stress in brain.
• Luteolin suppressed obesity-induced neuroinflammation in brain.
• Luteolin reduced obesity-induced neuron insulin resistance in brain.
• Luteolin reduced obesity-induced glucose metabolic disorder in brain.

The epidemic and experimental studies have confirmed that the obesity can lead to neuroinflammation, neurodegenerative diseases and adversely affect cognition. Despite the numerous elucidations on the impact of obesity on cognition decline, the contributors to the impairments in obesity remain unclear. Male C57BL/6J mice were fed either a control or high-fat diet (HFD) for 16 weeks and then randomized into four groups treated with their respective diets for 4 weeks including control diet (CD); control diet + luteolin (CDL); high-fat diet (HFD), high-fat diet + luteolin (HFDL). The dose of luteolin was 10 mg/kg, oral. We showed that adding luteolin in high-fat diet can significantly reduce body weight gain, food intake and plasma cytokines as well as improving glucose metabolism of mice on HFD. Importantly, we showed that luteolin treatment had the effects of alleviating neuroinflammation, oxidative stress and neuronal insulin resistance in the mouse brain, restored blood adipocytokines level to normal. Furthermore, luteolin increased the level of brain-derived neurotrophic factor (BDNF), the action of synapsin I (SYP) and postsynaptic density protein 95 (PSD-95) in the cortex and hippocampus as to that the behavioral performance in Morris water maze (MWM) and step-through task were significantly improved. These results indicate a previously unrecognized potential of luteolin in alleviating obesity-induced cognitive impairment for type-2 diabetes mellitus and Alzheimer disease (AD).