Gamma-oryzanol Prevents LPS-induced Brain Inflammation and Cognitive Impairment in Adult Mice

Rice ( L.) is the main food source for more than half of humankind. Rice is rich in phytochemicals and antioxidants with several biological activities; among these compounds, the presence of γ-oryzanol is noteworthy. The present study aims to explore the effects of γ-oryzanol on cognitive performance in a mouse model of neuroinflammation and cognitive alterations. Mice received 100 mg/kg γ-oryzanol (ORY) or vehicle once daily for 21 consecutive days and were then exposed to an inflammatory stimulus elicited by lipopolysaccharide (LPS). A novel object recognition test and mRNA expression of antioxidant and neuroinflammatory markers in the hippocampus were evaluated. ORY treatment was able to improve cognitive performance during the neuroinflammatory response. Furthermore, phase II antioxidant enzymes such as heme oxygenase-1 (HO-1) and NADPH-dehydrogenase-quinone-1 (NQO1) were upregulated in the hippocampi of ORY and ORY+LPS mice. Lastly, γ-oryzanol showed a strong anti-inflammatory action by downregulating inflammatory genes after LPS treatment. These results suggest that chronic consumption of γ-oryzanol can revert the LPS-induced cognitive and memory impairments by promoting hippocampal antioxidant and anti-inflammatory molecular responses.