Effect of Noni on memory impairment induced by hydrocortisone in mice

Background: Oxidative stress and memory impairment have been implicated, a common functional brain disease. Nuclear factor E2-related factor 2 (Nrf2) is highly induced in oxidative stress, indicating that Nrf2 is an emerging target of memory therapy. This study aimed to investigate the effect of Noni on brain memory impairment induced by hydrocortisone and its protection mechanism in mice. Methods Male Kuming mice were (n = 8/group) given hydrocortisone by gastric gavage for 14 consecutive days to establish the memory impairment model except for those in the control group. At the same day, the corresponding drugs were given by gastric gavage. The changes in ethology were examined. Brains were extracted and subjected to western blot analysis and biochemical analyses to assess the activities of oxidative stress. Results The middle and high-dose Noni groups ameliorated the ethology and the high-dose Noni group increased cerebral protein expressions of Nrf2, kelch-like ECH-associated protein 1 (KEAP1) and heme oxygenase-1 (HO-1), as compared to the model group. The arrangement of CA3 vertebral cells in hippocampus of mice was slightly compact and hyperchromatic and pyknosis were alleviated. Furthermore, the biochemical analyses showed the activities of related enzymes of oxidative stress in high-dose Noni group were increased. Conclusions Noni might be a powerful antioxidant that can protect nerve cell and may possess as a potential benefit for the treatment of memory impairment.