Dietary uptake of Salvia macilenta extract improves Nrf2 antioxidant signaling pathway and diminishes inflammation and apoptosis in amyloid beta-induced rats

Studies showed the protective role of Salvia in traditional medicine against neurodegenerative diseases. Salvia macilenta is one of the potent antioxidant herbs among Salvia species against oxidative stress. In the current study, the effect of oral administration of S. macilenta in the antioxidant, anti-inflammatory activities of Aβ-injected male albino Wistar rats was determined. Rats were received S. macilenta (50 mg/kg/day) orally, for ten successive days and then some of them received Aβ (10 ng/µl) in their hippocampus (CA1 region). Proteins involved in antioxidant defense system and inflammatory signaling pathways in the hippocampus and prefrontal cortex were evaluated using Western blotting technique. To study apoptosis, Western blotting technique and histological staining were used. Catalase activity, glutathione peroxidase (GSH) and nitric oxide levels were measured. Results demonstrated that S. macilenta increased Nrf2 protein level and decreased TNFα and IL-6 protein level in Aβ-injected rats compared to the Aβ-injected group in the hippocampus and prefrontal cortex. Histological analysis showed pretreatment with S. macilenta decreased apoptosis levels in the hippocampus and prefrontal cortex, about 41 and 42%, compared to Aβ-injected rats, respectively. This study showed that catalase activity was changed in the S. macilenta + Aβ group compared to the Aβ-injected rats. Also, GSH level was increased in the S. macilenta + Aβ group compared to the Aβ-injected rat. Orally treatment of S. macilenta extract in Aβ-injected rats could ameliorate protective pathways and, so, it can be one of the proposed dietary supplements for the prevention of Alzheimer’s disease and dementia.