The Effect of Picein on Inhibitory Avoidance Memory and Activity of Antioxidant Enzymes in Hippocampus of Male Rats with Scopolamine-Induced Injury

Alzheimer disease (AD) is a common neurologic disorder, impairing memory and spatial perception. Consistent with the extensive search for its treatment, we investigated the effect of Picein on inhibitory avoidance memory, lipid peroxidation, and the activity of hippocampal antioxidant enzymes in rats. Forty adult male Wistar rats were randomized into control group (no intervention), model group (intraperitoneal injection of 3-mg/kg scopolamine), and three interventional groups (1.5-, 2.5-, and 5-mg/kg intraventricular Picein, once a day for 7 days, 24 h after scopolamine injection). After behavioral test, the rats' hippocampus was isolated for measuring oxidative stress markers, including enzymes superoxide dismutase (SOD), malondialdehyde (MDA), glutathione peroxidase (GPX), catalase (CAT), and total antioxidant capacity (TAC). One-way ANOVA was used for comparing numeric variables among the groups using SPSS v.21. The results showed scopolamine decreased SOD, GPX, and CAT enzymes, and TAC level, and increased MDA level, compared with the control group (P < 0.001) that confirmed the scopolamine-induced AD model. The two doses of 2.5- and 5-mg/kg Picein increased latency for entering the dark room, compared to the scopolamine group (P < 0.05), making them similar to the control group. The number of entries into the dark room in the 2.5-mg/kg Picein reduced and approached the control group (P < 0.05). The 2.5-mg/kg Picein decreased MDA and increased SOD, GPX, and TAC, more than 5 mg/kg Picein, both different than scopolamine; only 2.5-mg/kg Picein had different CAT, compared to scopolamine group (P < 0.05). In conclusion, by lowering oxidative stress in the hippocampus, Picein was able to prevent the scopolamine-induced impaired learning and avoidance memory in rats.