Effects of the hydroalcoholic extract of Rosa damascena on learning and memory in male rats consuming a high-fat diet

Context: High-fat diet (HFD) can cause deficits in learning and memory through oxidative stress and increase Alzheimer disease risk. Rosa damascena Mill. (Rosaceae) extract possesses potent antioxidant properties. Objective: This study investigated the effects of the hydroalcoholic extracts of petals of R. damascena on learning and memory in male rats consuming an HFD. Materials and methods: Forty male Wistar rats (200-250 g) were randomly assigned to four groups: control, R. damascena extract, HFD and HFD+extract. The extract (1 g/kg bw daily) was administered by oral gavage for 1 month. Animals were allowed free access to high-fat chow for 3 months. The Morris water maze and the passive avoidance learning tests were used to assess learning and memory. Results: In the passive avoidance learning test, the step-through latencies in the retention test (STLr) of the extract (147.4 +/- 23.3) and HFD (150.3 +/- 25.2) groups were significantly lower than those of the control group (270.4 +/- 10.5) (respectively, p < 0.001 and p < 0.01). STLr was significantly higher in the HFD+extract group (265.3 +/- 10.6) than in the HFD group (150.3 +/- 25.2) (p < 0.01). Time spent in the dark compartment (TDC) in the HFD+extract group (5.3 +/- 2.6) was significantly lower than that in the HFD group (85.8 +/- 19.1) (p < 0.05). Discussion and conclusion: Our results indicate that, while HFD or R. damascena extract alone leads to memory deficits, R. damascena extract exerted a positive effect on HFD-induced memory deficits. We hypothesize that the observed effects of R. damascena extract are likely due to its strong antioxidant properties.