Anethole improves spatial memory and reduces oxidative stress in rats on a calorie-dense diet

Abstract The fragrant organic monoterpene anethole is a component of anise and fennel essential oils. The research intended to evaluate the effects of anethole on spatial memory and oxidative stress in rats on a calorie-dense diet (CDD). Male Wistar rats ( n = 50) were allocated into 5 groups: Control, CDD, CDD + A62.5, CDD + A125, and CDD + A250. The dietary intervention lasted for 10 weeks, during which anethole at doses 62.5, 125, and 250 mg kg −1 was daily orally administered to the last three groups. In the 9th week, the open field test (OFT) for locomotor activity and the spatial object recognition test for spatial memory assessment were carried out. At the end of the experiment, the endogenous antioxidant enzyme superoxide dismutase (SOD) was measured in serum, and the thiobarbituric acid reactive substances (TBARS) were measured in whole-brain homogenate as markers of lipid peroxidation. The OFT showed no significant differences in the locomotor activity across the groups. The consumption of CDD resulted in a decline in spatial memory manifested by the decrease of the recognition index, while anethole treatment prevented this effect in a concentration-dependent manner. In CDD group, the activity of SOD was significantly reduced ( P < 0 .05 vs. Control), while the brain TBARS were significantly elevated ( P < 0 .05 vs. Control). SOD level in CDD + A250 group was comparable to that of the control group. TBARS levels in all anethole-treated groups did not differ significantly from the control value. In conclusion, anethole prevented CDD-induced spatial memory impairment and reduced oxidative stress in rats on a calorie-dense diet.