Effects of Hypericum Scabrum extract on anxiety and oxidative stress biomarkers in rats fed a long-term high-fat diet

The continuous and long-term consumption of a high-fat diet (HFD) leads to weight gain and obesity. A HFD and obesity increase the risks of psychiatric disorders, such as anxiety and depression. In this study, we investigated the effects of a Hypericum Scabrum (H. scabrum) extract, which is an antioxidant, on anxiety in rats fed a long-term HFD. Sixty male Wistar rats were divided into the following six groups: (1) Control (standard diet), (2) Ext100 [standard diet supplemented with extract (100 mg/kg once/day)], (3) Ext300 [ standard diet supplemented with extract (300 mg/kg once/day)], (4) HFD, (HFD), (5) HFD + Ext100, and (6) HFD + Ext300. The groups were fed their diet for 3 months. Anxiety was measured with the elevated plus-maze test. At the end of the study, blood samples were taken, and biochemical parameters and oxidative stress biomarker levels were determined in the plasma. Compared to the control group, the HFD group exhibited significant decreases in both the time in the open arms and number of entries into the open arms. H. scabrum extract supplementation significantly increased these parameters in the HFD-fed groups. The HFD significantly increased serum malondialdehyde levels and significantly decreased total glutathione levels, while H. scabrum extract supplementation significantly reversed these parameters. In conclusion, these results showed that a HFD increased anxiety behavior. In contrast, H. scabrum extract supplementation had anxiolytic effects and reversed the effects of the HFD, which suggested that the effects of H. scabrum extract supplementation were due to its strong antioxidant properties.