Effects of the Dietary Addition of Amaranth (Amaranthus mantegazzianus) Protein Isolate on Antioxidant Status, Lipid Profiles and Blood Pressure of Rats

The effects of the dietary addition of 2.5 % (w/w) Amaranthus mantegazzianus protein isolate (AI) on blood pressure, lipid profiles and antioxidative status of Wistar rats were evaluated. Six diets were used to feed animals during 28 days: (base (AIN93G), Chol (cholesterol 1 %, w/w), CE (alpha-tocopherol 0.005 %, w/w), CholE (cholesterol 1 % (w/w) + alpha-tocopherol 0.005 %, w/w), CAI (AI 2.5 % w/w), CholAI (cholesterol 1 % (w/w) + AI 2.5 %, w/w). Lipid profiles of plasma and liver and faecal cholesterol content were analyzed. Antioxidant status was evaluated by the ferric reducing activity of plasma (FRAP), the 2-thiobarbituric acid (TBA) assay and superoxide dismutase (SOD) activity in plasma and liver. Blood pressure was measured in the tail artery of rats. CholA group presented a significant (alpha < 0.05) reduction (16 %) in the plasma total cholesterol. In liver, the intake of cholesterol (Chol group) induced a significant increment in cholesterol and triglycerides (2.5 and 2.3 times, respectively), which could be decreased (18 % and 47 %, respectively) by the addition of AI (CholA group). This last group also showed an increased faecal cholesterol excretion (20 %). Increment (50 %) in FRAP values, diminution of TBA value in plasma and liver (70 % and 38 %, respectively) and diminution of SOD activity (20 %) in plasma of CholA group suggest an antioxidant effect because of the intake of AI. In addition, CA and CholA groups presented a diminution (18 %) of blood pressure after 28 days.