Lupin seeds lower plasma lipid concentrations and normalize antioxidant parameters in rats

This study was designed to test bitter and sweet lupin seeds for lipid-lowering and for their antioxidative activities in hypercholesterolemic rats. The levels of plasma lipid, malondialdehyde (MDA) and whole blood reduced glutathione (GSH), as well as the activities of transaminases (ALT and AST), lactate dehydrogenase (LDH) in plasma, superoxide dismutase (SOD), glutathione peroxidase (GPx) in erythrocytes and plasma glutathione reductase (GR), glutathione-S-transferase (GST) and catalase (CAT) were examined. A hypercholesterolemia-induced diet manifested in the elevation of total lipids (TL), total cholesterol (TC), triglycerides (TG), LDL-C and MDA levels, ALT, AST, LDH activities and the depletion of GSH and enzymic antioxidants. The supplementation of a hypercholesterolemia-induced diet with bitter and sweet lupin seeds significantly lowered the plasma levels of TL, TC, TG and LDL-C. ALT, AST and LDH activities slightly decreased in treated groups compared with the hypercholesterolemic group (HC). Furthermore, the content of GSH significantly increased while MDA significantly decreased in treated groups compared with the HC group. In addition, the bitter lupin seed group improved enzymic antioxidants compared with the HC group. In general, the results indicated that the bitter lupin seed supplements are better than those containing sweet lupin seeds. These results suggested that the hypocholesterolemic effect of bitter and sweet lupin seed supplements might be due to their abilities to lower the plasma cholesterol level as well as to slow down the lipid peroxidation process and to enhance the antioxidant enzyme activity.