Amaranth squalene reduces serum and liver lipid levels in rats fed a cholesterol diet

Abstract

In this study, the hypocholesterolaemic effect of amaranth grain, oil and squalene are examined. In experiment 1, rats are given a semi-purified diet containing 1% (w/w) cholesterol for four weeks and either amaranth grain (AG; 300 g/kg) or amaranth oil (AO; 90 g/kg) substituted in experimental groups. Both AG and AO lowered serum and hepatic cholesterol and triglyceride levels. Faecal excretion of cholesterol and bile acid in the AO group increased, while AG affected only bile acid excretion. In experiment 2, rats were fed the cholesterol diet for four weeks and injected (i.p.) with saline (control), amaranth squalene (AS) or shark liver squalene (SS, 200 mg/kg) for seven days. The hypolipidaemic effects of AS were evident in both serum and liver. In addition, AS markedly increased faecal excretions of cholesterol and bile acid, and slightly inhibited 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase activity. In contrast, none of these effects were observed in the SS group. This preliminary study suggests that the cholesterol-lowering effect of AS may be mediated by increased faecal elimination of steroids through interference with cholesterol absorption, and that different sources of squalene (plant versus animal) may affect cholesterol metabolism differently.