Rice α-globulin decreases serum cholesterol concentrations in rats fed a hypercholesterolemic diet and ameliorates atherosclerotic lesions in apolipoprotein E-deficient mice

► We isolated a rice globulin fraction from rice flour and then it was composed of a single protein, α-globulin. ► Oral administration of rice α-globulin improves hypercholesterolemia in rats fed a hypercholesterolemic diet. ► The mechanism of hypocholesterolemic effect of rice α-globulin is inhibiting cholesterol absorption in the intestine. ► Oral administration of rice α-globulin inhibits atherosclerosis development in apolipoprotein E-deficient mice. ► The anti-atherosclerotic effect exerts by mechanism(s) other than the regulation of serum MCP-1 and NO concentrations. The hypocholesterolemic and antiatherogenic effects of rice α-globulin remain unclear. We investigated the hypocholesterolemic effect of rice α-globulin in rats fed a hypercholesterolemic diet. The rats were divided into 4 groups and were orally administrated the following three proteins or a vehicle for 4weeks: rice protein, rice α-globulin, or soy β-conglycinin at a dose of 100mg/kg body weight or carboxymethylcellulose to the control rats. In the rice α-globulin group, serum cholesterol concentrations were 28% lower than the control group and fecal neutral steroid excretion was increased by 30%. The hypocholesterolemic effect of rice α-globulin was equal to soy β-conglycinin in SD rats fed the hypercholesterolemic diet. However, the serum cholesterol concentrations in the rice protein group did not change compared to the control group. To investigate the antiatherogenic effects of rice α-globulin, male apolipoprotein E-deficient mice were orally administered the same dose of rice α-globulin for 9weeks. The en face lesion area in the aorta was 46% lower than in the control group. In conclusion, administration of rice α-globulin improves hypercholesterolemia in rats fed a hypercholesterolemic diet by increasing the fecal excretion of neutral sterols, and inhibits atherosclerosis development in apolipoprotein E-deficient mice. The anti-atherosclerotic effect exerts by mechanism(s) other than the regulation of serum MCP-1 and NO concentrations.