The fat and protein fractions of freshwater clam (Corbicula fluminea) extract reduce serum cholesterol and enhance bile acid biosynthesis and sterol excretion in hypercholesterolaemic rats fed a high-cholesterol diet

Abstract

We investigated whether the fat and protein fractions of freshwater clam (Corbicula fluminea) extract (FCE) could ameliorate hypercholesterolaemia in rats fed a high-cholesterol diet. We also explored the mechanism and the components that exert the hypocholesterolaemic effect of FCE. The doses of the fat and protein fractions were equivalent to those in 30 % FCE. The fat and protein fractions of FCE, two major components of FCE, significantly reduced the serum and hepatic cholesterol levels. The fat fraction more strongly reduced serum cholesterol levels than the same level of total FCE. The excretion of faecal neutral sterols increased in rats fed the total the FCE and the fat fraction of FCE. On the other hand, faecal bile acid levels were greater in rats fed the total FCE and the fat and protein fractions of FCE than in control animals. The hepatic gene expression of ATP-binding cassette transporter G5 and cholesterol 7a-hydroxylase was up-regulated by the administration of the total FCE and both the fat and protein fractions of FCE. These results showed that the fat and protein fractions of FCE had hypocholesterolaemic properties, and that these effects were greater with the fat fraction than with the protein fraction. The present study indicates that FCE exerts its hypocholesterolaemic effects through at least two different mechanisms, including enhanced excretion of neutral sterols and up-regulated biosynthesis of bile acids.

Dietary freshwater clam (Corbicula fluminea) extract suppresses accumulation of hepatic lipids and increases in serum cholesterol and aminotransferase activities induced by dietary chloretone in rats

“…11,[14][15][16][17][18] Briefly, freshwater clams were steamed until their shells opened, and then the edible portions were removed. Edible portions were minced, extracted with boiling water, and passed through an 80-mesh filter.…”

“…Studies have reported that freshwater clam extract (FCE) protects against liver injury, [11][12][13] ameliorates hypercholesterolemia [14][15][16][17] and fatty liver disease, 11,15) and accelerates ethanol metabolism.…”

“…11) Previously, we focused particularly on the hypocholesterolemic effects of FCE [14][15][16][17] and found that FCE not only has hypocholesterolemic effects but also other beneficial effects against fatty liver disease 15) and fatty acid metabolism. 18) Furthermore, FCE prevents the acute injury to liver cells induced by D-galactosamine, 11) hemorrhage, 12) or carbon tetrachloride (CCl 4 ).…”

Fermented Miso with Adzuki Beans or Black Soybeans Decreases Lipid Peroxidation and Serum Cholesterol in Mice fed a High-Fat Diet

“…Buhman et al also demonstrated that feeding psyllium to rats enhanced the level of hepatic cholesterol 7α-hydroxylase mRNA as well as fecal bile acid and total steroid excretions [47]. Chijimatsu et al speculated that the hypocholesterolaemic effects of freshwater clam (Corbicula fluminea) extract might be due to increased fecal neutral sterol, bile acid excretion and hepatic cholesterol 7a-hydroxylase gene expression [4]. Another group has also demonstrated beneficial effects of the fermented adzuki bean paste on serum cholesterol in rats.…”

“…As intake of meat increases, blood cholesterol increases due to excess of cholesterol intake [3]. Chijimatsu et al fed high cholesterol diet to rats leading to the increase in blood cholesterol in these rats [4].…”