Hypocholesterolaemic effects of an ethanol precipitate of Kabosu juice in stroke-prone spontaneously hypertensive rats fed a cholesterol-free diet.

Abstract

1. We have previously identified strong inhibitory effects of Kabosu (Citrus sphaerocarpa Hort.) juice precipitate (KJP) on cholesterol elevation in stroke-prone spontaneously hypertensive rats (SHRSP) fed a cholesterol diet. In the present study, to elucidate the hypocholesterolaemic mechanism, we examined the effect of dietary KJP on lipid metabolism by using SHRSP fed a cholesterol-free diet. 2. Compositions of the experimental diet containing 10% KJP powder were adjusted to those of the control diet. Seven-week-old male SHRSP were fed control or experimental diet for 2 weeks with free access to the diet and water. 3. Serum levels of cholesterol, phospholipid and triglyceride of the KJP group were significantly reduced, which was due to decreases in the very low-density lipoprotein (VLDL), low-density lipoprotein (LDL) and high-density lipoprotein (HDL) fractions. 4. Serum concentrations of apolipoproteins A-I and E (apoA-I and E) of the KJP group were significantly lower than those of the control group, whereas no significant differences were observed in serum apoB and apoA-IV between the two groups. 5. In liver, there were no significant differences in the contents of lipids or relative liver weight between the two groups. The activity of microsomal cholesterol 7alpha-hydroxylase of the KJP group tended to increase, whereas that of microsomal acyl-coenzyme A : cholesterol acyltransferase was significantly reduced, compared with the control group. 6. These results indicate that dietary KJP produces reductions of serum lipid levels, which are due to reductions in VLDL, apoE HDL and apoA-I HDL, and may promote catabolism and excretion of hepatic cholesterol in SHRSP fed a cholesterol-free diet.