Effects of Cycloartenol on Absorption and Serum Levels of Cholesterol in Rats

抄録

The possibility that cycloartenol magnifies the hypocholes-terolemic effect of β-sitosterol was studied in two strains of rats fed on cholesterol-enriched (0.5%) diets. Cycloartenol was added to diets containing 1.0% or 0.5% β-sitosterol at the 0.05% level and to diet free of plant sterol at the 0.5% level. In one experiment, diets included sodium cholate (0.125%). Due to the potent hypocholesterolemic efficacy of β-sitosterol under the present dietary regimens, no clear additional effect (so-called synergistic effect) of cycloartenol was observed. However, in the experiment using Wistar rats, the decrease in serum apo A-I due to feeding cholesterol was ameliorated more effectively in combination with β-sitosterol than with β-sitosterol alone. The hepatic deposition of choles-terol was mitigated by dietary β-sitosterol, and further, although slightly, by a combination of β-sitosterol and cycloartenol, except in the experi-ment with diets containing sodium cholate. Fecal excretion of neutral and acidic steroids was not meaningly magnified by cycloartenol. Cycloartenol itself was not as effective as β-sitosterol in mitigating lipid disorders due to dietary cholesterol. The rate of appearance of cholesterol in the thoracic duct lymph was not interfered with further by a combination of β-sitosterol and cycloartenol compared to β-sitosterol alone. This trimethylsterol was absorbed at a rate approximately 4-fold higher than that of β-sitosterol, though much lower compared to cholesterol. These results suggest a preference for cycloartenol in cholesterol dynamics. However, cycloartenol seems unlikely to influence cholesterol absorption in the small intestine.