出版社：American Society for Biochemistry and Molecular Biology
摘要：Plant stanols and sterols of the 4-desmethyl family (e.g., sitostanoland sitosterol) effectively decrease LDL cholesterol concentrations,whereas 4,4-dimethylsterols (-amyrin and lupeol) do not. Serumcarotenoid concentrations, however, are decreased by both plantsterol families. The exact mechanisms underlying these effectsare not known, although effects on micellar composition havebeen suggested. With a liver X receptor (LXR) coactivator peptiderecruitment assay, we showed that plant sterols and stanolsfrom the 4-desmethylsterol family activated both LXR and LXRß,whereas 4,4-dimethyl plant sterols did not. In fully differentiatedCaco-2 cells, the functionality of this effect was shown bythe increased expression of ABCA1, one of the known LXR targetgenes expressed by Caco-2 cells in measurable amounts. The LXR-activatingpotential of the various plant sterols/stanols correlated positivelywith ABCA1 mRNA expression. Reductions in serum hydrocarboncarotenoids could be explained by the effects of the 4-desmethylfamily and 4,4-dimethylsterols on micellar carotenoid incorporation.
Our findings indicate that the decreased intestinal absorptionof cholesterol and carotenoids by plant sterols and stanolsis caused by two distinct mechanisms.Abbreviations: ABC, ATP binding cassette; LXR, liver X receptor; SREBP-2, sterol-regulatory element binding protein-2
Supplementary key words cholesterol • antioxidant • ATP binding cassette transporter • liver X receptor
-amyrin and lupeol) do not. Serum carotenoid concentrations, however, are decreased by both plant sterol families. The exact mechanisms underlying these effects are not known, although effects on micellar composition have been suggested. With a liver X receptor (LXR) coactivator peptide recruitment assay, we showed that plant sterols and stanols from the 4-desmethylsterol family activated both LXR
