Phytosterol ester constituents affect micellar cholesterol solubility in model bile

Andrew W. Brown, Jiliang Hang, Patrick H Dussault, Timothy P Carr

Research output: Contribution to journalArticle

35 Citations (Scopus)

Abstract

Plant sterols and stanols (phytosterols) and their esters are nutraceuticals that lower LDL cholesterol, but the mechanisms of action are not fully understood. We hypothesized that intact esters and simulated hydrolysis products of esters (phytosterols and fatty acids in equal ratios) would differentially affect the solubility of cholesterol in model bile mixed micelles in vitro. Sodium salts of glycine- and taurine-conjugated bile acids were sonicated with phosphatidylcholine and either sterol esters or combinations of sterols and fatty acids to determine the amount of cholesterol solubilized into micelles. Intact sterol esters did not solubilize into micelles, nor did they alter cholesterol solubility. However, free sterols and fatty acids altered cholesterol solubility independently (no interaction effect). Equal contents of cholesterol and either campesterol, stigmasterol, sitosterol, or stigmastanol (sitostanol) decreased cholesterol solubility in micelles by approximately 50% compared to no phytosterol present, with stigmasterol performing slightly better than sitosterol. Phytosterols competed with cholesterol in a dose-dependent manner, demonstrating a 1:1 M substitution of phytosterol for cholesterol in micelle preparations. Unsaturated fatty acids increased the micelle solubility of sterols as compared with saturated or no fatty acids. No differences were detected in the size of the model micelles. Together, these data indicate that stigmasterol combined with saturated fatty acids may be more effective at lowering cholesterol micelle solubility in vivo.

Original languageEnglish (US)
Pages (from-to)855-862
Number of pages8
JournalLipids
Volume45
Issue number9
DOIs
StatePublished - Sep 1 2010

Fingerprint

Phytosterols
Bile
Micelles
Solubility
Esters
Cholesterol
Sterols
Stigmasterol
Fatty Acids
Taurine
Dietary Supplements
Bile Acids and Salts
Phosphatidylcholines
Unsaturated Fatty Acids
Nonesterified Fatty Acids
LDL Cholesterol
Glycine
Hydrolysis
Substitution reactions
Salts

Keywords

  • Bile
  • Cholesterol absorption
  • Mixed micelle
  • Phytosterol esters
  • Phytosterols
  • Plant stanol
  • Plant sterol

ASJC Scopus subject areas

  • Biochemistry
  • Organic Chemistry
  • Cell Biology

Cite this

Phytosterol ester constituents affect micellar cholesterol solubility in model bile. / Brown, Andrew W.; Hang, Jiliang; Dussault, Patrick H; Carr, Timothy P.

In: Lipids, Vol. 45, No. 9, 01.09.2010, p. 855-862.

Research output: Contribution to journalArticle

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