Solubility in and affinity for the bile salt micelle of plant sterols are important determinants of their intestinal absorption in rats

Abstract

Intestinal absorption of various plant sterols was investigated in thoracic duct-cannulated normal rats. Lymphatic recovery was the highest in campesterol, intermediate in brassicasterol and sitosterol, and the lowest in stigmasterol and sitostanol. Higher solubility in the bile salt micelle was observed in sitosterol, campesterol, and sitostanol than in brassicasterol and stigmasterol. The solubility of the latter two sterols was extremely low. When the affinity of plant sterols for the bile salt micelle was compared in an in vitro model system, which assessed sterol transfer from the micellar to the oil phase, the transfer rate was the highest in brassicasterol, intermediate in campesterol and stigmasterol, and lowest in sitosterol and sitostanol. Although no significant correlations between lymphatic recovery of plant sterols and their micellar solubility or transfer rate from the bile salt micelle were observed, highly positive correlation was obtained between the lymphatic recovery and the multiplication value of the micellar solubility and the transfer rate. These observations strongly suggest that both solubility in and affinity for the bile salt micelle of plant sterols are important determinants of their intestinal absorption in rats.

Missense Mutation inAbcg5in SHRSP Rats Does Not Accelerate Intestinal Absorption of Plant Sterols: Comparison with Wistar Rats

“…It has been found that the incorporation of sterols through Niemann-pick C1-like 1 protein (NPC1L1) 20) and simple diffusion 21) is an important determinant in their intestinal absorption. We must evaluate the possibility that NPC1L1 and simple diffusion might compensate for malfunction of ABCG5/ABCG8 in SHRSP rats.…”

Membranolytic Activity of Bile Salts: Influence of Biological Membrane Properties and Composition

“…However, it is also observed that the antimicrobial activity depends on the tested microorganisms and can cover the range from no antimicrobial activity up to very strong activity. One reason for this is the different lipid composition of the membrane of the microorganism [8,11,12,15], which strongly influences the membranolytic activity of detergents or peptides.…”

“…mixed vesicles, mixed micelles, depending on the lipid to detergent ratio, are formed [8,9]. It is described that the microdomains contained in the mixed micelles were able to solubilise cholesterol [10][11][12][13][14]. An important aspect in the formation of mixed micelles lies in the fact that the mixed micelle association lowers the monomeric activity of bile salts and thus prevents the solubilisation and thus destruction and membranolytic effect of the apical membrane of the epithelial cells [15,16].…”

Factors Affecting Intestinal Absorption of Cholesterol and Plant Sterols and Stanols

“…Solubility in bile salt micelles is thought to be an essential factor affecting the intestinal absorption of cholesterol and plant sterols 1 . Another important factor in the intestinal lumen is the releasability of monomer sterols from bile salt micelles before their incorporation into brush border membranes of intestinal epithelial cells 2,3 . The affinity of sterols for bile salt micelles determines their releasability from these micelles.…”

“…The 24 h lymphatic recovery of radiolabeled cholesterol was about 10-fold higher than that of radiolabeled sitosterol. Figure 3 shows the 24 h lymphatic recovery of various plant sterols and sitostanol 3 . The recovery of campesterol was highest, whilst those of stigmasterol and sitostanol were lowest, and those of brassicasterol and sitosterol were intermediate.…”