β-Muricholic acid; potentiometric and cholesterol-dissolving properties

• Published in: Biochimica et biophysica acta Vol. 918; no. 1; pp. 1 - 10
• Main Authors: Montet, Jean-Claude, Parquet, Michel, Sacquet, Edmond, Montet, Anne-Marie, Infante, Recaredo, Amic, Jean
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 13.03.1987; Elsevier; North-Holland
• Subjects: Animals; Bile acid; Biological and medical sciences; Chemical Phenomena; Chemistry, Physical; Chenodeoxycholic Acid; Cholesterol; Cholesterol monohydrate crystal; Cholic Acids; Fundamental and applied biological sciences. Psychology; Hydrogen-Ion Concentration; Liver. Bile. Biliary tracts; Mass Spectrometry; Mathematics; Mesophase; Micelle; Micelles; Potentiometry; Rats; Solubility; Ursodeoxycholic Acid; Vertebrates: digestive system; β-Muricholic acid; Micelle; Cholesterol monohydrate crystal; Mesophase; β-Muricholic acid; Bile acid; Vertebrata; Mammalia; Rat; Liver; Rodentia; Biosynthesis; Physicochemical properties
• ISSN: 0005-2760; 0006-3002; 1879-145X; 1878-2434
• DOI: 10.1016/0005-2760(87)90002-6

Some physicochemical properties of β-niuricholic acid (3α,6β,7β-trihydroxyβ-cholanic acid), a major bile acid biosynthesized by rat liver, were determined and compared to those of ursodeoxycholic and chenodeoxycholic acids. From potentiometric studies, the following characteristics of β-muricholic acid were shown: a low monomer solubility (13 μM), a high equilibrium precipitation pH (7.92 for 30 mM solution), an apparent critical micellar concentration of 4 mM, and a very low micellar capacity of the bile salt to dissolve the protonated bile acid. Sodium β-muricholate solution (30 mM) poorly solubilized cholesterol, as indicated by a bile salt/cholesterol molar ratio of 1430, whereas saturation ratios obtained with chenodeoxycholate and ursoseoxycholate were 24 and 384, respectively. Sodium β-muricholate (30 mM)/phosphatidylcholine/cholesterol mixtures contained non-micellar aggregates from very low cholesterol concentrations. At physiological phosphatidylcholine concentrations, sodium β-muricholate (100 mM) dissolved cholesterol crystals via essentially lamellar liquid-crystal formation. These solubilizing properties might have important physiological relevance to the dissolution of cholesterol gallstones in man.