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5α-Cyprinol sulfate was isolated from bile of the Asiatic carp, Cyprinus carpio. 5α-Cyprinol sulfate was surface active and formed micelles; its critical micellization concentration (CMC) in 0.15 M Na+ using the maximum bubble pressure device was 1.5 mM; by dye solubilization, its CMC was ∼4 mM. At concentrations >1 mM, 5α-cyprinol sulfate solubilized monooleylglycerol efficiently (2.1 molecules per mol micellar bile salt). When infused intravenously into the anesthetized rat, 5α-cyprinol sulfate was hemolytic, cholestatic, and toxic. In the isolated rat liver, it underwent little biotransformation and was poorly transported (Tmax ≅ 0.5 μmol/min/kg) as compared with taurocholate. 5α-Cyprinol, its bile alcohol moiety, was oxidized to its corresponding C27 bile acid and to allocholic acid (the latter was then conjugated with taurine); these metabolites were efficiently transported. 5α-Cyprinol sulfate inhibited taurocholate uptake in COS-7 cells transfected with rat asbt, the apical bile salt transporter of the ileal enterocyte. 5α-Cyprinol had limited aqueous solubility (0.3 mM) and was poorly absorbed from the perfused rat jejunum or ileum. Sampling of carp intestinal content indicated that 5α-cyprinol sulfate was present at micellar concentrations, and that it did not undergo hydrolysis during intestinal transit.These studies indicate that 5α-cyprinol sulfate is an excellent digestive detergent and suggest that a micellar phase is present during digestion in cyprinid fish.

The Shoebill stork, an enigma phylogenetically, was found to contain as its dominant biliary bile acid 16α-hydroxychenodeoxycholic acid, a heretofore undescribed bile acid. The bile acid occurred as its taurine N-acyl amidate; structure was established by nuclear magnetic resonance (NMR) and mass spectrometry (MS). A search for this novel bile acid in other Ciconiiformes showed that it constituted >92% of biliary bile acids in five of nine herons in the Ardidae, but was absent in all other families (Ciconiidae, Threskiornithidae, Scopidae, Phoenicopteridae). The presence of this biochemical trait in the Shoebill stork and certain herons suggests that these birds are closely related.—Hagey, L. R., C. D. Schteingart, H-T. Ton-Nu, and A. F. Hofmann. A novel primary bile acid in the Shoebill stork and herons and its phylogenetic significance. J. Lipid Res. 2002. 43: 685–690.

Some commercial preparations of common natural conjugated bile salts contain impurities (e.g., amines, lipids, and calcium) that are likely to affect their physicochemical properties. A method was developed for purifying commercial preparations of sodium salts of glycine- and taurine-conjugated bile acids. The method consists of passage of a dilute aqueous solution of the sodium bile salt through three columns in sequence: graphitized carbon, a hydrophobic bonded octadecylsilane (C18) cartridge, and a calcium-chelating resin. The final solution was extracted with chloroform, and the purified bile salt was then isolated by freeze-drying, with a yield of 65-75%. Each bile salt purified by this method was compared with the corresponding bile salt purified by conventional adsorption chromatography on a silicic acid column, using a mixture of methanol and chloroform as eluant. Purity was assessed by visible spectra, by surface tension measurements (using the maximum bubble-pressure method and a Wilhelmy wire method), by chloroform extractability of impurities in the conjugated bile acid, by liposome solubilization, and by chemical analysis of the calcium content. Both purification methods removed colored and surface-active impurities, but the new method was always as or more effective than silicic acid column chromatography. Calcium ion, present in commercial bile salts in concentrations up to 16 mmol/mol bile salt, was removed completely by the three-column method, but not by silicic acid chromatography. The new method is thus a simple, rapid, and efficient procedure for purification of the sodium salts of glycine- and taurine-conjugated bile acids for physicochemical measurements, in which elimination of surface-active impurities and polyvalent cations is desired.

The biliary bile acid composition of 30 species of pigeons and doves belonging to seven genera in the avian order Columbiformes was determined using TLC, HPLC, GLC/MS, LSIMS, and NMR. In 23 of 25 species of fruit pigeons and doves, chenodeoxycholic acid was the major bile acid (> 50%). In only 1 species (Ptilinopus ornatus) was cholic the major bile acid. A number of species (7 of 15 species in the genus Ptilinopus, and 6 of 9 species in the genus Ducula) contained 1 beta,3 alpha,7 alpha-trihydroxy-5 beta-cholan-24-oic acid in proportions ranging from 2 to 43%. This 1 beta-hydroxy derivative of chenodeoxycholic acid has not been previously identified as a major biliary bile acid in vertebrates. Five of 15 species of the genus Ptilinopus, 5 of 9 species of the genus Ducula, and the only species examined for the genus Gymnophaps contained 23R-hydroxy chenodeoxycholic acid in detectable proportions, ranging from 1 to 4%. Bile acids were conjugated (in N-acyl linkage) with glycine and taurine in 28 species and with only taurine in 2 species. The fruit pigeons are the first non-mammalian genera identified to date in whom bile acids are conjugated with glycine, as well as with taurine. An incidental finding was that a gallbladder was present in 3 genera (Ptilinopus, Ducula, and Gymnophaps) and absent in 4 genera (Gallicolumba, Chalcophaps, Otidiphaps, and Treron).