HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Roda, A. Articles by Fini, A. Search for Related Content PubMed PubMed Citation Articles by Roda, A. Articles by Fini, A. Social Bookmarking                      What's this?

Journal of Lipid Research, Vol 31, 1433-1443, Copyright © 1990 by Lipid Research, Inc.

ARTICLES

Bile acid structure-activity relationship: evaluation of bile acid lipophilicity using 1-octanol/water partition coefficient and reverse phase HPLC

A Roda, A Minutello, MA Angellotti and A Fini
Istituto di Chimica Analitica, Universita di Messina, Italy.

Two independent methods have been developed and compared to determine the lipophilicity of a representative series of naturally occurring bile acids (BA) in relation to their structure. The BA included cholic acid (CA), chenodeoxycholic acid (CDCA), ursodeoxycholic acid (UDCA), deoxycholic acid (DCA), hyodeoxycholic acid (HDCA), ursocholic acid (UCA), hyocholic acid (HCA), as well as their glycine and taurine amidates. Lipophilicity was determined using a 1-octanol/water shake- flask procedure and the experiments were performed at different pH and ionic strengths and at initial BA concentrations below their critical micellar concentrations (CMC) and the water solubility of the protonated form. The experimental data show that both the protonated (HA) and ionized (A-) forms of BA can distribute in 1-octanol, and consequently a partition coefficient for HA (logP' HA) and for A- (logP' A-) must be defined. An equation to predict a weighted apparent distribution coefficient (D) value as a function of pH and pKa has been developed and fits well with the experimental data. Differences between logP for protonated and ionized species for unconjugated BA were in the order of 1 log unit, which increased to 2 for glycine-amidate BA. The partition coefficient of the A- form increased with Na+ concentration and total ionic strength, suggesting an ion-pair mechanism for its partition into 1-octanol. Lipophilicity was also assessed using reverse phase chromatography (C-18-HPLC), and a capacity factor (K') for ionized species was determined. Despite a broad correlation with the logP data, some BA behaved differently. The logP values showed that the order of lipophilicity was DCA greater than CDCA greater than UDCA greater than HDCA greater than HCA greater than CA greater than UCA for both the protonated and ionized unconjugated and glycine-amidate BA, while the K' data showed an inversion for some BA, i.e., DCA greater than CDCA greater than CA greater than HCA greater than UDCA greater than HDCA greater than UCA. The logP data fitted well with other indirect measurements of BA monomeric lipophilicity such as albumin binding or accessible total hydrophobic surface area data calculated by energy minimization and molecular computer graphics. Differences between unconjugated and amidated BA are consistent with the presence of an amide bond and a lower pKa when pH dependence was studied. Capacity factors, on the other hand, were related to properties of BA micelles such as cholesterol-solubilizing capacity and membrane disruption, reflecting the BA detergency.(ABSTRACT TRUNCATED AT 400 WORDS)
CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				M. A Gauthier, P. Simard, Z. Zhang, and X.X Zhu Bile acids as constituents for dental composites: in vitro cytotoxicity of (meth)acrylate and other ester derivatives of bile acids J R Soc Interface, December 22, 2007; 4(17): 1145 - 1150. [Abstract] [Full Text] [PDF]

				J. P. Hamilton, G. Xie, J.-P. Raufman, S. Hogan, T. L. Griffin, C. A. Packard, D. A. Chatfield, L. R. Hagey, J. H. Steinbach, and A. F. Hofmann Human cecal bile acids: concentration and spectrum Am J Physiol Gastrointest Liver Physiol, July 1, 2007; 293(1): G256 - G263. [Abstract] [Full Text] [PDF]

				A. M. Dopico, J. V. Walsh Jr., and J. J. Singer Natural Bile Acids and Synthetic Analogues Modulate Large Conductance Ca2+-activated K+ (BKCa) Channel Activity in Smooth Muscle Cells J. Gen. Physiol., February 22, 2002; 119(3): 251 - 273. [Abstract] [Full Text] [PDF]

				A. A. Al-Jabri, M. D. Wigg, E. Elias, R. Lambkin, C. O. Mills, and J. S. Oxford In vitro anti-HIV-1 virucidal activity of tyrosine-conjugated tri- and dihydroxy bile salt derivatives J. Antimicrob. Chemother., May 1, 2000; 45(5): 617 - 621. [Abstract] [Full Text] [PDF]

				T. Kitazawa, T. Terasaki, H. Suzuki, A. Kakee, and Y. Sugiyama Efflux of Taurocholic Acid Across the Blood-Brain Barrier: Interaction with Cyclic Peptides J. Pharmacol. Exp. Ther., August 1, 1998; 286(2): 890 - 895. [Abstract] [Full Text]