Simultaneous analysis and retention behavior of the glucuronide, glucoside, and N-acetylglucosaminide conjugates of bile acids in conventional and inclusion high-performance liquid chromatographic methods

Simultaneous analysis and structure-retention correlation were examined for various glycosidic-conjugated bile acids in reversed-phase high-performance liquid chromatography (HPLC). The substrates examined included the beta-glucuronide, beta-glucoside, and beta-N-acetylglucosaminide conjugates of C-24 bile acids related to lithocholic, hyodeoxycholic, chenodeoxycholic, ursodeoxycholic, deoxycholic, hyocholic, and cholic acids having an O-beta-D-glycosidic linkage at the position C-3, C-6, or C-7 in the 5 beta-steroid nucleus. The bile acids as their fluorescence-sensitive C-24 pyrenacyl ester derivatives were measured on a C-18 reversed-phase column, eluting with methanol-water mixtures in the absence and presence of methyl-beta-cyclodextrin (Me-beta-CD). Changes in the retentions of these compounds depended significantly not only on the Me-beta-CD concentration but rather on the methanol content, implying the possible formation of solute-Me-beta-CD-methanol ternary complexes by hydrogen-bonding interactions. The combined use of conventional and inclusion HPLC retention data reported herewith provided important information for characterizing the structures of bile acid glycosides as well as inclusion complexes. (C) 1998 Elsevier Science B.V.