Determination of the glucurono-conjugated position in bile alcohol glucuronides present in a patient with cerebrotendinous xanthomatosis.

The determination of the glucurono-conjugated position in three bile alcohol glucuronides secreted in bile of a patient with cerebrotendinous xanthomatosis was carried out by a nuclear magnetic resonance study. The bile sample was extracted with ethanol and chromatographed on an ion-exchange column, a reverse-phase partition column and a silica gel column to isolate glucurono-conjugates of 5 beta-cholestane-3 alpha, 7 alpha, 12 alpha, 25-tetrol, 5 beta-cholestane-3 alpha, 7 alpha 12 alpha, 23-tetrol, and 5 beta-cholestane-3 alpha, 7 alpha, 12 alpha, 23, 25-pentol. Proton and 13C nuclear magnetic resonance spectra of the two biliary bile alcohol glucuronides, 5 beta-cholestane-3 alpha, 7 alpha, 12 alpha, 25-tetrol glucuronide and 5 beta-cholestane-3 alpha, 7 alpha, 12 alpha, 23, 25-pentol glucuronide were identical with those of the synthetic glucuronide 7 alpha, 12 alpha, 25-trihydroxy-5 beta-cholestane-3 alpha-O beta-D-glucopyranosyluronic acid and the isolated glucuronide 3 alpha, 7 alpha, 12 alpha, 25-tetrahydroxy-5 beta-cholestane-23-O-beta-D-glucopyranosyluronic acid from urine of a patient with cerebrotendinous xanthomatosis, respectively. Hence, the glucurono-conjugated positions of the biliary 25-tetrol glucuronide and the biliary 23,25-pentol glucuronide were C-3 and C-23, respectively. By comparison of the 13C chemical shift data with that of the unconjugated bile alcohol, 5 beta-cholestane-3 alpha, 7 alpha, 12 alpha, 23-tetrol, the glucurono-conjugated position of the natural 23-tetrol glucuronide was determined to be C-23. Thus, the natural 23-tetrol glucuronide can be formulated as 3 alpha, 7 alpha, 12 alpha-trihydroxy-5 beta-cholestane-23-O-beta-D-glucopyranosyluronic acid.