A method for the isolation of bilirubin from feces.

The recent observation that certain antibiotics depress or even temporarily eliminate the bacterial reduction of bilirubin in the colon suggested that the feces under such circumstances might be an excellent source of bilirubin. The possibility was also at hand that bilirubin labeled with N15 or Cl3 might thus be made available in significant amounts, assuming a prior administration of isotopic glycine or acetate. Crystalline bilirubin is’ customarily prepared from bile or cattle gallstones and numerous procedures for its isolation from these sources have been described (1). Fischer and Libowitsky (2) obtained it, together with stercobilin, from the feces of an individual with hemolytic anemia. In this instance, it appeared that either the transit time of the intestinal contents was too short or the bacterial flora too inefficient to reduce the bilirubin completely. As will be noted in the following, this method has not proved satisfactory nor has any previous description been found of a satisfactory method for obtaining crystalline bilirubin from feces. Suppression of urobilinogen formation and excretion of bilirubin in the feces can readily be induced by the use of aureomycin (3), terramycin (4), and neomycin.’ After oral administration of these drugs for several days (in daily doses of 2, 4, 6 gm. respectively), the fecal urobilinogen drops to very low values, and the feces now give a strongly positive Fouchet reaction for bilirubin. To isolate it in crystalline form, the method of Fischer and Libowitsky (2) was first tried. Essentially, this procedure consists in acidification with tartaric acid and prolonged extraction of the feces with a mixture of ether and alcohol. After drying the fecal residue, the bilirubin is extracted with chloroform. In our hands, this extraction has proved inefficient, and from normal individuals receiving terramycin only traces of bilirubin were obtained. The following method was therefore developed.