Lxxxv. Urochrome as a Derivative of Chlorophyll

IN a series of papers Palmer and his co-workers have shown that many animal pigments are derived from carotene and xanthophyll [Palmer and Eckles 1914; Palmer and Kempster 1919], therefore it was thought desirable to find out if urochrome also is derived from plant pigments. Preliminary experiments were performed with human urine. The urine was collected in twenty-four hour samples, preserved with chloroform and the urochrome was extracted by the method of Garrod [1874] from one tenth of each daily quantity and the alcohol extracts were compared by a colorimeter. By restricting the amount of plant pigments in the diet the colour extracted by the above method was reduced by about one fifth. This led to experiments being carried out using guinea-pigs, as it is possible to give them diets with greater variation in plant pigments. The urochrome was extracted as above by Garrod's method and the amount of colour was estimated from the volume of the extract and its depth of colour. The experiments show that a diet deficient in plant pigments is associated with a urine deficient in yellow pigment. As the chemical composition of urochrome indicates that it is an acid substance giving reactions for pyrrole [Dombrowski, 1907], and might be a derivative of chlorophyll [Willstiitter and Stoll, 1913], further experiments were carried out contrasting a diet containing carrots with one containing green pigments (carrot tops) with the result that the green parts of plants caused a marked increase in the amount of colour in the urine whilst the yellow pigments did not show any appreciable effects. The experiments are so easy of repetition that full experimental details need not be given. One experiment on a guinea-pig is included to show the extent of variations in colour produced by changes in diet. Guinea-pig weight 335 g. Date Volume of urine Relative colour 1921 Diet c.c. of extract