Abstract
The fate of cinnamic acid (C6H5CH:CHCOOH) after its administration to the animal organism has been examined repeatedly. The following facts are known. Cinnamic acid given by mouth to humans is oxidized to benzoic acid which is excreted in the urine linked with glycine in the form of hippuric acid. 1 , 2 In cats and dogs after the administration of phenylpropionic acid not only hippuric acid but also small amounts of cinnamoylglycine are excreted. 3 After administration of cinnamic acid hippuric acid with small traces of cinnamoylglycine are found. 4 After administration of cinnamic acid by mouth to dogs 65-70% of the excreted benzoic acid is present in the form of benzoylglycuronic acid and 30% in the form of hippuric acid. 5 The isolated kidney of calves and sheep is able to oxidize cinnamic acid to benzoic acid during perfusion. 6 However, the isolated kidney of the dog is not able to oxidize cinnamic acid but only conjugates the cinnamic acid with glycine to form cin-namoylglycine. 7 Excretion of cinnamoylglycuronic acid has not been observed previously. We have reéxamined the question whether after cinnamic acid administration to humans free or conjugated cinnamic acid could be found in the urine.
Experimental. Six g of cinnamic acid were given after dissolving in 200 cc of water and neutralizing. The urine excreted within the first 4 hours of the experiment was examined in order to compare the results obtained with Quick's hippuric acid test.
1. Glycuronic acid was excreted in considerable amounts. The urine always gave a positive naphthoresorcin reaction. 8 The amount of glycuronic acid varied between 300 and 800 mg determined with the Shaffer-Hartmann technic. 9
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