ISOLATION OF 3-HYDROXYANTHRANILIC ACID FROM PATHOLOGICAL HUMAN URINE AFTER ADMINISTRATION OF l-TRYPTOPHAN

Abstract

Iiotake and Sakata have reported that the ingestion of 3 gm. of tryptophan or 1 gm. of kynurenine by a human subject resulted in an increase in the "diazo reaction" (red color with alkaline diazobenzenesulfonic acid) in the urine (1).The urine of a patient with pulmonary tuberculosis showed a strong increase in this reaction after ingestion of 2 gm. of tryptophan.More recently, Japanese authors have reported (2) that, of nineteen patients with pulmonary tuberculosis to whom 0.5 gm. of tryptophan was fed, five excreted kynurenine; this was not observed with normal subjects who mere fed 3 gm. of tryptophan.The diazo reaction, not given by kynurenine, is clearly given by xanthurenic acid, the metabolic product of tryptophan discovered by one of us (Musajo), and by urine containing it.In view of this, Chiancone (3) in 1935 gave a young man suffering from bilateral t.uberculosis 3 gm. of n-tryptophan in a single dose, and to another young man he gave 1.5 gm. of L-kynurenine, but no xanthurenic acid was found in the urines by methods at our disposal at that time.We have restudied the problem of the interpretation of the diazo reaction in the urines of patients with pulmonary tuberculosis in the light of new information which has appeared concerning the biological transformations of tryptophan.Among these products of metabolism are 3hydroxyanthranilic acid and 3-hydroxykynurenine (4), both of which give the diazo reaction.3-Hydroxyanthranilic acid is believed to be derived from tryptophan through kynurenine and 3-hydroxykynurenine.By isolation of 3-hydroxyanthranilic acid as the methyl ester and comparison with the synthetic product, we have been able to show its presence in the urine of a patient with bilateral pulmonary tuberculosis who had ingested 5 gm. of n-tryptophan.From the urines of two other patients, to whom L-tryptophan (100 mg. per kilo) was administered, we were not able to isolate 3-hydrosyanthranilic acid.It is to be noted that the disease was less severe in these last two patients.EXPERIMENTAL Synthesis of Meihyl Ester of .!I-Hydroxyanthranilic Acid-300 mg. of 3hydroxyanthranilic acid (5) are dissolved in 7 ml. of absolute methanol