A HYDROPHILIC TETRAHYDRO-BETA-CARBOLINE IN HUMAN URINE

A substance that exhibited a tryptophan-like fluorescence peak at 354 nm on excitation at 295 nm at neutral pH was isolated from human urine . This compound was determined by visible-light absorption spectroscop y, fluorescence spectroscopy, H-1 and C-13 NMR spectroscopies, and FAB -MS to be 1-(1',2',3',4',5' entyl)-1,2,3,4-tetrahydro-2-carboline-3-ca rboxylic acid. This compound, named tetrahydropentoxyline, is a new ty pe of hydrophilic tetrahydro-beta-carboline, and its elution position was between those of 4-pyridoxic acid and kynurenic acid on C-18 rever sed-phase HPLC. The amount of tetrahydropentoxyline excreted in the ur ine of normal subjects [n=21; age, 45 (SD 20) years] was about 5.2 (SD 1.0) mg per day.