Identification of Tetrahydro-β-carboline-3-carboxylic Acid in Foodstuffs, Human Urine and Human Milk

• Published in: The Journal of nutrition Vol. 121; no. 5; pp. 646 - 652
• Main Authors: Adachi, Junko, Mizoi, Yasuhiko, Naito, Takeaki, Ogawa, Yumi, Uetani, Yoshiyuki, Ninomiya, Ichiya
• Format: Journal Article
• Language: English
• Published: Bethesda, MD Elsevier Inc 01.05.1991; American Society for Nutritional Sciences
• Subjects: acide organique; acidos organicos; Adult; adulte; adultos; adults; alcoholic beverages; Alcoholic Beverages - analysis; aliment pour nourrisson; alimentos para ninos; almidon; amidon; analysis; Analytical, structural and metabolic biochemistry; bebes; bebidas alcoholicas; Biological and medical sciences; boisson alcoolisee; breast milk; Carbolines; Carbolines - analysis; Carbolines - urine; carboxylic acids; chemical composition; chemistry; Chromatography, High Pressure Liquid; compose nitrose; composicion quimica; composition chimique; compuestos nitrosos; corn starch; diet; dieta; endogenous synthesis; enfant en bas age; farine; Female; fermented products; flour; flours; Food Analysis; food composition; Fundamental and applied biological sciences. Psychology; harinas; Heterocyclic compounds, pigments; human milk; human urine; Humans; Infant; infant foods; infant formulas; Infant, Newborn; infants; lait; lait humain; leche; leche humana; mais; maiz; maize; Male; Mass Spectrometry; milk; Milk, Human; Milk, Human - chemistry; Miscellaneous; nitroso compounds; organic acids; orina; Other biological molecules; productos de la soja; productos fermentados; produit a base de soja; produit fermente; regime alimentaire; soybean products; starch; tetrahydro-β-carboline; urine; tetrahydro-β-carboline; human milk; endogenous synthesis; human urine; humans; Human; Origin; Urine; Exogenous; Nitrogen heterocycle; Tryptophan; Biosynthesis; Metabolism; Fermented product; Endogenous; Human milk; Food; Quantitative analysis
• ISSN: 0022-3166; 1541-6100
• DOI: 10.1093/jn/121.5.646

1-Methyl-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid (MTCA) and 1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid (TCCA), both precursors of mutagenic N-nitroso compounds (N-nitrosamines, 1-methyl-2-nitroso-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid and 2-nitroso-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid), were detected in various foodstuffs, urine from healthy human subjects and human milk. A purification procedure, involving a chemically-bonded material followed by HPLC combined with fluorometric detection, was used for the quantitative determination of these compounds, allowing the separation of two diastereoisomers of MTCA. An HPLC and mass spectrometry method was also developed for their identification. Comparing the concentration of MTCA and TCCA in fermented products and raw materials suggested that tetrahydro-β-carbolines may have been produced through fermentation or by condensation of tryptophan and acetaldehyde formed from ethanol added as a food preservative. This is the first report of excretion of tetrahydro-β-carbolines in human urine and human milk. A comparison of the concentrations of tetrahydro-β-carbolines in urine from human infants and human milk indicates that tetrahydro-β-carbolines may be synthesized endogenously in humans. A possible pathway of tryptophan metabolism in plants and animals is presented.