Tryptophan pyrolysate

The 3-amino-1 -mcthyl-5//-pyrido[4,3-b]indolc derivatives (31 Trp-P-1) and (32 Trp-P-2) were found as tryptophane pyrolysates in broiled fish and meat and in pyrolysates of protein and amino acids by Sugimura and coworkers198. These mutagens are heterocyclic amines and exhibit mutagenicity in the Ames test supplemented with S-9 mix198. The pyridoindole derivatives Trp-P-1 and Trp-P-2 are /V-hydroxylated at the exocyclic amino group to form proximate reactive compounds. 

Kada, T., K. Morita, and T. Inoue. Anti-mutagenic action of vegetable factor(s) on the mutagenic principle of tryptophan pyrolysate. Mutat Res 1978 53 351-353. 

Arimoto, S., Nakano, N., Ohara, Y, Tanaka, K. Hayatsu, H. (1982) A solvent effect on the mutagenicity of tryptophan-pyrolysate mutagens in the SalmonellalraarwaaMan microsome assay. Mutat. Res., 102, 105-112... 

Chromosome aberrations have been reported in Syrian hamster embryo (SHE) cells after treatment with a DMSO extract of tryptophan pyrolysate. At a dose of 30 pg/ml, 69 exchanges and 29 chromosome or chromatid breaks were observed among 200 metaphases. Gaps and minutes were noted as well (33). Sasaki, et al. (34) also observed chromosome aberrations in human and Chinese hamster cell lines after exposure to Trp-P-1 and Trp-P-2. 

Tryptophan pyrolysates have also been found to induce sister chromatid exchanges in cultured mammalian cell lines. Tohda et al. (35) tested Trp-P-1, Trp-P-2, 2-Amino-6-methyldipyrido[l,2-oi 3, 2 -dj imidazole(Glu-P-1), and AaC in a permanent cell line of human lymphoblastoid cells. All four compounds were active at a concentration of 10 M, but inclusion of S9 mix was necessary. Similar results are reported by Sasaki, a. (34) in 2 human and Chinese hamster cell lines. 

Although not necessarily a genotoxic event, in vitro cell transformation is included in this section. The basic fraction of a tryptophan pyrolysate and synthetic Trp-P-1 and Trp-P-2 were tested for transforming activity in Syrian golden hamster embryo cells (37). The percent of morphologically transformed colonies was 1.5, 1.3 and 0.54 for Trp-P-2, Trp-P-1 and 3-methyl-cholanthrene (3MC), respectively. The optimum concentrations for Trp-P-1 and Trp-P-2 were 0.5 pg/ml versus 1.0 pg/ml for 3MC. 

No morphologically transformed colonies were seen in control cultures. Cells transformed in this way also exhibited the ability to grow in soft agar and formed anaplastic fibrosarcomas when transplanted into the cheek pouches of four-week old male hamsters (J5 0. Tsuda et l. (33) also demonstrated morphological transformation in primary cultures of Syrian hamster embryo cells by crude tryptophan pyrolysates. In this experiment, a concentration of 50 pg/ml of pyrolysate induced 1.8% transformed colonies. The control transformation frequency was 0.028%. 

The basic fraction of tryptophan pyrolysate was also tested by oral administration to Wistar rats over 2 years (40). The most advanced lesions obtained at the higher (but not the lower) dose were neoplastic nodules in the liver, an intermediate step in the process of hepatic carcinogenesis. The authors state that, historically, pre-neoplastic lesions in rats of this strain have never been seen in their laboratory without administration of carcinogens. Trp-P-2, as a pure compound, has also been tested in ACI rats in a lifetime (870 days) study (41). In this study, 10 male and 9 female animals survived more than 400 days on a diet containing 0.01% Trp-P-2. Neoplastic nodules were again seen in the livers of treated females, but none occurred in the males of the experimental group or any of the control animals. 

Yamazoe, Y., Ishii, K., Kamataki, T., Kato, R., and Sugimura, T., Isolation and characterization of active metabolites of tryptophan-pyrolysate mutagen, TRP-P-2, formed by rat liver microsomes, Chemico-Biol. Interact., 30, 125, 1980. 

Matsukura, N., Kawachi, T., Wakabayashi, K., Ohgaki, H., Morino, K., Sugimura, T., Nukaya, H., and Kosuge, T., Liver cancer and precancerous changes in rats induced by the basic fraction of tryptophan pyrolysate, Cancer Lett., 13, 181,1981. 

Degawa, M., Hishinuma, T., Yoshida, H., and Hashimoto, Y., Species, sex and organ differences in induction of a cytochrome P-450 isozyme responsible for carcinogen activation Effects of dietary hepatocarcinogenic tryptophan pyrolysate components in mice and rats, Carcinogenesis, 8, 1913, 1987. 

Millon, H., Bur, H., and Turesly, R., Thermospray liquid chromatographic-mass spectrometric analysis of mutagenic substances present in tryptophan pyrolysates, J. Chromatogr., 394, 201-208, 1987. 

In the late 1970s, Japanese investigators, in their detailed studies of components of various cooked foods, isolated and identified the first of a series of Af-heterocyclic amines as pyrolysis products of several amino acids. Sugimura et al. (3829) reported the isolation and identification of 3 -am ino-1,4-dimethyl-5//-py rido[4,3 -fcjindole (designated as Trp-P-1) IV and 3-amino-l-methyl-5//-pyrido[4,3-fc] indole (Trp-P-2) V (Figure XVII.F-2) from tryptophan pyrolysates. 

Sugimura Isolation and characterization of active metabolites of tryptophan pyrolysate mutagen, Trp-P-2, 4386. 

Vanscheeuwijck, P.M., A. Teredesai, P.M. Terpstra, J. Verbeeck, P. Kuhl, B. Gerstenberg, S. Gebel, and E.L. Carmines Evaluation of the potential effects of ingredients added to cigarettes. Part 4 Subchronic inhalation studies Food Chem. Toxicol. 40 (2002) 113-131. Akimoto, H., A Kawai, H. Nomura, M. Nagao, T. Kawachi, and T. Sugimura Synthesis of potent mutagens in tryptophan pyrolysates Chem. Lett. (1977) 1061. Appleton, B.S. Levulinic acid pyrolysis Memorandum, 1986, March 3, see www.rjrtdocs.com 511373917 -3917. 

Takeda, K., T. Ohta, K. Shudo, T. Okamoto, K. Tsuji, and T. Kosuge Synthesis of a mutagenic principle isolated from tryptophan pyrolysate Chem. Pharm. Bull. 256 (1978) 2145. 

Norharman, iS-carboline, is produced by pyrolysis of tryptophan. Harman, 1-methylnorharman, is also present in a pyrolysate of tryptophan. During purification of mutagenic compounds in tryptophan pyrolysates Trp-P-1 and Trp-P-2, it was found that norharman and harman enhanced the mutagenicities of Trp-P-1 and Trp-P-2 under certain incubation conditions, namely,... 

Aimno-l,4-dimethyl-5//-pyrido[4,3- >]indole (Trp-P-1) is a tryptophan pyrolysate and formed in cooked meat and fish. For example, the broiled beef contains 0.21 ng/g in Trp-P-1, and sardine 13 ng/g (i, 2). This compound is known as a potent carcinogen in the liver of rodents (3). According to the in vivo study, administrated Trp-P-1 was detectable in plasma for longer than 3 weeks (4) and detected in various kinds of tissues including the liver, spleen and thymus (5). Thus, Trp-P-1 is considered to be absorbed in and transported to various tissues through blood and lymph. We have demonstrated that Trp-P-1 induces apoptosis in rat hepatocytes 6-8), splenocytes and thymocytes (9). Our recent study showed Trp-P-1 also induced apoptosis in mononuclear cells (MNCs including lymphocytes and monocytes) from rats and human peripheral blood 10). 

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