TY - JOUR
T1 - Iron-chlorophyllin-mediated conversion of 3-hydroxyamino-1-methyl-5H- pyrido[4,3-b]indole (Trp-P-2(NHOH)) into its nitroso derivative
AU - Arimoto-Kobayashi, Sakae
AU - Inada, Naomi
AU - Nakano, Hiromi
AU - Rai, Haruki
AU - Hayatsu, Hikoya
N1 - Funding Information:
This work was supported in part by the Grant-in-Aid for Cancer Research (8-5) from the Ministry of Health and Welfare (for H.H.) and by the Grant from Kudo Science Foundation (for S.A.-K.).
PY - 1998/5/25
Y1 - 1998/5/25
N2 - Early work from our laboratory has shown that the mutagenicity of heterocyclic amines in Salmonella can be inhibited by hemin and chlorophyllins. We have speculated that the inhibition is a result of complex formation between heterocyclic amines and the pigments, and the speculation has been given a line of experimental evidence. We have now found that ferric-chlorophyllin (Fe-chlorophyllin) can modify the mutagenicity of 3- hydroxyamino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2(NHOH)), a metabolically activated form of 3-amino-1-methyl-SH-pyrido[4,3-b]indole (Trp-P-2). The mutagenicity of Trp-P-2(NHOH) in Salmonella typhimurium TA 98 (without S9) was strongly inhibited by an addition of an equimolar Fe-chlorophyllin in the pre-incubation mixture. Fe-chlorophyllin also inhibited the mutagenicity of 2-hydroxyamino-6-methyldipyrido[1,2-a:3',2'-d] imidazole (Glu-P-1(NHOH)). A rapid change in the UV spectrum of a mixture of Trp-P-2(NHOH) and Fe- chlorophyllin was observed. Analysis by high performance liquid chromatography showed that Trp-P-2(NHOH) was converted into 3-nitroso-1- methyl-5H-pyrido[4,3-b]indole (Trp-P-2(NO)), the mutagenic potency of which is a quarter of that of Trp-P-2(NHOH). Furthermore, the mutagenicity of Trp- P-2(NO), in turn, was inhibited by Fe-chlorophyllin. We conclude that the suppression of the mutagenicity of Trp-P-2(NHOH) is ascribable to the oxidative function of Fe-chlorophyllin, coupled with its ability to form complex formation with the planar surface of the heterocyclic amine molecules.
AB - Early work from our laboratory has shown that the mutagenicity of heterocyclic amines in Salmonella can be inhibited by hemin and chlorophyllins. We have speculated that the inhibition is a result of complex formation between heterocyclic amines and the pigments, and the speculation has been given a line of experimental evidence. We have now found that ferric-chlorophyllin (Fe-chlorophyllin) can modify the mutagenicity of 3- hydroxyamino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2(NHOH)), a metabolically activated form of 3-amino-1-methyl-SH-pyrido[4,3-b]indole (Trp-P-2). The mutagenicity of Trp-P-2(NHOH) in Salmonella typhimurium TA 98 (without S9) was strongly inhibited by an addition of an equimolar Fe-chlorophyllin in the pre-incubation mixture. Fe-chlorophyllin also inhibited the mutagenicity of 2-hydroxyamino-6-methyldipyrido[1,2-a:3',2'-d] imidazole (Glu-P-1(NHOH)). A rapid change in the UV spectrum of a mixture of Trp-P-2(NHOH) and Fe- chlorophyllin was observed. Analysis by high performance liquid chromatography showed that Trp-P-2(NHOH) was converted into 3-nitroso-1- methyl-5H-pyrido[4,3-b]indole (Trp-P-2(NO)), the mutagenic potency of which is a quarter of that of Trp-P-2(NHOH). Furthermore, the mutagenicity of Trp- P-2(NO), in turn, was inhibited by Fe-chlorophyllin. We conclude that the suppression of the mutagenicity of Trp-P-2(NHOH) is ascribable to the oxidative function of Fe-chlorophyllin, coupled with its ability to form complex formation with the planar surface of the heterocyclic amine molecules.
KW - Antimutagenicity
KW - Chlorophyllin
KW - Food pyrolysate mutagen
KW - Inhibition of mutagenicity
KW - Superoxide dismutase-like action
KW - Trp-P- 2(NHOH)
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U2 - 10.1016/S0027-5107(98)00033-5
DO - 10.1016/S0027-5107(98)00033-5
M3 - Article
C2 - 9685672
AN - SCOPUS:0032565539
VL - 400
SP - 259
EP - 269
JO - Mutation Research - Fundamental and Molecular Mechanisms of Mutagenesis
JF - Mutation Research - Fundamental and Molecular Mechanisms of Mutagenesis
SN - 0027-5107
IS - 1-2
ER -