The Experts below are selected from a list of 105 Experts worldwide ranked by ideXlab platform
Yoshinari Ohnishi - One of the best experts on this subject based on the ideXlab platform.
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inhibitory effects of centella asiatica on azoxymethane induced Aberrant Crypt Focus formation and carcinogenesis in the intestines of f344 rats
Food and Chemical Toxicology, 2004Co-Authors: P Bunpo, Keiko Kataoka, Hideki Arimochi, Tomomi Kuwahara, Usanee Vinitketkumnuen, Haruyuki Nakayama, Yoshimi Bando, Keisuke Izumi, Yoshinari OhnishiAbstract:Effects of the water extract of Centella asiatica Linn. on formation of azoxymethane (AOM)-induced Aberrant Crypt foci (ACF) and intestinal tumorigenesis in male F344 rats were investigated. Treatment with the extract significantly decreased the number of larger ACF (with four or more Crypts per Focus) in the large intestine in the early stage, while the number of methylated DNA adducts was not decreased compared with that in the AOM-treated group. In the post-initiation stage, the extract significantly decreased the total number of ACF and the number of larger ACF, accompanied by a decrease in the 5-bromo-2'-deoxyuridine-labeling index and an increase in the induction of apoptotic cells in the colonic mucosa. The incidences of neoplasms, the numbers of adenocarcinomas in the small intestines and entire intestines, and sizes of neoplasms in the entire intestines in rats fed C. asiatica extract at a dose of 10 mg/kg were smaller than those in rats given AOM alone (p < 0.05). The extract at a dose of 100 mg/kg significantly reduced the multiplicity of neoplasms in the small intestine (p < 0.05). These results suggest that inhibition of the formation of AOM-induced ACF by C. asiatica extract is associated with modification of cell proliferation and induction of apoptosis in colonic Crypts and that the extract has a chemopreventive effect on colon tumorigenesis.
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antimutagenicity of murdannia loriformis in the salmonella mutation assay and its inhibitory effects on azoxymethane induced dna methylation and Aberrant Crypt Focus formation in male f344 rats
The Journal of Medical Investigation, 2002Co-Authors: Yaowarate Intiyot, Takemi Kinouchi, Keiko Kataoka, Hideki Arimochi, Tomomi Kuwahara, Usanee Vinitketkumnuen, Yoshinari OhnishiAbstract:An 80% ethanol extract of Murdannia loriformis, a Thai medicinal plant, was examined for antimutagenic activity and cancer chemopreventive activity. In the Salmonella mutation assay, the extract showed antimutagenicity against 2-amino-3-methylimidazo [4,5-f]quinoline, 2-amino-3,4-dimethylimidazo[4,5-f]quinoline, 2-amino-3,8-dimethylimidazo [4,5-f]quinoxaline, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine, 2-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole, 3-amino-1-methyl-5H-pyrido[4,3-b]indole, 2-amino-6-methyldipyrido [1,2-a:3',2'-d] imidazole, 2-aminodipyrido[1,2-a:3',2'-d]imidazole, 2-aminoanthracene, 2-(2-furyl)-3-(5-nitro-2-furyl) acrylamide, N-methyl-N'-nitro-N-nitrosoguanidine and methylazoxymethanol acetate and reduced their mutagenicities to 31.4-67.9% at the dose of 10 mg/plate. However, it did not inhibit the mutagenicities of 2-amino-9H-pyrido[2,3-b]indole, 2-amino-3-methyl-9 H-pyrido[2,3-b]indole, benzo[a]pyrene,N-ethyl-N'-nitro-N-nitrosoguanidine and 1-nitropyrene. The extract itself showed no mutagenicity. The chemopreventive activity of M. loriformis was examined using azoxymethane (AOM)-induced Aberrant Crypt Focus (ACF) formation in the colon of F344 rats. The extract at doses of 0.1-1.0 g/kg wt significantly inhibited ACF formation in the initiation stage (21-51%), although it was more effective at a lower dose. In the post-initiation stage, the extract also tended to inhibit ACF formation (12-27%) and significantly decreased the number of larger ACFs that have more than 3 Aberrant Crypts per Focus. The extract inhibited the formation of O6-methylguanine and N7-methylguanine in the colonic mucosa and muscular layers but not or increased in the liver. These results indicate that M. loriformis extract has antimutagenic activity toward various known mutagens and that it inhibits AOM-induced ACF formation both in the initiation and post-initiation stages in the rat colon.
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expression of human lactoferrin in bacteroides uniformis and its effect on azoxymethane induced Aberrant Crypt Focus formation in the rat colon
Anaerobe, 2001Co-Authors: Keiko Kataoka, Hideki Arimochi, Tomomi Kuwahara, Usanee Vinitketkumnuen, Haruyuki Nakayama, Teera Chewonarin, Hiroyuki Tsuda, Yoshinari OhnishiAbstract:Abstract To express a human lactoferrin (hLF) gene in Bacteroides uniformis, a member of the anaerobic microflora in the colon, we constructed a recombinant plasmid, pVLFK, by subcloning hLF cDNA to an Escherichia coli–Bacteroides shuttle vector, pVAL-1. The plasmid pVLFKwas transferred to B. uniformis strain BU1001 by the filter mating procedure creating strain TCTK101. The lactoferrin protein in B. uniformis strain TCTK101 was detected by Western blot analysis with an anti-human lactoferrin monoclonal antibody. A culture of strain TCTK101 inhibited the growth ofE. coli strain HB101 in vitro compared to a culture of strain TCTK11, which is a B. uniformis strain-carrying plasmid pVAL-1, suggesting that the lactoferrin produced from strain TCTK101 possesses biological activity. To determine the effect of lactoferrin-producing B. uniformis on the formation of azoxymethane-induced Aberrant Crypt foci (ACF), putative neoplastic lesions, overnight cultures of strains TCTK11 and TCTK101 were given to rats as drinking water. The numbers of ACF and ACF having more than three Crypts per Focus five weeks after the beginning of the experiment significantly increased in the group treated by a culture of strain TCTK11 compared with those in the non-treated water group. However, rats treated with a culture of strain TCTK101 carrying plasmid pVLFK showed a significantly lower number of ACF than rats with a culture of strain TCTK11 (34% reduction), suggesting that hLF which is produced in a prokaryotic expression system prevents formation of ACF in the rat colon.
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effects of roselle hibiscus sabdariffa linn a thai medicinal plant on the mutagenicity of various known mutagens in salmonella typhimurium and on formation of Aberrant Crypt foci induced by the colon carcinogens azoxymethane and 2 amino 1 methyl 6 phenylimidazo 4 5 b pyridine in f344 rats
Food and Chemical Toxicology, 1999Co-Authors: Takemi Kinouchi, Keiko Kataoka, Hideki Arimochi, Tomomi Kuwahara, Teera Chewonari, Usanee Vinitketkumnue, Yoshinari OhnishiAbstract:Abstract The 80% ethanol extract of roselle ( Hibiscus sabdariffa Linn.), a medicinal plant in Thailand, was examined for antimutagenic and chemopreventive activity in a colon carcinogenesis model. It reduced about 60–90% of the mutagenicity induced by 2-amino-1-methyl-6-phenylimidazo[4,5- b ]pyridine (PhIP) and other heterocyclic amines 2-amino-3-methylimidazo[4,5- f ]quinoline (IQ), 2-amino-3,4-dimethylimidazo[4,5- f ]quinoline(MeIQ),2-amino-3,8-dimethylimidazo[4,5- f ]quinoxaline(MeIQx),3-amino-1,4-dimethyl-5 H -pyrido[4,3- b ]indole (Trp-P-1), 3-amino-1-methyl-5 H -pyrido[4,3- b ]indole (Trp-P-2),2-amino-6-methyldipyrido[1,2- a :3′,2′- d ]imidazole (Glu-P-1),2-aminodipyrido[1,2- a :3′,2′- d ]imidazole (Glu-P-2), at a concentration of 12.5 mg/plate in the Salmonella mutation assay. The extract showed no mutagenicity and no antibacterial activity below this dose. Mutagenicity of methylazoxymethanol (MAM) acetate, which, like PhIP, is a colon carcinogen,was also efficiently inhibited by the roselle extract. To investigate chemoprevention by roselle in a colon carcinogenesis model, we examined the inhibitory effects of the roselle extract in F344 rats in which Aberrant Crypt Focus (ACF) formation was induced by azoxymethane (AOM) and PhIP. In the initiation stage, the number of AOM-induced ACF in the colon was significantly decreased by roselle (17–25%) compared with that in rats treated with AOM alone. The amount of O 6 -methylguanine in the colonic mucosa tended to be decreased in the roselle-treated rats. The number of PhIP-induced ACF was also significantly decreased by roselle treatment (22%) at a concentration of 1.0 g/kg body weight in the initiation stage. However, in the post-initiation stage of AOM-induced ACF formation, roselle increased the number of ACF, especially the number of foci which had more than three Crypts/Focus. These results indicate that roselle has antimutagenic activity against MAM acetate and heterocyclic amines and that it decreases the number of AOM- and PhIP-induced ACF in the initiation stage, although it rather increased the number of ACF in the post-initiation stage.
Roderick H Dashwood - One of the best experts on this subject based on the ideXlab platform.
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a comparison of whole wheat refined wheat and wheat bran as inhibitors of heterocyclic amines in the salmonella mutagenicity assay and in the rat colonic Aberrant Crypt Focus assay
Food and Chemical Toxicology, 2001Co-Authors: G Santanarios, R Shen, M Izquierdopulido, David E Williams, Roderick H DashwoodAbstract:Refined wheat, unrefined whole wheat, and wheat bran were studied for their ability to protect against heterocyclic amines (HCAs) in vitro and in vivo. Wheat bran, which binds HCAs in vitro, as well as refined wheat and unrefined whole wheat, inhibited the mutagenic activities of 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) and 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) when they were co-incubated and the supernatant (minus grain) was added to the Salmonella assay. The water-soluble fraction alone from refined and unrefined wheat, but not bran, also inhibited against these mutagens in vitro. In vivo, AIN-93G diets containing refined wheat or unrefined wheat were examined for their ability to inhibit IQ-induced colonic Aberrant Crypt foci (ACF) in the Fischer 344 rat. A slight increase in the number of AC/ACF (Aberrant Crypts/ACF) was seen after 16 weeks in rats treated post-initiation with refined wheat (P<0.05), and fewer foci with two or three Aberrant Crypts (ACF-2) were found in rats given unrefined whole wheat post-initiation compared with animals treated with the same diet during the initiation phase (P<0.05). There was no significant difference in the profile of IQ urinary metabolites or excretion of promutagens 0–48 h after carcinogen dosing, and grains had no effect on hepatic cytochrome P4501A1 (CYP1A1), CYP1A2, aryl sulfotransferase or N-acetyltransferase activities; however, a slightly higher UDP-glucuronosyl transferase activity was observed in rats fed unrefined wheat compared with refined wheat diets (P<0.05). Thus, despite their antimutagenic activities in vitro, only marginal effects were seen with refined and unrefined wheat in vivo with respect to hepatic enzyme activities, carcinogen metabolism and IQ-induced ACF in the rat colon.
Keiko Kataoka - One of the best experts on this subject based on the ideXlab platform.
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inhibitory effects of centella asiatica on azoxymethane induced Aberrant Crypt Focus formation and carcinogenesis in the intestines of f344 rats
Food and Chemical Toxicology, 2004Co-Authors: P Bunpo, Keiko Kataoka, Hideki Arimochi, Tomomi Kuwahara, Usanee Vinitketkumnuen, Haruyuki Nakayama, Yoshimi Bando, Keisuke Izumi, Yoshinari OhnishiAbstract:Effects of the water extract of Centella asiatica Linn. on formation of azoxymethane (AOM)-induced Aberrant Crypt foci (ACF) and intestinal tumorigenesis in male F344 rats were investigated. Treatment with the extract significantly decreased the number of larger ACF (with four or more Crypts per Focus) in the large intestine in the early stage, while the number of methylated DNA adducts was not decreased compared with that in the AOM-treated group. In the post-initiation stage, the extract significantly decreased the total number of ACF and the number of larger ACF, accompanied by a decrease in the 5-bromo-2'-deoxyuridine-labeling index and an increase in the induction of apoptotic cells in the colonic mucosa. The incidences of neoplasms, the numbers of adenocarcinomas in the small intestines and entire intestines, and sizes of neoplasms in the entire intestines in rats fed C. asiatica extract at a dose of 10 mg/kg were smaller than those in rats given AOM alone (p < 0.05). The extract at a dose of 100 mg/kg significantly reduced the multiplicity of neoplasms in the small intestine (p < 0.05). These results suggest that inhibition of the formation of AOM-induced ACF by C. asiatica extract is associated with modification of cell proliferation and induction of apoptosis in colonic Crypts and that the extract has a chemopreventive effect on colon tumorigenesis.
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antimutagenicity of murdannia loriformis in the salmonella mutation assay and its inhibitory effects on azoxymethane induced dna methylation and Aberrant Crypt Focus formation in male f344 rats
The Journal of Medical Investigation, 2002Co-Authors: Yaowarate Intiyot, Takemi Kinouchi, Keiko Kataoka, Hideki Arimochi, Tomomi Kuwahara, Usanee Vinitketkumnuen, Yoshinari OhnishiAbstract:An 80% ethanol extract of Murdannia loriformis, a Thai medicinal plant, was examined for antimutagenic activity and cancer chemopreventive activity. In the Salmonella mutation assay, the extract showed antimutagenicity against 2-amino-3-methylimidazo [4,5-f]quinoline, 2-amino-3,4-dimethylimidazo[4,5-f]quinoline, 2-amino-3,8-dimethylimidazo [4,5-f]quinoxaline, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine, 2-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole, 3-amino-1-methyl-5H-pyrido[4,3-b]indole, 2-amino-6-methyldipyrido [1,2-a:3',2'-d] imidazole, 2-aminodipyrido[1,2-a:3',2'-d]imidazole, 2-aminoanthracene, 2-(2-furyl)-3-(5-nitro-2-furyl) acrylamide, N-methyl-N'-nitro-N-nitrosoguanidine and methylazoxymethanol acetate and reduced their mutagenicities to 31.4-67.9% at the dose of 10 mg/plate. However, it did not inhibit the mutagenicities of 2-amino-9H-pyrido[2,3-b]indole, 2-amino-3-methyl-9 H-pyrido[2,3-b]indole, benzo[a]pyrene,N-ethyl-N'-nitro-N-nitrosoguanidine and 1-nitropyrene. The extract itself showed no mutagenicity. The chemopreventive activity of M. loriformis was examined using azoxymethane (AOM)-induced Aberrant Crypt Focus (ACF) formation in the colon of F344 rats. The extract at doses of 0.1-1.0 g/kg wt significantly inhibited ACF formation in the initiation stage (21-51%), although it was more effective at a lower dose. In the post-initiation stage, the extract also tended to inhibit ACF formation (12-27%) and significantly decreased the number of larger ACFs that have more than 3 Aberrant Crypts per Focus. The extract inhibited the formation of O6-methylguanine and N7-methylguanine in the colonic mucosa and muscular layers but not or increased in the liver. These results indicate that M. loriformis extract has antimutagenic activity toward various known mutagens and that it inhibits AOM-induced ACF formation both in the initiation and post-initiation stages in the rat colon.
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expression of human lactoferrin in bacteroides uniformis and its effect on azoxymethane induced Aberrant Crypt Focus formation in the rat colon
Anaerobe, 2001Co-Authors: Keiko Kataoka, Hideki Arimochi, Tomomi Kuwahara, Usanee Vinitketkumnuen, Haruyuki Nakayama, Teera Chewonarin, Hiroyuki Tsuda, Yoshinari OhnishiAbstract:Abstract To express a human lactoferrin (hLF) gene in Bacteroides uniformis, a member of the anaerobic microflora in the colon, we constructed a recombinant plasmid, pVLFK, by subcloning hLF cDNA to an Escherichia coli–Bacteroides shuttle vector, pVAL-1. The plasmid pVLFKwas transferred to B. uniformis strain BU1001 by the filter mating procedure creating strain TCTK101. The lactoferrin protein in B. uniformis strain TCTK101 was detected by Western blot analysis with an anti-human lactoferrin monoclonal antibody. A culture of strain TCTK101 inhibited the growth ofE. coli strain HB101 in vitro compared to a culture of strain TCTK11, which is a B. uniformis strain-carrying plasmid pVAL-1, suggesting that the lactoferrin produced from strain TCTK101 possesses biological activity. To determine the effect of lactoferrin-producing B. uniformis on the formation of azoxymethane-induced Aberrant Crypt foci (ACF), putative neoplastic lesions, overnight cultures of strains TCTK11 and TCTK101 were given to rats as drinking water. The numbers of ACF and ACF having more than three Crypts per Focus five weeks after the beginning of the experiment significantly increased in the group treated by a culture of strain TCTK11 compared with those in the non-treated water group. However, rats treated with a culture of strain TCTK101 carrying plasmid pVLFK showed a significantly lower number of ACF than rats with a culture of strain TCTK11 (34% reduction), suggesting that hLF which is produced in a prokaryotic expression system prevents formation of ACF in the rat colon.
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effects of roselle hibiscus sabdariffa linn a thai medicinal plant on the mutagenicity of various known mutagens in salmonella typhimurium and on formation of Aberrant Crypt foci induced by the colon carcinogens azoxymethane and 2 amino 1 methyl 6 phenylimidazo 4 5 b pyridine in f344 rats
Food and Chemical Toxicology, 1999Co-Authors: Takemi Kinouchi, Keiko Kataoka, Hideki Arimochi, Tomomi Kuwahara, Teera Chewonari, Usanee Vinitketkumnue, Yoshinari OhnishiAbstract:Abstract The 80% ethanol extract of roselle ( Hibiscus sabdariffa Linn.), a medicinal plant in Thailand, was examined for antimutagenic and chemopreventive activity in a colon carcinogenesis model. It reduced about 60–90% of the mutagenicity induced by 2-amino-1-methyl-6-phenylimidazo[4,5- b ]pyridine (PhIP) and other heterocyclic amines 2-amino-3-methylimidazo[4,5- f ]quinoline (IQ), 2-amino-3,4-dimethylimidazo[4,5- f ]quinoline(MeIQ),2-amino-3,8-dimethylimidazo[4,5- f ]quinoxaline(MeIQx),3-amino-1,4-dimethyl-5 H -pyrido[4,3- b ]indole (Trp-P-1), 3-amino-1-methyl-5 H -pyrido[4,3- b ]indole (Trp-P-2),2-amino-6-methyldipyrido[1,2- a :3′,2′- d ]imidazole (Glu-P-1),2-aminodipyrido[1,2- a :3′,2′- d ]imidazole (Glu-P-2), at a concentration of 12.5 mg/plate in the Salmonella mutation assay. The extract showed no mutagenicity and no antibacterial activity below this dose. Mutagenicity of methylazoxymethanol (MAM) acetate, which, like PhIP, is a colon carcinogen,was also efficiently inhibited by the roselle extract. To investigate chemoprevention by roselle in a colon carcinogenesis model, we examined the inhibitory effects of the roselle extract in F344 rats in which Aberrant Crypt Focus (ACF) formation was induced by azoxymethane (AOM) and PhIP. In the initiation stage, the number of AOM-induced ACF in the colon was significantly decreased by roselle (17–25%) compared with that in rats treated with AOM alone. The amount of O 6 -methylguanine in the colonic mucosa tended to be decreased in the roselle-treated rats. The number of PhIP-induced ACF was also significantly decreased by roselle treatment (22%) at a concentration of 1.0 g/kg body weight in the initiation stage. However, in the post-initiation stage of AOM-induced ACF formation, roselle increased the number of ACF, especially the number of foci which had more than three Crypts/Focus. These results indicate that roselle has antimutagenic activity against MAM acetate and heterocyclic amines and that it decreases the number of AOM- and PhIP-induced ACF in the initiation stage, although it rather increased the number of ACF in the post-initiation stage.
Hideki Arimochi - One of the best experts on this subject based on the ideXlab platform.
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inhibitory effects of centella asiatica on azoxymethane induced Aberrant Crypt Focus formation and carcinogenesis in the intestines of f344 rats
Food and Chemical Toxicology, 2004Co-Authors: P Bunpo, Keiko Kataoka, Hideki Arimochi, Tomomi Kuwahara, Usanee Vinitketkumnuen, Haruyuki Nakayama, Yoshimi Bando, Keisuke Izumi, Yoshinari OhnishiAbstract:Effects of the water extract of Centella asiatica Linn. on formation of azoxymethane (AOM)-induced Aberrant Crypt foci (ACF) and intestinal tumorigenesis in male F344 rats were investigated. Treatment with the extract significantly decreased the number of larger ACF (with four or more Crypts per Focus) in the large intestine in the early stage, while the number of methylated DNA adducts was not decreased compared with that in the AOM-treated group. In the post-initiation stage, the extract significantly decreased the total number of ACF and the number of larger ACF, accompanied by a decrease in the 5-bromo-2'-deoxyuridine-labeling index and an increase in the induction of apoptotic cells in the colonic mucosa. The incidences of neoplasms, the numbers of adenocarcinomas in the small intestines and entire intestines, and sizes of neoplasms in the entire intestines in rats fed C. asiatica extract at a dose of 10 mg/kg were smaller than those in rats given AOM alone (p < 0.05). The extract at a dose of 100 mg/kg significantly reduced the multiplicity of neoplasms in the small intestine (p < 0.05). These results suggest that inhibition of the formation of AOM-induced ACF by C. asiatica extract is associated with modification of cell proliferation and induction of apoptosis in colonic Crypts and that the extract has a chemopreventive effect on colon tumorigenesis.
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antimutagenicity of murdannia loriformis in the salmonella mutation assay and its inhibitory effects on azoxymethane induced dna methylation and Aberrant Crypt Focus formation in male f344 rats
The Journal of Medical Investigation, 2002Co-Authors: Yaowarate Intiyot, Takemi Kinouchi, Keiko Kataoka, Hideki Arimochi, Tomomi Kuwahara, Usanee Vinitketkumnuen, Yoshinari OhnishiAbstract:An 80% ethanol extract of Murdannia loriformis, a Thai medicinal plant, was examined for antimutagenic activity and cancer chemopreventive activity. In the Salmonella mutation assay, the extract showed antimutagenicity against 2-amino-3-methylimidazo [4,5-f]quinoline, 2-amino-3,4-dimethylimidazo[4,5-f]quinoline, 2-amino-3,8-dimethylimidazo [4,5-f]quinoxaline, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine, 2-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole, 3-amino-1-methyl-5H-pyrido[4,3-b]indole, 2-amino-6-methyldipyrido [1,2-a:3',2'-d] imidazole, 2-aminodipyrido[1,2-a:3',2'-d]imidazole, 2-aminoanthracene, 2-(2-furyl)-3-(5-nitro-2-furyl) acrylamide, N-methyl-N'-nitro-N-nitrosoguanidine and methylazoxymethanol acetate and reduced their mutagenicities to 31.4-67.9% at the dose of 10 mg/plate. However, it did not inhibit the mutagenicities of 2-amino-9H-pyrido[2,3-b]indole, 2-amino-3-methyl-9 H-pyrido[2,3-b]indole, benzo[a]pyrene,N-ethyl-N'-nitro-N-nitrosoguanidine and 1-nitropyrene. The extract itself showed no mutagenicity. The chemopreventive activity of M. loriformis was examined using azoxymethane (AOM)-induced Aberrant Crypt Focus (ACF) formation in the colon of F344 rats. The extract at doses of 0.1-1.0 g/kg wt significantly inhibited ACF formation in the initiation stage (21-51%), although it was more effective at a lower dose. In the post-initiation stage, the extract also tended to inhibit ACF formation (12-27%) and significantly decreased the number of larger ACFs that have more than 3 Aberrant Crypts per Focus. The extract inhibited the formation of O6-methylguanine and N7-methylguanine in the colonic mucosa and muscular layers but not or increased in the liver. These results indicate that M. loriformis extract has antimutagenic activity toward various known mutagens and that it inhibits AOM-induced ACF formation both in the initiation and post-initiation stages in the rat colon.
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expression of human lactoferrin in bacteroides uniformis and its effect on azoxymethane induced Aberrant Crypt Focus formation in the rat colon
Anaerobe, 2001Co-Authors: Keiko Kataoka, Hideki Arimochi, Tomomi Kuwahara, Usanee Vinitketkumnuen, Haruyuki Nakayama, Teera Chewonarin, Hiroyuki Tsuda, Yoshinari OhnishiAbstract:Abstract To express a human lactoferrin (hLF) gene in Bacteroides uniformis, a member of the anaerobic microflora in the colon, we constructed a recombinant plasmid, pVLFK, by subcloning hLF cDNA to an Escherichia coli–Bacteroides shuttle vector, pVAL-1. The plasmid pVLFKwas transferred to B. uniformis strain BU1001 by the filter mating procedure creating strain TCTK101. The lactoferrin protein in B. uniformis strain TCTK101 was detected by Western blot analysis with an anti-human lactoferrin monoclonal antibody. A culture of strain TCTK101 inhibited the growth ofE. coli strain HB101 in vitro compared to a culture of strain TCTK11, which is a B. uniformis strain-carrying plasmid pVAL-1, suggesting that the lactoferrin produced from strain TCTK101 possesses biological activity. To determine the effect of lactoferrin-producing B. uniformis on the formation of azoxymethane-induced Aberrant Crypt foci (ACF), putative neoplastic lesions, overnight cultures of strains TCTK11 and TCTK101 were given to rats as drinking water. The numbers of ACF and ACF having more than three Crypts per Focus five weeks after the beginning of the experiment significantly increased in the group treated by a culture of strain TCTK11 compared with those in the non-treated water group. However, rats treated with a culture of strain TCTK101 carrying plasmid pVLFK showed a significantly lower number of ACF than rats with a culture of strain TCTK11 (34% reduction), suggesting that hLF which is produced in a prokaryotic expression system prevents formation of ACF in the rat colon.
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effects of roselle hibiscus sabdariffa linn a thai medicinal plant on the mutagenicity of various known mutagens in salmonella typhimurium and on formation of Aberrant Crypt foci induced by the colon carcinogens azoxymethane and 2 amino 1 methyl 6 phenylimidazo 4 5 b pyridine in f344 rats
Food and Chemical Toxicology, 1999Co-Authors: Takemi Kinouchi, Keiko Kataoka, Hideki Arimochi, Tomomi Kuwahara, Teera Chewonari, Usanee Vinitketkumnue, Yoshinari OhnishiAbstract:Abstract The 80% ethanol extract of roselle ( Hibiscus sabdariffa Linn.), a medicinal plant in Thailand, was examined for antimutagenic and chemopreventive activity in a colon carcinogenesis model. It reduced about 60–90% of the mutagenicity induced by 2-amino-1-methyl-6-phenylimidazo[4,5- b ]pyridine (PhIP) and other heterocyclic amines 2-amino-3-methylimidazo[4,5- f ]quinoline (IQ), 2-amino-3,4-dimethylimidazo[4,5- f ]quinoline(MeIQ),2-amino-3,8-dimethylimidazo[4,5- f ]quinoxaline(MeIQx),3-amino-1,4-dimethyl-5 H -pyrido[4,3- b ]indole (Trp-P-1), 3-amino-1-methyl-5 H -pyrido[4,3- b ]indole (Trp-P-2),2-amino-6-methyldipyrido[1,2- a :3′,2′- d ]imidazole (Glu-P-1),2-aminodipyrido[1,2- a :3′,2′- d ]imidazole (Glu-P-2), at a concentration of 12.5 mg/plate in the Salmonella mutation assay. The extract showed no mutagenicity and no antibacterial activity below this dose. Mutagenicity of methylazoxymethanol (MAM) acetate, which, like PhIP, is a colon carcinogen,was also efficiently inhibited by the roselle extract. To investigate chemoprevention by roselle in a colon carcinogenesis model, we examined the inhibitory effects of the roselle extract in F344 rats in which Aberrant Crypt Focus (ACF) formation was induced by azoxymethane (AOM) and PhIP. In the initiation stage, the number of AOM-induced ACF in the colon was significantly decreased by roselle (17–25%) compared with that in rats treated with AOM alone. The amount of O 6 -methylguanine in the colonic mucosa tended to be decreased in the roselle-treated rats. The number of PhIP-induced ACF was also significantly decreased by roselle treatment (22%) at a concentration of 1.0 g/kg body weight in the initiation stage. However, in the post-initiation stage of AOM-induced ACF formation, roselle increased the number of ACF, especially the number of foci which had more than three Crypts/Focus. These results indicate that roselle has antimutagenic activity against MAM acetate and heterocyclic amines and that it decreases the number of AOM- and PhIP-induced ACF in the initiation stage, although it rather increased the number of ACF in the post-initiation stage.
Tomomi Kuwahara - One of the best experts on this subject based on the ideXlab platform.
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inhibitory effects of centella asiatica on azoxymethane induced Aberrant Crypt Focus formation and carcinogenesis in the intestines of f344 rats
Food and Chemical Toxicology, 2004Co-Authors: P Bunpo, Keiko Kataoka, Hideki Arimochi, Tomomi Kuwahara, Usanee Vinitketkumnuen, Haruyuki Nakayama, Yoshimi Bando, Keisuke Izumi, Yoshinari OhnishiAbstract:Effects of the water extract of Centella asiatica Linn. on formation of azoxymethane (AOM)-induced Aberrant Crypt foci (ACF) and intestinal tumorigenesis in male F344 rats were investigated. Treatment with the extract significantly decreased the number of larger ACF (with four or more Crypts per Focus) in the large intestine in the early stage, while the number of methylated DNA adducts was not decreased compared with that in the AOM-treated group. In the post-initiation stage, the extract significantly decreased the total number of ACF and the number of larger ACF, accompanied by a decrease in the 5-bromo-2'-deoxyuridine-labeling index and an increase in the induction of apoptotic cells in the colonic mucosa. The incidences of neoplasms, the numbers of adenocarcinomas in the small intestines and entire intestines, and sizes of neoplasms in the entire intestines in rats fed C. asiatica extract at a dose of 10 mg/kg were smaller than those in rats given AOM alone (p < 0.05). The extract at a dose of 100 mg/kg significantly reduced the multiplicity of neoplasms in the small intestine (p < 0.05). These results suggest that inhibition of the formation of AOM-induced ACF by C. asiatica extract is associated with modification of cell proliferation and induction of apoptosis in colonic Crypts and that the extract has a chemopreventive effect on colon tumorigenesis.
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antimutagenicity of murdannia loriformis in the salmonella mutation assay and its inhibitory effects on azoxymethane induced dna methylation and Aberrant Crypt Focus formation in male f344 rats
The Journal of Medical Investigation, 2002Co-Authors: Yaowarate Intiyot, Takemi Kinouchi, Keiko Kataoka, Hideki Arimochi, Tomomi Kuwahara, Usanee Vinitketkumnuen, Yoshinari OhnishiAbstract:An 80% ethanol extract of Murdannia loriformis, a Thai medicinal plant, was examined for antimutagenic activity and cancer chemopreventive activity. In the Salmonella mutation assay, the extract showed antimutagenicity against 2-amino-3-methylimidazo [4,5-f]quinoline, 2-amino-3,4-dimethylimidazo[4,5-f]quinoline, 2-amino-3,8-dimethylimidazo [4,5-f]quinoxaline, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine, 2-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole, 3-amino-1-methyl-5H-pyrido[4,3-b]indole, 2-amino-6-methyldipyrido [1,2-a:3',2'-d] imidazole, 2-aminodipyrido[1,2-a:3',2'-d]imidazole, 2-aminoanthracene, 2-(2-furyl)-3-(5-nitro-2-furyl) acrylamide, N-methyl-N'-nitro-N-nitrosoguanidine and methylazoxymethanol acetate and reduced their mutagenicities to 31.4-67.9% at the dose of 10 mg/plate. However, it did not inhibit the mutagenicities of 2-amino-9H-pyrido[2,3-b]indole, 2-amino-3-methyl-9 H-pyrido[2,3-b]indole, benzo[a]pyrene,N-ethyl-N'-nitro-N-nitrosoguanidine and 1-nitropyrene. The extract itself showed no mutagenicity. The chemopreventive activity of M. loriformis was examined using azoxymethane (AOM)-induced Aberrant Crypt Focus (ACF) formation in the colon of F344 rats. The extract at doses of 0.1-1.0 g/kg wt significantly inhibited ACF formation in the initiation stage (21-51%), although it was more effective at a lower dose. In the post-initiation stage, the extract also tended to inhibit ACF formation (12-27%) and significantly decreased the number of larger ACFs that have more than 3 Aberrant Crypts per Focus. The extract inhibited the formation of O6-methylguanine and N7-methylguanine in the colonic mucosa and muscular layers but not or increased in the liver. These results indicate that M. loriformis extract has antimutagenic activity toward various known mutagens and that it inhibits AOM-induced ACF formation both in the initiation and post-initiation stages in the rat colon.
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expression of human lactoferrin in bacteroides uniformis and its effect on azoxymethane induced Aberrant Crypt Focus formation in the rat colon
Anaerobe, 2001Co-Authors: Keiko Kataoka, Hideki Arimochi, Tomomi Kuwahara, Usanee Vinitketkumnuen, Haruyuki Nakayama, Teera Chewonarin, Hiroyuki Tsuda, Yoshinari OhnishiAbstract:Abstract To express a human lactoferrin (hLF) gene in Bacteroides uniformis, a member of the anaerobic microflora in the colon, we constructed a recombinant plasmid, pVLFK, by subcloning hLF cDNA to an Escherichia coli–Bacteroides shuttle vector, pVAL-1. The plasmid pVLFKwas transferred to B. uniformis strain BU1001 by the filter mating procedure creating strain TCTK101. The lactoferrin protein in B. uniformis strain TCTK101 was detected by Western blot analysis with an anti-human lactoferrin monoclonal antibody. A culture of strain TCTK101 inhibited the growth ofE. coli strain HB101 in vitro compared to a culture of strain TCTK11, which is a B. uniformis strain-carrying plasmid pVAL-1, suggesting that the lactoferrin produced from strain TCTK101 possesses biological activity. To determine the effect of lactoferrin-producing B. uniformis on the formation of azoxymethane-induced Aberrant Crypt foci (ACF), putative neoplastic lesions, overnight cultures of strains TCTK11 and TCTK101 were given to rats as drinking water. The numbers of ACF and ACF having more than three Crypts per Focus five weeks after the beginning of the experiment significantly increased in the group treated by a culture of strain TCTK11 compared with those in the non-treated water group. However, rats treated with a culture of strain TCTK101 carrying plasmid pVLFK showed a significantly lower number of ACF than rats with a culture of strain TCTK11 (34% reduction), suggesting that hLF which is produced in a prokaryotic expression system prevents formation of ACF in the rat colon.
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effects of roselle hibiscus sabdariffa linn a thai medicinal plant on the mutagenicity of various known mutagens in salmonella typhimurium and on formation of Aberrant Crypt foci induced by the colon carcinogens azoxymethane and 2 amino 1 methyl 6 phenylimidazo 4 5 b pyridine in f344 rats
Food and Chemical Toxicology, 1999Co-Authors: Takemi Kinouchi, Keiko Kataoka, Hideki Arimochi, Tomomi Kuwahara, Teera Chewonari, Usanee Vinitketkumnue, Yoshinari OhnishiAbstract:Abstract The 80% ethanol extract of roselle ( Hibiscus sabdariffa Linn.), a medicinal plant in Thailand, was examined for antimutagenic and chemopreventive activity in a colon carcinogenesis model. It reduced about 60–90% of the mutagenicity induced by 2-amino-1-methyl-6-phenylimidazo[4,5- b ]pyridine (PhIP) and other heterocyclic amines 2-amino-3-methylimidazo[4,5- f ]quinoline (IQ), 2-amino-3,4-dimethylimidazo[4,5- f ]quinoline(MeIQ),2-amino-3,8-dimethylimidazo[4,5- f ]quinoxaline(MeIQx),3-amino-1,4-dimethyl-5 H -pyrido[4,3- b ]indole (Trp-P-1), 3-amino-1-methyl-5 H -pyrido[4,3- b ]indole (Trp-P-2),2-amino-6-methyldipyrido[1,2- a :3′,2′- d ]imidazole (Glu-P-1),2-aminodipyrido[1,2- a :3′,2′- d ]imidazole (Glu-P-2), at a concentration of 12.5 mg/plate in the Salmonella mutation assay. The extract showed no mutagenicity and no antibacterial activity below this dose. Mutagenicity of methylazoxymethanol (MAM) acetate, which, like PhIP, is a colon carcinogen,was also efficiently inhibited by the roselle extract. To investigate chemoprevention by roselle in a colon carcinogenesis model, we examined the inhibitory effects of the roselle extract in F344 rats in which Aberrant Crypt Focus (ACF) formation was induced by azoxymethane (AOM) and PhIP. In the initiation stage, the number of AOM-induced ACF in the colon was significantly decreased by roselle (17–25%) compared with that in rats treated with AOM alone. The amount of O 6 -methylguanine in the colonic mucosa tended to be decreased in the roselle-treated rats. The number of PhIP-induced ACF was also significantly decreased by roselle treatment (22%) at a concentration of 1.0 g/kg body weight in the initiation stage. However, in the post-initiation stage of AOM-induced ACF formation, roselle increased the number of ACF, especially the number of foci which had more than three Crypts/Focus. These results indicate that roselle has antimutagenic activity against MAM acetate and heterocyclic amines and that it decreases the number of AOM- and PhIP-induced ACF in the initiation stage, although it rather increased the number of ACF in the post-initiation stage.
