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Mitsuo Miyazawa - One of the best experts on this subject based on the ideXlab platform.
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Microbial O‐demethylation of sinesetin and Antimutagenic Activity of the metabolite
Journal of Chemical Technology & Biotechnology, 2005Co-Authors: Yoshiharu Okuno, Mitsuo MiyazawaAbstract:Biotransformation of sinesetin by Aspergillus niger afforded 4′-hydroxy-5,6,7,3′-tetramethoxyflavone on the basis of its spectroscopic data including IR, heteronuclear multiple quantum coherence (HMQC) and heteronuclear multiple bond connectivity (HMBC) analysis. Sinesetin and the metabolite showed Antimutagenic Activity against chemical mutagens 4-dimethyl-3H-imidazo[4,5-f]quinolin-2-amine (MeIQ) and 3-amino-14-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1) in the umu test using Salmonella typhimurium TA1535/pSK1002. Copyright © 2005 Society of Chemical Industry
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biotransformation of nobiletin by aspergillus niger and the Antimutagenic Activity of a metabolite 4 hydroxy 5 6 7 8 3 pentamethoxyflavone
Journal of Natural Products, 2004Co-Authors: Yoshiharu Okuno, Mitsuo MiyazawaAbstract:Biotransformation of nobiletin (1) by Aspergillus niger has been investigated, and the product obtained was determined as 4'-hydroxy-5,6,7,8,3'-pentamethoxyflavone (2). Antimutagenic Activity of compound 2 was found, which showed suppressive effects on umu gene expression of the SOS response to DNA damage in Salmonella typhimurium TA1535/pSK1002, induced by the chemical mutagens furylfuramide, MeIQ, and Trp-P-1.
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Biotransformation of Nobiletin by Aspergillus niger and the Antimutagenic Activity of a Metabolite, 4‘-Hydroxy-5,6,7,8,3‘-pentamethoxyflavone
Journal of natural products, 2004Co-Authors: Yoshiharu Okuno, Mitsuo MiyazawaAbstract:Biotransformation of nobiletin (1) by Aspergillus niger has been investigated, and the product obtained was determined as 4'-hydroxy-5,6,7,8,3'-pentamethoxyflavone (2). Antimutagenic Activity of compound 2 was found, which showed suppressive effects on umu gene expression of the SOS response to DNA damage in Salmonella typhimurium TA1535/pSK1002, induced by the chemical mutagens furylfuramide, MeIQ, and Trp-P-1.
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Antimutagenic Activity of phenylpropanoids from clove syzygium aromaticum
Journal of Agricultural and Food Chemistry, 2003Co-Authors: Mitsuo Miyazawa, Masayoshi HisamaAbstract:Phenylpropanoids that possess Antimutagenic Activity were isolated from the buds of clove (Syzygium aromaticum). The isolated compounds suppressed the expression of the umu gene following the induction of SOS response in the Salmonella typhimurium TA1535/pSK1002 that have been treated with various mutagens. The suppressive compounds were mainly localized in the ethyl acetate extract fraction of the processed clove. This ethyl acetate fraction was further fractionated by silica gel column chromatography, which resulted in the purification and subsequent identification of the suppressive compounds. Electron impact mass spectrometry, IR, and 1H and 13C NMR spectroscopy were then used to delineate the structures of the compounds that confer the observed Antimutagenic Activity. The secondary suppressive compounds were identified as dehydrodieugenol (1) and trans-coniferyl aldehyde (2). When using 2-(2-furyl)-3-(5-nitro-2-furyl)acrylamide (furylfuramide) as the mutagen, compound 1 suppressed 58% of the umu gene...
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Antimutagenic Activity of phenylpropanoids from clove syzygium aromaticum
Journal of Agricultural and Food Chemistry, 2003Co-Authors: Mitsuo Miyazawa, Masayoshi HisamaAbstract:Phenylpropanoids that possess Antimutagenic Activity were isolated from the buds of clove (Syzygium aromaticum). The isolated compounds suppressed the expression of the umu gene following the induction of SOS response in the Salmonella typhimurium TA1535/pSK1002 that have been treated with various mutagens. The suppressive compounds were mainly localized in the ethyl acetate extract fraction of the processed clove. This ethyl acetate fraction was further fractionated by silica gel column chromatography, which resulted in the purification and subsequent identification of the suppressive compounds. Electron impact mass spectrometry, IR, and (1)H and (13)C NMR spectroscopy were then used to delineate the structures of the compounds that confer the observed Antimutagenic Activity. The secondary suppressive compounds were identified as dehydrodieugenol (1) and trans-coniferyl aldehyde (2). When using 2-(2-furyl)-3-(5-nitro-2-furyl)acrylamide (furylfuramide) as the mutagen, compound 1 suppressed 58% of the umu gene expression as compared to the controls at a concentration of 0.60 micromol/mL, with an ID(50) (50% inhibitory dose) value of 0.48 micromol/mL, and compound 2 suppressed 63% of the umu gene expression as compared to the controls at a concentration of 1.20 micromol/mL, with an ID(50) value of 0.76 micromol/mL. Additionally, compounds 1 and 2 were tested for their ability to suppress the mutagenic Activity of other well-known mutagens such as 4-nitroquinolin 1-oxide (4NQO) and N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), which do not require liver metabolizing enzymes, and aflatoxin B(1) (AfB(1)) and 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1), which require liver metabolizing enzymes and activated Trp-P-1 and UV irradiation. Compounds 1 and 2 showed dramatic reductions in their mutagenic potential of all of the aforementioned chemicals or treatment. For the search of the structure-Activity relationship, the derivatives of 1 and 2 (1a and 2a-c) were also assayed with all mutagens. Finally, the Antimutagenic activities of compounds 1, 1a, 2, and 2a-c against furylfuramide, Trp-P-1, and activated Trp-P-1 were assayed by the Ames test using the S. typhimurium TA100 strain.
Michael J. Plewa - One of the best experts on this subject based on the ideXlab platform.
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Characterization and Antimutagenic Activity of soybean saponins
Mutation research, 2000Co-Authors: Mark A. Berhow, Elizabeth D. Wagner, Steven F. Vaughn, Michael J. PlewaAbstract:An extract was prepared from a commercial soybean-processing by-product (soybean molasses) and was fractionated into purified chemical components. In previous work, this extract (phytochemical concentrate, PCC) repressed induced genomic DNA damage, whole cell clastogenicity and point mutation in cultured mammalian cells. In the current study, a chemical fraction was isolated from PCC using preparative high-performance liquid chromatography (HPLC). This fraction, PCC100, repressed 2-acetoxyacetylaminofluorene (2AAAF)-induced DNA damage in Chinese hamster ovary (CHO) cells as measured by single cell gel electrophoresis (alkaline Comet assay). Using liquid chromatography-electrospray ionization-mass spectroscopy and 1H and 13C nuclear magnetic resonance (NMR) spectroscopy, PCC100 was shown to consist of a mixture of group B soyasaponins and 2,3-dihydro-2,5-dihydroxy-6-methyl-4H-pyran-4-one (DDMP) soyasaponins. These include soyasaponins I, II, III, IV, V, Be, betag, betaa, gammag and gammaa. Purified soyasapogenol B aglycone prepared from fraction PCC100 demonstrated significant antigenotoxic Activity against 2AAAF. To our knowledge, these data demonstrate for the first time the Antimutagenic Activity of soybean saponins in mammalian cells.
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characterization and Antimutagenic Activity of soybean saponins
Mutation Research, 2000Co-Authors: Mark A. Berhow, Elizabeth D. Wagner, Steven F. Vaughn, Michael J. PlewaAbstract:Abstract An extract was prepared from a commercial soybean-processing by-product (soybean molasses) and was fractionated into purified chemical components. In previous work, this extract (phytochemical concentrate, PCC) repressed induced genomic DNA damage, whole cell clastogenicity and point mutation in cultured mammalian cells. In the current study, a chemical fraction was isolated from PCC using preparative high-performance liquid chromatography (HPLC). This fraction, PCC100, repressed 2-acetoxyacetylaminofluorene (2AAAF)-induced DNA damage in Chinese hamster ovary (CHO) cells as measured by single cell gel electrophoresis (alkaline Comet assay). Using liquid chromatography–electrospray ionization–mass spectroscopy and 1H and 13C nuclear magnetic resonance (NMR) spectroscopy, PCC100 was shown to consist of a mixture of group B soyasaponins and 2,3-dihydro-2,5-dihydroxy-6-methyl-4H-pyran-4-one (DDMP) soyasaponins. These include soyasaponins I, II, III, IV, V, Be, βg, βa, γg and γa. Purified soyasapogenol B aglycone prepared from fraction PCC100 demonstrated significant antigenotoxic Activity against 2AAAF. To our knowledge, these data demonstrate for the first time the Antimutagenic Activity of soybean saponins in mammalian cells.
Mark A. Berhow - One of the best experts on this subject based on the ideXlab platform.
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Characterization and Antimutagenic Activity of soybean saponins
Mutation research, 2000Co-Authors: Mark A. Berhow, Elizabeth D. Wagner, Steven F. Vaughn, Michael J. PlewaAbstract:An extract was prepared from a commercial soybean-processing by-product (soybean molasses) and was fractionated into purified chemical components. In previous work, this extract (phytochemical concentrate, PCC) repressed induced genomic DNA damage, whole cell clastogenicity and point mutation in cultured mammalian cells. In the current study, a chemical fraction was isolated from PCC using preparative high-performance liquid chromatography (HPLC). This fraction, PCC100, repressed 2-acetoxyacetylaminofluorene (2AAAF)-induced DNA damage in Chinese hamster ovary (CHO) cells as measured by single cell gel electrophoresis (alkaline Comet assay). Using liquid chromatography-electrospray ionization-mass spectroscopy and 1H and 13C nuclear magnetic resonance (NMR) spectroscopy, PCC100 was shown to consist of a mixture of group B soyasaponins and 2,3-dihydro-2,5-dihydroxy-6-methyl-4H-pyran-4-one (DDMP) soyasaponins. These include soyasaponins I, II, III, IV, V, Be, betag, betaa, gammag and gammaa. Purified soyasapogenol B aglycone prepared from fraction PCC100 demonstrated significant antigenotoxic Activity against 2AAAF. To our knowledge, these data demonstrate for the first time the Antimutagenic Activity of soybean saponins in mammalian cells.
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characterization and Antimutagenic Activity of soybean saponins
Mutation Research, 2000Co-Authors: Mark A. Berhow, Elizabeth D. Wagner, Steven F. Vaughn, Michael J. PlewaAbstract:Abstract An extract was prepared from a commercial soybean-processing by-product (soybean molasses) and was fractionated into purified chemical components. In previous work, this extract (phytochemical concentrate, PCC) repressed induced genomic DNA damage, whole cell clastogenicity and point mutation in cultured mammalian cells. In the current study, a chemical fraction was isolated from PCC using preparative high-performance liquid chromatography (HPLC). This fraction, PCC100, repressed 2-acetoxyacetylaminofluorene (2AAAF)-induced DNA damage in Chinese hamster ovary (CHO) cells as measured by single cell gel electrophoresis (alkaline Comet assay). Using liquid chromatography–electrospray ionization–mass spectroscopy and 1H and 13C nuclear magnetic resonance (NMR) spectroscopy, PCC100 was shown to consist of a mixture of group B soyasaponins and 2,3-dihydro-2,5-dihydroxy-6-methyl-4H-pyran-4-one (DDMP) soyasaponins. These include soyasaponins I, II, III, IV, V, Be, βg, βa, γg and γa. Purified soyasapogenol B aglycone prepared from fraction PCC100 demonstrated significant antigenotoxic Activity against 2AAAF. To our knowledge, these data demonstrate for the first time the Antimutagenic Activity of soybean saponins in mammalian cells.
Victoria Yoxall - One of the best experts on this subject based on the ideXlab platform.
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Antimutagenic Activity of tea role of polyphenols
Current Opinion in Clinical Nutrition and Metabolic Care, 2003Co-Authors: Costas Ioannides, Victoria YoxallAbstract:PURPOSE OF REVIEW Tea is considered to be one of the most promising dietary chemopreventive agents and, consequently, it is being studied extensively worldwide. Despite the fact that tea has proved very efficient in affording protection against chemical-induced cancer in animal models of the disease, epidemiological studies do not always support the laboratory findings, so that the value of tea as a human anticarcinogen may be considered as 'not proven'. A major mechanism of the anticarcinogenic Activity of tea in animals is impairment of the interaction of carcinogens with DNA leading to mutations. The Antimutagenic Activity of tea as well as the underlying mechanisms will be reviewed, and the role of polyphenols, the postulated bioactive components, and caffeine will be critically evaluated. RECENT FINDINGS In rats, exposure to tea modulated the disposition of heterocyclic amines, a major group of food-borne carcinogens, stimulating the pathways that lead to deactivation, and this is concordant with the established ability of tea to modulate the carcinogen-metabolizing enzyme systems. These observations provide a rational mechanism for the anticarcinogenic Activity of tea in animals. SUMMARY The beneficial activities of tea have always been attributed to the polyphenols, as these are present in tea at substantial concentrations and are endowed with antioxidant Activity. It is becoming increasingly evident, however, that the bioavailability of these compounds is poor as a result of limited absorption and presystemic metabolism by mammalian and microbial enzymes. We propose that the biological Activity of tea may be mediated by caffeine and microbial metabolites of polyphenols.
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Antimutagenic Activity of tea: role of polyphenols.
Current opinion in clinical nutrition and metabolic care, 2003Co-Authors: Costas Ioannides, Victoria YoxallAbstract:Tea is considered to be one of the most promising dietary chemopreventive agents and, consequently, it is being studied extensively worldwide. Despite the fact that tea has proved very efficient in affording protection against chemical-induced cancer in animal models of the disease, epidemiological studies do not always support the laboratory findings, so that the value of tea as a human anticarcinogen may be considered as 'not proven'. A major mechanism of the anticarcinogenic Activity of tea in animals is impairment of the interaction of carcinogens with DNA leading to mutations. The Antimutagenic Activity of tea as well as the underlying mechanisms will be reviewed, and the role of polyphenols, the postulated bioactive components, and caffeine will be critically evaluated. In rats, exposure to tea modulated the disposition of heterocyclic amines, a major group of food-borne carcinogens, stimulating the pathways that lead to deactivation, and this is concordant with the established ability of tea to modulate the carcinogen-metabolizing enzyme systems. These observations provide a rational mechanism for the anticarcinogenic Activity of tea in animals. The beneficial activities of tea have always been attributed to the polyphenols, as these are present in tea at substantial concentrations and are endowed with antioxidant Activity. It is becoming increasingly evident, however, that the bioavailability of these compounds is poor as a result of limited absorption and presystemic metabolism by mammalian and microbial enzymes. We propose that the biological Activity of tea may be mediated by caffeine and microbial metabolites of polyphenols.
R Havenaar - One of the best experts on this subject based on the ideXlab platform.
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Antimutagenic Activity of green tea and black tea extracts studied in a dynamic in vitro gastrointestinal model.
Mutation research, 2001Co-Authors: C Krul, A Luiten-schuite, A Tenfelde, B Van Ommen, H Verhagen, R HavenaarAbstract:An in vitro gastrointestinal model, which simulates the conditions in the human digestive tract, was used to determine potential Antimutagenic Activity of extracts of black tea and green tea. In this paper, results are presented on the availability for absorption of potential Antimutagenic compounds present in tea and on the influence of the food matrix on this Activity. Between 60 and 180min after the tea was introduced into the model, Antimutagenic Activity was recovered from the jejunal compartment by means of dialysis: the dialysate appeared to inhibit the mutagenicity of the food mutagen MeIQx in the direct plate assay with Salmonella typhimurium (Ames test). The maximum inhibition was measured at 2h after the start of the experiment and was comparable for black tea and green tea extract. To determine the influence of food matrices on the Antimutagenic Activity of tea, the model was loaded with black tea together with milk or a homogenized standard breakfast. The maximum inhibition observed with black tea was reduced by 22, 42 and 78% in the presence of whole milk, semi-skimmed milk, and skimmed milk, respectively. Whole milk and skimmed milk abolished the Antimutagenic Activity of green tea by more than 90%; for semi-skimmed milk the inhibition was more than 60%. When a homogenized breakfast was added into the model together with the black tea extract, the Antimutagenic Activity was completely eliminated. When tea and MeIQx were added together into the digestion model, MeIQx mutagenicity was efficiently inhibited, with green tea showing a slightly stronger Antimutagenic Activity than black tea. In this case, the addition of milk had only a small inhibiting effect on the Antimutagenicity. Antioxidant capacity and the concentration of catechins were also measured in the jejunal dialysates. The reduction in Antimutagenic Activity corresponded with reduction in antioxidant capacity and with a decrease of concentration of three catechins, viz. catechin, epigallocatechin gallate and epigallocatechin. The in vitro gastrointestinal model appears to be a useful tool to study the Antimutagenicity of food components.
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Antimutagenic Activity of green tea and black tea extracts studied in a dynamic in vitro gastrointestinal model
Mutation Research, 2001Co-Authors: C Krul, A Luiten-schuite, A Tenfelde, B Van Ommen, H Verhagen, R HavenaarAbstract:An in vitro gastrointestinal model, which simulates the conditions in the human digestive tract, was used to determine potential Antimutagenic Activity of extracts of black tea and green tea. In this paper, results are presented on the availability for absorption of potential Antimutagenic compounds present in tea and on the influence of the food matrix on this Activity. Between 60 and 180 min after the tea was introduced into the model, Antimutagenic Activity was recovered from the jejunal compartment by means of dialysis: the dialysate appeared to inhibit the mutagenicity of the food mutagen MeIQx in the direct plate assay with Salmonella typhimurium (Ames test). The maximum inhibition was measured at 2 h after the start of the experiment and was comparable for black tea and green tea extract. To determine the influence of food matrices on the Antimutagenic Activity of tea, the model was loaded with black tea together with milk or a homogenized standard breakfast. The maximum inhibition observed with black tea was reduced by 22, 42 and 78% in the presence of whole milk, semi-skimmed milk, and skimmed milk, respectively. Whole milk and skimmed milk abolished the Antimutagenic Activity of green tea by more than 90%; for semi-skimmed milk the inhibition was more than 60%. When a homogenized breakfast was added into the model together with the black tea extract, the Antimutagenic Activity was completely eliminated. When tea and MeIQx were added together into the digestion model, MeIQx mutagenicity was efficiently inhibited, with green tea showing a slightly stronger Antimutagenic Activity than black tea. In this case, the addition of milk had only a small inhibiting effect on the Antimutagenicity. Antioxidant capacity and the concentration of catechins were also measured in the jejunal dialysates. The reduction in Antimutagenic Activity corresponded with reduction in antioxidant capacity and with a decrease of concentration of three catechins, viz. catechin, epigallocatechin gallate and epigallocatechin. The in vitro gastrointestinal model appears to be a useful tool to study the Antimutagenicity of food components. © 2001 Elsevier Science B.V.Chemicals/CAS: Antimutagenic Agents; Antioxidants; Plant Extracts