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Yang Y, Jiang X, Pandol SJ, Han YP, Zheng X. Green Plant Pigment, Chlorophyllin, Ameliorates Non-alcoholic Fatty Liver Diseases (NAFLDs) Through Modulating Gut Microbiome in Mice. Front Physiol 2021; 12:739174. [PMID: 34764881 PMCID: PMC8576288 DOI: 10.3389/fphys.2021.739174] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Accepted: 09/23/2021] [Indexed: 02/05/2023] Open
Abstract
Non-alcoholic fatty liver diseases (NAFLDs) along with metabolic syndrome and Type-2 diabetes (T2D) are increasingly prevalent worldwide. Without an effective resolution, simple hepatic steatosis may lead to non-alcoholic steatohepatitis (NASH), characterized by hepatocyte damage, chronic inflammation, necrosis, fatty degeneration, and cirrhosis. The gut microbiome is vital for metabolic homeostasis. Conversely, dysbiosis contributes to metabolic diseases including NAFLD. Specifically, diet composition is critical for the enterotype of gut microbiota. We reasoned that green pigment rich in vegetables may modulate the gut microbiome for metabolic homeostasis. In this study, C57BL/6 mice under a high fat diet (HFD) were treated with sodium copper chlorophyllin (CHL), a water-soluble derivative of chlorophyll, in drinking water. After 28 weeks of HFD feeding, liver steatosis was established accompanied by gut microbiota dysbiosis, intestinal impairment, endotoxemia, systemic inflammation, and insulin resistance. Administration of CHL effectively alleviated systemic and intestinal inflammation and maintained tight junction in the intestinal barrier. CHL rebalanced gut microbiota in the mice under high fat feeding and attenuated hepatic steatosis, insulin resistance, dyslipidemia, and reduced body weight. Fecal flora transplants from the CHL-treated mice ameliorated steatosis as well. Thus, dietary green pigment or the administration of CHL may maintain gut eubiosis and intestinal integrity to attenuate systemic inflammation and relieve NASH.
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Affiliation(s)
- You Yang
- Center for Diabetes and Metabolism Research, Division of Endocrinology and Metabolism, West China Hospital, Sichuan University, Chengdu, China.,The College of Life Sciences, Sichuan University, Chengdu, China
| | - Xile Jiang
- Department of Nutrition, West China College of Medicine, Sichuan University, Chengdu, China
| | | | - Yuan-Ping Han
- The College of Life Sciences, Sichuan University, Chengdu, China
| | - Xiaofeng Zheng
- Center for Diabetes and Metabolism Research, Division of Endocrinology and Metabolism, West China Hospital, Sichuan University, Chengdu, China
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Dashwood RH. Cancer interception by interceptor molecules: mechanistic, preclinical and human translational studies with chlorophylls. Genes Environ 2021; 43:8. [PMID: 33676582 PMCID: PMC7937315 DOI: 10.1186/s41021-021-00180-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 02/18/2021] [Indexed: 01/14/2023] Open
Abstract
Before 'cancer interception' was first advocated, 'interceptor molecules' had been conceived as a sub-category of preventive agents that interfered with the earliest initiation steps in carcinogenesis. Three decades ago, a seminal review cataloged over fifty synthetic agents and natural products that were known or putative interceptor molecules. Chlorophylls and their derivatives garnered much interest based on the potent antimutagenic activity in the Salmonella assay, and the subsequent mechanistic work that provided proof-of-concept for direct molecular complexes with planar aromatic carcinogens. As the 'interceptor molecule' hypothesis evolved, mechanistic experiments and preclinical studies supported the view that chlorophylls can interact with environmental heterocyclic amines, aflatoxins, and polycyclic aromatic hydrocarbons to limit their uptake and bioavailability in vivo. Support also came from human translational studies involving ultralow dose detection in healthy volunteers, as well as intervention in at-risk subjects. Antimutagenic and antigenotoxic effects of natural and synthetic chlorophylls against small alkylating agents also highlighted the fact that non-interceptor mechanisms existed. This gave impetus to investigations broadly related to free radical scavenging, anti-inflammatory effects, immune modulation and photodynamic therapy. Therapeutic aspects of chlorophylls also were investigated, with evidence for cell cycle arrest and apoptosis in human cancer cells. As the science has evolved, new mechanistic leads continue to support the use and development of chlorophylls and their porphyrin derivatives for cancer interception, beyond the initial interest as interceptor molecules.
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Affiliation(s)
- Roderick H Dashwood
- Center for Epigenetics & Disease Prevention, Texas A&M Health, 2121 West Holcombe Blvd, Houston, TX, 77030, USA.
- Department of Translational Medical Sciences, Texas A&M College of Medicine, Houston, TX, USA.
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Okaly JB, Mvogo A, Tabi CB, Ekobena Fouda HP, Kofané TC. Base pair opening in a damped helicoidal Joyeux-Buyukdagli model of DNA in an external force field. Phys Rev E 2020; 102:062402. [PMID: 33465949 DOI: 10.1103/physreve.102.062402] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 10/21/2020] [Indexed: 11/07/2022]
Abstract
Upon the Joyeux-Buyukdagli model of DNA, the helicoidal interactions are introduced, and their effects on the dynamical behaviors of the molecule investigated. A theoretical framework for the analysis is presented in an external force field, taking into account Stokes and hydrodynamics viscous forces. In the semi-discrete approximation, the dynamics of the molecule is found governed by the cubic complex Ginzburg-Landau (CGL) equation. By choosing an appropriate decoupling ansatz, the cubic CGL equation is transformed into a nonlinear differential equation whose analytical solitary wave-like solutions can be explored by means of the direct method, which is more tractable in case where the form of soliton solutions is known. Based on this, a dissipative bright-like soliton solution is obtained. Numerical experiments have been done, and relevant results were brought out, such as the quantitative and qualitative influences of the helical interactions on the parameters of the traveling bubble. The important role-played by these interactions in the DNA biological processes is brought out, showing that depending on the wave number, their effects can increase, decrease, or keep constant the bubble angular frequency, velocity, amplitude, and width, as well as the energy involved by enzymes in the initiation of DNA biological processes. This can prevent some coding or reading errors and resulting genetic damages. Analytical predictions and numerical experiments were in good agreement.
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Affiliation(s)
- J B Okaly
- Department of Physics, Faculty of Science, University of Yaounde I, P.O. Box 812, Yaounde, Cameroon
- African Centre of Excellence in Information and Communication Technologies, University of Yaounde I, P.O. Box 8390, Yaounde, Cameroon
| | - A Mvogo
- Department of Physics, Faculty of Science, University of Yaounde I, P.O. Box 812, Yaounde, Cameroon
- African Centre of Excellence in Information and Communication Technologies, University of Yaounde I, P.O. Box 8390, Yaounde, Cameroon
| | - C B Tabi
- Botswana International University of Science and Technology, Private Bag 16 Palapye, Botswana
| | - H P Ekobena Fouda
- Department of Physics, Faculty of Science, University of Yaounde I, P.O. Box 812, Yaounde, Cameroon
| | - T C Kofané
- Department of Physics, Faculty of Science, University of Yaounde I, P.O. Box 812, Yaounde, Cameroon
- African Centre of Excellence in Information and Communication Technologies, University of Yaounde I, P.O. Box 8390, Yaounde, Cameroon
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The theory of interceptor-protector action of DNA binding drugs. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2019; 149:131-146. [PMID: 30991057 DOI: 10.1016/j.pbiomolbio.2019.04.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 04/01/2019] [Accepted: 04/09/2019] [Indexed: 11/21/2022]
Abstract
The review discusses the theory of interceptor-protector action (the IPA theory) as the new self-consistent biophysical theory establishing a quantitative interrelation between parameters measured in independent physico-chemical experiment and in vitro biological experiment for the class of DNA binding drugs. The elements of the theory provide complete algorithm of analysis, which may potentially be applied to any system of DNA targeting aromatic drugs. Such analytical schemes, apart from extension of current scientific knowledge, are important in the context of rational drug design for managing drug's response by changing the physico-chemical parameters of molecular complexation.
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Buchelnikov AS, Evstigneev VP, Evstigneev MP. Hetero-association models of non-covalent molecular complexation. Phys Chem Chem Phys 2019; 21:7717-7731. [PMID: 30931443 DOI: 10.1039/c8cp03183e] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The present review discusses the current state-of-the-art in building models enabling the description of non-covalent equilibrium complexation of different types of molecules in solution, which results in the formation of supramolecular structures different in length and composition (hetero-association or supramolecular multicomponent co-polymerisation). The description is focused on standard physical and chemical quantities such as experimental observables and equilibrium parameters of interaction (equilibrium constants and concentrations). The major partial cases of the hetero-association models, such as finite and indefinite isodesmic and cooperative complexations, and Benesi-Hildebrand and Langmuir adsorption models are considered. Future challenges in the development of the hetero-association models are provided.
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Pentoxifylline affects idarubicin binding to DNA. Bioorg Chem 2016; 65:118-25. [DOI: 10.1016/j.bioorg.2016.02.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Revised: 02/17/2016] [Accepted: 02/18/2016] [Indexed: 01/21/2023]
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Suryavanshi S, Sharma D, Checker R, Thoh M, Gota V, Sandur SK, Sainis KB. Amelioration of radiation-induced hematopoietic syndrome by an antioxidant chlorophyllin through increased stem cell activity and modulation of hematopoiesis. Free Radic Biol Med 2015; 85:56-70. [PMID: 25872101 DOI: 10.1016/j.freeradbiomed.2015.04.007] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Revised: 03/08/2015] [Accepted: 04/03/2015] [Indexed: 02/05/2023]
Abstract
Hematopoietic stem cells and progenitor cells (HSPC) are low in abundance and exhibit high radiosensitivity and their ability to divide dramatically decreases following exposure to ionizing radiation. Our earlier studies have shown antiapoptotic, immune-stimulatory, and antioxidant effects of chlorophyllin, a constituent of the over the counter drug derifil. Here we describe the beneficial effects of chlorophyllin against radiation-induced hematopoietic syndrome. Chlorophyllin administration significantly enhanced the abundance of HSPC in vivo. It induced a transient cell cycle arrest in lineage-negative cells in the bone marrow. However, the chlorophyllin-treated mice exposed to whole body irradiation (WBI) had a significantly higher proportion of actively dividing HSPC in the bone marrow as compared to only WBI-exposed mice. It significantly increased the number of colony forming units (CFUs) by bone marrow cells in vitro and spleen CFUs in irradiated mice in vivo. Pharmacokinetic study showed that chlorophyllin had a serum half-life of 141.8 min in mice. Chlorophyllin upregulated antiapoptotic genes and antioxidant machinery via activation of prosurvival transcription factors Nrf-2 and NF-κB and increased the survival and recovery of bone marrow cells in mice exposed to WBI. Chlorophyllin stimulated granulocyte production in bone marrow and increased the abundance of peripheral blood neutrophils by enhancing serum levels of granulocyte-colony stimulation factor (GCSF). Most importantly, prophylactic treatment of mice with chlorophyllin significantly abrogated radiation-induced mortality. Chlorophyllin mitigates radiation-induced hematopoietic syndrome by increasing the abundance of hematopoietic stem cells, enhancing granulopoiesis, and stimulating prosurvival pathways in bone marrow cells and lymphocytes.
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Affiliation(s)
- Shweta Suryavanshi
- Radiation Biology and Health Sciences Division, Bio-Science Group, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India
| | - Deepak Sharma
- Radiation Biology and Health Sciences Division, Bio-Science Group, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India
| | - Rahul Checker
- Radiation Biology and Health Sciences Division, Bio-Science Group, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India
| | - Maikho Thoh
- Radiation Biology and Health Sciences Division, Bio-Science Group, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India
| | - Vikram Gota
- Clinical Pharmacology, Advanced Centre for Treatment Research and Education in Cancer, Tata Memorial Centre, Kharghar, Navi Mumbai 410210, India
| | - Santosh K Sandur
- Radiation Biology and Health Sciences Division, Bio-Science Group, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India.
| | - Krishna B Sainis
- Radiation Biology and Health Sciences Division, Bio-Science Group, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India
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Buchelnikov AS, Evstigneev MP. Quantitative correlation of the in vitro biological effect with parameters of molecular complexation in mutagen-interceptor systems. J Theor Biol 2014; 357:268-71. [PMID: 24972156 DOI: 10.1016/j.jtbi.2014.06.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Revised: 06/09/2014] [Accepted: 06/11/2014] [Indexed: 10/25/2022]
Abstract
According to the theory of interceptor-protector action a quantitative link between the physico-chemical parameters of molecular complexation and in vitro biological effect in aromatic drug-interceptor systems must exist. In the present communication such link between relative change in mutagenicity of IQ-type aromatic mutagens on addition of aromatic interceptor molecules with equilibrium hetero-association constants of mutagen-interceptor complexation has been found using the published in vitro data in bacteria cell systems.
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Affiliation(s)
- Anatoly S Buchelnikov
- Department of Biology and Chemistry, Belgorod State University, Belgorod 308015, Russia
| | - Maxim P Evstigneev
- Department of Biology and Chemistry, Belgorod State University, Belgorod 308015, Russia; Department of Physics, Sevastopol National Technical University, Sevastopol 299053, Russia.
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Woziwodzka A, Gołuński G, Wyrzykowski D, Kaźmierkiewicz R, Piosik J. Caffeine and other methylxanthines as interceptors of food-borne aromatic mutagens: inhibition of Trp-P-1 and Trp-P-2 mutagenic activity. Chem Res Toxicol 2013; 26:1660-73. [PMID: 24102551 DOI: 10.1021/tx4002513] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Caffeine is one of the most important biologically active food components. In this article, we demonstrate that caffeine and other methylxanthines significantly reduce the mutagenic activity of two food-derived heterocyclic aromatic amines, Trp-P-1 and Trp-P-2 in the Salmonella typhimurium TA98 strain. Moreover, protection against Trp-P-1-induced mutagenicity was independent of liver S9 enzymatic fraction, suggesting that mechanisms other than modulation of mutagen bioactivation can contribute to the observed protective effects. UV-vis spectroscopy and computational studies revealed that methylxanthines intercept Trp-P-1 and Trp-P-2 in noncovalent molecular complexes, with association constants (KAC) in the 10(2) M(-1) range. Enthalpy values (ΔH about -30 kJ·mol(-1)) of mutagen-methylxanthine heterocomplexation obtained microcalorimetrically correspond to stacking (π-π) interactions. Finally, we demonstrated that the biological activity of Trp-P-1 and Trp-P-2 is strictly dependent on the presence of the mutagen in a free (unbound with methylxanthine) form, suggesting that mutagen sequestration in stacking heterocomplexes with methylxanthines can decrease its bioavailability and diminish its biological effects.
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Affiliation(s)
- Anna Woziwodzka
- Laboratory of Biophysics, Intercollegiate Faculty of Biotechnology UG-MUG , Kładki 24, 80-822 Gdańsk, Poland
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Heterocyclic Aromatic Amines Heterocomplexation with Biologically Active Aromatic Compounds and Its Possible Role in Chemoprevention. ACTA ACUST UNITED AC 2013. [DOI: 10.1155/2013/740821] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Food-borne heterocyclic aromatic amines (HCAs) are known mutagens and carcinogens present especially in Western population diet, which contains large amount of meat and its products. HCAs are capable of interacting with DNA directly through the formation of covalent adducts, however this process requires biological activation in liver, mainly by cytochrome P450 enzymes. This process may produce mutations and in consequence may contribute to the development of cancer. However, there are many studies showing that several biologically active aromatic compounds (BACs) may protect against genotoxic effects of HCAs. Direct interactions and noncovalent heterocomplexes formation may be one of the most important mechanisms of such protection. This work describes several BACs present in human diet, which are capable of molecular complexes formation with HCAs and protect cells as well as whole organisms against HCAs action.
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Quantification of the interceptor action of caffeine on the in vitro biological effect of the anti-tumour agent topotecan. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2011; 40:969-80. [PMID: 21674180 DOI: 10.1007/s00249-011-0712-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2011] [Revised: 05/01/2011] [Accepted: 05/16/2011] [Indexed: 10/18/2022]
Abstract
Using published in vitro data on the dependence of the percentage of apoptosis induced by the anti-cancer drug topotecan in a leukaemia cell line on the concentration of added caffeine, and a general model of competitive binding in a system containing two aromatic drugs and DNA, it has been shown to be possible to quantify the relative change in the biological effect just using a set of component concentrations and equilibrium constants of the complexation of the drugs. It is also proposed that a general model of competitive binding and parameterization of that model may potentially be applied to any system of DNA-targeting aromatic drugs under in vitro conditions. The main reasons underpinning the proposal are the general feature of the complexation of aromatic drugs with DNA and their interaction in physiological media via hetero-association.
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Woziwodzka A, Gwizdek-Wiśniewska A, Piosik J. Caffeine, pentoxifylline and theophylline form stacking complexes with IQ-type heterocyclic aromatic amines. Bioorg Chem 2010; 39:10-7. [PMID: 21146849 DOI: 10.1016/j.bioorg.2010.11.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2010] [Revised: 10/29/2010] [Accepted: 11/03/2010] [Indexed: 12/20/2022]
Abstract
Methylxanthines (MTX), in particular caffeine (CAF), are known as the most widely consumed alkaloids worldwide. Many accumulated statistical data indicate the protective effect of CAF intake against several types of cancer. One of the possible explanations of this phenomenon is direct non-covalent interaction between CAF and aromatic mutagen/carcinogen molecules through stacking (π-π) complexes formation. Here we demonstrate that CAF and other MTX, pentoxifylline (PTX) and theophylline (TH), form stacking complexes with carcinogenic imidazoquinoline-type (IQ-type) food-borne heterocyclic aromatic amines (HCAs). We estimated neighborhood association constants (K(AC) of the order of magnitude of 10(2)M(-1)) in neutral and acidic environment and enthalpy changes (ΔH values between -15.1 and -39.8kJ/mol) for these interactions using UV-Vis spectroscopy, calculations based on thermodynamical model of mixed aggregation and titration microcalorimetry. Moreover, using Ames test with Salmonella typhimurium TA98 strain and recently developed mutagenicity assay based on bioluminescence of Vibrio harveyi A16 strain, we demonstrated a statistically significant reduction in HCAs mutagenic activity in the presence of MTX.
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Affiliation(s)
- Anna Woziwodzka
- Department of Molecular and Cellular Biology, Intercollegiate Faculty of Biotechnology UG and MUG, Kładki 24, Gdańsk, Poland
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Attenuation of acridine mutagen ICR-191--DNA interactions and DNA damage by the mutagen interceptor chlorophyllin. Biophys Chem 2008; 135:69-75. [PMID: 18423964 DOI: 10.1016/j.bpc.2008.03.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2007] [Revised: 03/18/2008] [Accepted: 03/18/2008] [Indexed: 11/24/2022]
Abstract
We have investigated the ability of chlorophyllin (CHL) to interact with acridine mutagen ICR-191 (2-methoxy-6-chloro-9-(3-(2-chloroethyl)aminopropylamino)acridine) and also its ability to decrease binding of ICR-191 to DNA in a simple three-component competition system: CHL-ICR-DNA. Our data indicate a strong association of ICR-191 with CHL, stronger even than the association of ICR-191 with DNA. Calculations based on the measured affinity data show that a two- to three-fold excess of CHL reduces by about two-fold the concentration of the mutagen-DNA complex. We also exposed human leukemic HL-60 cells to ICR-191 in the absence and presence of CHL and measured the mutagen-induced DNA damage. The extent of DNA damage was assessed by analysis of histone H2AX phosphorylation. While ICR-191 induced significant increase in expression of phosphorylated H2AX (gammaH2AX), particularly in DNA replicating cells, this increase was totally abolished in the cells treated with ICR-191 in the presence of CHL.
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Santos-Cervantes ME, Ibarra-Zazueta ME, Loarca-Piña G, Paredes-López O, Delgado-Vargas F. Antioxidant and antimutagenic activities of Randia echinocarpa fruit. PLANT FOODS FOR HUMAN NUTRITION (DORDRECHT, NETHERLANDS) 2007; 62:71-7. [PMID: 17577670 DOI: 10.1007/s11130-007-0044-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2007] [Accepted: 04/12/2007] [Indexed: 05/15/2023]
Abstract
We report for the first time the antioxidant and antimutagenic activities of fractions from Randia echinocarpa fruit, which is a Rubiaceae plant native to Sinaloa, Mexico. This fruit has been traditionally used in the prevention or treatment of cancer, among other diseases. The pulp of the fruit was sequentially extracted with solvents of different polarity (i.e. hexane, chloroform, methanol and water). A high extraction yield was obtained with methanol (72.17% d.w.). The aqueous extract showed the highest content of phenolics (2.27 mg/g as ferulic acid equivalents) and the highest antioxidant activity based on the beta-carotene bleaching method (486.15). The commercial antioxidant BHT was used as control (835.05). Antimutagenic activity of the aqueous extract (0-500 microg/tube) was evaluated using the Salmonella microsuspension assay (YG1024 strain) and 1-NP as the mutagen (50 and 100 ng/tube). The aqueous extract was neither toxic nor mutagenic and the percentage of inhibition on 1-NP mutagenicity was 32 and 53% at doses of 50 and 100 ng/tube, respectively. The results of the double incubation assay suggest that the extract inhibited the mutagenicity of 1-NP by a combination of desmutagenic and bioantimutagenic effects.
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Affiliation(s)
- María Elena Santos-Cervantes
- Maestría en Ciencia y Tecnología de Alimentos, Facultad de Ciencias Químico Biológicas, Universidad Autónoma de Sinaloa, Culiacán Sin, Mexico
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Abstract
Heterocyclic amines (HAs) occur at the ppb range in foods. Most of them demonstrate potent mutagenicity in bacteria mutagenicity test, and some of them have been classified by the International Agency for Research on Cancer as probable/possible human carcinogens. Their capability of formation even during ordinary cooking practices implies frequent exposure by the general public. Over the past 30 years, numerous studies have been stimulated aiming to alleviate human health risk associated with HAs. These studies contribute to the understanding of their formation, characterization, and quantification in foods; their mutagenesis/carcinogenesis, mechanisms of antimutagenesis by chemical or phytogenic modulators; and strategies to inhibit their formation. The chemistry of HAs, their implications in human health, factors influencing their formation, and feasible ways of suppression will be briefly reviewed. Their occurrence in trace amounts in foods necessitates continuous development and amelioration of analytical techniques. Various inhibitory strategies, ranging from modifying cooking conditions to incorporation of different modulators, have been developed. This will remain one of the foremost areas of research in the field of food chemistry and safety.
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Affiliation(s)
- Ka-Wing Cheng
- Department of Botany, The University of Hong Kong, Hong Kong, PR China
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Pietrzak M, Wieczorek Z, Wieczorek J, Darzynkiewicz Z. The "interceptor" properties of chlorophyllin measured within the three-component system: intercalator-DNA-chlorophyllin. Biophys Chem 2006; 123:11-9. [PMID: 16650923 PMCID: PMC3488280 DOI: 10.1016/j.bpc.2006.03.018] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2006] [Revised: 03/28/2006] [Accepted: 03/30/2006] [Indexed: 10/24/2022]
Abstract
In aqueous solutions, in the presence of double-stranded DNA, chlorophyllin (CHL) forms complexes with each of the three DNA intercalators: acridine orange (AO), quinacrine mustard (QM), and doxorubicin (DOX). The evidence for these interactions was obtained by measurement changes in the absorption and fluorescence spectra of the mixtures containing DNA and intercalators during titration with CHL. A model of simple competition between DNA and CHL for the intercalator was used to define the measured interactions. The concentrations of the complexes estimated based on this model were consistent with the concentrations obtained by actual measurement of the absorption spectra. The present data provide further support for the role of chlorophyllin as an "interceptor" that may neutralize biological activity of aromatic compounds including mutagens and antitumor drugs.
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Affiliation(s)
- Monika Pietrzak
- Department of Physics and Biophysics, University of Warmia and Mazury in Olsztyn, Oczapowskiego 4, 10-719 Olsztyn, Poland
| | - Zbigniew Wieczorek
- Department of Physics and Biophysics, University of Warmia and Mazury in Olsztyn, Oczapowskiego 4, 10-719 Olsztyn, Poland
- Corresponding author: Tel./fax: +48 89 523 45 47. (Z. Wieczorek)
| | - Jolanta Wieczorek
- Department of Commodities and Food Research, University of Warmia and Mazury in Olsztyn, Cieszyński Square 1, 10-726 Olsztyn, Poland
| | - Zbigniew Darzynkiewicz
- Brander Cancer Research Institute at New York Medical College, Hawthorne, NY, 10532, USA
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Wu CH, Yen GC. Antigenotoxic properties of Cassia tea (Cassia tora L.): mechanism of action and the influence of roasting process. Life Sci 2004; 76:85-101. [PMID: 15501482 DOI: 10.1016/j.lfs.2004.07.011] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2004] [Accepted: 07/30/2004] [Indexed: 11/27/2022]
Abstract
Antigenotoxic properties and the possible mechanisms of water extracts from Cassia tora L. (WECT) treated with different degrees of roasting (unroasted and roasted at 150 and 250 degrees C) were evaluated by the Ames Salmonella/microsome test and the Comet assay. Results indicated that WECT, especially unroasted C. tora (WEUCT), markedly suppressed the mutagenicity of 2-amino-6-methyldipyrido(1,2-a:3':2'-d)imidazole (Glu-P-1) and 3-amino-1,4-dimethyl-5H-pyrido(4,3-b)indole (Trp-P-1). In the Comet assay performed on human lymphocytes, WECT exhibited significant protective effect on Trp-P-1-mediated DNA damage followed the order of unroasted (55%) > roasted at 150 degrees C (42% ) > roasted at 250 degrees C (29%). Pre-treatment of the lymphocytes with WEUCT resulted in 30% repression of DNA damage. However, no significant effect on excision-repair system was found during DNA damage expression time in post-treatment scheme (p>0.05). WEUCT showed 84% scavenging effect on oxygen free radicals generated in the activation process of mutagen detected by electron paramagentic resonance system. Two possible mechanisms were considered: (1) neutralization the reactive intermediate of Trp-P-1; and (2) protecting cells directly as an antioxidant that scavenge the oxygen radicals from the activation process of mutagen. The individual anthraquinone content in extracts of C. tora was measured by HPLC. Three anthraquinones, chrysophanol, emodin and rhein, have been detected under experimental conditions. The anthraquinone content decreased with increased roasting temperature. Each of these anthraquinones demonstrated significant antigenotoxicity against Trp-P-1 in the Comet assay. In conclusion, our data suggest that the decrease in antigenotoxic potency of roasted C. tora was related to the reduction in their anthraquinones.
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Affiliation(s)
- Chi-Hao Wu
- Department of Food Science, National Chung Hsing University, 250 Kuokuang, Road, Taichung 40227, Taiwan
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19
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Negishi T, Shinoda A, Ishizaki N, Hayatsu H, Sugiyama C. No Effects of Chlorophyllin on IQ (2-Amino-3-methylimidazo[4,5-f]-quinoline)-genotoxicity and -DNA Adduct Formation in Drosophila. Biol Pharm Bull 2004; 27:242-3. [PMID: 14758044 DOI: 10.1248/bpb.27.242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Previously we demonstrated that chlorophyllin suppressed the genotoxicities of many carcinogens. However, the genotoxicity of IQ (2-amino-3-methylimidazo[4,5-f]quinoline), a carcinogenic heterocyclic amine, was not suppressed in Drosophila. On the contrary, it has been reported that chrolophyllin suppressed the genotoxicity of IQ in rodents, rainbow trout and Salmonella. We demonstrated that the chlorophyllin-induced suppression of MeIQx (2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline)-genotoxicity was associated with a decrease in MeIQx-DNA adduct formation in Drosophila larval DNA. MeIQx represents another type of heterocyclic amine and is similar to IQ in structure. In this study we utilized (32)P-postlabeling to examine whether chlorophyllin reduced IQ-DNA adduct formation in Drosophila DNA in the same way as MeIQx. The results revealed that the formation of IQ-DNA adducts was unaffected by treatment with chlorophyllin. This was consistent with the absence of any inhibitory effect on genotoxicity as observed in the Drosophila repair test. These results suggest that IQ-behavior in Drosophila is not affected by chlorophyllin, indicating that the process of IQ-DNA adduct formation followed by expression of genotoxicity in Drosophila may be different from that in other organisms.
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Affiliation(s)
- Tomoe Negishi
- Faculty of Pharmaceutical Sciences, Okayama University, Tsushima, Okayama 700-8530, Japan
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20
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Rigonato J, Mantovani MS, Jordão BQ. Mechanism of Action of Chlorophyllin against Mitomycin-C Mutagenicity in Allium cepa. CYTOLOGIA 2004. [DOI: 10.1508/cytologia.69.459] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Janaina Rigonato
- Departamento de Biologia Geral, Centro de Ciências Biológicas, Universidade Estadual de Londrina
| | - Mário Sérgio Mantovani
- Departamento de Biologia Geral, Centro de Ciências Biológicas, Universidade Estadual de Londrina
| | - Berenice Quinzani Jordão
- Departamento de Biologia Geral, Centro de Ciências Biológicas, Universidade Estadual de Londrina
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21
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Pietrzak M, Wieczorek Z, Stachelska A, Darzynkiewicz Z. Interactions of chlorophyllin with acridine orange, quinacrine mustard and doxorubicin analyzed by light absorption and fluorescence spectroscopy. Biophys Chem 2003; 104:305-13. [PMID: 12834849 PMCID: PMC3480723 DOI: 10.1016/s0301-4622(02)00387-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The present study was designed to estimate the ability of chlorophyllin (CHL) to interact with two acridine mutagens, quinacrine mustard (QM) and acridine orange (AO), and with the antitumor anthracycline doxorubicin (Dox). To this end, aqueous solutions of QM, AO or Dox during titration with CHL were subjected to spectrophotometry and spectrofluorimetry to detect possible interactions between these reagents. The data indicate that CHL forms complexes with AO, QM or Dox in these solutions. The presence of the complexes was manifested by a bathochromic shift of the absorption spectra, as well as by strong quenching of the fluorescence of each of these mutagens in the presence of CHL. CHL, thus, may serve as an interceptor of these mutagenic acridines in different in vivo or in vitro applications. Its ability to interact with Dox may potentially be utilized to detoxify patients overdosed with this or similar drugs.
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Affiliation(s)
- Monika Pietrzak
- Department of Physics and Biophysics, University of Warmia and Mazury in Olsztyn, Oczapowskiego 4, 10-719 Olsztyn, Poland
| | - Zbigniew Wieczorek
- Department of Physics and Biophysics, University of Warmia and Mazury in Olsztyn, Oczapowskiego 4, 10-719 Olsztyn, Poland
- Corresponding author. Tel./fax: +48-89-523-4547. (Z. Wieczorek)
| | - Alicja Stachelska
- Department of Physics and Biophysics, University of Warmia and Mazury in Olsztyn, Oczapowskiego 4, 10-719 Olsztyn, Poland
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22
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Lyles MB, Cameron IL. Interactions of the DNA intercalator acridine orange, with itself, with caffeine, and with double stranded DNA. Biophys Chem 2002; 96:53-76. [PMID: 11975993 DOI: 10.1016/s0301-4622(02)00036-4] [Citation(s) in RCA: 115] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Caffeine (CAF) inhibits the intercalation of acridine orange (AO) into cellular DNA. Optical absorption and fluorescence spectroscopy were employed to determine the molecular interactions of AO with itself, with CAF, and with double stranded herring sperm DNA (dsDNA). AO dimerization was observed at concentrations >2 micromol. The sharp increase in fluorescence (lambda(em)=530 nm) at 5 micromol of AO was attributed to AO multimer formation. From 0.5 to 5.0 micromol, the AO self-association binding constant (K(assoc)) was determined to be 38620 mol(-1), however, the presence of 150 mmol NaCl increased K(assoc) to 118000 mol(-1) attributed to the charge neutralization. The K(assoc) for AO with CAF was confirmed to be 256 mol(-1). K(assoc) for the binding of AO with 20 micromol DNA ranged from, 32000 mol(-1) at 2 micromol AO, to approximately 3700 mol(-1) at 10 micromol AO, in the absence of NaCl. This AO concentration dependency of K(assoc) value with DNA was attributed to AO intercalation into dsDNA at high dsDNA/AO ratios, and electrostatic binding of AO to dsDNA at low AO ratios. The findings provide information used to explain fluorescence intensity values at lambda(em) at 530 nm from studies that combine AO, caffeine, and dsDNA.
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Affiliation(s)
- Mark B Lyles
- Department of Cellular and Structural Biology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, 78229-3900, USA
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23
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Sugiyama C, Nakandakari N, Hayatsu H, Arimoto-Kobayashi S. Preventive effects of chlorophyllin fixed on chitosan towards DNA adduct formation of 3-amino-1-methyl-5H-pyrido [4,3-b]indole in CDF1 mice. Biol Pharm Bull 2002; 25:520-2. [PMID: 11995936 DOI: 10.1248/bpb.25.520] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Chlorophyllin, a water-soluble derivative of chlorophyll, is known to suppress the mutagenic and carcinogenic action of compounds having polycyclic structures, e.g., heterocyclic amines and aflatoxin B1. Recently, we reported that chlorophyllin fixed on chitosan (chl-chitosan), which is insoluble in water, can efficiently and tightly trap these heterocyclic amines. We have studied whether this adsorption to chl-chitosan can result in an interference with DNA-adduct formation caused by 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2), a heterocyclic amine, in CDF1 mice, in which Trp-P-2 had been shown to induce hepatocellular carcinomas. Mice were fed a diet containing Trp-P-2 with or without chl-chitosan. After 3 d of feeding, DNA-adduct formation in liver and lung was examined by 32P-postlabeling analysis. Adducts formed from Trp-P-2 were significantly decreased by the chl-chitosan addition (p<0.05, t-test). These results suggest that the uptake of Trp-P-2 into the mouse was lowered by its adsorption to chl-chitosan, either within the digestive tract or within the food itself. This trapping agent, chl-chitosan, is thus worthy of study for cancer chemoprevention.
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24
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Lyles MB, Cameron IL, Rawls HR. Structural basis for the binding affinity of xanthines with the DNA intercalator acridine orange. J Med Chem 2001; 44:4650-60. [PMID: 11741482 DOI: 10.1021/jm9904708] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Caffeine (CAF), a methyl-substituted xanthine, interacts with polyaromatic DNA intercalators and has been hypothesized to interfere with their intercalation into DNA. Optical absorption spectroscopy was used to determine the binding affinities (K(assoc)) and structural effects of a series of methyl-substituted xanthines and a series of methyl-substituted uric acids (8-oxoxanthine) with the known DNA intercalator acridine orange (AO). There is evidence that complexation occurred (K(assoc) > or = 150 M(-1); binding curve saturation approximately > or =50%) between AO and 1,7-dimethylxanthine (155 M(-1)), 1,3-dimethylxanthine (theophylline, 157 M(-1)), 1,3,7-trimethylxanthine (CAF, 256 M(-1)), 1,3-dimethyl-8-chloroxanthine (413 M(-1)), 1,3,7,9-tetramethyl-8-oxyxanthine (tetramethyl uric acid or TMU, 552 M(-1)), and theophylline ethylenediamine (aminophylline, 596 M(-1)). No definitive evidence of complexation occurred between AO and 16 other substituted xanthines or purines, although there was some evidence of weak complexation (K(assoc) < 150 M(-1)) between AO and eight of the sixteen. Three common structural similarities were identified among those compounds found to form significant bonding with AO: (i) the N(1) or N(3) on the xanthine structure must be substituted with a methyl group; (ii) oxygen or chlorine substitution at C(8) increases binding affinity to AO when resonate states remain unchanged; and (iii) K(assoc) increases with an increase in number of methyl group substitutions on the 1- or 3-methylxanthine core structure. These results are explained on the basis of complex stabilization due predominately to hydrophobic attraction, with a contribution from charge transfer between donor and acceptor components. This information can be used in the manipulation of the physical or chemical characteristics of biologically active polyaromatic molecules.
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Affiliation(s)
- M B Lyles
- Department of Cellular and Structural Biology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, Texas 78229, USA
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25
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Kumar SS, Devasagayam TP, Bhushan B, Verma NC. Scavenging of reactive oxygen species by chlorophyllin: an ESR study. Free Radic Res 2001; 35:563-74. [PMID: 11767414 DOI: 10.1080/10715760100301571] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
The antioxidant effects of chlorophyllin (CHL), a water-soluble analog of the green plant pigment chlorophyll, on different reactive oxygen species (ROS) were investigated by electron spin resonance (ESR) spectroscopy. As a standard, we have used the ability of CHL to scavenge the stable 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical. CHL inhibits the formation of 5,5-dimethyl-1-pyrroline-N-oxide adduct with hydroxyl radical (DMPO-.OH adduct) generated by gamma-radiation in a dose-dependent manner. At a concentration of 1 mM, CHL caused more than 90% inhibition of ESR signal intensity of this adduct. However, the results obtained with the Fenton reaction were different. We also found evidence for the inhibition of 1O2-dependent formation of the 2,2,6,6-tetramethyl-piperidine oxide (TEMPO) radical during photosensitization of methylene blue with visible light. CHL was also able to inhibit hydrogen peroxide induced oxidation of phenol red. The rate constant of the reaction of CHL with H2O2 was found to be 2.7 x 10(6) M-1 s-1. In conclusion, CHL has potent antioxidant ability involving scavenging of various physiologically important ROS.
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Affiliation(s)
- S S Kumar
- Cell Biology Division, Bhabha Atomic Research Centre, Mumbai 400 085, India
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26
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Bez GC, Jordão BQ, Vicentini VE, Mantovani MS. Investigation of genotoxic and antigenotoxic activities of chlorophylls and chlorophyllin in cultured V79 cells. Mutat Res 2001; 497:139-45. [PMID: 11525916 DOI: 10.1016/s1383-5718(01)00251-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Chlorophyll and its derivatives are examples of plant compounds (purified and/or extracted) which appear to protect DNA from damage caused by chemical or physical agents, although some studies have identified clastogenic activity of these compounds. This study was carried out to assess the genotoxic activity of chlorophyll-a (Chl-a), -b (Chl-b) and chlorophyllin (Chl) and their antigenotoxic activity against the DNA damage induced by methyl methanesulphonate (MMS) under conditions of simultaneous, pre-, post-treatment, and simultaneous treatment after pre-incubation of the chemical with MMS. The micronucleus (MN) test was used in binucleated cells (induced by cytochalasin-B) of a mammalian cell line (V79). The three concentrations of Chl-a, Chl-b or Chl (0.1375, 0.275, 0.55microM) were not genotoxic and the genotoxic action of MMS (400microM) decreased (74-117%) under all treatment conditions. The results showed that there was no significant difference among the treatment types, the concentration or the nature of chlorophyll used. The data obtained suggest that Chl-a, Chl-b and Chl when associated with the DNA damaging agent, MMS, may protect the DNA by desgenotoxic action and/or by bio-antigenotoxic mechanisms, with the similar efficiency.
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Affiliation(s)
- G C Bez
- Departamento de Biologia Geral, Centro de Ciências Biológicas, Universidade Estadual de Londrina, Londrina, Paraná, Brazil
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27
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Rajendran R, Ohta Y. Binding activity of natto (a fermented food) and Bacillus natto isolates to mutagenic-carcinogenic heterocyclic amines. Can J Microbiol 2001; 47:935-42. [PMID: 11718547 DOI: 10.1139/w01-094] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The fermented food, whole meal Natto, viscous polymeric material from Natto, Natto bean, cooked soya bean, and 28 bacterial isolates from Natto were studied for their binding capacity to foodborne mutagenic-carcinogenic heterocyclic amines. The mutagenic heterocyclic amines used were Trp-P-1 (3-amino-1,4-dimethyl-5H-pyrido(4,3-b)indole); Trp-P-2 (3-amino-1-methyl-5H-pyrido(4,3-b)indole); Glu-P-1 (2-amino-6-methyldipyrido(1,2-a:3'2'-d)imidazole); PhIP (2-amino-1-methyl-6-phenylimidazo(4,5-b)pyridine); IQ (2-amino-3-methylimidazo(4,5-f)quinoline); MeIQ (2-amino-3,4-dimethylimidazo(4,5-f)quinoxaline); MeIQx (2-amino-3,8-dimethylimidazo(4,5-f)quinoxaline); and MeAalphaC (2-amino-3-methyl-9H-pyrido(2,3)indole). The lyophilized Natto and other fractions of Natto exhibited high binding activity towards Trp-P-1, Trp-P-2, PhIP, and MeAalphaC, while Glu-P-1, IQ, and MeIQ were not effectively bound. The binding capacity of bacterial isolates (Bacillus natto) were isolate-mutagen dependent. Heat treated lyophilized cells, cell wall, and cytoplasmic contents of the bacterial isolate with the highest binding capacity were analyzed for their ability to bind different heterocyclic amines. The results indicate the importance of the cell wall in binding to heterocyclic amines, whereas the cytoplasmic contents were less effective. Heat-treated cells were not much different from that of viable cells in their binding. The impact of different factors, such as pH, incubation time, metal ions, different concentrations of sodium chloride and alcohol, various enzymes, and acetylation of mutagens on binding of Trp-P-1 and IQ, were discussed. The significance of the present results is also discussed from the viewpoint that Natto, a fermented food, is able to scavenge dietary mutagenic heterocyclic amines through binding.
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Affiliation(s)
- R Rajendran
- Laboratory for Microbial Biochemistry, Faculty of Applied Biological Sciences, Hiroshima University, Higashi-Hiroshima, Japan
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28
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Reddy AP, Harttig U, Barth MC, Baird WM, Schimerlik M, Hendricks JD, Bailey GS. Inhibition of dibenzo[a,l]pyrene-induced multi-organ carcinogenesis by dietary chlorophyllin in rainbow trout. Carcinogenesis 1999; 20:1919-26. [PMID: 10506105 PMCID: PMC2386994 DOI: 10.1093/carcin/20.10.1919] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Cancer chemoprevention by dietary chlorophyllin (CHL) was investigated in a rainbow trout multi-organ tumor model. In study 1, duplicate groups of 130 juvenile trout were treated for 2 weeks with control diet, 500 p.p.m. dibenzo[a,l]pyrene (DB[a,l]P) or 500 p.p.m. DB[a,l]P + 2052 p.p.m. CHL, then returned to control diet. DB[a,l]P alone proved somewhat toxic but induced high tumor incidences in liver (61%), stomach (91%) and swimbladder (53%) 11 months after initiation. CHL co-feeding abrogated DB[a,l]P acute toxicity and reduced tumor incidences to 18% in liver, 34% in stomach and 3% in swimbladder (P = 0.01). A second tumor and DNA adduct study using a non-toxic initiation protocol (200 p.p.m. DB[a,l]P +/- 4000 p.p.m. CHL for 4 weeks) confirmed these results. Potential CHL inhibitory mechanisms were investigated. Dietary CHL inhibited hepatic DB[a, l]P-DNA adducts in the two tumor studies by 89 and 76%, respectively. CHL was shown to complex strongly with DB[a,l]P (K(d1,2) = 1.59 +/- 0.01 microM, stoichiometry 2CHL:DB[a,l]P) and strongly inhibited DB[a,l]P mutagenesis in the Salmonella assay. Significant inhibition occurred at CHL concentrations substantially less than stoichiometric with DB[a,l]P and thus not reflecting simple DB[a,l]P sequestration via complexation. These initial findings suggest that CHL chemoprevention reflects complexation that might limit DB[a,l]P uptake in vivo, antimutagenic mechanisms such as catalytic degradation of the proximate electrophile in target cells, or both. These results demonstrate that dietary CHL is a reproducibly effective chemopreventive agent for DB[a,l]P multi-organ tumorigenesis in trout and suggest that reduced DB[a,l]P-DNA adducts may be predictive biomarkers of CHL reduction of DB[a,l]P-initiated hepatic tumors.
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Affiliation(s)
- A P Reddy
- Department of Environmental Toxicology, Oregon State University, Corvallis, OR 97331, USA
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29
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Abstract
The cooking of meat and fish produces heterocyclic amine mutagens, including 2-amino-1-methyl-6-phenylimidazo[4,5b]pyridine (PhIP) and 2-amino-3-methylimidazo[4,5-f]quinoline (IQ). Chronic administration of PhIP or IQ to the F344 rat induces tumors at several sites, including adenocarcinomas of the colon, and short-term treatment leads to the formation of colonic aberrant crypt foci (ACF). We have used these end-points to identify potential chemopreventive agents that might be effective against heterocyclic amine colon carcinogens. Typically, IQ or PhIP were administered to groups of 10-15 rats by oral gavage on alternating days in weeks 3 and 4, and ACF were scored after 8, 12, or 16 weeks or tumors were detected at 52 weeks. To distinguish between 'blocking' and 'suppressing' agents, potential inhibitors were administered during the initiation or post-initiation phases, respectively, and subsequent studies focused on the inhibitory mechanisms. Among the most effective inhibitors identified to date, and their major mechanisms, were the following: chlorophyllin (molecular complex formation); indole-3-carbinol (inhibition and induction of cytochromes P450 and phase II enzymes); green and black tea catechins (induction of UDP-glucuronosyl transferase, inhibition of NADPH-cytochrome P450 reductase, scavenging of reactive intermediates); and conjugated linoleic acids (inhibition of cytochrome P450 and prostaglandin H synthase).
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Affiliation(s)
- M Xu
- The Linus Pauling Institute, and Department of Environmental and Molecular Toxicology, Oregon State University, Corvallis 97331-6512, USA
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30
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Kumar SS, Chaubey RC, Devasagayam TP, Priyadarsini KI, Chauhan PS. Inhibition of radiation-induced DNA damage in plasmid pBR322 by chlorophyllin and possible mechanism(s) of action. Mutat Res 1999; 425:71-9. [PMID: 10082917 DOI: 10.1016/s0027-5107(98)00250-4] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Naturally occurring compounds capable of protecting DNA against ionizing radiation and chemical mutagens have considerable potential for prevention of mutation-based health impairment including cancer and other degenerative diseases. Chlorophyllin (CHL), a water-soluble derivative of chlorophyll, has been examined for its ability to protect DNA against radiation induced strand breaks using an in vitro plasmid DNA system. Gamma-radiation, up to a dose of 6 Gy (dose rate 1.25 Gy/min), induced a dose-dependent increase in single-strand breaks (ssbs) in plasmid pBR322 DNA. CHL per se did not induce, but inhibited radiation-induced ssbs in a concentration-dependent manner; 500 microM giving about 90% protection. The protection afforded by CHL was comparatively less than that of trolox, a water-soluble analogue of alpha-tocopherol. To elucidate the underlying mechanism(s), reaction of CHL with the radiation-derived hydroxyl radical (.OH) and deoxyribose peroxyl radical (ROO.) was studied by pulse radiolysis. CHL exhibited a rate constant of 6.1+/-0.4x109 M-1 s-1 with.OH and 5.0+/-1.3x107 M-1 s-1 with ROO. To our knowledge, this is the first report providing direct evidence of free radical-scavenging properties of CHL. The results showed that CHL, effectively protects plasmid DNA against ionizing radiation, in an in vitro system independent of DNA repair or other cellular defense mechanisms. The ability of CHL to scavenge. OH and ROO., may contribute to its protective effects against radiation induced DNA damage in the pBR322 system.
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Affiliation(s)
- S S Kumar
- Cell Biology Division, Bhabha Atomic Research Centre, Mumbai 400 085, India
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31
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Kim SG, Surh YJ, Miller JA. Inhibitory effects of chlorophyllin on micronucleus formation induced by ethyl carbamate and its proximate and ultimate carcinogenic forms in mouse peripheral reticulocytes. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 1999; 34:57-60. [PMID: 10462725 DOI: 10.1002/(sici)1098-2280(1999)34:1<57::aid-em9>3.0.co;2-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Affiliation(s)
- S G Kim
- McArdle Laboratory for Cancer Research, School of Medicine, University of Wisconsin, Madison, Wisconsin, USA
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32
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Dashwood R, Negishi T, Hayatsu H, Breinholt V, Hendricks J, Bailey G. Chemopreventive properties of chlorophylls towards aflatoxin B1: a review of the antimutagenicity and anticarcinogenicity data in rainbow trout. Mutat Res 1998; 399:245-53. [PMID: 9672663 DOI: 10.1016/s0027-5107(97)00259-5] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The anticarcinogenic activity of chlorophyllin (CHL), a water-soluble derivative of chlorophyll, was first reported in rainbow trout. This review describes certain experiments which set the stage for long-term tumor bioassays, in trout and other species, using CHL and various food-borne carcinogens. Initial work with trout and rat liver enzymes in the Salmonella assay showed that CHL was a potent antimutagen towards heterocyclic amines, polycyclic aromatic hydrocarbons, aflatoxins and other classes of mutagen. Antimutagenic activity was further demonstrated using the corresponding direct-acting mutagens in the absence of an exogenous metabolizing system. Mutagen-inhibitor interaction (molecular complex formation) was identified in spectrophotometry studies, suggesting that CHL acts as an 'interceptor molecule'. In vivo, CHL reduced hepatic AFB1-DNA adducts and hepatocarcinogenesis when the inhibitor and carcinogen were co-administered in the diet. Finally, co-injection of inhibitor and AFB1 into trout embryos established that CHL was more effective than chlorophyll a in reducing AFB1-DNA adducts 2 weeks after injection, and liver tumors after 1 year.
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Affiliation(s)
- R Dashwood
- Department of Environmental Biochemistry, University of Hawaii, Honolulu 96822, USA
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33
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Abraham SK, Singh SP, Kesavan PC. In vivo antigenotoxic effects of dietary agents and beverages co-administered with urethane: assessment of the role of glutathione S-transferase activity. Mutat Res 1998; 413:103-10. [PMID: 9639686 DOI: 10.1016/s1383-5718(98)00008-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Antigenotoxic effects and changes in glutathione S-transferase (GST) activity were assessed in mice after oral co-administration of urethane (URE) with aqueous extracts of dietary vegetables (carrot, spinach and cabbage), spices (cinnamon, pepper, cumin, clove and cardamom), tea and coffee. The results of the genotoxicity assay (micronucleus test) demonstrated dose-related antigenotoxic effects after URE was co-administered with aqueous extracts of vegetables, spices, tea and coffee. Inhibition of GST activity was observed 4 h after treatment with URE alone. Co-administration of URE with extracts of vegetables, coffee and spices resulted in dose-related attenuation of the inhibitory effect of URE on GST activity. However, tea had no effect on inhibition of GST activity by URE. Hence an association between antigenotoxicity and GST activity could not be established.
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Affiliation(s)
- S K Abraham
- School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India
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Chernomorsky S, Rancourt R, Virdi K, Segelman A, Poretz RD. Antimutagenicity, cytotoxicity and composition of chlorophyllin copper complex. Cancer Lett 1997; 120:141-7. [PMID: 9461030 DOI: 10.1016/s0304-3835(97)00304-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The preparation of chlorophyllin copper complex (CCC), shown to be a tumor promoter in an animal model (Nelson, R.L. (1992) Chlorophyllin, an antimutagen, acts as a tumor promoter in the rat-dimethylhydrazine colon carcinogenesis model. Anticancer Res., 12, 737-740), also inhibits the activities of direct- and indirect-acting mutagens in the Salmonella assay and exhibits cytostatic and cytocidal effects toward myeloma cells. Data from elemental analyses, spectrophotometry and reversed-phase high-performance liquid chromatography indicate that CCC preparations generally used in antimutagenic/anticarcinogenic experiments are variable, complex mixtures of structurally distinct porphyrins lacking copper in some instances. This variability of the composition may be a cause for the differences reported for the tumor promotion activity of CCC.
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Affiliation(s)
- S Chernomorsky
- Department of Biochemistry, Rutgers University, New Brunswick, NJ 08903-0231, USA
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Affiliation(s)
- A P Odin
- Institute of General Genetics, Russian Academy of Sciences, Moscow, Russia
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González de Mejía E, Loarca-Piña G, Ramos-Gómez M. Antimutagenicity of xanthophylls present in Aztec Marigold (Tagetes erecta) against 1-nitropyrene. Mutat Res 1997; 389:219-26. [PMID: 9093387 DOI: 10.1016/s1383-5718(96)00151-9] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The principal natural food colorants used in modern food manufacture are anthocyanins, betalains, carotenoids, chlorophylls, riboflavin and caramel. Carotenoids (carotenes and xanthophylls) occur naturally in some foods such as carrots, red tomatoes, butter, cheese, paprika, palm oil, corn kernels, marigold petals, annatto, and red salmon. Carotenoids (alpha- or beta-carotene and xanthophylls) are excellent antioxidants and inhibit some types of cancers. In the present study, we used the Salmonella typhimurium tester strain YG1024 in the plate-incorporation test to examine the antimutagenicity of xanthophylls extracted from Aztec Marigold (Tagetes erecta) on 1-nitropyrene (1-NP) mutagenicity. Further, we investigated the effect of lutein on DNA-repair system of tester strain YG1024, using a preincubation test. The possible mechanism of lutein on 1-NP mutagenicity was studied by comparing the absorption spectrum of lutein, 1-NP and lutein plus 1-NP. In a dose-response curve of 1-NP, the mutagenic potency was 4317 revertants/nmol, and the dose of 0.06 microgram of 1-NP/plate was chosen for the antimutagenicity studies. Lutein and xanthophylls from Aztec Marigold (pigments for poultry and human use) inhibited mutagenicity of 1-NP in a dose-dependent manner. Lutein and the pigments were not toxic to the bacteria at the concentrations tested (0.002, 0.02, 0.2, 2.0 and 10 micrograms/plate). The percentages of inhibition of 1-NP mutagenicity were 72%, 92% and 66.2% for lutein (10 micrograms/plate), pigment for poultry use (10 micrograms/plate) and pigment for human use (2 micrograms/plate), respectively. Lutein had no effect on the DNA-repair system of strain YG1024. A new peak was detected at 429 nm when lutein was added at 1-NP, and it was stable throughout the incubation time. The results suggest that the major mechanisms of lutein against 1-NP mutagenicity is the potential formation of a complex between lutein and 1-NP, which could limit the bioavailability of 1-NP.
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Affiliation(s)
- E González de Mejía
- Departamento de Investigación y Posgrado, Facultad de Química, Universidad Autónoma de Querétaro, México
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Te C, Gentile JM, Baguley BC, Pearson AE, Gregory T, Ferguson LR. In vivo effects of chlorophyllin on the antitumour agent cyclophosphamide. Int J Cancer 1997; 70:84-9. [PMID: 8985095 DOI: 10.1002/(sici)1097-0215(19970106)70:1<84::aid-ijc13>3.0.co;2-d] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Cyclophosphamide (CP) is a potent antitumour agent used against many forms of cancer and against certain other diseases. Chlorophyllin (CHL), which is obtained by hydrolysis of chlorophyll to remove phytyl alcohol, is an efficient antimutagenic agent and has been used as a dietary supplement or to diminish the intensity of the discomforting side effects of CP therapy. We undertook to determine the antimutagenic effectiveness of CHL against CP in a mouse model and to determine whether the antitumour efficacy of CP was compromised in vivo by CHL treatment. Experiments utilised CHL administered either in drinking water (1%) for 2 days before treatment, or by gavage (200 mg/kg) 2 hr before treatment with CP (220 mg/kg). Urinary mutagenicity following CP treatment, as determined by the Salmonella/microsome assay, was decreased by both regimes of CHL co-treatment. Similarly, the increase in micronuclei in bone marrow polychromatic erythrocytes in response to CP was reduced by concomitant CHL treatment. In contrast, antitumour efficacy, as determined by growth delay of Colon 38 adenocarcinomas, was not diminished by CHL treatment. We conclude that CHL may have beneficial effects when used in combination with CP therapy.
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Affiliation(s)
- C Te
- Department of Biology, Hope College, Holland, MI, USA
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Hernaez J, Xu M, Dashwood R. Effects of tea and chlorophyllin on the mutagenicity of N-hydroxy-IQ: studies of enzyme inhibition, molecular complex formation, and degradation/scavenging of the active metabolites. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 1997; 30:468-474. [PMID: 9435888 PMCID: PMC2266694 DOI: 10.1002/(sici)1098-2280(1997)30:4<468::aid-em12>3.0.co;2-b] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Green tea and black tea inhibit the formation of carcinogen-DNA adducts and colonic aberrant crypts in rats given 2-amino-3-methylimidazo[4, 5-f]quinoline (IQ), a mutagen from cooked meat. The Salmonella mutagenicity assay was used in the present study to test individual constituents of tea as inhibitors of 2-hydroxyamino-3-methylimidazo[4, 5-f]quinoline (N-hydroxy-IQ), a direct-acting metabolite of IQ. Testing of pure compounds at doses relevant to their levels in tea identified epigallocatechin (EGC) and epigalocatechin-3-gallate (EGCG) as the primary antimutagens. Studies of the inhibitory mechanisms established that the rate of degradation of N-hydroxy-IQ under aqueous conditions was not increased significantly in the presence of tea, in contrast to the results obtained with the complexing agent chlorophyllin (CHL), which rapidly degraded the mutagen. Interaction between N-hydroxy-IQ and several tea constituents was detected in spectrophotometric studies, but the binding constants were only on the order of 1 x 10(3) M-1, suggesting that mechanisms other than complex formation might prevail under the conditions of the Salmonella assay. Comparison of the results in two different strains of Salmonella typhimurium, TA98 and TA98/1,8-DNP6, indicated that the antimutagenic activity of EGCG was dependent, at least in part, on a functional O-acetyltransferase activity in the bacteria. These studies suggest that tea constituents inhibit the enzyme(s) which generate the aryl nitrenium ion and directly scavenge the reactive electrophile, whereas CHL complexes with heterocyclic amines and facilitates the degradation of active metabolites.
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Affiliation(s)
- J Hernaez
- Department of Environmental Biochemistry, University of Hawaii, Honolulu 96822, USA
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Loarca-Piña G, Kuzmicky PA, González de Mejía E, Kado NY, Hsieh DP. Antimutagenicity of ellagic acid against aflatoxin B1 in the Salmonella microsuspension assay. Mutat Res 1996; 360:15-21. [PMID: 8657205 DOI: 10.1016/s0165-1161(96)90232-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Ellagic acid (EA) is a phenolic compound with antimutagenic and anticarcinogenic properties. It occurs naturally in some foods such as strawberries, raspberries, grapes, black currants and walnuts. In the present study, we used the Salmonella microsuspension assay to examine the antimutagenicity of EA against the potent mutagen aflatoxin B1 (AFB1) using tester strains TA98 and TA100. Further, we used a two-stage incubation procedure that incorporates washing the bacterial cells free of the incubation mixture after the first incubation to investigate EA and AFB1 interaction. Three different concentrations of AFB1 (2.5, 5 and 10 ng/tube) were tested against five different concentrations of EA for TA98 and TA100. EA significantly inhibited mutagenicity of all doses of AFB1 in both tester strains with the addition of S9. EA alone was not mutagenic at the concentrations tested. The greatest inhibitory effect of EA on AFB1 mutagenicity occurred when EA and AFB1 were incubated together. Lower inhibition was apparent when the cells were first incubated with EA followed by a second incubation with AFB1, and also when the cells were first incubated with AFB1 followed by a second incubation with EA alone. The results of the sequential incubation studies support the hypothesis that one mechanism of inhibition could involve the formation of a chemical complex between EA and AFB1.
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Affiliation(s)
- G Loarca-Piña
- Departamento de Investigación y Posgrado, Facultad de Química, Universidad Autónoma de Querétaro, México
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Park KK, Surh YJ. Chemopreventive activity of chlorophyllin against mouse skin carcinogenesis by benzo[a]pyrene and benzo[a]pyrene-7,8-dihydrodiol-9,10-epoxide. Cancer Lett 1996; 102:143-9. [PMID: 8603362 DOI: 10.1016/0304-3835(96)04173-0] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Chlorophyllin (CHL), the sodium and copper salt of chlorophyll, was tested for its chemopreventive activity against tumorigenesis induced by benzo[a]pyrene (B[a]P) and its ultimate electrophilic and carcinogenic metabolite, benzo[a]pyrene-7,8-dihydrodiol-9,10-epoxide(BPDE). Administration of CHL (15 mg/kg body wt) by gavage to female ICR mice 30 min prior to a topical application of B[a]P or BPDE resulted in significant reduction in both incidence and multiplicity of skin tumors initiated by these carcinogens. CHL was rapidly distributed in the skin and other tissues of mice after oral administration. Taken together, these results suggest that CHL is a potential chemopreventive agent.
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Affiliation(s)
- K K Park
- Department of Biochemistry, Yonsei University College of Medicine, Seoul, South Korea
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41
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Waters MD, Stack HF, Jackson MA, Brockman HE, De Flora S. Activity profiles of antimutagens: in vitro and in vivo data. Mutat Res 1996; 350:109-29. [PMID: 8657173 DOI: 10.1016/0027-5107(95)00097-6] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
In this review, retinol, chlorophyllin, and N-acetylcysteine are examined and compared with regard to their antimutagenic activity against some promutagens and a group of direct-acting alkylating agents. The promutagens included aflatoxin B1, certain polycyclic aromatic hydrocarbons (e.g., benzo[a]pyrene), and certain heterocyclic amines (e.g., food pyrolysates). Results of antimutagenicity testing selected from data surveyed in the published literature are displayed graphically as activity profiles of antimutagens showing both the doses tested and the extent of inhibition or enhancement of mutagenic activity. All three antimutagens are discussed in terms of their putative mechanisms of action in vitro and in vivo with emphasis on the xenobiotic metabolizing enzyme systems.
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Affiliation(s)
- M D Waters
- U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA
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42
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Dashwood R, Yamane S, Larsen R. Study of the forces of stabilizing complexes between chlorophylls and heterocyclic amine mutagens. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 1996; 27:211-218. [PMID: 8625957 DOI: 10.1002/(sici)1098-2280(1996)27:3<211::aid-em6>3.0.co;2-h] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Chlorophyllin (CHL), a water-soluble derivative of chlorophyll, forms molecular complexes with heterocyclic amine mutagens in vitro. In a previous study [Dashwood and Guo (1993): Environ Mol Mutagen, 22:164-171], we observed an inverse correlation between the binding constants of several mutagen-CHL complexes and the antimutagenic potency of CHL in the Salmonella assay. The present investigation utilized molecular mechanics methods of energy minimization and spectrophotometric titration to examine structural features of chlorophylls, chlorins, and porphyrins that might be important for complex formation with heterocyclic amines. The exocyclic amine group of the mutagen aligned consistently with acid groups in CHL, suggesting that H-bond or electrostatic interactions facilitate complex formation. Replacement of the exocyclic amine with a nitro group abrogated this specific orientation and raised the minimized energies of the complexes. No relationship was found between complex strength and the specific positions of amine or methyl groups on the mutagen. However, the presence of methyl groups increased the minimized energies and lowered the binding constants of the complexes, perhaps due to partial disruption of pi-pi interaction by steric effects. All of the compounds examined, including chlorophyll a, required the presence of pi-pi interactions to form stable complexes with the heterocyclic amines. In general, the present results were in agreement with the inhibitory potency of each compound in the Salmonella assay, and they provide further support for the hypothesis that chlorophylls in the diet might act as interceptor molecules of food-borne carcinogens and mutagens.
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Affiliation(s)
- R Dashwood
- Department of Environmental Biochemistry, University of Hawaii, Honolulu 96822, USA
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Larsen RW, Jasuja R, Hetzler RK, Muraoka PT, Andrada VG, Jameson DM. Spectroscopic and molecular modeling studies of caffeine complexes with DNA intercalators. Biophys J 1996; 70:443-52. [PMID: 8770220 PMCID: PMC1224942 DOI: 10.1016/s0006-3495(96)79587-5] [Citation(s) in RCA: 79] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Recent studies have demonstrated that caffeine can act as an antimutagen and inhibit the cytoxic and/or cytostatic effects of some DNA intercalating agents. It has been suggested that this inhibitory effect may be due to complexation of the DNA intercalator with caffeine. In this study we employ optical absorption, fluorescence, and molecular modeling techniques to probe specific interactions between caffeine and various DNA intercalators. Optical absorption and steady-state fluorescence data demonstrate complexation between caffeine and the planar DNA intercalator acridine orange. The association constant of this complex is determined to be 258.4 +/- 5.1 M-1. In contrast, solutions containing caffeine and the nonplanar DNA intercalator ethidium bromide show optical shifts and steady-state fluorescence spectra indicative of a weaker complex with an association constant of 84.5 +/- 3.5 M-1. Time-resolved fluorescence data indicate that complex formation between caffeine and acridine orange or ethidium bromide results in singlet-state lifetime increases consistent with the observed increase in the steady-state fluorescence yield. In addition, dynamic polarization data indicate that these complexes form with a 1:1 stoichiometry. Molecular modeling studies are also included to examine structural factors that may influence complexation.
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Affiliation(s)
- R W Larsen
- Department of Chemistry, University of Hawaii at Manoa, Honolulu 96822, USA.
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Guo D, Horio DT, Grove JS, Dashwood RH. Inhibition by chlorophyllin of 2-amino-3-methylimidazo-[4,5-f]quinoline-induced tumorigenesis in the male F344 rat. Cancer Lett 1995; 95:161-5. [PMID: 7656225 DOI: 10.1016/0304-3835(95)03882-w] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
This report describes a 1-year carcinogenicity bioassay in which male F344 rats received 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) by gavage 2-3 times per week throughout the first 35 weeks of study, while 0.1% sodium/copper chlorophyllin (CHL) was given concomitantly in the drinking water. The carcinogen dose was calculated to provide an average exposure of 4.2 mg IQ/rat per day, equivalent to that reported in previous carcinogenicity study in which rats were given 0.03% IQ in the diet. Adjusted for length of follow-up, inhibition was highly significant for total tumor burden (P < 0.001), and for specific sites was significant in the small intestine and Zymbal's gland (P < or = 0.1), and in the liver (P < 0.01). In rats given CHL, the first onset of tumors in the Zymbal's gland was delayed from week 20 to 36, but was shortened from week 31 to 26 in the skin (P < 0.05). These results support a chemopreventive role for CHL in several of the major target organs for IQ tumorigenesis in the rat, but raise concerns over possible deleterious effects in the skin.
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Affiliation(s)
- D Guo
- Department of Environmental Biochemistry, University of Hawaii, Honolulu 96822, USA
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45
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Edenharder R, Leopold C, Kries M. Modifying actions of solvent extracts from fruit and vegetable residues on 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) and 2-amino-3,4-dimethylimidazo[4,5-f]quinoxaline (MeIQx) induced mutagenesis in Salmonella typhimurium TA 98. Mutat Res 1995; 341:303-18. [PMID: 7531289 DOI: 10.1016/0165-1218(95)90101-9] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The edible parts of 13 fruits--apples, apricots, bananas, blackberries, sweet cherries, red currants, white grapes, oranges, peaches, pears, plums, raspberries, and strawberries--and of 12 vegetables--asparagus, green beans, broccoli, brussels sprouts, red and white cabbage, carrots, cauliflower, onions, green peppers, spinach, and tomatoes--were squeezed in order to separate juices and residues. The residues were washed, lyophilized, and extracted sequentially with n-hexane, dichloromethane, acetone, and 2-propanol. Solvent extracted materials were tested in Salmonella typhymurium TA 98 for antimutagenicity against IQ and MeIQx. We found antimutagenic activities in 96% of the n-hexane extracts, 64% of the dichloromethane extracts, 44% of the acetone extracts, and 36% of the 2-propanol extracts. Since no or only minor differences were seen between the mutagens IQ and MeIQx investigations were continued with IQ only. Additional antimutagenic activities were detected in a total of 29.6% of extracts tested when an enzyme preparation with glycosidase-activities (fecalase) was included in the assay. These activities were found in originally inactive or less active dichloromethane, acetone, and 2-propanol extracts, and are therefore strongly suggestive for the liberation of antimutagenic aglycones from inactive glycosides. The existence of possibly a multitude of antimutagenic factors in fruits and vegetables was further substantiated by: (1) solvent partitioning of the n-hexane extracts of cauliflower, peaches, and spinach; (2) separation of the n-hexane and dichloromethane extracts of cauliflower, peaches, and spinach into acidid, neutral, and basic compounds; (3) chromatographic analysis of the n-hexane and dichloromethane extracts of spinach. Taken together, antimutagenic activities were present in 32 of 36 subfractions, corresponding to 88.9%. In the green vegetables beans, broccoli, and spinach the known antimutagen chlorophyll was proven to contribute considerably to antimutagenic potency. Other important contributions may be caused by various fibers: (I) antimutagenicity of fruit and vegetable solvent extracts was extensively heat stable; (II) heating surprisingly caused an increase of antimutagenic potencies or generated new antimutagenic activities in several solvent fractions, especially of broccoli, white and red cabbage. Indeed, mutagenicity induced by IQ was strongly reduced by lignin, weakly by alginic acid and pectin A, while cellulose, gum arabic, gum guar, and xylan were ineffective. With respect to the mechanisms of antimutagenicity binding of IQ by various fibers and inhibition of cytochrome P-450-dependent monooxygenases might be of major importance since no solvent fraction of any fruit or vegetable was able to reduce mutagenic activity induced by N-OH-IQ in S. typhimurium TA 98NR.
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Affiliation(s)
- R Edenharder
- Department of Hygiene, University of Mainz, Germany
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Abstract
Reports on an inverse relationship between the consumption of fresh vegetables and human gastrointestinal cancer have been followed by screening for the protective activity of a large number of plant extracts, including leafy vegetables. Chlorophyll is ubiquitous in all green plant parts. Chlorophyllins are derivatives of chlorophyll in which the central magnesium atom is replaced by other metals, such as cobalt, copper or iron. An attempt has been made in this article to review the relative efficacy of chlorophyll and chlorophyllin in modifying the genotoxic effects of various known toxicants.
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Affiliation(s)
- D Sarkar
- Department of Botany, University of Calcutta, India
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47
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Tachino N, Guo D, Dashwood WM, Yamane S, Larsen R, Dashwood R. Mechanisms of the in vitro antimutagenic action of chlorophyllin against benzo[a]pyrene: studies of enzyme inhibition, molecular complex formation and degradation of the ultimate carcinogen. Mutat Res 1994; 308:191-203. [PMID: 7518046 DOI: 10.1016/0027-5107(94)90154-6] [Citation(s) in RCA: 81] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Mechanisms of the antimutagenic action of chlorophyllin (CHL) towards benzo[a]pyrene (BP) were studied in vitro. In the Salmonella assay, CHL inhibited the mutagenic activity of BP in the presence of an S9 activation system and was particularly effective against the direct-acting ultimate carcinogen, benzo[a]pyrene-7,8-dihydrodiol-9,10-epoxide (BPDE). Spectral studies indicated that the time-dependent hydrolysis of BPDE to tetrols was augmented in the presence of CHL concentrations on the order of 5 microM. Dose-related inhibition of several cytochrome P450-dependent enzyme activities was observed upon addition of CHL to in vitro incubations. Spectral changes for the interaction between CHL and cytochrome P450 indicated that CHL does not bind to the active site of the enzyme, but exerts its inhibitory effect indirectly. This was achieved by inhibiting NADPH-cytochrome P450 reductase (Ki approximately 120 microM with cytochrome c as substrate), and did not involve lowering of the effective substrate concentration by complex formation with the procarcinogen. It is concluded that the in vitro antimutagenic activity of CHL towards BP involves accelerated degradation of the ultimate carcinogen, with inhibition of carcinogen activation occurring only at high CHL concentrations. The latter mechanism is unlikely to occur in vivo following p.o. administration due to the limited uptake of CHL from the gut, but tissue concentrations may be sufficiently high to cause degradation of BPDE.
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Affiliation(s)
- N Tachino
- Department of Environmental Biochemistry, University of Hawaii, Honolulu 96822
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