Clastogenic Activity Research Articles

Phyto-cytogenotoxic potential assessment of two medicinal plants: Davilla nitida (Vahl) Kubitzki and Davilla elliptica (A. St.-Hill) (Dilleniaceae)

ABSTRACT Humans have been using plants in the treatment of various diseases for millennia. Currently, even with allopathic medicines available, numerous populations globally still use plants for therapeutic purposes. Although plants constitute a safer alternative compared to synthetic agents, it is well established that medicinal plants might also exert adverse effects. Thus, the present investigation aimed to assess the phytotoxic, cytotoxic, and genotoxic potential of two plants from the Brazilian Cerrado used in popular medicine, Davilla nitida (Vahl) Kubitzki, and Davilla elliptica (A. St.-Hil.). To this end, germination, growth, and cell cycle analyses were conducted using the plant model Lactuca sativa. Seeds and roots were treated with 0.0625 to 1 g/L for 48 hr under controlled conditions. The germination test demonstrated significant phytotoxic effects for both species at the highest concentrations tested, while none of the extracts produced significant effects in the lettuce growth test. In the microscopic analyses, the aneugenic and cytotoxic action of D. elliptica was evident. In the case of D. nitida greater clastogenic action and induction of micronuclei, (MN) were noted suggesting that the damage initiated by exposure to these extracts was not repaired or led to apoptosis. These findings indicated that the observed plant damage was transmitted to the next generation of cells by way of MN. These differences in the action of the two species may not be attributed to qualitative variations in the composition of the extracts as both are similar, but to quantitative differences associated with synergistic and antagonistic interactions between the compounds present in these extracts.

Antigenotoxic Activity of Polyphenolic Composition BP-C2 in Mouse Germ Cells In Vivo.

In vivo antigenotoxic activity of BP-C2 composition (at doses of 60, 80, and 120 mg/kg) based on polyphenolic compounds derived from hydrolyzed lignin was evaluated in mouse germ cells. The BP-C2 composition dose-dependently reduced the aneugenic activity of topoisomerase II inhibitor etoposide in mouse oocytes without affecting the clastogenic activity of the genotoxicant. In mouse testicular cells, the BP-C2 composition reduced the DNA-damaging activity of the pro-oxidant genotoxicant dioxidine, but not etoposide. The cytoprotective activity of BP-C2 composition was revealed in relation to etoposide-induced cytotoxicity.

Synthetic Colors in Food: A Warning for Children's Health.

This study addressed the harmful effects of artificial colors in pediatric populations, including children diagnosed with Autism Spectrum Disorder (ASD) and Attention Deficit Hyperactivity Disorder (ADHD), as well as those without behavioral disorders. There is a consensus that synthetic food colorings have several impacts on consumers, especially pediatrics, due to their influence on sensory appeal, which can encourage preference for certain foods. The results revealed that these color additives are directly linked to a series of health problems, with a greater impact on children, including a predisposition to pathological conditions such as carcinogenic, allergenic, mutagenic, cytotoxic, and clastogenic activities, as well as gastrointestinal and respiratory problems, in addition to behavioral changes in children with and without diagnosed disorders. The harms of synthetic dyes in children with or without comorbidities are worrying and require a careful and proactive approach from parents, caregivers and public authorities.

Enhancement of the Clastogenic Effects of Topotecan In Vivo by Tyrosyl-DNA Phosphodiesterase 1 Inhibitors.

Topotecan administered intraperitoneally at single doses of 0.25, 0.5, and 1 mg/kg induced chromosomal aberrations in bone marrow cells of F1(CBA×C57BL/6) hybrid mice in a dose-dependent manner. A tyrosyl-DNA phosphodiesterase 1 (TDP1) inhibitor, an usnic acid derivative OL9-116 was inactive in a dose range of 20-240 mg/kg, but enhanced the cytogenetic effect of topotecan (0.25 mg/kg) at a dose of 40 mg/kg (per os). The TDP1 inhibitor, a coumarin derivative TX-2552 (at doses of 20, 40, 80, and 160 mg/kg per os), increased the level of aberrant metaphases induced by topotecan (0.25 mg/kg) by 2.1-2.6 times, but was inactive at a dose of 10 mg/kg. The results indicate that TDP1 inhibitors enhance the clastogenic activity of topotecan in mouse bone marrow cells in vivo and are characterized by different dose profiles of the co-mutagenic effects.

Comprehensive Ocular and Systemic Safety Evaluation of Polysialic Acid-Decorated Immune Modulating Therapeutic Nanoparticles (PolySia-NPs) to Support Entry into First-in-Human Clinical Trials.

An inflammation-resolving polysialic acid-decorated PLGA nanoparticle (PolySia-NP) has been developed to treat geographic atrophy/age-related macular degeneration and other conditions caused by macrophage and complement over-activation. While PolySia-NPs have demonstrated pre-clinical efficacy, this study evaluated its systemic and intraocular safety. PolySia-NPs were evaluated in vitro for mutagenic activity using Salmonella strains and E. coli, with and without metabolic activation; cytotoxicity was evaluated based on its interference with normal mitosis. PolySia-NPs were administered intravenously in CD-1 mice and Sprague Dawley rats and assessed for survival and toxicity. Intravitreal (IVT) administration in Dutch Belted rabbits and non-human primates was assessed for ocular or systemic toxicity. In vitro results indicate that PolySia-NPs did not induce mutagenicity or cytotoxicity. Intravenous administration did not show clastogenic activity, effects on survival, or toxicity. A single intravitreal (IVT) injection and two elevated repeat IVT doses of PolySia-NPs separated by 7 days in rabbits showed no signs of systemic or ocular toxicity. A single IVT inoculation of PolySia-NPs in non-human primates demonstrated no adverse clinical or ophthalmological effects. The demonstration of systemic and ocular safety of PolySia-NPs supports its advancement into human clinical trials as a promising therapeutic approach for systemic and retinal degenerative diseases caused by chronic immune activation.

Mutagenicity and safety evaluation of Ashwagandha (Withania somnifera) root aqueous extract in different models

Withania somnifera (Ashwagandha) also called as Indian ginseng, a revered herb from Indian traditional system of medicine is a rejuvenator and tonic (Rasayana) used for its varied benefits. The roots of ashwagandha exhibit properties like anti-inflammatory, aphrodisiac, anthelmintic, astringent, diuretic, stimulant and thermogenic. However, data of ashwagandha on its mutagenic effects are lacking. In the present study, in-vitro genotoxicity tests were used to evaluate the mutagenic potential of Ashwagandha Root Extract (ARE). Concentrations of 0.156 to 5.00 mg/plate ARE were used for conducting Bacterial reverse mutation test (BRMT). For chromosome aberration (CA) test ARE was used in concentrations of 0.25 to 2.00 mg/ml, and for micronucleus (MN) tests ARE concentrations of 500/1000/2000 mg/kg were used. Acute oral toxicity was conducted in Wistar rats (n = 25) as per the OECD guideline (#423) with doses of 500/1000/2000 mg/kg body weight in male Swiss albino mice for morbidity and mortality for 3 days. The BRMT and CA tests were conducted with and without metabolic activation (S9). The study was approved by the institutional ethics committee (IEC) and institutional animal ethics committee (IAEC). ARE failed to show any mutagenic effects up to a dose of 5 mg/plate in BRMT. Also, ARE did not show any clastogenic activity in doses up to 2 mg/ml in CA test and in micronucleus test up to 2000 mg/kg body weight. These results were observed with and without metabolic activation (S9) under the stated experimental conditions. No mortality, morbidity, or any clinical signs were observed up to 3 days following ARE administration. Ashwagandha root extract failed to show any mortality in doses up to 2000 mg/kg oral dosage and did not show any mutagenic (genotoxic) effects in high concentrations.

Genotoxicity assessment of 1,4-anhydro-4-seleno-D-talitol (SeTal) in human liver HepG2 and HepaRG cells

1,4-Anhydro-4-seleno-D-talitol (SeTal) is a highly water-soluble selenosugar with interesting antioxidant and skin-tissue-repair properties; it is highly stable in simulated gastric and gastrointestinal fluids and is a potential pharmaceutical ingredient that may be administered orally. Hepatic toxicity is often a major problem with novel drugs and can result in drug withdrawal from the market. Predicting hepatotoxicity is therefore essential to minimize late failure in the drug-discovery process. Herein, we report in vitro studies to evaluate the cytotoxic and genotoxic potential of SeTal in HepG2 and hepatocyte-like differentiated HepaRG cells. Except for extremely high concentrations (10 mM, 68 h-treatment in HepG2), SeTal did not affect the viability of each cell type. While the highest examined concentrations (0.75 and 1 mM in HepG2; 1 mM in HepaRG) were observed to induce primary DNA damage, SeTal did not exhibit clastogenic or aneugenic activity toward either HepG2 or HepaRG cells. Moreover, no significant cytostasis variations were observed in any experiment. The clearly negative results observed in the CBMN test suggest that SeTal might be used as a potential active pharmaceutical ingredient. The present study will be useful for the selection of non-toxic concentrations of SeTal in future investigations.

In vitro evaluation of cytotoxicity and genotoxicity of porous nickel titanium dental implants produced by metal injection molding technique.

Porous NiTi (pNiTi) is a promising biomaterial for functional long-term implantation that has been produced using various manufacturing techniques and tested for biocompatibility. pNiTi produced using a more recent technology of Metal Injection Molding (MIM) has shown better physical and mechanical properties than those produced by earlier manufacturing methods, but its biocompatibility has yet to be determined. Hence, extracts from pNiTi dental implants produced by MIM were tested for cytotoxicity and genotoxicity in this work. Its toxicity was evaluated at the cellular and in vitro levels using elution and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assays. Short-term testing revealed that pNiTi extract was cytocompatible with L-929 fibroblast and V79-4 lung cells, with no cell lysis or reactivity observed, respectively (USP grade 0). Following exposure to varied extract concentrations, good cell viability was observed where the lowest concentration showed the highest optical density (OD) and cell viability (2.968 ± 0.117 and 94%, respectively), and the highest concentration had the least OD and cell viability (2.251 ± 0.054 and 71%, respectively). pNiTi extracts demonstrated genocompatibility in two independent assays: mutagenic potential using a bacterial reverse mutation test and a clastogenic effect on chromosomes using the micronucleus test. Similar to the negative control reactions, there was no significant increase in revertant colonies following exposure to 100% pNiTi extract with and without metabolic activation (p = .00). No DNA clastogenic activity was caused by pNiTi at varied extract concentrations as compared to the negative control when tested with and without metabolic activation (p = .00). As a result, both cytotoxic and genotoxic investigations have confirmed that pNiTi dental implants utilizing the MIM process are cytocompatible and genocompatible in the short term, according to the International Standard, ISO 10993 - Parts 3, 5, and 33.

In Vitro Effects of Zirconia Nanoparticles: Uptake, Genotoxicity, and Mutagenicity in V-79 cells.

Zirconia nanoparticles are used in various industrial and biomedical applications such as dental implants, thermal barrier sprays, and fuel cells. The interaction of nanoparticles with the environment and humans is inevitable. Despite the enormous application potential of these nanoparticles, there are still some gaps in the literature regarding potential toxicological mechanisms and the genotoxicity of zirconia nanoparticles. The lung is one of the main exposure routes to nanomaterials; therefore, the present study was designed to determine the genotoxic and mutagenic effect of zirconia NPs in V-79 lung cells. Zirconia nanoparticles showed significant internalization in cells at 100μg/mL and 150μg/mL concentrations. Zirconia nanoparticles showed low cytotoxicity and were found to generate ROS in V-79 cells. In alkaline comet assay, zirconia nanoparticles (10μg/mL, 50μg/mL, and 100μg/mL) exposed cells exhibited significant DNA strand breaks, while the neutral comet assay, which was used for double-strand break assessment, only revealed significant damage at 100μg/mL. Chromosomal aberration induced by zirconia nanoparticles mainly resulted in the generation of gaps, few fragments, and breaks which signifies the low clastogenic activity of these nanoparticles in the V-79 cell line. In MN assay, zirconia nanoparticles resulted in no significant micronuclei induction at any given concentration. In the HPRT mutation assay, the particle shows a dose-dependent increase in the mutant frequency. It is evident from the result that zirconia nanoparticles cause dose-dependent cytotoxicity and genotoxicity, but still, more studies are needed to evaluate the clastogenic potential and the possible mechanism involved.

Pyrene-polyethylene glycol-modified multi-walled carbon nanotubes: Genotoxicity in V79-4 fibroblast cells

The genotoxicity of pyrene-polyethylene glycol-modified multi-walled carbon nanotubes (MWCNT-PyPEG), engineered as a nanoplatform for bioapplication, was evaluated. Toxicity was assessed in hamster lung fibroblast cells (V79–4). MTT and Cell Titer Blue methods were used to evaluate cell viability. Genotoxicity was measured by the comet assay and the cytokinesis-block micronucleus cytome (CBMN-Cyt) assay, and fluorescence in situ hybridization (FISH) was used to test induction of structural chromosome aberrations (clastogenic activity) and/or numerical chromosome changes (aneuploidogenic activity). Exogenous metabolic activation enzymes were used in the CBMN-Cyt and FISH tests. Only with metabolic activation, the hybrids caused chromosomal damage, by both clastogenic and aneugenic processes.

Evaluation of an Antimalarial Herbal Recipe and its Individual Plant Extracts for DNA Fragmentation and Clastogenicity Potential in Swiss Albino Mice

In this study, water extracts of leaves of Azadirachta indica and stem bark of Alstonia boonei, and their recipe were evaluated at 25.0%, 50.0% and 100.0% following DNA fragmentation and micronucleus assays in Swiss albino mice. Distilled water and 0.05% sodium azide served as negative and positive controls, respectively. The levels of superoxide dismutase, catalase and malondialdehyde in the treated mice were determined. The FTIR technique was adopted to identify the functional groups of phytochemicals present, and the proximate constituents were also determined. The individual extracts of A. indica and A. boonei were not mutagenic while the recipe was not significantly mutagenic compared to the controls. Water extract of A. indica had the least clastogenic activity, while A. boonei extract was most cytotoxic towards erythrocytes proliferation. Superoxide dismutase and catalase activities of the extracts and recipe were dose-dependent; however, the recipe at 100.0% recorded best activity, with highest amount of total proteins. A. indica recorded highest suppression of generation of malondialdehyde molecules. The phytochemicals in the extracts and recipe contained hydroxyl and carbonyl functional groups, and their proximate constituents were almost the same except for the crude protein and fiber contents of the recipe. Conclusively, extract of A. indica at the tested doses in this study was found to be less toxic to the mitotic cell division in the bone marrow, DNA and chromosomes in Swiss albino mice than the extract of A. boonei and recipe.

The evaluation of the efficacy and potential genotoxic hazard of combined SAHA and 5-FU treatment in the chemoresistant colorectal cancer cell lines

5-Fluorouracil (5-FU) is an essential chemotherapeutic drug for colorectal cancer (CRC) treatment. However, the frequent development of drug resistance has dramatically affected its clinical use. Therefore, novel treatment strategies are critical to improving patient outcomes. Herein, we investigated the ability of the epigenetic drug SAHA to increase the sensitivity of chemoresistant CRC cells to 5-FU. In addition, we evaluated the potential genotoxic risk of SAHA+5-FU combination treatment. As a model system, we used three CRC cell lines, HT-29, SW480, and HT-29/EGFP/FUR, differing in their resistance to 5-FU. CRC cell lines were exposed to sub-toxic SAHA concentrations for 24 h, followed by a 48 h treatment with 5-FU. The cytotoxicity of SAHA, 5-FU, and SAHA+5-FU was measured by the MTT test, the genotoxicity by the comet assay, and the micronucleus test. The apoptotic/necrotic activity was assessed using morphological criteria.We found a synergic decrease in the viability of HT-29 and SW480 cells, but not the most resistant HT-29/EGFP/FUR cells after combined SAHA+5-FU exposure compared to 5-FU. Remarkably, SAHA most efficiently induced apoptosis in HT-29/EGFP/FUR cells compared to HT-29 and SW480 cells. Combined SAHA+5-FU treatment resulted in a synergistic increase in apoptotic/necrotic cells in HT-29 cell line, while rather additive/sub-additive effect was determined in the SW480 and HT-29/EGFP/FUR cells. At the same time, however, a synergistic rise in micronuclei was found in CRC cell lines (at least at some concentrations). We have shown that SAHA can sensitize CRC cells to 5-FU; therefore, epigenetic and convential drug combinations could be beneficial for the patients. However, the increase in micronucleus formation after combined SAHA+5-FU treatment indicates a potential health hazard. The clastogenic activity could contribute to cancer heterogeneity, favoring progeny of such aberrant cells to clonal expansion. Therefore, developing new specific epigenetic drugs or nanocarriers for targeted drug delivery might reduce the potential genotoxic risk.

Oxidative Stress, Mutations and Chromosomal Aberrations Induced by In Vitro and In Vivo Exposure to Furan.

Furan is a volatile compound that is formed in foods during thermal processing. It is classified as a possible human carcinogen by international authorities based on sufficient evidence of carcinogenicity from studies in experimental animals. Although a vast number of studies both in vitro and in vivo have been performed to investigate furan genotoxicity, the results are inconsistent, and its carcinogenic mode of action remains to be clarified. Here, we address the mutagenic and clastogenic activity of furan and its prime reactive metabolite cis-2 butene-1,4-dial (BDA) in mammalian cells in culture and in mouse animal models in a search for DNA lesions responsible of these effects. To this aim, Fanconi anemia-derived human cell lines defective in the repair of DNA inter-strand crosslinks (ICLs) and Ogg1−/− mice defective in the removal of 8-hydroxyguanine from DNA, were used. We show that both furan and BDA present a weak (if any) mutagenic activity but are clear inducers of clastogenic damage. ICLs are strongly indicated as key lesions for chromosomal damage whereas oxidized base lesions are unlikely to play a critical role.

Chemical composition, phytotoxicity and cytogenotoxicity of essential oil from leaves of Psidium guajava L. cultivars

Natural products with biological activity, such as essential oils, can be used in the search for and development of ecological herbicides as an alternative to reduce the damage caused by synthetic herbicides. This work to aimed to determine the chemical composition and phytotoxic properties of the essential oils, at concentrations of 3000, 1500, 750, 375 and 187.5 µg/mL, of four cultivars of Psidium guajava (guava) evaluated on germination and root growth of plant models Lactuca sativa and Sorghum bicolor, as well as in the L. sativa cell cycle. Exposure to essential oils reduced germination and root growth in bioassays, especially at the highest concentration (3000 µg/mL). The essential oils interfered in the normal dynamics of the cell cycle of L. sativa at most concentrations, causing a decrease in the mitotic index and increasing of chromosomal alterations, evidencing aneugenic and clastogenic action. The biological activity of the oils was associated with the presence of sesquiterpenes and monoterpenes found here, such as caryophyllene oxide, (E) -caryophyllene, and limonene. Thus, the essential oils of cultivars of guava demonstrated the promising potential for use as natural herbicides.

Transcription-associated topoisomerase 2α (TOP2A) activity is a major effector of cytotoxicity induced by G-quadruplex ligands.

G-quadruplexes (G4) are non-canonical DNA structures found in the genome of most species including human. Small molecules stabilizing these structures, called G4 ligands, have been identified and, for some of them, shown to induce cytotoxic DNA double-strand breaks. Through the use of an unbiased genetic approach, we identify here topoisomerase 2α (TOP2A) as a major effector of cytotoxicity induced by two clastogenic G4 ligands, pyridostatin and CX-5461, the latter molecule currently undergoing phase I/II clinical trials in oncology. We show that both TOP2 activity and transcription account for DNA break production following G4 ligand treatments. In contrast, clastogenic activity of these G4 ligands is countered by topoisomerase 1 (TOP1), which limits co-transcriptional G4 formation, and by factors promoting transcriptional elongation. Altogether our results support that clastogenic G4 ligands act as DNA structure-driven TOP2 poisons at transcribed regions bearing G4 structures.

Kinetics of γH2AX and phospho-histone H3 following pulse treatment of TK6 cells provides insights into clastogenic activity

The desire for in vitro genotoxicity assays to provide higher information content, especially regarding chemicals' predominant genotoxic mode of action, has led to the development of a novel multiplexed assay available under the trade name MultiFlow®. We report here on an experimental design variation that provides further insight into clastogens' genotoxic activity. First, the standard MultiFlow DNA Damage Assay-p53, γ H2AX, phospho-histone H3 was used with human TK6 lymphoblastoid cells that were exposed for 24 continuous hours to each of 50 reference clastogens. This initial analysis correctly identified 48/50 compounds as clastogenic. These 48 compounds were then evaluated using a short-term, 'pulse' treatment protocol whereby cells were exposed to test chemical for 4 h, a centrifugation/washout step was performed, and cells were allowed to recover for 20 h. MultiFlow analyses were accomplished at 4 and 24 h. The γ H2AX and phospho-histone H3 biomarkers were found to exhibit distinct differences in terms of their persistence across chemical classes. Unsupervised hierarchical clustering analysis identified three groups. Examination of the compounds within these groups showed one cluster primarily consisting of alkylators that directly target DNA. The other two groups were dominated by non-DNA alkylators and included anti-metabolites, oxidative stress inducers and chemicals that inhibit DNA-processing enzymes. These results are encouraging, as they suggest that a simple follow-up test for in vitro clastogens provides mechanistic insights into their genotoxic activity. This type of information will contribute to improve decision-making and help guide further testing.

Toxicological evaluation of a glycan preparation from an enzymatic hydrolysis of Saccharomyces cerevisiae

The aim of this paper was to provide a comprehensive toxicological and safety evaluation of a yeast cell wall preparation (YCWP) for use as an animal feed ingredient. The following toxicological assessments were carried out: the mutagenic activity was tested using the Ames’ Test in five Salmonella typhimurium strains; clastogenic activity was investigated using the mammalian micronucleus test in Swiss ICO OF1 (IOPS Caw) mice; genotoxic activity was assessed using the in vitro mammalian chromosomal aberration test in human lymphocytes; acute oral toxicity was tested by administration of a single dose of 2000 mg/kg BW. Eye and skin irritation were assessed in rabbits according to OECD guidelines; skin sensitivity was established in guinea pigs by means of the Buehler test, while acute dermal and inhalation studies in rats were further completed, also according to OECD guidelines. All conducted tests were considered valid under the experimental conditions. No significant mutagenic activity or genotoxic activity was observed, and it was concluded that the test article did not induce any clastogenic effect. YCWP was found to be mildly irritating to the eye, slightly irritating to the skin but was found to be non-sensitizing in the guinea pig. The acute oral, dermal and inhalation studies did not yield any evidence of gross toxicity or pharmacological effects.

Toxicological and Epigenetic Studies of Two Types of Ale Beer, Tyrosol and Iso-Alpha Humulone

Although many benefits drawn from beer consumption are claimed, the epidemiological records are contradictory with respect to cancer prevention. The purpose of this study was to investigate the possible health-related activities involving genome safety and the ageing processes of two types of lyophilised ale beers (blond and stout), as well as two of their bioactive compounds (tyrosol and iso-alpha humulone). A multipurpose trial set of in vivo toxicity, antitoxicity, mutagenicity, antimutagenicity, lifespan and healthspan assays using Drosophila melanogaster were used. In parallel, several in vitro assays were designed using the cancer cell line HL-60 in order to establish the possible chemopreventive activity of the selected substances, where epigenetic modulation of DNA methylation changes, clastogenic activity and tumour cell inhibition growth were evaluated. The safety of the four substances was confirmed: lyophilised blond ale beer (LBAB), lyophilised stout ale beer (LSAB), tyrosol and iso-alpha humulone were neither toxic nor genotoxic. Moreover, all substances, except tyrosol, revealed the ability to protect individual genomes against oxidative radicals and to exert antimutagenic activity against the genotoxin hydrogen peroxide. With respect to the degenerative process indicators of lifespan and healthspan, tyrosol was the only compound that did not exert any influence on the life extension of Drosophila; LBAB induced a significant lifespan extension in D. melanogaster; LSAB and its distinctive compound iso-alpha humulone induced a reduction in longevity. The in vitro assays showed the cytotoxic activity of LBAB, LSAB and tyrosol against HL-60 cells. Moreover, proapoptotic DNA fragmentation or DNA strand breakage was observed for both types of beers and iso-alpha humulone at different concentrations. Furthermore, the lyophilised ale beers and tyrosol exhibited an increasing genome-wide methylation status, while iso-alpha humulone exhibited a demethylation status in repetitive cancer cell sequences. Although the biological activities assigned to beer consumption cannot be linked to any specific molecule/element due to the complexity of the phenolic profile, as well as the multifactor brewing process, the results obtained let us propose lyophilised ale beers as safe potential nutraceutical beverages when consumed in moderate amounts. The prevention of toxicity and genetic oxidative damage, as well as the induction of tumor cell death and modulation of the methylation status, are the key activities of beer that were shown in the present research.

Genomic Instability Is an Early Event in Aluminium-Induced Tumorigenesis.

Genomic instability is generally considered as a hallmark of tumorigenesis and a prerequisite condition for malignant transformation. Aluminium salts are suspected environmental carcinogens that transform mammary epithelial cells in vitro through unknown mechanisms. We report here that long-term culture in the presence of aluminium chloride (AlCl3) enables HC11 normal mouse mammary epithelial cells to form tumours and metastases when injected into the syngeneic and immunocompetent BALB/cByJ strain. We demonstrate that AlCl3 rapidly increases chromosomal structural abnormalities in mammary epithelial cells, while we failed to detect direct modulation of specific mRNA pathways. Our observations provide evidence that clastogenic activity—a well-recognized inducer of genomic instability—might account in part for the transforming abilities of aluminium in mammary epithelial cells.

In Vitro Genotoxicity and Molecular Docking Study of Ellagic Acid

Background: Ellagic Acid (EA) is a polyphenolic compound that is classified in the natural antioxidants group. Polyphenolic compounds that exert antioxidant activity possess particular importance for scientists, food producers and consumers due to their positive effects on human health. However, despite considerable evidence that EA shows antigenotoxic activity by binding to DNA, there is no systematic genotoxicity study of this substance, which can covalently bind to DNA. This study aims to reveal the possible genotoxic activity of EA using widely accepted assays for the assessment of DNA clastogenic activity: sister chromatid exchange, chromosome aberration, micronucleus and comet assays as well as to predict the interactions among EA and DNA through molecular docking. Methods: Different assays were carried out to identify the clastogenic activity of EA on human lymphocyte DNA using Sister Chromatid Exchange (SCE), Chromosome Aberration (CA), Micronucleus (MN) and single-cell gel electrophoresis (SCGE/comet) assays. For this aim, human peripheral blood lymphocytes were treated with EA (60, 80 and 100 μg/ml) for 24 and 48 hrs in the SCE, CA and MN assays and for 1 hr in the comet assay. Furthermore, molecular docking experiments were also performed to calculate the binding energy of EA on human B-DNA structure (B-DNA dodecamer) as well as to predict noncovalent interactions among these macromolecules. Results: At the concentrations and treatment times (24- or 48-hr) tested, EA did not induce either SCE or Chromosome Aberrations (CAs) as compared to the negative and solvent controls. Although EA slightly increased the percentage of Micronucleated Binuclear (%MNBN) cells as well as the percentage of Micronucleus (%MN) in 24 or 48-hr treatment periods at all concentrations, this increase was not statistically significant as compared to both controls. The effect of EA on DNA replication (nuclear division) was determined by the Proliferation Index (PI), the Nuclear Division Index (NDI) and the Mitotic Index (MI). No statistically significant differences were observed in the PI or NDI in 24- or 48-hr treatment periods in human lymphocyte cultures treated with EA at various concentrations. EA generally had no significant effect on the MI, as observed with the PI and NDI. Discussion: Although the concentrations of 60 and 80 μg/mL at a 24-hr treatment period and the concentrations of 60 μg/mL and 100 μg/mL at 48-hr treatment period generally decreased the MI, those decreases were not statistically significant when compared to negative and solvent controls. Moreover, none of the concentrations of EA tested in this study were able to increase DNA damage determined by the tail DNA length, %DNA in tail and tail moment parameters in the comet assay. Although the amount of DNA damage in the comet assay decreased with increasing concentrations of EA, this decrease was not statistically significant as compared to both controls. However, molecular docking experiments interestingly showed that the binding free energy of EA with B-DNA was -7.84 kcal/mol-1, indicating a strong interaction between the two molecules. Conclusion : Although the findings of our study show that EA does not have genotoxic potential in human chromosomes, molecular docking experiments revealed strong hydrogen bonding between EA and B-DNA molecules. Therefore, it has been proposed that the prevailing information suggesting that the molecules that bind to DNA cause genotoxic effects should be reconsidered from a wider perspective.