Base-pair Substitution Mutations Research Articles

Hypoxia-inducible factor-1α plays roles in Epstein-Barr virus's natural life cycle and tumorigenesis by inducing lytic infection through direct binding to the immediate-early BZLF1 gene promoter.

When confronted with poor oxygenation, cells adapt by activating survival signaling pathways, including the oxygen-sensitive transcriptional regulators called hypoxia-inducible factor alphas (HIF-αs). We report here that HIF-1α also regulates the life cycle of Epstein-Barr virus (EBV). Incubation of EBV-positive gastric carcinoma AGS-Akata and SNU-719 and Burkitt lymphoma Sal and KemIII cell lines with a prolyl hydroxylase inhibitor, L-mimosine or deferoxamine, or the NEDDylation inhibitor MLN4924 promoted rapid and sustained accumulation of both HIF-1α and lytic EBV antigens. ShRNA knockdown of HIF-1α significantly reduced deferoxamine-mediated lytic reactivation. HIF-1α directly bound the promoter of the EBV primary latent-lytic switch BZLF1 gene, Zp, activating transcription via a consensus hypoxia-response element (HRE) located at nt -83 through -76 relative to the transcription initiation site. HIF-1α did not activate transcription from the other EBV immediate-early gene, BRLF1. Importantly, expression of HIF-1α induced EBV lytic-gene expression in cells harboring wild-type EBV, but not in cells infected with variants containing base-pair substitution mutations within this HRE. Human oral keratinocyte (NOK) and gingival epithelial (hGET) cells induced to differentiate by incubation with either methyl cellulose or growth in organotypic culture accumulated both HIF-1α and Blimp-1α, another cellular factor implicated in lytic reactivation. HIF-1α activity also accumulated along with Blimp-1α during B-cell differentiation into plasma cells. Furthermore, most BZLF1-expressing cells observed in lymphomas induced by EBV in NSG mice with a humanized immune system were located distal to blood vessels in hypoxic regions of the tumors. Thus, we conclude that HIF-1α plays central roles in both EBV’s natural life cycle and EBV-associated tumorigenesis. We propose that drugs that induce HIF-1α protein accumulation are good candidates for development of a lytic-induction therapy for treating some EBV-associated malignancies.

Natural two Taraxacum species effective against frame shift and base pair substitution mutations: mutagenic, antimutagenic and antioxidant evaluation

Plant or plant products have gained increasing importance in recent years due to their lower toxicity and side effects in pharmacology and food industries. The genus Taraxacum have been used as traditional medicine since ancient times. In this study, antioxidant, mutagenic and antimutagenic properties of two Taraxacum species namely T. mirabile and T. farinosum were investigated. Antioxidant properties were determined by different test systems including DPPH radical scavenging, reducing power (CUPRAC and FRAP assays) and phosphomolybdenum assays. Total phenolic and flavonoid contents were also reported. Mutagenic and anti-mutagenic activities were tested by Ames assay. It was seen that Taraxacum species have moderate antioxidant and antimutagenic activities ranging between moderate to strong. However, the species were found to be non-mutagenic. It was determined that total phenolic and flavonoid contents in T. mirabile (23.43 mgGAE/g extract and 4.58 mgRE/g extract) was higher than T. farinosum (17.54 mgGAE/g extract and 3.37 mgRE/g extract). According to our results, the Taraxacum species could be considered as a source of natural agents in nutraceutical and pharmaceutical areas.

Alcohol, Aldehydes, Adducts and Airways.

Drinking alcohol and smoking cigarettes results in the formation of reactive aldehydes in the lung, which are capable of forming adducts with several proteins and DNA. Acetaldehyde and malondialdehyde are the major aldehydes generated in high levels in the lung of subjects with alcohol use disorder who smoke cigarettes. In addition to the above aldehydes, several other aldehydes like 4-hydroxynonenal, formaldehyde and acrolein are also detected in the lung due to exposure to toxic gases, vapors and chemicals. These aldehydes react with nucleophilic targets in cells such as DNA, lipids and proteins to form both stable and unstable adducts. This adduction may disturb cellular functions as well as damage proteins, nucleic acids and lipids. Among several adducts formed in the lung, malondialdehyde DNA (MDA-DNA) adduct and hybrid malondialdehyde-acetaldehyde (MAA) protein adducts have been shown to initiate several pathological conditions in the lung. MDA-DNA adducts are pre-mutagenic in mammalian cells and induce frame shift and base-pair substitution mutations, whereas MAA protein adducts have been shown to induce inflammation and inhibit wound healing. This review provides an insight into different reactive aldehyde adducts and their role in the pathogenesis of lung disease.

Assessing the Mutagenic Potential of Surface Sediments from Beijing Guanting Reservoir to Salmonella typhimurium

Mutagenicity of organic extracts from Beijing Guanting Reservoir sediments was investigated with TA98 and TA100 of Salmonella typhimurium. TA98 and TA100 were employed to detect frameshift mutation and base-pair substitution mutation, respectively. For TA100, no positive result was found, while TA98 was more sensitive and pro-mutagenic frameshift mutagens were mainly detected in sediments. Sediments from northern and southern Guanting Reservoir were at potential mutagenic risk. No mutagenicity was found in the sediments from the entrance of the tributaries, but strong mutagenicity was observed in the sediments from the outlet of the reservoir. Chemical analysis was also performed, and poor correlation was found between mutagenicity and organochlorine pesticides (OCPs). However, significant positive correlation was found for polycyclic aromatic hydrocarbons (PAHs) (r = 0.603–0.946), which showed that PAHs were dominated for the tested mutagenicity in the sediments. Polychlorinated biphenyls (PCBs) might induce mutagenicity or promote the mutagenicity of other substances.

Eco-genotoxicity of six anticancer drugs using comet assay in daphnids

The eco-genotoxicity of six anti-neoplastic drugs, 5-fluorouracil, capecitabine, cisplatin, doxorubicin, etoposide, and imatinib, belonging to five classes of anatomical therapeutic classification (ATC), was studied applying the in vivo comet assay on cells from whole organisms of Daphnia magna and Ceriodaphnia dubia. For the first time, this test was performed in C. dubia. In addition, to have a wider genotoxic/mutagenic profile of the anticancer drugs selected, SOS chromotest and Salmonella mutagenicity assay were performed. The comet results showed that all drugs induced DNA damage, in both Cladocerans, with environmental concern; indeed Doxorubicin induced DNA damage in the order of tens of ngL−1 in both crustaceans, as well as 5-flurouracil in C. dubia and cisplatin in D. magna. In the SOS Chromotest all drugs, except imatinib, were able to activate the repair system in Escherichia coli PQ37 while in the Salmonella mutagenicity assay, doxorubicin was the only drug able to cause direct and indirect frameshift and base-pair substitution mutations. Comet assay was the most sensitive tool of genotoxic exposure assessment, able to detect in vivo the adverse effects at concentration lower than those evaluated in vitro by bacterial assays.

Effects of prochloraz on DNA damage, lipid peroxidation and antioxidant system in vitro

Prochloraz is a broad-spectrum contact imidazol fungicide used against several diseases in wheat, barley and oleaginous plants but also for treatment of flower production. Although prochloraz has endocrine disrupting and hepatocarcinogenic effects, there is lack of data on toxic effects of prochloraz. Therefore, we aimed to investigate the DNA damage effects of prochloraz in NRK-52E cells by using Ames and Comet assay. By using a standard alkaline Comet assay procedure, there was no DNA damage observed after 24 h prochloraz exposure. It also showed that prochloraz caused neither base-pair substitution nor frame shift mutations by using TA98, TA100 strains, respectively, with/without metabolic activation in Ames assay. Both Comet and Ames assays, the exposure concentrations were 12.5, 25, 50 and 100 µM. IC50 value of prochloraz was determined as 110.76 µM in NRK-52E cells by MTT cytotoxicity test. Also, we evaluated possible effects of prochloraz on lipid peroxidation, reduced glutathione (GSH), oxidized glutathione (GSSG) and antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) and glutathione reductase (GSH-Rd) in NRK-52E cells at 1–50 µM concentrations. Prochloraz induced lipid peroxidation and altered glutathione contents and antioxidant enzyme activities in NRK-52E cells. Our results indicated that prochloraz showed no evidence of mutagenicity and DNA damage; however, some alterations were observed on lipid peroxidation and antioxidant systems in prochloraz treatment.

Differences in biomarker expression in HNSCC according to p53 status.

5523 Background: Patients with p53 wildtype head and neck squamous cell carcinoma (HNSCC) tend to be HPV-positive, which associates with better prognosis. The purpose of this study was to explore biomarker expression profiles for insight into molecular differences in HNSCC patients based on p53 status. Methods: TP53 gene sequencing using the AmpliChip p53 microarray (Roche Molecular Systems, Inc.) was attempted on 61 HNSCC patients previously tested with Caris Target Now tumor profiling service. DNA was extracted from a FFPE sample, amplified and processed on the AmpliChip p53 microarray to detect single base pair substitution and deletion mutations in exons 2 - 11 and their flanking splice sites in the TP53 gene (GenBank X54156). EGFR FISH , HER2 IHC and 22 other predictive biomarkers, e.g. TS, TOPO2A, MGMT, etc., were assayed and retrospectively analyzed. All tests were performed in a CLIA-certified lab and interpreted by board-certified pathologists or cytogeneticists. Statistical analysis was performed using SPSS (PASW statistics17) for parametric and non-parametric tests of independence. Results: 52 cases provided sufficient quality DNA for p53 analysis and results revealed a mutation rate of 25% in HNSCC patients. Interestingly, only EGFR FISH and HER2 IHC (p=.002 and p=.004, respectively) were differentially expressed in wildtype vs. mutated p53. Matched-pair analysis in the p53 mutated subgroup (n=13) showed no significant trend regarding EGFR status (p=.763) but a slight trend towards HER-2 negativity (p=.020). In the p53 wildtype subgroup (n=39), a strong association with EGFR FISH non-amplification (n=28, 71.8%, p<.001) as well as HER-2 negativity (n=38, 97.4%, p<.001) was shown. Conclusions: To our knowledge, this is the first analysis of differential biomarker expression profiles in HNSCC based on p53 status. We hypothesize that the absence of EGFR amplification in the p53 wildtype cancers may be a contributing factor to the improved prognosis observed in HPV-positive HNSCC. Additionally, the strong association between p53 wildtype HNSCC patients and EGFR non-amplification suggests EGFR-targeted therapies like cetuximab would likely fail in p53 wildtype patients.

Evidence for hormesis in mutagenicity dose–response relationships

This study assessed the occurrence of hormetic dose responses from three previously published data sets [1–3] with 825 chemicals in three Ames assay tester strains (i.e., TA97, TA98, TA100) with and without the S9 fraction, using a five dose protocol and semi-log dose spacing. Ninety-five (95) (11.5%) chemicals satisfied the multiple a priori entry criteria, with a total of 107 assays. Of the assays satisfying the entry criteria, 61 involved TA100, a strain that detects base-pair substitution mutations. 29.5% (18/61) satisfied the statistical evaluative criteria for hormesis, exceeding that predicted by chance by 4.0-fold (p<0.001). The remaining 46 assays involved TA97 and TA98, strains that detect frameshift mutations. Of these 46 assays, the overall responses for the lowest two doses closely approximated the control response (e.g., 101.77% of the control for TA98; 99.20% for TA97). Only 2.2% (1/46) of the assays satisfied the evaluative criteria for hormesis. In conclusion, these data support a hormetic model for TA100, whereas the responses for TA97 and TA98 are consistent with a threshold dose–response model.

AN INVESTIGATION OF MUTAGENIC ACTIVITIES OF SOME 9- SUBSTITUEDPHENANTHRENE DERIVATIVES WITH AMES / SALMONELLA / MICROSOME TEST

In this study, three different 9-Substituted phenantrene derivatives that were synthesized to be used as basic matter for drugs were tested for their mutagenic potency in strains TA 98 and TA 100 of Salmonella typhimurium by using Ames test. Therefore, both strains were tested in the absence or presence of S9 metabolic activation, for five different doses of each test substances in two paralel independent experiments. In the absence of metabolic activation, while only one of the compounds were causing frame-shift mutations, two of them were determined to induce base pair substitution mutations. In the presence of metabolic activation, while two of the compounds were mutagenic for TA 98, base pair substitution mutations were not detected for any of the substances. Each of the compounds tested were found to be mutagenic for at least one strain in the presence or absence of S9.

Mutagenicity, genotoxicity and carcinogenic risk assessment of indoor dust from three major cities around the Pearl River Delta

The mutagenicity and genotoxicity of workplace dust including commercial office, secondary school, shopping mall, hospital, electronics factory and manufacturing plant in Hong Kong and settled house dust from Hong Kong, Shenzhen and Guangzhou were measured. Results indicated that indoor dust contained both frameshift and base pair substitution mutagens. Dust from manufacturing plant showed highest mutagenic potency on TA98±S9 and TA100±S9 activation, whereas, electronics factory showed highest genotoxicity with and without S9 activation. TA100 (−S9) mutagenic potency was significantly correlated with genotoxicity expressed as SOSIP (−S9) of workplace dust (r2=0.37, p<0.01). The total PAHs concentration of settled house dust from PRD ranged from 1.63 to 29.2μg/g. Linear regression analyses indicated that the PAHs likely accounted for about 45% of the TA98 with S9 mutagenic activity of workplace dust. TA98 (−S9) mutagenicity (r2=0.27, p<0.05) and SOSIP (−S9) of house dust (r2=0.41, p<0.01) were both significantly correlated with the number of inhabitants in the house. To achieve a more accurate cancer risk assessment, the oral bioaccessibility of B(a)A, Chry, B(b+k)F, B(a)P, D(ah)A and I(cd)P in different dust ranging from 1.3% to 17% was taken into account. Risk assessments indicated that about 26% of house dust samples resulted in unacceptable cancer risk (>1×10−6) for preschool children.

Mutagenicity of Walnut Creek and Troy (Alabama) Wastewater Treatment Plant Influent and Effluent

Abstract Samples from Walnut Creek, upstream of the Troy Wastewater Treatment Plant (TWWTP), and the influents to and effluents from the TWWTP were assayed for mutagenicity using the Salmonella typhimurium fluctuation test. Samples were prepared with metabolic activation (channel catfish S9 and rat S9 enzymes) and without using TA100 and TA98 strains of Salmonella. Results indicated that catfish S9 enzymes (FS9) were more capable of activating base-pair substitution mutagens in upstream samples than rat S9 enzymes (RS9). For influent samples, RS9 activated higher levels of base-pair and frameshift mutagens than FS9. The comparison of changes from influent to effluent samples showed a significant reduction in base-pair and no change in frameshift mutagens with FS9; conversely, no change in base-pair and a significant reduction in frameshift mutagens with RS9 were found. For direct-acting compounds (without enzymatic activation), a significant increase in frameshift mutations was found in effluent compared ...

Study of Antimutagenic Potential of Phytoconstituents Isolated from Terminalia arjuna in the Salmonella/Microsome Assay

Two fractions ET-1 and TW isolated from Terminalia arjuna were evaluated for their antimutagenic potential against 4-nitro-o-phenylenediamine (NPD) in TA98, sodium azide in TA100 and 2-aminofluorene, in both TA98 and TA100 tester strains of Salmonella typhimurium using bacterial reverse mutation assay. Both the fractions inhibited the mutagenicity of 2AF significantly in both the strains. ET-1 fraction inhibited the mutagenicity of base pair substitution mutagen sodium azide by 77.41% at 1×10 3 μg/0.1ml. It did not inhibit the mutagenicity of NPD. TW fraction showed insignificant inhibitory activity against the mutagenicity of NPD and sodium azide in TA100 and TA98 tester strains respectively. 1 H-NMR, 13 C-NMR and IR-spectroscopic data of the fractions revealed ET-1 fraction as a diglycoside of triterpene and TW fraction as tannin in nature.

Mutagenic potentials of Amberlite XAD-2-resin extracts obtained from river and drinking waters in the Northwest district of Chiba, Japan

Amberlite XAD-2 resin extracts of river and drinking water sampled from the Northwest district of Chiba Prefecture in each month during the period from January to December 2008 were investigated to characterize and determine their mutagenic potentials and polycyclic aromatic hydrocarbon (PAH) levels. The extracts from the river water were shown to be mutagenic in Salmonella typhimurium TA98 (a flameshift mutagen) without S9 mix, with higher mutagenic responses in summer and early fall seasons. While the drinking water extracts exhibited weak mutagenicity in both the TA98 and TA100 strains (a base-pair substitution mutagen) without S9 mix, with high mutagenic responses in fall and early winter seasons. GC/MS determinations of the water concentrates showed some seasonal scatter in PAH levels in river water. In contrast, comparatively high concentrations of PAHs were observed for drinking water samples collected during warmer seasons. Statistical studies revealed that there is a lower correlation between the levels of flameshift mutagenicity and the concentrations of PAH in the river water concentrations, but a higher correlation between them in the drinking water samples.

Using the Salmonella assay to delineate the dispersion routes of mutagenic compounds from coal wastes in contaminated soil

The mutagenicity of acidic and organic extracts of surface soil under the influence of a coal-fired power plant was evaluated by Salmonella/microsome assay using strains TA97a, TA98 and TA100 in the absence and presence of exogenous metabolic systems (S9 mix). Additionally, strains YG1041 and YG1042 (sensitive to nitroderivatives) were used for the organic extracts. In general, the responses were higher in the organic extracts in the presence of S9 mix. The comparison between strains TA98 and TA100 and their derived strains YG1041 and YG1042, respectively, allowed the detection of the presence of nitro-aromatic compounds in some sampling areas, which was confirmed by chemical analysis. The interpretation of the set of mutagenesis data suggests that there are two important mutagenic compound dispersion routes in the area of study: frameshift mutagens were dispersed predominantly by runoff and leaching, while base-pair substitution mutagens were dispersed mainly by the atmosphere. This mutagenic damage might be attributed to the effects of several substances detected in the area, such as aliphatic hydrocarbons and the metals aluminum, cadmium, lead and iron.

Cytotoxic and genotoxic effects of [Ru(phi) 3] 2+ evaluated by Ames/ Salmonella and MTT methods

In this work, we synthesized and evaluated the cytotoxic effect of [Ru(phi) 3] 2+, on rat C6 glioma cell line. Cell viability was determined by assay with 3-(4-5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT). The mutagenicity of [Ru(phi) 3] 2+ was studied in vitro by using two strains of Salmonella typhimurium with frameshift mutation (TA98) and base-pair substitution mutation (TA100) were used in plate incorporation assay in the absence of metabolic activation. According to the results, the Ru compound is not toxic but mutagenic, and it shows cytotoxic effect towards C6 rat glioma cells in100 μM.

Nutrition and Mutagenesis

Diet-related mutagenesis plays an etiologic role in chronic diseases, including cardiovascular disease and cancer. Many dietary mutagens are DNA reactive, leading to distinct spectra of base-pair substitution mutations and structural chromosome changes. Examples include aflatoxin B1, ochratoxin A, ptaquiloside, various pyrrolizidine alkaloids, heterocyclic amines including 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine, and polycyclic aromatic hydrocarbons such as benzo[a]pyrene. However, endogenously or exogenously formed reactive species, inhibitors of topoisomerase II enzymes (e.g., flavonoids), of DNA repair (e.g., caffeine), or of the mitotic spindle (possibly acrylamide), also cause mutations, including structural chromosome changes and copy number variants. Genomic instability also results from inadequate nutrient intake (e.g., folate and selenium). Antimutagens include vitamin C, carotenoids, chlorophyllin, dietary fibers, and plant polyphenols acting through various mechanisms. Polymorphisms in genes for nutrient uptake, metabolism, and excretion will affect dietary intake in determining individual risk of disease development. Human studies utilizing nutrigenomic/nutrigenetic technologies will be essential to quantifying and overcoming diet-related mutagenesis.

Massively parallel pyrosequencing in HIV research

1411–1415Keywords: DNA sequence, homogeneous PCR products, pyrosequencingThe new massively parallel sequencing methods are soastonishing that one wonders whether space aliens aresecretly behind them. One technician, running a singleinstrument,canobtainuptoapproximately1billionbasesof DNA sequence in a few days. Here we describe thenew sequencing methods, briefly present a few appli-cations in HIV research, and then speculate on futuredirections.

Gene identification and allele-specific marker development for two allelic low phytic acid mutations in rice (Oryza sativa L.)

Phytic acid (PA, myo-inositol 1,2,3,4,5,6-hexakisphosphate) is an important anti-nutritional component in cereal and legume grains. PA forms of phosphorus (P) and its salts with micronutrient cations, such as iron and zinc, are indigestible in humans and non-ruminant animals, and hence could affect food/feed nutritional value and cause P pollution of ground water from animal waste. We previously developed a set of low phytic acid (LPA) rice mutants with the aim to increase their nutritional quality. Among them, one line, i.e., Os-lpa-XQZ-1 (hereafter lpa 1-2), was identified to have a mutation allelic to the KBNT lpa 1-1 mutation (hereafter lpa 1-1), which was already delimited to a 47-kb region on chromosome 2. In this study, we searched the candidate gene for these two allelic LPA mutations using T-DNA insertion mutants, mutation detection by CEL I facilitated mismatch cleavage, and gene sequencing. The TIGR locus LOC_Os02g57400 was revealed as the candidate gene hosting these two mutations. Sequence analysis showed that the lpa 1-1 is a single base pair substitution mutation, while lpa 1-2 involves a 1,475-bp fragment deletion. A CAPS marker (LPA1_CAPS) was developed for distinguishing the lpa 1-1 allele from lpa 1-2 and WT alleles, and InDel marker (LPA1_InDel) was developed for differentiating the lpa 1-2 allele from lpa 1-1 and WT ones. Analysis of two populations derived from the two mutants with wild-type varieties confirmed the complete co-segregation of these two markers and LPA phenotype. The LOC_Os02g57400 is predicted to encode, through alternative splicing, four possible proteins that are homologous to the 2-phosphoglycerate kinase reported in hyperthermophilic and thermophilic bacteria. The identification of the LPA gene and development of allele-specific markers are of importance not only for breeding LPA varieties, but also for advancing genetics and genomics of phytic acid biosynthesis in rice and other plant species.

Frequency and spectrum of ENU-induced mutation in the X174 transgene in mouse splenic lymphocytes and their significance to spontaneous transgenic rodent mutation frequencies

A perceived disadvantage of transgenic rodent mutation assays is that spontaneous mutant frequencies are high compared to those of endogenous genes and may consequently reduce sensitivity to induced mutation. We have previously argued that unrepaired G:T mismatches from spontaneous deamination of 5-methylcytosine at CpG sites could be converted to apparent in vivo mutations in the bacterial recovery systems because of rapid, random, mismatch repair in Escherichia coli. In this study, we have measured mutation frequencies in spleen of male mice induced by N-ethyl-N-nitrosourea (ENU) using the PhiX174 transgene, which is not subject to mismatch repair in E.coli, using single-burst analysis, a unique method to identify in vivo mutation. In order to compare our results to those using the lacI and cII transgenes, we converted all mutant frequencies to base pair substitution (bps) mutation frequencies per nucleotide based on mutant spectra from this study and published literature. We found this frequency in control spleen to be similar for lacI (3.8 +/- 0.7 x 10(-8)) and PhiX174 (3.1 +/- 1.2 x 10(-8)) at 6 weeks of age. We found a strong age dependence for spontaneous lacI mutation that extrapolated to a value at conception (1.8 +/- 0.9 x 10(-8)) that was not significantly different from the human germ line bps mutation frequency per nucleotide of 1.7 +/- 0.2 x 10(-8). These two transgenes provided similar mutational responses to 40 mg/kg ENU, 7- to 9-fold. In contrast, the cII target gene in the same tissue produces both spontaneous and induced mutation frequencies approximately 10 times higher, for unknown reasons. We conclude that the spontaneous mutant frequencies measured by the lacI and PhiX174 transgenes in this moderately dividing tissue accurately measure in vivo mutation frequencies at early ages. For these two transgenes, seemingly high mutant frequencies may reflect the expected accumulation of somatic mutation with age.

Mutagenicity and antimutagenicity of teas used in popular medicine in the salmonella/microsome assay

Plant species are widely used in tea form in Brazil, but little is known about scientific aspects of the effect of these aqueous extracts on human health or on genetic material. Mutagenic and antimutagenic activities of three plant species, Vitex montevidensis Cham. (Lamiaceae), Gochnatia cordata Less. (Asteraceae) and G. polymorpha (Asteraceae) in the Salmonella/microsome assay were evaluated. No mutagenic activity was found for base-pair substitution (TA100) and frameshift mutations (TA98) in the three extracts studied. Low indexes of mutagenesis inhibition induced for the V. montevidensis extract with the sodium azide mutagen and results of co-mutagenesis with 4-oxide-1-nitroquinoline were observed for the three extracts evaluated without addition of a rat liver metabolic system fraction (S9 mix). Assays with S9 mix showed significant antimutagenic properties against mutagenesis induced by 2-aminofluorene, both for TA98 (67% of the assays) and for TA100 (100% of the assays). This protective activity was possibly related to properties described for flavonoids and/or tannins acting as potential inactivators of enzymes involved in the mutagen metabolism.