Simplified protocol for evaluating the genotoxic risk of hospital wastewater

To evaluate the genotoxicity of hospital wastewater, we drew up a simplified protocol based on two well-known tests: the SOS chromotest and the Ames fluctuation test. Three concentrations of wastewater samples were directly tested without extraction or concentration. By fixing three significance levels in genotoxicity response for each test, we could classify the samples in five categories ranging from nongenotoxic to highly genotoxic. This simplified classification thus constitutes an invaluable help in making the nonscientist public aware of the genotoxic risk of hospital wastewater and can be applied in a screening approach to chemicals in the environment.     

Genetic damage induced by electronic waste leachates and contaminated underground water in two prokaryotic systems

The inappropriate and unsafe management practices related to disposal and recycling of electronic wastes in Nigeria has led to environmental and underground water contamination. Reports on the level and type of contamination as well as the possible DNA damage effects of this contamination are insufficient. This study evaluated the DNA damaging potential of e-waste simulated and raw leachates, and its contaminated underground water using the SOS chromotest on Escherichia coli PQ37 and the Ames Salmonella fluctuation test on Salmonella typhimurium strains TA98 and TA100, without and with metabolic activation. Physico-chemical parameters of the samples were also analyzed. The result of the Ames test showed induction of base pair substitution and frameshift mutation by the test samples. However, the TA100 was the more responsive strain for the three samples in terms of mutagenic index in the absence and presence of metabolic activation. The SOS chromotest results were in agreement with those of the Ames Salmonella fluctuation test. Nevertheless, the E. coli PQ37 system was slightly more sensitive than the Salmonella assay for detecting genotoxins in the tested samples. Lead, cadmium, manganese, copper, nickel, chromium, arsenic, and zinc contents analyzed in the samples were believed to play a significant role in the observed DNA damage in the microbial assays. The results of this study showed that e-waste simulated and raw leachates, and its contaminated underground water are of potential mutagenic and genotoxic risks to the exposed human populace.     

Genotoxicity of cyanobacterial extracts containing microcystins from Polish water reservoirs as determined by SOS chromotest and comet assay

Toxicity of cyanobacterial blooms, an increasing problem around the world, is connected to the increase in bloom samples containing microcystins, caused by excessive eutrophication of drinking- and recreational water reservoirs. Microcystins are the most common group of cyanobacterial hepatotoxins. In Poland they are produced mainly by the Microcystis genus. The toxicity of microcystins has been well documented, but investigation into their genotoxicity has been insufficient relative to the study of their overall toxicity. Therefore, the aim of this study was the estimation and comparison of the genotoxicity of cyanobacterial extracts with microcystins (CEMs) using the SOS chromotest (bacterial test) with Escherichia coli PQ37 and the comet assay with human lymphocytes. Cyanobacterial bloom samples were collected in the summer months from two Polish water reservoirs, one at Sulejów and one at Jeziorsko. The SOS chromotest, which used prokaryotic cells (without metabolic activation), and the comet assay, which used eukaryotic cells, both indicated the potential genotoxic effect of CEMs. Cyanobacterial extracts caused DNA damage in human lymphocytes in vitro. The maximum level of DNA damage was observed after 12 h incubation with CEMs. The bacterial test indicated a dependence of the degree of CEM genotoxicity, the composition, and the concentration of microcystins in each bloom sample examined with the time of exposure. Differences between the genotoxicity of cyanobacterial extract and the standard microcystin-LR were noticeable. This was probably caused by the interaction of different microcystin variants. The results showed that CEMs from Polish water reservoirs were genotoxic, which was reflected by the stimulation of the SOS repair system in bacterial cells (SOS chromotest) and by the damage induced in DNA in human lymphocytes (comet assay).     

Genotoxicity risk assessment of diversely substituted quinolines using the SOS chromotest

Quinolines are aromatic nitrogen compounds with wide therapeutic potential to treat parasitic and microbial diseases. In this study, the genotoxicity of quinoline, 4‐methylquinoline, 4‐nitroquinoline‐1‐oxide (4‐NQO), and diversely functionalized quinoline derivatives and the influence of the substituents (functional groups and/or atoms) on their genotoxicity were tested using the SOS chromotest. Quinoline derivatives that induce genotoxicity by the formation of an enamine epoxide structure did not induce the SOS response in Escherichia coli PQ37 cells, with the exception of 4‐methylquinoline that was weakly genotoxic. The chemical nature of the substitution (C‐5 to C‐8: hydroxyl, nitro, methyl, isopropyl, chlorine, fluorine, and iodine atoms; C‐2: phenyl and 3,4‐methylenedioxyphenyl rings) of quinoline skeleton did not significantly modify compound genotoxicities; however, C‐2 substitution with α‐, β‐, or γ‐pyridinyl groups removed 4‐methylquinoline genotoxicity. On the other hand, 4‐NQO derivatives whose genotoxic mechanism involves reduction of the C‐4 nitro group were strong inducers of the SOS response. Methyl and nitrophenyl substituents at C‐2 of 4‐NQO core affected the genotoxic potency of this molecule. The relevance of these results is discussed in relation to the potential use of the substituted quinolines. The work showed the sensitivity of SOS chromotest for studying structure–genotoxicity relationships and bioassay‐guided quinoline synthesis. © 2013 Wiley Periodicals, Inc. Environ Toxicol 30: 278–292, 2015.     

Detecting genotoxic activity in industrial effluents using the SOS Chromotest microplate assay

The SOS Chromotest, a cost-effective short-term bacterial genotoxicity screening assay, was performed to appraise its capacity for detecting the presence of soluble genotoxic activity in industrial effluent samples (organic and inorganic chemical plants, metallurgical plants, pulp and paper mills, municipal wastewater treatment plants). An optimized methodology, based on criteria taking into account β-galactosidase activity (the indicator of SOS gene induction), alkaline phosphatase activity (the indicator of cytotoxicity), and two genotoxicity measurement end points (minimum genotoxic concentration and maximum induction factor), was employed to generate reliable results that overcame the potential interferences inherent to complex wastewaters. Of 48 effluent samples tested, 37 (77%) elicited a significant induction of the Escherichia coli PQ37 SOS response. Effluents from inorganic chemical plants and pulp and paper mills displayed the most potent responses, with and without metabolizing enzymes (S9 mix). In general, chemical data available for some wastewaters supported SOS Chromotest positive responses. The genotoxic activity of whole effluents subjected to a 5-day aeration treatment was as high as that of native (unaerated) samples, suggesting that soluble genotoxicants are relatively recalcitrant to oxidation, although reductions in genotoxic activity did occur. This study indicates that the SOS Chromotest is sufficiently sensitive to screen for the presence of soluble DNA-damaging agents in a wide variety of unconcentrated wastewater samples. © 1996 by John Wiley & Sons, Inc.     

Genotoxicity studies on sediments using a modified SOS chromotest

Noting that the inducibility of samples tested with the SOS Chromotest increased with increasing colour development time, a slightly modified Chromotest procedure was developed and applied to six sediment samples from Prince Edward Island. The samples tested by this newly developed short-term genotoxicity test showed weak inducibility expressed by the SOSIP—SOS Inducing Potency. Five of the six samples were activated by the addition of S-9 fraction, commonly used with the Ames/Microsome test. Only one of the samples showed toxic activity by the Microtox test.     

Comparative assessment of the SOS Chromotest kit and the Mutatox test with the Salmonella plate incorporation (Ames test) and fluctuation tests for screening genotoxic agents

Genuine needs for rapid, simple, and cost-efficient biotesting procedures to screen an ever-increasing number of chemicals and environmental samples are making the search for such assays a constant endeavor. With respect to genotoxicity screening, we compared, in this study, the performance of two novel assays (Vibrio fischeri M169 Mutatox? assay and the Escherichia coli PQ37 SOS Chromotest kit assay) with two well-established Ames testing procedures (plate incorporation and fluctuation assays). Testing material included 14 chemicals (10 potentially directly acting and 4 indirectly acting compounds) reflecting different chemical classes (2 inorganics, 2 pesticides, 2 halogenated hydrocarbons, 2 alkylating agents, 2 aromatic amines, 1 chlorophenol, and 3 polycyclic aromatic hydrocarbons). Comparative assessment criteria included (1) interprocedural agreement in detecting presence or absence of genotoxicity, (2) accuracy in being able to recognize animal (non)carcinogens, and (3) sensitivity (detection of lowest actively genotoxic concentration). In terms of qualitative responses, both the SOS Chromotest (86% agreement) and Mutatox assays (93% agreement) were good predictors of the Ames testing mutagenicity. For their capability to correctly discriminate between (non)carcinogens, accuracy was 82% (9 of 11 chemicals) for Mutatox, 73% (8 of 11 chemicals) for Ames testing, and 64% (7 of 11 chemicals) for the SOS Chromotest. In general, the Salmonella-based assays proved more sensitive (6 times out of 9 chemicals) than the Mutatox (3 times out of 9 chemicals) and the SOS Chromotest (never more sensitive). Overall, this study demonstrates reliable performances by both the SOS Chromotest and Mutatox for chemical genotoxicity screening when results are referenced to the well-validated Ames assay. Although additional comparative data with other chemicals will be required, it appears likely that these more practical and cost-efficient procedures can be presently useful to screen genotoxic activity of various xenobiotics and environmental samples. © 1994 by John Wiley & Sons, Inc..     

Genotoxicity of 22 pesticides in microtitration SOS chromotest

The authors adapted microtitration techniques to the SOS Chromotest, and thereby established a simple and reliable modified genotoxicity test: the Microtitration SOS Chromotest. This test employs microtitration techniques and photometric analysis with numerical readout. These data are integrated into the computerized data processing program Statistical Analysis System to obtain genotoxicity and toxicity results of a chemical or chemical mixture within 16 h. In order to test the applicability of the new system, the genotoxicity and toxicity of 22 pesticides were studied. A two-sample t test was employed to determine the level of significance (p < 0.05). Nine of the pesticides were found to induce the SOS response in Escherichia coli cells. Their relative degrees of induction based on SOS inducing potency values are as follows: captafol > captan > folpet > dinoseb > ferbam > linuron > alachlor > phosmet > cacodylic acid. The addition of rat liver S9 mix does not transform the nongenotoxic pesticides tested into genotoxic forms but significantly decreases the inducing ability of most positive pesticides. The Microtitration SOS Chromotest is rapid and efficient in providing evidence for decision-making related to cleanup of chemical spills and discharges where time is a critical factor. This method maintains its high accuracy and sensitivity compared with conventionally used assays. The studies of pesticide genotoxicity using this test confirm the applicability, reliability, and sensitivity of the Microtitration SOS Chromotest as a simple, efficient, and rapid genotoxicity prescreening system as well as an excellent research tool for genotoxic mechanism studies.     

No evidence of the genotoxic potential of gold,silver, zinc oxide and titanium dioxide nanoparticles in the SOS chromotest

Gold nanoparticles (Au NPs), silver nanoparticles (Ag NPs), zinc oxide nanoparticles (ZnO NPs) and titanium dioxide nanoparticles (TiO₂ NPs) are widely used in cosmetic products such as preservatives, colorants and sunscreens. This study investigated the genotoxicity of Au NPs, Ag NPs, ZnO NPs and TiO₂ NPs using the SOS chromotest with Escherichia coli PQ37. The maximum exposure concentrations for each nanoparticle were 3.23 mg l^–1 for Au NPs, 32.3 mg l^–1 for Ag NPs and 100 mg l^–1 for ZnO NPs and TiO₂ NPs. Additionally, in order to compare the genotoxicity of nanoparticles and corresponding dissolved ions, the ions were assessed in the same way as nanoparticles. The genotoxicity of the titanium ion was not assessed because of the extremely low solubility of TiO₂ NPs. Au NPs, Ag NPs, ZnO NPs, TiO₂ NPs and ions of Au, Ag and Zn, in a range of tested concentrations, exerted no effects in the SOS chromotest, evidenced by maximum IF (IFmax) values of below 1.5 for all chemicals. Owing to the results, nanosized Au NPs, Ag NPs, ZnO NPs, TiO₂ NPs and ions of Au, Ag and Zn are classified as non‐genotoxic on the basis of the SOS chromotest used in this study. To the best of our knowledge, this is the first study to evaluate the genotoxicity of Au NPs, Ag NPs, ZnO NPs and TiO₂ NPs using the SOS chromotest. Copyright © 2012 John Wiley & Sons, Ltd.     

Testing of SOS induction of artificial polycyclic musk fragrances in E. coli PQ37 (SOS chromotest)

Synthetic fragrances are widespread in the environment. Residues were found in animals, human tissues and breast milk. Therefore, six artificial polycyclic musk fragrances—Galaxolide, Tonalide, Celestolide, Phantolide, Cashmeran and Traseolide—were tested for SOS induction using the Escherichia coli PQ37 genotoxicity assay (SOS chromotest) in the presence (+S9) and absence (−S9) of an exogenous metabolizing system. All compounds tested exhibited no SOS inducing potency with the SOS chromotest. These results could be rated as one indicator of the biological inactivity of this group of compounds with respect to genotoxicity.     

Mutagenicity of Hypericum lysimachioides extracts

Hypericum (Hypericaceae) species are extensively used in several fields such as traditional medicine, food and crop protection. Despite its usage in many fields, the identification of the genotoxic potential of this herb is still incomplete. In this study, we evaluated genotoxic effects of the petroleum ether, hexane, ethyl acetate, and methanol extract of Hypericum lysimachioides Boiss. var. lysimachioides by Ames Salmonella/microsome test and SOS chromotest. The mutagenic activity of Hypericum lysimachioides var. lysimachioides extracts was investigated by using Salmonella typhimurium strains TA98 and TA100 and also the SOS chromotest with Escherichia coli PQ37 strain, with or without S9 metabolic activation. In this initial report we demonstrated that all extracts of H. lysimachioides var. lysimachioides showed significant mutagenic activity on both strains of Salmonella either with or without S9 mixture. No mutagenicity was found in the SOS chromotest either with or without S9 mixture. These results indicate a significant mutagenicity of the petroleum ether, hexane, ethyl acetate and methanol extracts of Hypericum lysimachioides var. lysimachioides in vitro. It can be suggested that quercetin and flavonol or their synergistic effects may be main mutagenic agents in the photopharmaceuticals Hypericum lysimachioides var. lysimachioides extract.     

The Comet Assay with Multiple Mouse Organs: Comparison of Comet Assay Results and Carcinogenicity with 208 Chemicals Selected from the IARC Monographs and U.S. NTP Carcinogenicity Database

ABSTRACT

The comet assay is a microgel electrophoresis technique for detecting DNA damage at the level of the single cell. When this technique is applied to detect genotoxicity in experimental animals, the most important advantage is that DNA lesions can be measured in any organ, regardless of the extent of mitotic activity. The purpose of this article is to summarize the in vivo genotoxicity in eight organs of the mouse of 208 chemicals selected from International Agency for Research on Cancer (IARC) Groups 1, 2A, 2B, 3, and 4, and from the U.S. National Toxicology Program (NTP) Carcinogenicity Database, and to discuss the utility of the comet assay in genetic toxicology.

Alkylating agents, amides, aromatic amines, azo compounds, cyclic nitro compounds, hydrazines, halides having reactive halogens, and polycyclic aromatic hydrocarbons were chemicals showing high positive effects in this assay. The responses detected reflected the ability of this assay to detect the fragmentation of DNA molecules produced by DNA single strand breaks induced chemically and those derived from alkali-labile sites developed from alkylated bases and bulky base adducts. The mouse or rat organs exhibiting increased levels of DNA damage were not necessarily the target organs for carcinogenicity. It was rare, in contrast, for the target organs not to show DNA damage. Therefore, organspecific genotoxicity was necessary but not sufficient for the prediction of organ-specific carcinogenicity. It would be expected that DNA crosslinkers would be difficult to detect by this assay, because of the resulting inhibition of DNA unwinding. The proportion of 10 DNA crosslinkers that was positive, however, was high in the gastrointestinal mucosa, stomach, and colon, but less than 50% in the liver and lung. It was interesting that the genotoxicity of DNA crosslinkers could be detected in the gastrointestinal organs even though the agents were administered intraperitoneally.

Chemical carcinogens can be classified as genotoxic (Ames test-positive) and putative nongenotoxic (Ames test-negative) carcinogens. The Ames test is generally used as a first screening method to assess chemical genotoxicity and has provided extensive information on DNA reactivity. Out of 208 chemicals studied, 117 are Ames test-positive rodent carcinogens, 43 are Ames test-negative rodent carcinogens, and 30 are rodent noncarcinogens (which include both Ames test-positive and negative noncarcinogens). High positive response ratio (110/117) for rodent genotoxic carcinogens and a high negative response ratio (6/30) for rodent noncarcinogens were shown in the comet assay. For Ames test-negative rodent carcinogens, less than 50% were positive in the comet assay, suggesting that the assay, which detects DNA lesions, is not suitable for identifying nongenotoxic carcinogens. In the safety evaluation of chemicals, it is important to demonstrate that Ames test-positive agents are not genotoxic in vivo. This assay had a high positive response ratio for rodent genotoxic carcinogens and a high negative response ratio for rodent genotoxic noncarcinogens, suggesting that the comet assay can be used to evaluate the in vivo genotoxicity of in vitro genotoxic chemicals. For chemicals whose in vivo genotoxicity has been tested in multiple organs by the comet assay, published data are summarized with unpublished data and compared with relevant genotoxicity and carcinogenicity data.

Because it is clear that no single test is capable of detecting all relevant genotoxic agents, the usual approach should be to carry out a battery of in vitro and in vivo tests for genotoxicity. The conventional micronucleus test in the hematopoietic system is a simple method to assess in vivo clastogenicity of chemicals. Its performance is related to whether a chemical reaches the hematopoietic system. Among 208 chemicals studied (including 165 rodent carcinogens), 54 rodents carcinogens do not induce micronuclei in mouse hematopoietic system despite the positive finding with one or two in vitro tests. Forty-nine of 54 rodent carcinogens that do not induce micronuclei were positive in the comet assay, suggesting that the comet assay can be used as a further in vivo test apart from the cytogenetic assays in hematopoietic cells. In this review, we provide one recommendation for the in vivo comet assay protocol based on our own data.     

Genotoxicity of nitrosated red wine and of the nitrosatable phenolic compounds present in wine: Tyramine, quercetin and malvidine-3-glucoside

Phenolic compounds and biogenic amines are known to be present in some foodstuffs which become directly genotoxic after nitrosation in vitro. Red wine has previously been shown to be genotoxic and this activity has been attributed mainly to flavonoids. Besides flavonoids, red wine contains a multiplicity of compounds, including biogenic amines. Using the Ames assay and the SOS chromotest, this study has shown that red wine and some of the nitrosatable molecules present in wine become directly genotoxic on nitrosation in vitro: these include the phenolic molecules tyramine, quercetin and malvidine-3-glucoside, whereas phenylethylamine and histamine were negative on nitrosation. Interestingly, quercetin had been predicted to be negative after nitrosation, using the CASE methodology. The concentrations of these three positive nitrosatable compounds in wine were determined by HPLC. Comparison of these concentrations and their respective levels of genotoxicity suggests that the genotoxicity after nitrosation is probably attributable to other molecules. It is also possible that synergistic effects may occur between various nitrosatable compounds in wine.     

Evaluation of the GADD45α‐GFP GreenScreen HC assay for rapid and reliable in vitro early genotoxicity screening

Twenty‐two of Galderma's proprietary compounds were tested in the GADD45α‐GFP ‘GreenScreen HC’ assay (GS), the SOS‐ChromoTest and the Mini‐Ames to evaluate GSs performance for early genotoxicity screening purposes. Forty more characterized compounds were also tested, including antibiotics: metronidazole, clindamycin, tetracycline, lymecycline and neomycin; and catecholamines: resorcinol mequinol, hydroquinone, one aneugen carbendazim, one corticoid dexamethasone, one peroxisome proliferator‐activated receptor rosiglitazone, one pesticide carbaryl and two further proprietary molecules with in vitro genotoxicity data. With proprietary molecules, this study concluded that the GS renders the SOS‐ChromoTest obsolete for in vitro screening. The GS confirmed all results of the Mini‐Ames test (100% concordance). Compared with the micronucleus test, the GS showed a concordance of 82%. With known compounds, the GS ranked the potency of positive results for catecholamines in accordance with other genotoxicity tests and showed very reproducible results. It confirmed positive results for carbendazim, for tetracycline antibiotics and for carbaryl. The GS produced negative results for metronidazole, a nitroreduction‐specific bacterial mutagen, for dexamethasone (a non‐genotoxic apoptosis inducer), for rosiglitazone (a GADD45γ promoter inducer) and for clindamycin and neomycin (inhibitors of macromolecular synthesis in bacteria). As such, the GS appears to be a reproducible, robust, specific and sensitive test for genotoxicity screening. Copyright © 2012 John Wiley & Sons, Ltd.     

A comparative study of five nitro musk compounds for genotoxicity in the SOS chromotest and Salmonella mutagenicity

Five nitro musk compounds widely used in cosmetics and detergents were examined for DNA-damaging and mutation-inducing properties. For this purpose two short-time assays were used, the SOS chromotest and the Salmonella/mammalian microsome test. Musk ambrette showed mutagenicity in Salmonella typhimurium TA 100 requiring metabolic activation by rat liver postmitochondrial supernatant (S9) but it lacked mutagenicity in the absence of S9 and genotoxicity in the SOS chromotest. Musk xylene, musk ketone, musk moskene and musk tibetene showed neither mutagenicity nor genotoxicity in the presence and absence of S9.     

Biochemical and genotoxic effects in the vicinity of a pulp mill discharge

Sediment and water samples were taken from five sites in Thunder Bay, one upstream (control) and four downstream locations from a bleached kraft pulp mill. Biochemical effects were examined by estimating the carbohydrate content and enzymatic activities of alkaline phosphatase, cellulase, and dehydrogenase in the sediment. Genotoxicity and toxicity of sediment and water were assessed by the SOS Chromotest, although liver microsomal samples were not used to screen for progenotoxic substances. Sediment and water samples were also analyzed for resin and fatty acids, which indicate the degree of effluent contamination. Significant differences in enzyme activity and carbohydrate content were found between sites. Genotoxic values were obtained for downstream water samples for most of the sampling months, however, the sediment only showed genotoxic activity in the July and October samples. The study showed that there are substances causing genotoxic and biochemical effects in the Kaministiquia River, Ontario. © 1994 by John Wiley & Sons, Inc..     

Evaluating genotoxicity associated with microcystin-LR and its risk to source water safety in Meiliang Bay, Taihu Lake

In recent years cyanobacteria blooms have become a severe problem in Taihu Lake, a large shallow eutrophic lake in China. Microcystins produced by certain genera of cyanobacteria can affect public health in this area because of their acute and chronic toxic effects. In this study, samples of cyanobacteria were collected and extracted by two solvent systems. The extracts were tested with three short-term genotoxicity assays, the ara test, the Ames test, and the SOS/umu test. In addition, temporal variation in the concentrations of microcystin-LR in the water samples was determined and monitored by an ELISA assay. Then the concentration of microcystin-LR in the drinking water was estimated. The risk of microcystin-LR exposure by drinking water was assessed according to tolerable daily intake (TDI). The three genotoxicity assays showed negative results regardless of the solvent system used, and there were clear inconsistencies in the spatiotemporal profiles of genotoxic potential and microcystin concentrations in Taihu Lake. Risk assessment showed that the drinking water from Taihu Lake was not safe from the end of July to the beginning of November because of a high concentration of microcystin-LR. Our study indicated the drinking water from Taihu Lake posed a risk because of the microcystin-LR, although it was neither genotoxic nor associated with genotoxicity of the lake water.     

A comparative study, with 40 chemicals, of the efficiency of the Salmonella assay and the SOS chromotest (kit procedure)

A comparison was made, for 40 compounds belonging to different chemical classes, of the mutagenicity as measured by the Salmonella assay and of the SOS-inducing potency as measured by the SOS chromotest kit procedure. It was found that most (78%) of the chemicals described as mutagens/carcinogens (14 compounds) were detected with a simplified Ames test procedure, using 3 strains (TA 97, TA 98, TA 100) and 3 concentrations of the tested material. The SOS chromotest, carried out following the recommendations of the commercially available kits, revealed that only 4 Ames test-positive compounds were mutagenic towards E. coli strain PQ 37.     

Evaluation of the antimutagenic,antigenotoxic, and antioxidant activities of Eriobotrya japonica leaves

Abstract

Context: The leaves of Eriobotrya japonica (Thunb.) Lindl. (Rosaceae) are used in traditional medicine to treat inflammatory diseases. However, information about the antigenotoxic and antioxidant properties of its leaves remains to be elucidated.

Objective: The objective of this work was to evaluate the mutagenic/antimutagenic, genotoxic/antigenotoxic, and antioxidant potentials of aqueous and total oligomers flavonoid (TOF) extracts from E. japonica.

Materials and methods: The mutagenic/antimutagenic and genotoxic/antigenotoxic potentials of extracts (50, 250, and 500?µg/plate) were evaluated, respectively, by the Ames test with 48?h incubation and the SOS chromotest test with 2?h incubation. The antioxidant capacity of these extracts (ranging from 50 to 700?µg/mL) was tested using xanthine/xanthine oxidase and the deoxyribose assays.

Results: Eriobotrya japonica extracts showed neither mutagenic nor genotoxic effect. The highest protective effect against methyl methanesulfonate and 2-aminoanthracene was obtained in the presence of aqueous extract, with IC₅₀ values of 80 and 140?µg/plate, respectively, against S. typhimurium TA104. Moreover, this extract (500?µg/plate) was also able to reduce significantly the genotoxicity induced by nitrofurantoin and aflatoxin B1 with IC₅₀ values of 140 and 240?µg/assay, respectively. Likewise, aqueous and TOF extracts inhibited xanthine oxidase and superoxide anion formation with IC₅₀ values ranging from 45 to 95 and from 70 to 90?µg/mL, respectively. However, TOF extract is more efficient in inhibiting hydroxyl radical and chelating iron ion with IC₅₀ values of 140 and 400?µg/mL, respectively, when compared with the aqueous extract.

Conclusion: Eriobotrya japonica prevents the genotoxicity of some carcinogenic substances probably thanks to its antioxidant capacities.