Genotoxicity testing of different types of beverages in the Drosophila wing Somatic Mutation And Recombination Test

In vivo assessment of the toxic impact of exposure to magnetic iron oxide nanoparticles (IONPs) using Drosophila melanogaster

Iron oxide nanoparticles (IONPs) have useful properties, such as strong magnetism and compatibility with living organisms which is preferable for medical applications such as drug delivery and imaging. However, increasing use of these materials, especially in medicine, has raised concerns regarding potential risks to human health. In this study, IONPs were coated with silicon dioxide (SiO2), citric acid (CA), and polyethylenimine (PEI) to enhance their dispersion and biocompatibility. Both coated and uncoated IONPs were assessed for genotoxic effects on Drosophila melanogaster. Results showed that uncoated IONPs induced genotoxic effects, including mutations and recombinations, while the coated IONPs demonstrated reduced or negligible genotoxicity. Additionally, bioinformatic analyses highlighted potential implications of induced recombination in various cancer types, underscoring the importance of understanding nanoparticle-induced genomic instability. This study highlights the importance of nanoparticle coatings in reducing potential genotoxic effects and emphasizes the necessity for comprehensive toxicity assessments in nanomaterial research.

Human Hazard Assessment Using Drosophila Wing Spot Test as an Alternative In Vivo Model for Genotoxicity Testing-A Review

Genomic instability, one of cancer's hallmarks, is induced by genotoxins from endogenous and exogenous sources, including reactive oxygen species (ROS), diet, and environmental pollutants. A sensitive in vivo genotoxicity test is required for the identification of human hazards to reduce the potential health risk. The somatic mutation and recombination test (SMART) or wing spot test is a genotoxicity assay involving Drosophila melanogaster (fruit fly) as a classical, alternative human model. This review describes the principle of the SMART assay in conjunction with its advantages and disadvantages and discusses applications of the assay covering all segments of health-related industries, including food, dietary supplements, drug industries, pesticides, and herbicides, as well as nanoparticles. Chemopreventive strategies are outlined as a global health trend for the anti-genotoxicity of interesting herbal extract compounds determined by SMART assay. The successful application of Drosophila for high-throughput screening of mutagens is also discussed as a future perspective.

Mutagenic and recombinogenic assessment of widely used pesticides on Drosophila melanogaster

The mutagenic potential of selected widely used pesticides: p,p'-dichlorodiphenyltrichloroethane (DDT); fenitrothion; propoxur; deltamethrin, bifenthrin; imidacloprid and thiametoxam was assessed using the wing spot test. Third-instar larvae of standard Drosophila melanogaster cross (ST), trans-heterozygous for the third chromosome recessive markers, multiple wing hairs (mwh) and flare (flr3) were chronically exposed to test compounds. Feeding ended with pupation of the surviving larvae. Genetic changes induced in somatic cells of the wing’s imaginal discs, mutant spots observed in marker-heterozygous (MH) and balancer-heterozygous (BH) flies were compared using the wing spot test, to estimate the genotoxic effects of these pesticides. In conclusion, exposure to 30 mg/mL deltamethrin, 40 mg/mL imidacloprid, 100 µg/mL DDT showed mutagenic and recombinagenic effects in the Drosophila wing spot test. In addition the results of chronic treatments performed at high doses showed mutagenic and recombinagenic effects in both genotypes

An insight into the genotoxicity assessment studies in dipterans

The dipterans have been widely utilized in genotoxicity assessment studies. Short life span, easy maintenance, production of large number of offspring in a single generation and the tissues with appropriate cell populations make these flies ideal for studies associated to developmental biology, diseases, genetics, genetic toxicology and stress biology in the group. Moreover, their cosmopolitan presence makes them suitable candidate for ecological bio-monitoring. An attempt has been made in the present review to reveal the significance of dipteran flies for assessing alterations in genetic content through various genotoxicity biomarkers and to summarize the gradual advancement in these studies. Recent studies on genotoxicity assays in dipterans have opened up a broader perspective for DNA repair related mechanistic studies, pre-screening of chemicals and environmental bio-monitoring. Studies in dipterans, other than Drosophila may be helpful in using them as an alternative model system for assessment of genotoxicity, especially at the gene level and further extension of these studies give a future insight to develop new strategies for maintaining environment friendly limits of the toxicants.

Antibacterial activities of medicinal plants used in Mexican traditional medicine

ETHNOPHARMACOLOGICAL RELEVANCE

We provide an extensive summary of the in vitro antibacterial properties of medicinal plants popularly used in Mexico to treat infections, and we discuss the ethnomedical information that has been published for these species.

MATERIALS AND METHODS

We carried out a bibliographic investigation by analyzing local and international peer-reviewed papers selected by consulting internationally accepted scientific databases from 1995 to 2014. We provide specific information about the evaluated plant parts, the type of extracts, the tested bacterial strains, and the inhibitory concentrations for each one of the species. We recorded the ethnomedical information for the active species, as well as their popular names and local distribution. Information about the plant compounds that has been identified is included in the manuscript. This review also incorporates an extensive summary of the available toxicological reports on the recorded species, as well as the worldwide registries of plant patents used for treating bacterial infections. In addition, we provide a list with the top plant species with antibacterial activities in this review RESULTS: We documented the in vitro antibacterial activities of 343 plant species pertaining to 92 botanical families against 72 bacterial species, focusing particularly on Staphylococcus aureus, Mycobacterium tuberculosis, Escherichia coli and Pseudomonas aeruginosa. The plant families Asteraceae, Fabaceae, Lamiaceae and Euphorbiaceae included the largest number of active species. Information related to popular uses reveals that the majority of the plants, in addition to treating infections, are used to treat other conditions. The distribution of Mexican plants extended from those that were reported to grow in just one state to those that grow in all 32 Mexican states. From 75 plant species, 225 compounds were identified. Out of the total plant species, only 140 (40.57%) had at least one report about their toxic effects. From 1994 to July 2014 a total of 11,836 worldwide antibacterial patents prepared from different sources were recorded; only 36 antibacterial patents from plants were registered over the same time period. We offered some insights on the most important findings regarding the antibacterial effects, current state of the art, and research perspectives of top plant species with antibacterial activities in vitro.

CONCLUSIONS

Studies of the antibacterial in vitro activity of medicinal plants popularly used in Mexico to treat infections indicate that both the selection of plant material and the investigation methodologies vary. Standardized experimental procedures as well as in vivo pharmacokinetic studies to document the effectiveness of plant extracts and compounds are necessary. This review presents extensive information about the medicinal plants possessing antibacterial activity that has been scientifically studied and are popularly used in Mexico. We anticipate that this review will be of use for future studies because it constitutes a valuable information tool for selecting the most significant plants and their potential antibacterial properties.

Cancer Prevention and Health Benefices of Traditionally Consumed Borago officinalis Plants

Nowadays, healthy eating is increasing the demand of functional foods by societies as sources of bioactive products with healthy qualities. For this reason, we tested the safety of the consumption of Borago officinalis L. and its main phenolic components as well as the possibility of its use as a nutraceutical plant to help in cancer prevention. The in vivo Drosophila Somatic Mutation and Recombination Test (SMART) and in vitro HL-60 human cell systems were performed, as well-recognized methods for testing genotoxicity/cytotoxicity of bioactive compounds and plant products. B. officinalis and the tested compounds possess antigenotoxic activity. Moreover, B. officinalis wild type cultivar exerts the most antigenotoxic values. Cytotoxic effect was probed for both cultivars with IC50 values of 0.49 and 0.28 mg · mL(-1) for wild type and cultivated plants respectively, as well as their constituent rosmarinic acid and the assayed phenolic mixture (IC50 = 0.07 and 0.04 mM respectively). B. officinalis exerts DNA protection and anticarcinogenic effects as do its component rosmarinic acid and the mixture of the main phenolics presented in the plant. In conclusion, the results showed that B. officinalis may represent a high value plant for pleiotropic uses and support its consumption as a nutraceutical plant.

Genotoxic, antigenotoxic and phytochemical assessment of Terminalia actinophylla ethanolic extract

Terminalia actinophylla has been used for anti-diarrheic and haemostatic purposes in Brazil. The fly spot data obtained after exposure of marker-heterozygous Drosophila melanogaster larvae to T. actinophylla ethanolic extract (TAE) in the standard (ST) and high bioactivation (HB) crosses revealed that TAE did not induce any statistically significant increment in any spot categories. Differences between the two crosses are related to cytochrome P450 (CYPs) levels. In this sense, our data pointed out the absence of TAE-direct and indirect mutagenic and recombinagenic action in the Somatic Mutation and Recombination Test (SMART). When the anti-genotoxicity of TAE was analyzed, neither mitomycin C (MMC) nor ethylmethanesulfonate (EMS) genotoxicity was modified by the post-exposure to TAE, which suggests that TAE has no effect on the mechanisms involved in the processing of the lesions induced by both genotoxins. In the mwh/flr(3) genotype, co-treatment with TAE may lead to a significant protection against the genotoxicity of MMC and a weak but significant effect in the toxic genetic action of EMS. The overall findings suggested that the favorable modulations by TAE could be, at least in part, due to its antioxidative potential.

Detection of transfluthrin and metofluthrin genotoxicity in the ST cross of the Drosophila Wing Spot Test

In this study, different concentrations of transfluthrin and metofluthrin have been assayed for genotoxicity by using the Wing Spot Test on Drosophila melanogaster. Standard cross was used in the experiment. Third-instar larvae that were trans-heterozygous for the two genetic markers mwh and flr(3) were treated at different concentrations (0.0103mgmL(-1), 0.103mgmL(-1) for transfluthrin and 6μgmL(-1), 60μgmL(-1) for metofluthrin) of the test compounds. Feeding ended with pupation of the surviving larvae and the genetic changes induced in somatic cells of the wing's imaginal discs lead to the formation of mutant clones on the wing blade. Results indicated that two experimental concentrations of transfluthrin and 60μgmL(-1) metofluthrin showed mutagenic and recombinogenic effects in both the marker-heterozygous (MH) flies and the balancer-heterozygous (BH) flies.

Antioxidant and anti-inflammatory effects of Urtica pilulifera extracts in type 2 diabetic rats

ETHNOPHARMACOLOGICAL RELEVANCE

"Urtica pilulifera has been traditionally used in Egyptian system as an herbal remedy to be a diuretic, antiasthmatic, anti-inflammatory, hypoglycemic, hemostatic, antidandruff and astringent"

AIM OF THE STUDY

To evaluate the potential effects of ethyl acetate (EA), chloroform (CHLOR) and hexane (HEXA) extracts of Urtica piluliferaas oral anti-diabetic agents as well as to evaluate their possible anti-oxidant and anti-inflammatory effects in type 2 diabetic rat model.

MATERIAL AND METHODS

Type 2 diabetes was induced by a high fat diet and low dose streptozotocin (STZ). Diabetic adult male albino rats were allocated into groups and treated according to the following schedule; Pioglitazone HCL (PIO), EA, CHLOR and HEXA extracts of Urtica pilulifera at two doses of 250 and 500 mg/kg were used. In addition, a normal control group and a diabetic control one were used for comparison. Blood glucose, insulin resistance, antioxidant enzymes, 8-hydroxy-2-deoxyguanosine (8-OHdG) as well as C-reactive protein and tumor necrosis factor-α levels were evaluated.

RESULTS

EA and CHLOR extracts of Urtica pilulifera exhibited a significant hypoglycemia associated with antioxidant and anti-inflammatory effects in diabetic rats; however, HEXA extract showed no beneficial effect. These activities are responsible, at least partly, for improvements that have been seen in hyperglycemia and insulin resistance of diabetic rats.

CONCLUSION

Our results encourage the traditional use of Urtica pilulifera extract as an antioxidant and anti-inflammatory agent as an additional therapy of diabetes.

Genotoxic evaluation of two oral antidiabetic agents in the Drosophila wing spot test

In this study, two sulfonylureas—glimepiride and glipizide—commonly used in type 2 diabetes mellitus were investigated for genotoxicity in the Drosophila wing spot test. For this purpose, three-day-old transheterozygous larvae were treated with three mutagenic compounds, and the results obtained were compared with the control group. Mutational or recombinogenic changes were recorded in two recessive genes— multiple wing hairs ( mwh) and flare ( flr3). Two recessive markers were located on the left arm of chromosome 3, mwh in map position 0.3, and flare-3 ( flr3) at 38.8, while the centromere was located in position 47.7. Wing spot tests are targeted on the loss of heterozygosity, which may be grounded in different genetic mechanisms such as mutation, mitotic recombination, deletion, half-translocation, chromosome loss, or nondisjunction. Genetic changes formatting in somatic cells of the imaginal discs cause nascence different mutant cloning in different body parts of adult flies. Our in vivo experiments demonstrated that glimepiride and glipizide show the genotoxicity, which is especially dependent on homologous somatic recombination.

Evaluation of potential genotoxicity of five food dyes using the somatic mutation and recombination test

In this study, different concentrations of five food dyes (amaranth, patent blue, carminic acid, indigotine and erythrosine) have been evaluated for genotoxicity in the Somatic Mutation and Recombination Test (SMART) of Drosophila melanogaster. Standard cross was used in the experiment. Larvae including two linked recessive wing hair mutations were chronically fed at different concentrations of the test compounds in standard Drosophila Instant Medium. Feeding ended with pupation of the surviving larvae. Wings of the emerging adult flies were scored for the presence of spots of mutant cells which can result from either somatic mutation or somatic recombination. For the evaluation of genotoxic effects, the frequencies of spots per wing in the treated series were compared to the control group, which was distilled water. The present study shows that carminic acid and indigotine demonstrated negative results while erythrosine demonstrated inconclusive results. In addition 25 mg mL(-1) concentration of patent blue and 12.5, 25 and 50 mg mL(-1) concentrations of amaranth demonstrated positive results in the SMART.

Chemical composition and in vitro cytotoxic, genotoxic effects of essential oil from Urtica dioica L

The aim of this study was to determine the chemical composition of Urtica dioica essential oil, and to evaluate its cytotoxic and genotoxic effects, using cytogenetic tests such as the cytokinesis-block micronucleus assay and chromosomal aberration analysis in human lymphocyte cultures in vitro. GC-MS analysis of U. dioica essential oil identified 43 compounds, representing 95.8% of the oil. GC and GC-MS analysis of the essential oil of U. dioica revealed that carvacrol (38.2%), carvone (9.0%), naphthalene (8.9%), (E)-anethol (4.7%), hexahydrofarnesyl acetone (3.0%), (E)-geranyl acetone (2.9%), (E)-β-ionone (2.8%) and phytol (2.7%) are the main components, comprising 72.2% of the oil. A significant correlation was found between the concentration of essential oil and the following: chromosomal aberrations, micronuclei frequency, apoptotic cells, necrotic cells, and binucleated cells.

Role of citrus juices and distinctive components in the modulation of degenerative processes: genotoxicity, antigenotoxicity, cytotoxicity, and longevity in Drosophila

It is well established that breakfast beverages contain high quantities of Citrus juices. The purpose of the present study was to assess the nutraceutical value of orange and lemon juices as well as two of their active compounds: hesperidin and limonene. Indicator assays were performed at three levels to evaluate different biological health promoter activities: (i) determination of the safety and DNA-damage protecting ability against free radicals by using the somatic mutation and recombination test (SMART) in Drosophila melanogaster, (ii) study of the modulating role for life span in Drosophila melanogaster, and (iii) measurement of the cytotoxic activity against the human tumor cell line HL60. The highest concentrations assayed for lemon juice and limonene (50% v/v and 0.73 mM, respectively) showed genotoxic activity as evidenced from SMART. Orange and lemon juices as well as hesperidin and limonene exhibit antigenotoxic activity against hydrogen peroxide used as an oxidative genotoxin. Life-span experiments revealed that the lower concentrations of orange juice, hesperidin, and limonene exerted a positive influence on the life span of Drosophila. Finally all substances showed cytotoxic activity, with hesperidin being least active. Taking into account the safety, antigenotoxicity, longevity, and cytotoxicity data obtained in the different assays, orange juice may be a candidate as a nutraceutical food as it (1) is not genotoxic, (2) is able to protect DNA against free radicals, and (3) inhibits growth of tumor cells.

Final Report of the Cosmetic Ingredient Review Expert Panel Amended Safety Assessment of Calendula officinalis—Derived Cosmetic Ingredients

Calendula officinalis extract, C officinalis flower, C officinalis flower extract, C officinalis flower oil, and C officinalis seed oil are cosmetic ingredients derived from C officinalis. These ingredients may contain minerals, carbohydrates, lipids, phenolic acids, flavonoids, tannins, coumarins, sterols and steroids, monoterpenes, sesquiterpenes, triterpenes, tocopherols, quinones, amino acids, and resins. These ingredients were not significantly toxic in single-dose oral studies using animals. The absence of reproductive/developmental toxicity was inferred from repeat-dose studies of coriander oil, with a similar composition. Overall, these ingredients were not genotoxic. They also were not irritating, sensitizing, or photosensitizing in animal or clinical tests but may be mild ocular irritants. The Cosmetic Ingredient Review (CIR) Expert Panel concluded that these ingredients are safe for use in cosmetics in the practices of use and concentration given in this amended safety assessment.

Genotoxic evaluation of antiepileptic drugs by Drosophila somatic mutation and recombination test

The study examines the potential genotoxicity of three antiepileptic drugs (phenytoin sodium, pregabalin, gabapentin) using the wing somatic mutation and recombination test (SMART) in Drosophila melanogaster. Trans-heterozygous (two genetic markers mwh and flr) third-instar larvae of D. melanogaster were treated with different concentrations of the test compounds. A positive correlation was observed between total mutations and the number of wings with morphologically detectable mutations. The observed mutations were classified according to size and type of mutation per wing. Phenytoin clearly increased the frequency of total spots at all concentrations above 1.25 microg/ml. Gabapentin also increased the frequency of total spots at concentrations of 40 and 80 microg/ml. This study shows that phenytoin and gabapentin have genotoxic effects according to the SMART test; however, pregabalin displays lower genotoxicity in the SMAR assay when compared with the other two antiepileptics. The results also show that all AED concentrations lower the survival rate of the flies.

Effect of different Thai traditional processing of various hot chili peppers on urethane-induced somatic mutation and recombination in Drosophila melanogaster: Assessment of the role of glutathione transferase activity

Four different Thai traditional chili peppers, namely bird pepper (Capsicum frutescens), red chili spur peppers (Capsicum annuum), green bell peppers and sweet pepper (C. annuum) were investigated for their antimutagenic properties. Each chili was prepared in three formulations commonly used for chili food processing; raw paste (chili ground in water), pickled in vinegar or stir-fried in palm oil. Each sample was tested for its antimutagenic effect against urethane by using the somatic mutation and recombination of wing hair of Drosophila melanogaster as an indicator. Three-day-old larvae, trans-heterozygous for two genetic markers, multiple wing hairs mwh and orrigon (ORR;flr3), were exposed to urethane alone or in combination with each chili formulation. The various processing methods for chilies differentially extracted the antimutagenic chili components. The specific chili as well as the method of processing influenced the observed antimutagenic properties against urethane. This suggested each chili contains a unique complex mixture of many antimutagens. Co-treatment and pre-treatment experiments showed that both direct and indirect protective mechanisms are involved in an 'activation' process to give antimutagenesis effects. An association between antigenotoxicity and glutathione transferase activity could not be established.

Genotoxicity and anti-genotoxicity of some traditional medicinal herbs

Six herbal infusions used worldwide (Matricaria chamomilla, Tilia cordata, Mentha piperita, Mentha pulegium, Uncaria tomentosa and Valeriana officinalis) were assayed for anti-genotoxicity using the Somatic Mutation And Recombination Test (SMART) in Drosophila melanogaster. All these infusions are traditionally used for various medical purposes, including anti-inflammatory processes. Hydrogen peroxide was used as an oxidative genotoxicant to test the anti-genotoxic potency of the medicinal infusions. None of these infusions showed a significant genotoxicity, quite the reverse they were able to behave as desmutagens, detoxifying the mutagen hydrogen peroxide. The phenolic content of such herbal infusions is argued to be the possible scavenger of reactive oxygen radicals produced by the hydrogen peroxide.

Genotoxicity of neutrons in Drosophila melanogaster. Somatic mutation and recombination induced by reactor neutrons

This paper describes the observation of a direct relationship between the absorbed doses of neutrons and the frequencies of somatic mutation and recombination using the wing somatic mutation and recombination test (SMART) of Drosophila melanogaster. This test was used for evaluating the biological effects induced by neutrons from the Triga Mark III reactor of Mexico. Two different reactor power levels were used, 300 and 1000 kW, and two absorbed doses were tested for each power level: 1.6 and 3.2 Gy for 300 kW and 0.84 and 1.7 Gy for 1000 kW. A linear relationship was observed between the absorbed dose and the somatic mutation and recombination frequencies. Furthermore, these frequencies were dependent on larval age: In 96-h-old larvae, the frequencies were increased considerably but the sizes of the spots were smaller than in 72-h-old larvae. The analysis of the balancer-heterozygous progeny showed a linear absorbed dose- response relationship, although the responses were clearly lower than found in the marker-trans-heterozygous flies. Approximately 65% of the genotoxicity observed is due to recombinational events. The results of the study indicate that thermal and fast neutrons are both mutagenic and recombinagenic in the D. melanogaster wing SMART, and that the frequencies are dependent on neutron dose, reactor power, and the age of the treated larvae.

Drosophila wing-spot test for genotoxic assessment of pollutants in water samples from urban and industrial origin

The Caí River (Rio Grande do Sul, Brazil) is an important watercourse that receives large amounts of industrial and untreated municipal discharges in its lower course. We employed the SMART in Drosophila melanogaster to evaluate the genotoxicity of surface waters collected from Caí sites receiving direct sewage discharge: from Montenegro (Km 52) and from São Sebastião do Caí (Km 78 and 80), and from two sites under the industrial influence (Km 13.6 and 18.6). The genotoxic analysis included three collections: March, June and September 1999, which were tested at crude sample and at 50 and 25% concentrations. Considering the industrial samples from Km 18.6 and 13.6, collected in March, June and September 1999, they were characterized as not having genetic toxicity. The urban samples collected in March--Km 52, 78 and 80--showed a significant increment in the frequencies of total spots. In Km 52 and 78 the genotoxic effect was associated to both mutational and recombinational events, although for Km 80 the increases observed were mainly related to the occurrence of homologous recombination. Moreover, the Km 80 crude sample from June and all the concentrations analyzed for Km 52 in September were also able to induce mitotic recombination. These effects were only observed in the ST cross, demonstrating the genotoxins present in the urban discharges act by direct interaction with the DNA of the somatic cells. The SMART in D. melanogaster was shown to be highly sensitive to detect genotoxic agents present in the aquatic environment, and must be better exploited for monitoring areas under anthropogenic discharges.

Genotoxicity testing of some organophosphate insecticides in the Drosophila wing spot test

In this study, different concentrations of some organophosphate insecticides (methyl parathion, azamethiphos, dichlorvos and diazinon) have been evaluated for genotoxicity in the wing somatic mutation and recombination test (SMART) of Drosophila melanogaster. Third-instar larvae trans-heterozygous for two genetic markers mwh and flr, were treated at different concentrations (1 ppm, 3 ppm, 5 ppm, 7 ppm, 10 ppm) of the test compounds. A positive correlation was observed between total mutations and the number of wings having mutations. In addition, the observed mutations were classified according to size and type of mutation per wing. Chemicals used were ranked in decreasing order according to their genotoxic effects as diazinon, dichlorvos, methyl parathion, azamethiphos.

Genotoxicity of vegetable cooking oils in the Drosophila wing spot test

Seven vegetable oils consumed by humans were tested for genotoxic activity in the Drosophila somatic mutation and recombination test. The oils included five seed oils (sesame, sunflower, wheat germ, flax, and soy oil) and both first-class extra-virgin and low-grade (refined) olive oil. Larvae of the standard (STD) and highly bioactive (NORR) crosses of Drosophila melanogaster were fed medium containing 6% and 12% of each of the oils. Flax oil produced the strongest response, while sesame, wheat germ, and soy oil showed some genotoxic activity. Sunflower and the low-grade olive oil gave inconclusive results, and extra-virgin olive oil was clearly nongenotoxic. It is argued that the genotoxicity is probably due to the fatty acid composition of the oils, which after peroxidation can form specific DNA-adducts.

Interference of tannic acid on the genotoxicity of mitomycin C, methylmethanesulfonate, and nitrogen mustard in somatic cells of Drosophila melanogaster

The modulating effects of tannic acid (TA) on somatic mutation and mitotic recombination induced by methylmethanesulfonate (MMS), nitrogen mustard (HN2), and mitomycin C (MMC) were evaluated in the standard (ST) cross of the wing spot test in Drosophila melanogaster using co- and posttreatment protocols. It was shown that TA alone did not modify the spontaneous frequencies of single and twin spots, which means that this polyphenol neither acts as a genotoxin nor exerts any antigenotoxic effect over spontaneous DNA lesions. However, the simultaneous administration of genotoxins with TA can lead to considerable alterations of the frequencies of induced wing spots in comparison to those with administration of the genotoxins alone. In fact, TA produced a significant increase in HN2-induced wing spots with enhancements between 90 and 160%. For MMS, the enhancement was 38% in the highest TA concentration tested. In contrast, a significant protective action of this polyphenol was observed in combined treatments with MMC (64 to 99% inhibition). Moreover, the data from TA posttreatments demonstrated that this agent is not effective in exerting protective or enhancing effects on the genotoxicity of MMS, HN2, or MMC. One feasible mechanism of TA action is its interaction with the enzyme systems catalyzing the metabolic detoxification of MMS and HN2, which may also be involved in the bioactivation of MMC.

Genotoxicity testing of six insecticides in two crosses of the Drosophila wing spot test

Among the great variety of genotoxicity assays available, the wing spot test in Drosophila melanogaster has some characteristics that make it very suited for the screening of genotoxic activity, i.e., it is an easy and inexpensive assay using a eukaryotic organism in vivo. One of the most interesting characteristics of the assay is its capacity to detect genotoxic activity of promutagens without the necessity of an exogenous metabolic activation system. In this paper we present results obtained with a recently developed high bioactivation cross of the wing spot test (NORR cross). The positive results obtained with the five well-known procarcinogens 7, 12-dimethylbenz[a]anthracene, N-nitrosopyrrolidine, p-dimethylaminoazobenzene, diethylnitrosamine and urethane clearly show that the NORR strains are similar to the other high bioactivation strains previously described, but they lack their methodological disadvantages. We have tested six insecticides, which are characterised by having contradictory results in other genotoxicity tests, using both the standard and the high bioactivation (NORR) cross. The six insecticides analysed are the pyrethroid allethrin, the methylenedioxyphenolic compound piperonyl butoxide, the chlorinated hydrocarbons dieldrin and endrin, and the organophosphates dimethoate and malathion. We obtained negative results for all six compounds. Our results show the suitability of the wing spot test for the evaluation of compounds at the first level of genotoxicity testing.

Induction of Mutation in Drosophila melanogaster fed a hexane extract of vegetables grown in soil contaminated with particulates from diesel engine exhaust

Trans-heterozygous larvae of the improved high-bioactivation cross Drosophila melanogaster (ORR;flr3/TM3, Ser females mated with mwh males) were fed with medium containing hexane extract of the edible portion of five vegetables grown in three different soil treatments for 48 hours. the wing hairs of the surviving flies were analysed for the frequency and size of single and twin spots. It was found that the clone induction frequency of the wing hairs of flies treated with a hexane extract of leaves of sacred basil and green kuang futsoi was not significantly different from that of the controls. Conclusive results were obtained when larvae were raised on the medium containing hexane extracts of lettuce and water spinach grown in contaminated soils. Interestingly, the extracts of multiply onion, grown both in the treated and in the untreated soils, induced mutation in the wing spot test. It was concluded that some plants grown in soil contaminated with diesel exhaust provoked mutagenic responses, whereas some showed negative results.

Analysis of the in vivo nitrosation capacity of the larvae used in the wing somatic mutation and recombination test of Drosophila melanogaster

The in vivo nitrosation capacity of third-instar larvae of Drosophila melanogaster was assessed using the wing somatic mutation and recombination test (SMART). Larvate derived from two different crosses, the standard cross (ST) and the high bioactivation cross (HB) both involving the recessive wing cell markers multiple wing hairs (mwh) and flare (flr3), were used. The HB cross is characterised by an increased cytochrome P450-dependent bioactivation capacity for promutagens and procarcinogens. The larvae were treated either with methyl urea, sodium nitrite or its combination. N-Nitrosomethylurea was used as a positive control. The wings of the resulting flies were analysed for the occurrence of mutant spots produced by various types of mutational events or by mitotic recombination. Methyl urea is negative in the ST and the HB cross, whereas sodium nitrite is weakly genotoxic in both crosses. However, the combination of both compounds produces highly increased frequencies of mutations and recombinations predominantly in the HB cross. The genotoxic effects produced by the combined treatments were considerably increased when mashed potatoes or an agar-yeast medium were used for the treatment instead of the standard instant medium. Treatment of larvae with the mixture resulting from the in vitro reaction of nitrosation precursors also resulted in high frequencies of induced spots comparable to those recorded with the potent genotoxin N-nitrosomethylurea. Further experiments showed that the genotoxic effect resulting from the in vivo exposure to nitrosation precursors can be reduced by co-treatment with catechin, a known nitrosation inhibitor. The present study demonstrates that the wing spot test is well suited for the determination of genotoxicity produced by in vivo nitrosation processes and for the study of their modulation by individual compounds or dietary complex mixtures.

Protection by coffee against somatic genotoxicity in Drosophila: role of bioactivation capacity

The protective effects of coffee against somatic mutation and mitotic recombination induced by cyclophosphamide (CPH), mitomycin C (MMC) and urethane (URE) were evaluated in the standard (ST) and high bioactivation (HB) crosses of the wing spot test in Drosophila melanogaster. These two crosses are characterized by different constitutive levels of cytochrome )-450-dependent enzyme activities. 3-day old larvae transheterozygous for the wing cell markers mwh (multiple wing hairs) and flr3 (flare3) were fed until pupation on medium containing a genotoxin alone or its combination with different concentrations of instant coffee. subsequently, the wings of the resulting adult flies were analysed for detecting single spots (mwh or flr3) originating from mutational or recombinational events as well as twin spots (mwh and flr3) originating exclusively from recombination. The results showed high sensitivity of the HB cross to URE. Co-administration of instant coffee was effective in exerting significant dose-related inhibitory effects on the genotoxicity of URE in the ST and the genetically susceptible HB cross. Similarly, coffee showed significant dose-related inhibitory effects on the genotoxicity of MMC in both crosses. The same protective effect was also observed with one concentration of coffee in combination with CPH. Pretreatment of 2-day-old HB larvae with coffee for 24 hr followed by treatment with URE was also effective in significantly reducing the induction of mutation and recombination. The magnitude of the protective effects of coffee against these three genotoxins was independent of the genotype of the larvae used for treatment, that is it was independent of the bioactivation capacity of these larvae. The study demonstrates the suitability of this assay for obtaining qualitative and quantitative data on the result of interactions among a genotoxin, an inhibitor of genotoxicity and bioactivation capacity of the host.