Direct Mutagenicity Research Articles

Effect of some edible mushrooms on nitrite treated beef concentrate using Ames test

This study evaluated the possibility that extracts from some edible mushrooms (button, shiitake, oyster and abalone) could modulate the formation of the mutagen precursor during extended period cooking of beef and the direct mutagen produced from interaction between nitrite and beef concentrate. The concentrates from beef boiled with the mushroom samples did not show the mutagenicity when tested with the Ames test using Salmonella typhimurium strains TA98 and TA100 in the absence of metabolic activation. After treated with nitrite, they exhibited the mutagenicity towards both strains. The results showed that the addition of mushroom extracts to the beef concentrate before treated with nitrite did not reduce the mutagenicity. However, the actual mutagenicity of the mixtures of mushroom extracts and beef concentrates treated with nitrite was less than the calculated value. Exceptions were found in button and oyster mushroom extracts on TA98. Thus, it was indicated that some mutagen precursors presented in all concentrates could interact with nitrite and addition of these mushrooms could not reduce the formation of the mutagen precursors.

Comparison of BTX Profiles and Their Mutagenicity Assessment at Two Sites of Agra, India

In the present study, the concentrations of three volatile organic compounds (VOCs), namely, acronym for benzene, toluene, and xylenes (BTX) were assessed because of their role in the tropospheric chemistry. Two representative sites, a roadside and a petrol pump, were chosen for sample collection. VOCs were collected using SKC-activated charcoal tubes and SKC personal sampler and characterized by gas chromatograph using flame ionization detector. Among BTX, benzene had the highest concentration. At the roadside, mean concentration of benzene, toluene, o-,m-xylene, and p-xylene were 14.7 ± 2.4 μgm−3, 8.1 ± 1.2 μgm−3, 2.1 ± 0.8 μgm−3, and 5.1 ± 1.2 μgm−3, respectively. At the petrol pump, the mean concentrations of benzene, toluene, o-,m-xylene and p-xylene were 19.5 ± 3.7 μgm−3, 12.9 ± 1.1 μgm−3, 3.6 ± 0.5 μgm−3 and 11.1 ± 1.5 μgm−3, respectively, and were numerically higher by a fraction of 2. Monthly variation of BTX showed maximum concentration in winter. Inter-species ratios and inter-species correlation indicated traffic as the major source of BTX. Extracts of samples were positive in both Salmonella typhimurium tester strains TA98 and TA100 without metabolic activation suggesting the presence of direct mutagens in ambient air that can cause both frame-shift and base-pair mutation. The mutagenic response was greater for TA100 than TA98 suggesting greater activity for base-pair mutagenicity than frame-shift mutagenicity and was found to be statistically significant.

Polycyclic Aromatic Hydrocarbon Emissions and Mutagenicity Assessment of Exhaust from a Diesel Generator

Diesel fuel and diesel exhaust are known to be highly mutagenic partly because of the presence of polyaromatic hydrocarbons (PAHs) and their derivatives. The present study investigated the PAHs content in the diesel fuel fed to a diesel generator and also in the gas and particulate phase of generator emissions. Mutagenicity of the exhaust was also determined. Exhaust emissions were collected by a stack sampler: gas phase on XAD-2 resin while particulate phase on glass fibre thimble. PAHs were characterized by a gas chromatograph by using a flame ionization detector. The low molecular weight PAHs dominated in the fuel, whereas the high molecular weight PAHs dominated in the exhaust with a greater emission factor in the particulate phase. The results reveal the pyrosynthesis of high molecular weight PAHs during the combustion process. Emissions also increased with increase in load. Extract of exhaust emissions were positive in both Salmonella typhimurium tester strains TA 98 and TA 100 without metabolic activation, suggesting the presence of direct mutagens that can cause both frame-shift and base-pair mutation. The mutagenic response was greater for TA 100 than TA 98, suggesting greater activity for base-pair mutagenicity than frame-shift mutagenicity. Mutagenic activity increased with the increase in load.

Involvement of nitro-compounds in the mutagenicity of urban Pm2.5 and Pm10 in Turin

Fine particles can be active carriers of toxic compounds into the alveoli of the lungs. Among these compounds are numerous mutagens and carcinogens. The direct mutagenicity per unit mass of fine particulate matter (PM) is significantly higher than that of coarse particles, especially in urban areas. In this study, the mutagenic properties of urban PM2.5 and PM10 were evaluated, and the role of nitro-compounds was estimated. PM2.5 and PM10 samplings, and measurements of NOx and some PAHs were performed daily in 2007 in Turin, following a consolidated in vitro test – the Salmonella mutagenicity assay – conducted with organic extracts of PM2.5 and PM10. The mutagenic properties were assessed for each month of sampling with Salmonella typhimurium strain TA98 and TA98-derived strains: a nitroreductase-deficient mutant strain (TA98NR) and an additional nitroreductase-producing plasmid strain (YG1021). The annual measured mean levels of PM2.5 and PM10 were 34 ± 20 and 48 ± 18 μg/m 3. The PM2.5/PM10 ratio ranged from 0.36 to 0.89. The Salmonella assay showed higher mutagenicity in autumn/winter (20 ± 15 TA98NR; 54 ± 39 TA98; 173 ± 161 YG1021 net revertants/m 3) compared with spring/summer (2 ± 2 TA98NR; 7 ± 8 TA98; 24 ± 27 YG1021 net revertants/m 3) ( p < 0.01). There are also statistically significant seasonal differences in the gravimetric analysis data. The number of TA98 net revertants per μg of PM2.5 is 6.5 times greater than per μg PM10. Moreover, the bioassay results showed an amplified response in the YG1021 strain and a reduced response in the TA98NR strain. The net revertant ratio TA98NR/YG1021 is 11 ± 4 for organic extracts of PM2.5 and 13 ± 6 for extracts of PM10 ( p < 0.01). There is a significant correlation between the NOx and PAH concentrations. These findings illustrate the relevant role of nitro compounds, and they underline the priority in improving preventive measures to reduce air pollution by nitrated molecules.

Radical Scavenging Capacity and Antimutagenic Properties of Purified Proteins from Solanum betaceum Fruits and Solanum tuberosum Tubers

In this study, antioxidant activities in free-radical-mediated oxidative systems and the genotoxic/antigenotoxic effects of two proteins with molecular mass around 17 kDa, purified from Solanum betaceum fruits (cyphomine) and Solanum tuberosum tubers (solamarine), were investigated. Both proteins inhibited uric acid formation with IC(50) values between 55 and 60 μg/mL, and both proteins were able to reduce oxidative damage by scavenging hydroxyl radicals and superoxide anion in a dose-dependent manner. Furthermore, the DPPH• reduction assay showed SC(50) values of 55-73 μg/mL. Cyphomine and solamarine were able to retain their antioxidant activity after heat treatment at 80 °C for 15 min. Allium cepa and Salmonella /microsome assays showed no genotoxic and mutagenic effects. Solamarine showed an antimutagenic effect against a direct mutagen (4-nitro-o-phenylenediamine). Consequently, the present study showed that the investigated proteins are promising ingredients for the development of functional foods with a beneficial impact on human health and an important source for the production of bioactive peptides.

Effects of Ripening Process on the Mutagenicity and Antimutagenicity of Sufu, a Chinese Traditional Fermented Product of Soybean

In the present study, sufu, the cheese-like fermented product of soybean, was prepared by ripening salted tofu cubes in Aspergillus oryzae-fermented rice–soybean koji mash at 35 °C for a period of 16 days. This mixture was held at room temperature (ca. 25 °C) for another 1 month. The mutagenicity and antimutagenicity exerted by the methanol extract of non-fermented tofu and sufu against 4-nitroquinoline N-oxide (4-NQO), a direct mutagen, and 3, 2-dimethyl-4-amino-biphenyl hydrochloride (DMAB), an indirect mutagen, on Salmonella typhimurium TA 100 were examined. Results revealed that the methanol extract of non-fermented tofu and sufu samples collected at various ripening intervals exhibited neither toxicity nor mutagenicity, yet did display antimutagenicity against mutagens across the dose levels examined. Generally, a dose-dependent antimutagenic effect was noted across the dose range examined. The antimutagenicity of the tofu extract toward 4-NQO and DMAB was enhanced significantly (P < 0.05) through fermentation. Generally, the antimutagenicity of the sufu extract increased with the extension of ripening period. Furthermore, the extract of the non-fermented tofu and sufu, regardless of ripening period, showed a significantly higher (P < 0.05) antimutagenicity against DMAB than 4-NQO.

Steric effects on the direct mutagenicity of N-acyloxy-N-alkoxyamides—Probes for drug–DNA interactions

N-Acyloxy-N-alkoxyamides (see structure 1, below) are direct-acting mutagens for which a QSAR has been established that predicts with accuracy their activity in the bacterial reverse-mutation assay (Ames test) in Salmonella typhimurium TA100. Steric bulk next to oxygen on the alkoxyl side-chain in structure 4 has no impact on activity, but branching at the position adjacent (alpha) to the ester-carbonyl of the leaving group in structure 5 strongly inhibits mutagenicity. Both results reflect the manner in which these molecules interact with DNA. The alkoxyl group has greater flexibility, which minimises steric effects within the major groove. Bulk adjacent to the carbonyl of the ester group must impose conformational constraints that impede reaction at the N7 position of guanine. A new, expanded QSAR shows a clear dependence of activity on logP, although with a smaller coefficient relative to indirect-acting mutagens.

Sensitivity of Allium and Nicotiana in cellular and acellular comet assays to assess differential genotoxicity of direct and indirect acting mutagens

We have evaluated the extent of DNA damage induced by direct and indirect mutagens by cellular and acellular comet assays in two plant systems, Nicotiana tabacum (wild type tobacco) and Allium cepa (common onion). The objectives of this study were: (1) to generate dose–response curves for DNA migration values from root and shoot nuclei of A. cepa and N. tabacum treated with the direct acting mutagens, ethyl methanesulphonate (EMS), hydrogen peroxide (H 2O 2) and the indirect acting mutagen, cadmium chloride (CdCl 2), (2) to assess the differential response between isolated nuclei and nuclei of root and shoot and of both plants and (3) to examine the differences of sensitivity between direct and indirect acting mutagens by cellular and acellular comet assays. Similar sensitivities were evident in both plant systems to direct and indirect acting mutagens. The combination of cellular and acellular comet assays provided valuable insight to the mode of action of the genotoxicants used. The data obtained demonstrated the estimable capacity of the two plant systems to evaluate genotoxicity under different stress conditions and suggests Allium is a more desirable test system for rapid monitoring of genotoxicity.

Estimation of the contribution of ultrafine particles to lung deposition of particle-bound mutagens in the atmosphere

The present study was performed to estimate the contributions of fine and ultrafine particles to the lung deposition of particle-bound mutagens in the atmosphere. This is the first estimation of the respiratory deposition of atmospheric particle-bound mutagens. Direct and S9-mediated mutagenicity of size-fractionated particulate matter (PM) collected at roadside and suburban sites was determined by the Ames test using Salmonella typhimurium strain TA98. Regional deposition efficiencies in the human respiratory tract of direct and S9-mediated mutagens in each size fraction were calculated using the LUDEP computer-based model. The model calculations showed that about 95% of the lung deposition of inhaled mutagens is caused by fine particles for both roadside and suburban atmospheres. Importantly, ultrafine particles were shown to contribute to the deposition of mutagens in the alveolar region of the lung by as much as 29% (+ S9) and 26% (−S9) for the roadside atmosphere and 11% (+ S9) and 13% (−S9) for the suburban atmosphere, although ultrafine particles contribute very little to the PM mass concentration. These results indicated that ultrafine particles play an important role as carriers of mutagens into the lung.

Inhibitory effects of molasses on mutation and nitric oxide production

In this study, the effects of four molasses related products including cane molasses (CM), carob molasses (CAM), grape molasses (GM), and sorghum molasses (SM) on the antimutation and nitric oxide (NO) production were examined. The results showed that the four molasses products, particularly CAM, inhibited the mutagenicity of 2-aminoanthracene (2-AA), an indirect mutagen; and 4-nitroquinoline-N-oxide (4-NQO), a direct mutagen in Salmonellatyphimurium TA98 and TA100. In addition, CAM also showed a higher ABTS radical inhibition, reducing activity, and decreasing lipid oxidative damage more than the others kinds of molasses. In the range of 0–0.8mg/ml, the inhibitory effect of all molasses products on NO generation in lipopolysaccharide (LPS) stimulated macrophages increased with increasing concentrations, and CAM showed the best inhibition of NO production. These data suggested that the four molasses related products display their biological activities in terms of antioxidation, antimutation, and anti-inflammation.

1-Methoxy-3-indolylmethyl glucosinolate; a potent genotoxicant in bacterial and mammalian cells: Mechanisms of bioactivation

1-Methoxy-3-indolylmethyl (1-MIM) glucosinolate, contained in many Brassica vegetables, is strongly mutagenic in Salmonella typhimurium TA100 when activated by myrosinase. Here, we describe the synthesis and evaluation of two breakdown products, 1-MIM nitrile and 1-MIM alcohol. 1-MIM nitrile was not mutagenic and 1-MIM alcohol showed low direct mutagenicity in TA100, indicating that other breakdown products mediated the mutagenicity of 1-MIM glucosinoate/myrosinase in this strain. However, 1-MIM alcohol was strongly mutagenic to a TA100-derived strain expressing human sulphotransferase SULT1A1. Likewise, 1-MIM glucosinolate (with myrosinase) showed 10 times higher mutagenic activity in TA100-SULT1A1 than in strain TA100. Identical adducts, N 2-(1-MIM)-dG and N 6-(1-MIM)-dA, were detected in both strains, but the levels were higher in TA100-hSULT1A1. A similar influence of SULT1A1 was observed in recombinant V79-hSULT1A1 cells compared to parental SULT-deficient Chinese hamster V79 cells. 1-MIM glucosinolate (with myrosinase) as well as 1-MIM alcohol induced sister chromatid exchange in both cell lines, but with clearly higher efficiency in V79-hSULT1A1 cells. Gene mutation assays were conducted at the HPRT locus with 1-MIM alcohol in V79-hSULT1A1 cells, and with 1-MIM glucosinolate/myrosinase in V79 parental cells. In both cases, the result was clearly positive. Thus, 1-MIM glucosinolate is mutagenic in bacterial and mammalian cells via at least two different metabolites.

Mutagenicity of Airborne Particulates Assessed by Salmonella Assay and the SOS Chromotest in Wrocław, Poland

Ambient air particulate matter less than 2.5 μm in aerodynamic diameter (PM2.5) samples were collected during summer and autumn using a Staplex high-volume air sampler. They were later extracted with dichloromethane in a Soxhlet apparatus. Polyaromatic hydrocarbon (PAH) content in extracts was determined by the high-performance liquid chromatography technique using fluorescence detection, whereas the nitro-PAH content was determined by gas chromatography using mass detection. Four Salmonella typhimurium strains (TA98, TA100, YG1041, and YG1042) were used in assays conducted with and without metabolic activation. The extracts were also tested with the SOS chromotest supplied by Environmental Biodetection Products Incorporated. The obtained results confirmed the Salmonella assay and the SOS chromotest usability for the purpose of atmospheric pollution monitoring within an urban agglomeration. The atmospheric pollution extracts under examination differed among each other regarding total content and percentage of individual compounds, depending on the season of sampling. The highest total PAH content and the highest nitro-PAH content in the tested samples as well as the most extensive range of detected compounds were found in the autumn season (heating season). The highest mutagenicity was noted for PM2.5 samples collected in autumn. The high values of mutagenicity ratios and induction factors were obtained from assays carried out with and without metabolic activation, which is an argument for the presence of promutagens and direct mutagens. The YG1041 strain proved to be the most effective in detection of mutagenicity of the suspended dust extracts because of its notably high sensitivity to nitro-aromatic compounds. The SOS chromotest was very sensitive to a large spectrum of genotoxic air pollutants and showed a high degree of similarity with the results of the Salmonella assay. In comparison with the frequently used Ames test, the SOS chromotest enables quick analysis of the genotoxic effects of samples using only one tester strain. In addition, its miniaturized design decreases the consumption of tested samples.

Effects of the aqueous extract of sugarcane leaves on antimutation and nitric oxide generation

In this study, the effects of a water extract of sugarcane leaves (WSL) on antimutation and nitric oxide (NO) production were investigated. The results showed that WSL inhibited the mutagenicity of benzo[a]pyrene (BP), an indirect mutagen; and N-methyl- N′-nitrosoguanidine (MNNG), a direct mutagen toward Salmonella typhimurium TA 98 and TA 100. In addition, WSL, in the range of 0–0.4 mg/ml, showed superoxide inhibiting, NO scavenging, and reducing activity, as well as decreased lipid oxidative damage. In the range of 0–1 mg/ml, the inhibitory effect of WSL on NO generation in lipopolysaccharide (LPS) stimulated macrophages increased with increasing concentrations. A high performance liquid chromatography analysis revealed that the polyphenolic constituents, such as caffeic acid, ferulic acid, apigenin, and vitexin were present in WSL. These data suggested that WSL exhibiting biological activities could contribute to antimutation, anti-inflammation as well as antioxidation.

Genotoxic and antimutagenic activities of extracts from pseudocereals in the Salmonella mutagenicity assay

Extracts of amaranth (Amaranthus L.), sorghum (Sorghumbicolor L.) and Japanese millet (Echinochloafrumentacea L.) were evaluated for mutagenicity in Salmonellatyphimurium strains TA98, TA100 and TA102. All three pseudocereal extracts were also assessed for their antimutagenic properties against the direct mutagens 2-nitrofluorene (2NF) for strain TA98, 3-(5-nitro-2-furyl)acrylic acid (5NFAA) for TA100 and H2O2 for TA102 strain and against the indirect mutagen aflatoxin B1 (AFB1). No mutagenicity was induced by any of the pseudocereal extracts when tested at concentrations as high as 50mg/ml. All three extracts showed similar antimutagenicity against 5NFAA and no antimutagenicity against 2NF. The number of revertants induced by H2O2 extract was inhibited in order amaranth>Japanese milet>sorghum. All extracts were effective in the inhibition of mutagenic activity of aflatoxin B1. The total polyphenol content as well as the amount of the flavonoids and phenolic acids as main component of polyphenolics were also determined.

Inhibitory Effect of Dimethyl Sulfoxide on the Mutagenicity of Promutagens in the Ames Test

The effect of dimethyl sulfoxide (DMSO) on the mutagenicity of 14 promutagens belonging to several chemical classes and one direct mutagen as a reference compound was examined in the Ames preincubation test, to clarify how much the test results were affected by its inhibitory activity on metabolic enzymes. The mutagens were assayed by the preincubation method using the TA100 or WP2uvrA(pKM101) bacterial test strains in the presence of 1% and 14% DMSO (concentrations in treatment mixture) with S9 mix for 12 promutagens that are known to be activated by CYP enzymes or without S9 mix for 2 promutagens that are known to be activated by bacterial nitroreductase enzymes, and the direct-mutagen. The data indicate that the mutagenicity of 11 of the 14 promutagens was significantly reduced in the presence of 14% DMSO as compared with that in the presence of 1% DMSO, while the 3 remaining promutagens and the direct mutagen exhibited mutagenicity of equal degree at both concentrations. The largest inhibitory effect of DMSO was found on the nitrosamines in WP2uvrA(pKM101) and TA100, and no cytotoxicity was detected by survival test, with 14% DMSO in WP2uvrA(pKM101), at any amounts of dimethylnitrosamine. Further equivalent or slightly lower cytotoxicity in the presence of 14% DMSO than in the presence of 1% DMSO was detected by decrease in the bacterial background-lawn density, as a whole. These observations suggest that the reduction in the yield of revertant colonies in the presence of 14% DMSO with the 11 chemicals was not due to cytotoxicity of DMSO. The inhibitory effect of DMSO on the mutagenicity of the promutagens can be explained by its inhibitory effect on the drug-metabolizing enzymes involved in the activation/detoxification pathways. Use of DMSO at a low concentration, such as 1%, may be suggested for the Ames test, as for other in vitro genotoxicity tests.

Cytotoxic Effect of Dimethyl Sulfoxide in the Ames Test

Dimethyl sulfoxide (DMSO) is generally believed to be non-cytotoxic at the concentrations used in the routine Ames test. In the present study, we found that DMSO reduced the number of bacterial survivors at a concentration of 14% in the treatment mixture (0.1 mL of DMSO in 0.7 mL of treatment mixture) under some assay conditions. The cytotoxicity emerged even before preincubation, and it was largely dependent on the bacterial strains used and the cell density of the treated cells; a low toxicity was detected at a low cell density. The most potent cytotoxicity was observed in the TA100 and TA1535 strains with S9 mix, where the reduction in survivors was about 60-90%, before or after preincubation. This reduction was, however, not accompanied by a significant diminution in the bacterial background lawn. The reduction in survivors does not seem to affect the sensitivity of mutagen detection, because no significant decrease in the number of induced revertants was observed in the preincubation assay using a direct mutagen, methyl methanesulfonate.

Nitrosation of Glutathione and Nitration of Tyrosine by N-Nitrosoproline with Ultraviolet Light

N-Nitrosoproline was thought to be nonmutagenic and noncarcinogenic because of its stability. However, it has been reported that N-nitrosoproline releases nitric oxide and shows direct mutagenicity by UV light irradiation. In this study, nitrosation and nitration of glutathione and tyrosine by N-nitrosoproline with UV light are tested. When a neutral solution of N-nitrosoproline and glutathione was irradiated with UV light of 365 nm generated from an 8 W mercury lamp, S-nitrosoglutathione was formed. When a neutral solution of N-nitrosoproline and tyrosine was irradiated with the UV light, a small amount of 3-nitrotyrosine was generated. A similar intensity of UV light of 254 nm induced formation of S-nitrosoglutathione and 3-nitrotyrosine with lesser efficiencies. When UV light of 365 nm was irradiated to a neutral mixture of N-nitrosoproline, gluthathione and tyrosine, a similar amount of S-nitrosoglutathione was generated, while the yield of 3-nitrotyrosine greatly decreased. Similar results to the 365 nm UV light irradiation were observed by sunlight. These results suggest that N-nitrosoproline may induce nitrosation and nitration of cellular components in humans with sunlight.

Antioxidant, anti-microbial and antimutagenicity activities of pistachio ( Pistachia vera) green hull extract

Antioxidant, anti-microbial and antimutagenicity activities of pistachio ( Ahmadaghaei variety) green hull extracts (crude and purified extracts) were studied. At first, different solvents were compared for determining of the best solvent for extraction of phenolic compounds from pistachio green hull. Water and acetonitrile with 49.32 and 6.22 (mg of gallic acid equivalents/g sample) were the best and the worst solvent in the extraction of phenolic compounds, respectively. The antioxidant capacity of crude and purified extracts were assessed through ABTS assay, DPPH assay and β-carotene bleaching (BCB) method. A concentration-dependent antioxidative capacity was verified in ABTS, DPPH assays and BCB method. The anti-microbial capacity was screened against Gram positive and Gram negative bacteria, and fungi. Aqueous and purified extracts inhibited the growth of Gram positive bacteria; Bacillus cereus was the most susceptible one with MIC of 1 mg/mL and 0.5 mg/mL for the crude and purified extracts, respectively. The results of antimutagenicity test showed that phenolic compounds of pistachio green hull have antimutagenicity activity against direct mutagen of 2-nitrofluorene. The results obtained indicate that pistachio green hull may become important as a cheap and noticeable source of compounds with health protective potential and anti-microbial activity.

Exploratory investigation of the chemical characteristics and relative toxicity of ambient air particulates from two New Zealand cities

We examined the chemical composition and biological response associated with particulate emissions from the two largest cities in New Zealand, Auckland and Christchurch. The organic and water-soluble fractions were isolated from the particulate matter (PM). The organic fraction was examined for PAH content, direct mutagenicity, CYP1A1 induction, and cytotoxicity and TNF-α release in RAW264.7 macrophages. The water-soluble fraction was examined for metal content, and cytotoxicity and TNF-α release in RAW264.7 macrophages. Particulate, PAH and water-soluble metal concentrations were all higher in PM collected from Christchurch, being highest in May–July when woodburners for home heating are widely in use. In contrast, PM from Auckland showed the highest concentrations in March, but PAH and metal concentrations were highest in July. We found marked differences in the biological response elicited by ambient air PM: the organic extracts of Christchurch PM 2.5 and PM 10 showed higher mutagenicity and CYP1A1 induction compared with PM 10 from Auckland. In contrast, water-soluble extracts of Auckland PM were more cytotoxic and resulted in greater TNF-α release than those from Christchurch PM, although they had a lower metal content. The organic fraction of PM from both cities did not induce any cytokine release, and the organic extract from Auckland samples showed no cytotoxicity; smaller PM mass was available for testing for these samples. Biological responses typically occurred at lower doses of the organic extract, indicating that organic components may be more important in eliciting effects than water-soluble components. Preliminary apportionment of the biological responses to the dominant sources of PM in both cities–woodburners and vehicles–was undertaken. This indicated that for both cities, vehicles have a greater contribution to the direct mutagenic activity of ambient PM than woodsmoke, despite a lower contribution to ambient PM. In contrast, woodsmoke is estimated to have a greater contribution to CYP1A1 induction of ambient PM. The calculated activity forms only a small proportion of the activity observed in extracts of ambient PM from Christchurch, particularly for mutagenicity, and may indicate a significant influence of atmospheric transformation processes on biological response. Only data for mutagenicity and CYP1A1 activity could be used for apportionment as low and/or variable cytotoxicity or TNF-α release response were obtained for either the individual source or ambient PM at the doses tested. Further, in the case of the water-soluble extracts from Auckland, additional components are suggested to have a role in the observed activity.

Antigenotoxic and Antioxidant Activities of Fruit Extracts from (Tunisian) Pistacia Lentiscus

Genotoxic and antigenotoxic activities against direct acting mutagen nifuroxazide, and indirect acting genotoxin aflatoxine B1 (AFB1) of extracts prepared from fruits of Pistacia lentiscus, were studied using the SOS chromotest with Escherichia coli PQ 37 as a tester organism. It was found that different extracts showed no genotoxicity when tested with E. coli PQ 37 strain either with or without microsomal extract. On the other hand, our results showed that ethyl acetate fraction and total oligomers flavonoids (TOF) extract obtained from P. lentiscus significantly decreased the genotoxicicity induced by AFB1 (10 μg/assay) and nifuroxazide (20 μg/assay). In addition to antigenotoxic activity, these extracts showed an important free radical scavenging activity towards the 2,2-diphenyl-2-picrylhydrazyl (DPPH) free radical and an important antioxidant activity using xanthine/xanthine oxidase system.