Evaluation of the mutagenicity and antimutagenicity of extracts from oat,buckwheat and wheat bran in the Salmonella/microsome assay

This study examined the mutagenic and antimutagenic activities of the DMSO extracts from the oat, buckwheat and wheat bran, which are good sources of polyphenols with antioxidant and anticarcinogenic properties. Extracts from buckwheat and wheat bran showed no mutagenic activity. Oat extract showed slight mutagenic effect in Salmonella typhimurium TA102. The antimutagenic activities against direct-acting (3-(5-nitro-2-furyl)acrylic acid, 2-nitrofluorene, hydrogen peroxide) and indirect-acting (aflatoxin B1) mutagens were also investigated using Ames test with S. typhimurium TA98, TA100 and TA102. Cereal extracts exhibit concentration-dependent protective antigenotoxic activity against all used mutagens. The total phenolic content in studied cereal extracts expressed as gallic acid equivalent increases in the order: buckwheat < wheat bran < oat. Total flavonoid content expressed as rutin equivalent increases in the order: oat < wheat bran < buckwheat.     

Antioxidant and anti-inflammatory activities of quercetin 7-O-β-D-glucopyranoside from the leaves of Brasenia schreberi

Brasenia schreberi Gmel. (Cabombaceae) is an aquatic plant that grows in eastern Asia, Australia, Africa, and North and Central America. B. schreberi leaf extracts were obtained by sequential solvent extraction with dichloromethane, methanol, and water. The antioxidant potential of each extract was assessed by using the oxygen radical absorbance capacity (ORAC) assay. With this method, methanol and water extracts were found to be active with mean ± standard deviation values of 7 ± 2 and 5.1 ± 0.5?μmol Trolox? equivalents (TE)/mg, respectively. Two major phenolic compounds, quercetin-7-O-β-D-glucopyranoside and gallic acid, were respectively isolated from the methanolic and water extracts. Both compounds exhibited antioxidant activities, in particular quercetin-7-O-β-D-glucopyranoside (ORAC value, 18 ± 4 μmol TE/μmol). In contrast to its well-known antioxidant homologue quercetin, quercetin-7-O-β-D-glucopyranoside does not inhibit growth of human fibroblasts (WS-1) or murine macrophages (RAW 264.7). Some flavonoids have been reported to possess beneficial effects in cardiovascular and chronic inflammatory diseases associated with overproduction of nitric oxide. Quercetin-7-O-β-D-glucopyranoside possesses anti-inflammatory activity, inhibiting expression of inducible nitric oxide synthase and release of nitric oxide by lipopolysaccharide-stimulated RAW 264.7 macrophages in a dose-dependent manner. Quercetin-7-O-β-D-glucopyranoside also inhibited overexpression of cyclooxygenase-2 and granulocyte macrophage-colony-stimulating factor.     

Changes in the mutagenic effect of a medium containing aflatoxin B1 as a result of the yeast activity

Changes in the mutagenic activity of the nutrient medium containing aflatoxin Br as a result of living activity of the yeast Rhodotorula mucilaginosa I B has been studied. Reduction of mutagenic activity of the medium when tested on the strains Salmonella typhimurium TA98 (6.3 times fold), TA100 (2.2 times fold), AG262 (2 times fold) has been revealed. The data obtained leads to the conclusion that the technology, based on the use of the indicated strain of the yeast for the treatment of food and feed stuffs contaminated by aflatoxin B1, can be used.     

Mutagenic activity of surface waters adjacent to a nuclear fuel processing facility

Surface waters adjacent to a nuclear fuel processing facility were extracted, using XAD-resin adsorption followed by solvent elution, and the extracts were assayed for mutagenic potential by the AmesSalmonella-mammalian microsome test. Dose-related mutagenic responses with TA102 (+ S9) were produced with the extracts of water samples obtained from a creek receiving waste-water from the processing facility (specific mutagenic activities of 7,250 to 8,250 net revertants per L equivalent of water). The creek water extracts were not mutagenic with TA102 in the absence of S9, or with any other tester strain (i.e., TA97, TA98, TA100, and TA1535) in the presence or absence of S9. Surface water samples downstream and upstream of this creek were not mutagenic; apparently indicating the lack of persistence of the observed mutagenicity. The major constituent in the mutagenic creek water extracts was identified as tributylphosphate (TBP) by gas chromatography-mass spectrometry. However, TBP was not mutagenic with TA102 (+ S9) at doses ranging from 196 g/plate to 9.8 ng/plate. Because tester strain TA102 detects oxidative mutagenesis due to x-rays and ultraviolet radiation, it is possible that the observed mutagenicity of creek water extracts was due to radionuclides complexed to TBP.     

Protective effects of methanol extracts from Cladonia rangiformis and Umbilicaria vellea against known mutagens sodium azide and 9-aminoacridine

Lichens and their various extracts have been occasionally used in the treatment of many diseases. Cladonia rangiformis and Umbilicaria vellea are two important species of these lichens and they have several biological activities. In the present study, methanol extracts of these lichens, which are grown in the Eastern Anatolia Region of Turkey, were isolated, and their mutagenic and antimutagenic properties were investigated by using AMES-Salmonella and Zea mays Root Tip Mitotic Index mutagenicity and antimutagenicity assay systems. Known mutagens sodium azide (NaN(3)) and 9-Aminoacridine (9-AA) were used to determine antimutagenic properties of methanol extracts. The results showed that all methanol extracts, investigated in the present study, can be considered genotoxically safe because they do not have mutagenic activity at the tested concentrations. Besides, all of them have antimutagenic activity against 9-AA known as a model intercalator agent in the AMES-Salmonella test system. The inhibition rates obtained from the antimutagenicity assays ranged from 37.07% (C. rangiformis-5 μg/plate) to 54.39% (C. rangiformis-5 μg/plate). Furthermore, all the methanol extracts have significant antimutagenic activity against NaN(3) mutagenicity in Z. mays Root Tip Mitotic Index assay system. These activities are valuable towards an extension of the employ of these drugs as new phytotherapeutic or preservative ingredients.     

Mutagenicity and antimutagenicity testing of six chemicals associated with the pungent properties of specific spices as revealed by the Ames Salmonella/microsomal assay

Three compounds, capsaicin, thymol and borneol, were initially screened for mutagenic activity using Salmonella typhimurium strains TA97, TA98 and TA100, with and without S9 metabolic activation, and 20 min standard preincubation time. Three other compounds, allyl isothiocyanate, eugenol and cinnamaldehyde, were screened for mutagenic activity as above, but with a prolonged, nonstandard preincubation time of up to 120 minutes. All six test compounds used in the assays are associated with the pungent properties of some specific spices in which the test compounds can be found to exist naturally. The first objective of this study was to observe if mutagenic activity can be correlated to the pungent properties of these six test compounds. However, due to toxicity and the observation that only capsaicin was mutagenic, using strain TA100 in the presence of S9 metabolic activation, it was not possible to deduce any relationship between mutagenicity and the test chemials' pungent properties. Naturally occurring capsaicin, found in the spice Capsicum annum, was detected and quantified using thin layer and gas chromatographic techniques.The final objective was to detect the presence of antimutagenic factor(s) in C. annum that would suppress the mutagenicity of capsaicin. When the mutagenic capsaicin and 2-aminoanthracene were assayed in the presence of C. annum acetone extract, using strain TA100 with S9 metabolic activation, the mutagenic response of both the mutagens were reduced by approximately 50%. Assaying capsaicin and 2-aminoanthracene in the presence of chlorophyll, the mutagenic response of the two mutagens was reduced by less than 40%. From this observation it was inferred that chlorophyll can successfully suppress the mutagenicity activities of capsaicin and 2-aminoanthracene, together with other antimutagenic factors that were present in the acetone extract of C. annum.     

八种天然食物对黄曲霉素素B1和真菌提取物诱变效应的抑制

Eight natural foods were tested for their antimutagenic activities on AFB1, metabolic extracts of A. versicolor and A. ochraceus which induced mutagenic activity in TA 98 and TA 100 mutants. The tested substances were extracted repeatedly with acetone. The revertance induced by AFB1, metabolic extracts of A. versicolor and A. ochraceus were significantly decreased when the eight natural foods were added into the medium. The results showed that the eight natural foods had different degrees of anti-mutagenic effect in vitro, suggesting that anti-mutagenic substances were present in these natural foods. It is considered that these foods may be practically valuable in the chemoprophylaxis of liver cancer in men.     

Protective properties of five newly synthesized cyclic compounds against sodium azide and N-methyl-N'-nitro-N-nitrosoguanidine genotoxicity

The current study aims to determine the antimutagenic potential of five newly synthesized cyclic compounds against the genotoxic agents sodium azide (NaN?) and N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). The mutant bacterial tester strains were NaN?-sensitive Salmonella typhimurium TA1535 and MNNG-sensitive Escherichia coli WP2uvrA. According to the results, all the test compounds showed significant antimutagenic activity. The inhibition rates ranged from 26.05% (Compound 4-1 μg/plate) to 68.54% (Compound 5-0.01 μg/plate) for NaN? and from 32.44% (Compound 3-1 μg/plate) to 60.77% (Compound 5-1 μg/plate) for MNNG genotoxicity. Moreover, the mutagenic potential of the test compounds was investigated using the same strains. The results showed that all the test compounds do not have mutagenic potential on the bacterial strains at the tested concentrations. Thus, the findings of the present study give valuable information about chemical prevention from NaN? and MNNG genotoxicity.     

Bioassay-directed chemical characterization of genotoxic agents in the dissolved and particulate water phases of the Besos and Llobregat Rivers (Barcelona,Spain)

Particulate (>0.22 m) and dissolved phases of water concentrates (600 mL) of Llobregat and Besos Rivers (Barcelona, Spain), were tested in the Salmonella/microsome assay, tester strains TA98 and TA100. Most of them showed significant mutagenic activity. However, independently of the application of exogenous metabolic activation, the dimethylsulfoxide extracts of the particulate matter exhibited a stronger mutagenic activity than the dissolved phase. This indicated that both rivers are chronically polluted by frameshift and base-pair substitution mutagens and promutagens. In order to investigate their identity, a bioassay-directed column chromatography fractionation of the base-neutrals isolated from the dissolved and particulate phases of Besos river water (7 L) was carried out. The mutagenic activity (TA98) was higher in presence of S9 and was recovered in the more polar fractions, where several mutagenic agents were identified by capillary GC-MS in the negative ion chemical ionization mode (NICI). Among them, o-tolidine, nitroquinoline, nitroaniline, dichlorobenzidine and several aromatic quinones were candidates for fraction mutagenicity.     

Mutagenic activity of chlorinated surface waters and humic acid solutions

The mutagenicity of the chlorination by‐products in water supplies of the Venetian region (Italy) and in humic acid solutions were analysed. The samples were concentrated with XAD‐2 resin and tested for mutagenic activity on Salmonella typhimurium TA98 and TA100 strains. Significant mutagenic activity on TA98 strain in the presence (raw water) or absence (chlorinated water) of metabolic activation was observed only for the Po river. All other raw and chlorinated water samples did not induce significant mutagenic effects under the test conditions. The absence of mutagenic activity in almost all the raw water samples suggests very low concentrations of genotoxic pollutants. However, the low values of natural organic carbon and the appropriate treatment conditions used in the local water plants could well explain the negative results obtained for chlorinated waters. In comparison with water samples, the extracts of chlorinated humic‐rich solutions gave highly toxic and mutagenic effects on both the Salmonella strains, with and without metabolic activation. The addition of H₂O₂ at different times from the start of the chlorination greatly influenced the level of the observed mutagenic effects.     

2,3,7,8 Tetrachlorodibenzodioxin in fish from the pigeon river of Eastern Tennessee,USA: Its toxicity and mutagenicity as revealed by the Ames Salmonella assay

Levels of 2,3,7,8 tetrachlorodibenzodioxin (TCDD) were determined in both striated muscle (fillets) and whole body extracts of fish specimens harvested during a two-year period (1987–1989) from the Pigeon River (between Hartford and Newport) of Eastern Tennessee (USA). Whole body (wet weight) fish extract levels as high as 117 g/kg body weight and composite fish fillet (wet weight) extract levels as high as 87 g/kg fillet weight were observed. Pure TCDD was found to be highly toxic to theSalmonella typhimurium strains TA97, TA98, and TA100 at dosages which exceeded 825 ng TCDD/ml in the top agar of the Ames Salmonella assay. An 825 ng/ml TCDD dosage was not mutagenic to any of the tested Salmonella strains, either with or without metabolic activation (S9 mix). However, when acidic fish extracts from the Pigeon River were tested for mutagenicity, most of the fish extracts were mutagenic to Salmonella strains TA97, TA98, and TA100. These mutagenic extracts also demonstrated mutagenic dose-response curves. Other chemicals within the extracts as well as synergistic effects may account for the mutagenicity.     

Identification of genotoxic compounds used in leather processing industry

The release of mutagens from 7 carbon black-based leather dyes and from leather samples at various stages of finishing was determined. After vigorous treatment with toluene, 4 commercial dyes yelded mutagenic extracts on Salmonella typhimurium in the presence of microsomal enzymes. Only in one case were the responsible chemicals identified as polycyclic aromatic hydrocarbons. The low bioavailability of mutagens contained in carbon black and their low mutagenic activity suggest that the risk associated with the use of these dyes is probably negligible. Soxhlet extracts with ethanol from finished leather were mutagenic on strain TA98 of Salmonella typhimurium in the absence of S9 mix. Analysis of extracts of leather samples at various intermediate stages of processing showed that mutagenic activity was detectable after the colouring process. The responsible compound was identified as a nitroazo dye (Colour Index: Acid Brown 83), with a mutagenic potential of about 4 revertant/micrograms. Eighteen commercial tannins containing mainly Cr(III) sulphates were assessed for genotoxicity. Most were contaminated with Cr(VI), a known mutagenic and carcinogenic agent, at levels sufficient to induce an increased frequency of SCE (sister chromatid exchanges) in mammalian cells (CHO, chinese hamster ovary) tested in vitro.     

Correlation of mutagenicity and tumorigenicity of betel quid and its ingredients

The mutagenic activity of betel quid and its ingredients was determined using Salmonella typhimurium tester strains TA 100, TA 1535, TA 98, and TA 1538, both in the presence and absence of S9 mixture. Aqueous extracts of betel quid (BQ), betel quid with tobacco (BQT), and betel nut (BN) were mutagenic in strain TA 100. Aqueous extract of betel leaf (BL) was not mutagenic in any of the four strains. Arecoline and arecaidine, which are major alkaloids present in BN, were mutagenic in all four tester strains. Tumorigenicity studies in Swiss mice given the above constituents showed that BN and BQ induced lung tumors (47% and 26%, respectively). However, when BN was fed with BL, tumorigenicity was lowered to 38%. BL alone was not tumorigenic. Thus, the mutagenicity of betel quid and its ingredients is correlated with tumorigenicity.     

Correlation of mutagenicity and tumorigenicity of betel quid and its ingredients

The mutagenic activity of betel quid and its ingredients was determined using Salmonella typhimurium tester strains TA 100, TA 1535, TA 98, and TA 1538, both in the presence and absence of S9 mixture. Aqueous extracts of betel quid (BQ), betel quid with tobacco (BQT), and betel nut (BN) were mutagenic in strain TA 100. Aqueous extract of betel leaf (BL) was not mutagenic in any of the four strains. Arecoline and arecaidine, which are major alkaloids present in BN, were mutagenic in all four tester strains.

Tumorigenicity studies in Swiss mice given the above constituents showed that BN and BQ induced lung tumors (47% and 26%, respectively). However, when BN was fed with BL, tumorigenicity was lowered to 38%. BL alone was not tumorigenic. Thus, the mutagenicity of betel quid and its ingredients is correlated with tumorigenicity.     

Assessment of the mutagenic potential of ethanol auto engine exhaust gases by the Salmonella typhimurium microsomal mutagenesis assay, using a direct exposure method.

The mutagenic activity of the new Brazilian fuel, ethanol, was determined by employing the Salmonella typhimurium microsomal mutagenesis assay (TA97, TA98, TA100, TA102, and TA104) and a direct exposure method. This methodology was first used to determine the mutagenic activity of gasoline, revealing mutagenic activity of base-pair substitution without any need for metabolic activation, indicating the presence of direct-action mutagens. Experiments with ethanol suggest an indirect mutagenic activity of the oxidant type. The exposure system was considered suitable for future studies of gaseous mixtures.     

Chemopreventive Effects of the Juice of Vitis coignetiae Pulliat on Two-Stage Mouse Skin Carcinogenesis

Our study revealed the inhibitory effect of Vitis coignetiae Pulliat, known as Yamabudo in Japan, at the stages of multi-step carcinogenesis. The juice of Vitis coignetiae (Y-grape juice) was antimutagenic toward dimethylbenzo[a]anthracene (DMBA), aflatoxin B1, and benzo[a]pyrene in the Ames test. The Y-grape juice was also antigenotoxic in the micronucleus test using HepG2 cells toward DMBA and aflatoxin B1. Topical and oral administration of the Y-grape juice to mice inhibited the induction of inflammation of 12-O-tetradecanoylphorbol-13-acetate (TPA). Topical and oral administration of the Y-grape juice significantly decreased the incidence and mean number of tumors in mice skin with the 2-stage tumorigenesis protocol. To elucidate the mechanisms underlying the antiinflammatory and antitumor promotion activity of the Y-grape juice, the effect of Y-grape juice on cyclooxygenase-2 (COX-2) activity in mouse ear treated with TPA was studied. Both topical and oral application of the Y-grape juice inhibited the TPA-induced increase in COX-2 activity. Caftaric acid, isolated and identified from the Y-grape juice, was antimutagenic toward DMBA and prevented TPA-induced inflammation in mice, suggesting caftaric acid participates in chemopreventive effect/activities of Y-grape juice.     

松茸提取物体外抑制染发剂致突变作用

目的　寻找安全有效的抗突变生物资源 ,为降低染发剂致突变危害提供实验依据。方法　采用修改的Ames试验 ,观察真菌植物松茸提取物对染发剂致突变作用的影响。结果　松茸提取物能显著抑制染发剂的致突变作用 (P <0 0 1) ,对测试菌株TA97、TA98和TA10 0 的诱发回变菌落形成的抑制率最高分别达到 96 9% ,99 6 %和 95 4 % ,其抑制作用间存在明显的剂量 反应关系。结论　松茸提取物对染发剂致突变具有显著的抑制和抗突变作用     

A fraction of beech wood mutagenic in the Salmonella/mammalian microsome assay

Summary Base-pair substitution mutagens were isolated from the dusts of several untreated samples of beech wood and tested for mutagenicity in the Salmonella/mammalian microsome assay. These compounds reverted Salmonella typhimurium his^– TA100 in the presence of Aroclor-induced rat S9. These mutagens were found to be toxic to the cells when tested in a histidine-rich medium (complete medium). Mutagenicity of the non-fractionated wood-dust extracts due to the presence of some inhibitory compounds of wood could not be confirmed significantly. These inhibitors counteracted the reversion of bacteria when the known mutagens, such as benzo(a)pyrene, aflatoxin B₁ and ethyl methanesulfonate, were tested. The results indicate that beech wood-dust contains mutagenic constituent(s) which may contribute to their assumed tumor bearing effects among wood-workers.     

The results of microbial mutation test for forty-three industrial chemicals

The mutagenicity of 43 industrial chemicals in Salmonella typhimurium (TA98, TA100, TA1535, TA1537, and TA1538) and Escherichia coli (WP2uvrA) was examined. The output of these chemicals in Japan is more than a million kilograms per year. The mutation test was carried out under the condition of absence and presence of rat microsomal activation. Two chemicals, hexamethylenetetramine and 4,4'-methylenediphenyldiisocyanate, showed mutagenic activity in S. typhimurium TA98 and TA100 by metabolic activation. Hexamethylenetetramine also showed mutagenic activity in TA98 without microsomal activation. No mutagenic activity was observed in the 41 chemicals including 4 volatile and gaseous compounds.     

Nonmutagenicity of curcumin and its antimutagenic action versus chili and capsaicin

Turmeric, which is one of the commonly used spices in Indian cooking, was tested for mutagenicity using the Ames test. The alcoholic extract of fresh or dried turmeric, its principal components, and pyrolyzed turmeric powder and curcumin were tested for mutagenicity in Salmonella typhimurium strains with and without metabolic activation. None of these were mutagenic in all the tester strains. Chilies (which are used with turmeric powder) and their principal alkaloid capsaicin were mutagenic in the TA 98 with S9 mixture. We tested curcumin, which is the principal component of turmeric, for its antimutagenic effect. It showed dose-dependent decreases in mutagenicity of chili extract and capsaicin. Also, we compared the antimutagenicity of curcumin with other known antioxidants, including BHA, vitamins E and C, and vegetable oils. These all showed dose-dependent decreases in mutagenicity of chili extract and capsaicin. These studies show that although there are few mutagenic principles in Indian food, there is still quite a large number of antimutagenic principles in the Indian diet that will modulate the activity of environmental mutagens.