Mutagenic activity promoted by amentoflavone and methanolic extract of Byrsonima crassa Niedenzu

Byrsonima crassa is a plant pertaining to the Brazilian central savannah-like belt of vegetation and popularly used for the treatment of gastric dysfunctions and diarrhoea. The methanol extract contains catechin, tannins, terpenes and flavonoids; both mutagenic potential and antioxidant properties have been ascribed to flavonoids. The mutagenicity of some flavonoids is believed to be associated with the formation of reactive oxygen species and seems to depend on the number and position of hydroxyl groups. In the present study the mutagenic activity of the methanol, chloroform and 80% aqueous methanol extracts, as well as acetate and aqueous sub-fractions, of this medicinal plant were evaluated by Salmonella typhimurium assay, using strains TA100, TA98, TA102 and TA97a, and in mouse reticulocytes. The results showed mutagenic activity of the methanolic extract in the TA98 strain without S9, but no mutagenicity to mouse cells in any of the extracts. The acetate fraction showed strong signs of mutagenicity without S9, suggesting that in this enriched fraction were concentrated the compounds that induced mutagenic activity. The aqueous fraction showed no mutagenic activity. The TLC and HSCCC analyses of the acetate fraction with some standard compounds permitted the isolation of the quercetin-3-O-beta-D-galactopyranoside, quercetin-3-O-alpha-L-arabinopyranoside, amentoflavone, methyl gallate and (+)-catechin, of which only the amentoflavone exhibited positive mutagenicity to TA98 (+S9, -S9).     

Antimutagenicity of some flowers grown in Thailand

The mutagenicity of dichloromethane, methanol and water extracts of Antigonon leptopus Hook. & Arn., Curcuma sessilis Gage, Hibiscus rosa-sinensis Linn., Ixora coccinea Linn., Millingtonia hortensis Linn., Nelumbo nucifera Gaertn., Plumeria obtusa Linn., Punica granatum Linn., Rhinacanthus nasutus ((Linn.) Kurz.) and Syzygium malaccense ((Linn.) Merr.& Perry) before and after nitrite treatment was firstly investigated in the Ames test. Their antimutagenicity against the product of the reaction mixture of 1-aminopyrene nitrite model in the absence of metabolic activation on Salmonella typhimurium TA 98 and TA 100 was evaluated. The results showed that none of the samples was mutagenic. Most nitrite-treated samples but dichloromethane extracts of Hibiscus rosa-sinensis, Plumeria obtusa, Syzygium malaccense, methanol extract of Syzygium malaccense and water extract of Hibiscus rosa-sinensis were mutagenic. The nitrite treated methanol extract of Nelumbo nucifera exhibited the highest mutagenicity on both strains. All dichloromethane extracts of flowers decreased the mutagenicity induced by the product of 1-aminopyrene nitrite model on both tester strains. Methanol extract of Curcuma sessilis and Punica granatum (15 mg/plate) showed the highest antimutagenic activity in TA 98 and TA 100, respectively. The protective effects of these flower extracts might be due to the presence of antimutagenic components that were supposed to be flavonoids.     

Tinospora cordifolia, a safety evaluation

Tinospora cordifolia is one of the indispensable medicinal plants used in veterinary folk medicine/Ayurvedic system of medicine for the treatment of diverse diseases and recommended for improving the immune system by means of body resistance. In the current study, we evaluated the genotoxic risk of the aqueous extract of T. cordifolia (TC) in a battery of four different genotoxicity tests viz., Ames, in vitro chromosome aberration (CA), rodent bone marrow micronucleus (MN), and Comet assay. Experimental results confirmed that in Ames test up to 5000 μg/plate of TC did not exhibit any mutagenic effect in Salmonella typhimurium mutant strains (TA97a, TA98, TA100, TA102, and TA1535). In CA assay, TC was not clastogenic to human peripheral blood lymphocytes up to a concentration of 3000 μg/ml. In MN and Comet assays, TC was pre-treated for 7 days at three dose levels (150, 200 and 250 mg/kg body weight) orally to male Balb/c mice. The results showed that TC treatment did not display clastogenicity and DNA damaging effect in bone marrow erythrocytes and peripheral blood lymphocytes respectively.     

Ames mutagenicity tests of products from a heated potato-starch system

A charred sample was prepared from potato starch heated with ammonium carbonate at 600°C in a flask under a nitrogen stream. The water produced was collected and extracted with methylene chloride. The basic fraction obtained from the extract exhibited strong mutagenicity in Ames assays using Salmonella typhimurium strains TA98 or TA100 with metabolic activation (rat-liver S-9 mix). The basic fraction was further fractionated by silica gel column chromatography and subsequently by Scphadex column chromatography. Some of the resulting fractions exhibited strong mutagenic activities in S. typhimurium strain TA98 with S-9 mix.     

Mutagenicity and toxicity studies of p-phenylenediamine and its derivatives

The mutagenicity of p-phenylenediamine and its derivatives was tested using Ames Salmonella strains TA98 and TA100. p-Phenylenediamine was weakly mutagenic to TA98 with metabolic activation. 2-Nitro-p-phenylenediamine was directly mutagenic to both strains, while 2-methyl-p-phenylenediamine required S9 mix. All the test compounds induced a dose-related increase in chromosomal aberrations m Chinese hamster ovary (CHO) cells in the absence of the S9 mix. The mutagenicity and toxicity of these compounds did not correlate with their oxidation potentials, or any other tested physicochemical properties including the energy difference between the lowest unoccupied and the highest occupied molecular orbital, ionization potential, and dipole moment.     

Use of in vitro assays to assess the potential antigenotoxic and cytotoxic effects of saffron (Crocus sativus L.)

Saffron is harvested from the dried, dark red stigmas of Crocus sativus L. flowers. It is used as a spice for flavoring and coloring food and as a perfume. It is often used for treating several diseases. We assessed the antimutagenic, comutagenic and cytotoxic effects of saffron and its main ingredients using the Ames/Salmonella test system, two well known mutagens (BP, 2AA), the in vitro colony formation assay and four different cultured human normal (CCD-18Lu) and malignant (HeLa, A-204 and HepG2) cells. When only using the TA98 strain in the Ames/Salmonella test system, saffron showed non-mutagenic, as well as non-antimutagenic activity against BP-induced mutagenicity, and demonstrated a dose-dependent co-mutagenic effect on 2-AA-induced mutagenicity. The saffron component responsible for this unusual comutagenic effect was safranal. In the in vitro colony formation test system, saffron displayed a dose-dependent inhibitory effect only against human malignant cells. All isolated carotenoid ingredients of saffron demonstrated cytotoxic activity against in vitro tumor cells. Saffron crocin derivatives possessed a stronger inhibitory effect on tumor cell colony formation. Overall, these results suggest that saffron itself, as well as its carotenoid components might be used as potential cancer chemopreventive agents.     

Mutagenic activity of cytostatic methyl hydrazones with different strains of Salmonella typhimurium

Experiments are performed to ascertain the mutagenic properties of four new cytostatic methyl-hydrazones in the Ames test using different strains of Salmonella typhimurium. As could be demonstrated all four hydrazones are mutagenic per se without a metabolic activation through rat liver microsomes (S-9 fraction). Whereas the -chloroethyl hydrazones B1 and B2 cause a base-pair substitution with the strains TA100 and TA1535 the methyl-hydrazones EB4 and CyB4 both cause base-pair substitution with TA100 and frameshift mutation with TA98. At both strains the mutagenic activity of CyB4 ist powerful. Furthermore, no relation could be detected between the mutagenic properties of the methyl-hydrazones and their alkylating behaviour on 4-(4-nitrobenzyl)-pyridine.     

Biological and chemical studies on overheated brewed coffee

Vapour formed from overheated decaffeinated coffee was condensed and tested for mutagenicity using the Ames assay in Salmonella typhimurium strains TA98 and TA100. Vapour produced at 73 and 100 degrees C exhibited no mutagenicity. The basic fraction of vapour produced at 350 degrees C showed weak mutagenicity towards strains TA98 with metabolic activation. The chemical analysis of this fraction identified pyridines and pyrazines as the major constituents. None of the compounds identified in this fraction has been reported as mutagenic when tested in the Ames assay.     

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.     

An evaluation of acetone extracts from six plants in the AMES mutagenicity test

Acetone extracts from six plants were evaluated for mutagenic activity with the Salmonella/mammalian-microsome mutagenicity test (Ames) utilizing tester strains TA98 and TA100 and in the presence and absence of induced rat liver microsomes. Extracts from alfalfa (Medicago sativa), lettuce (Lactuca sativa) and thread-leaf groundsel (Senecio longilobus) produced only negative responses. Comfrey (Symphytum officinale) and tansy ragwort (Senecio jacobaea) extracts produced toxic responses that were abolished in the presence of the microsomal bioactivation system. Bracken (Pteridium aquilinum) and tansy ragwort extracts produced positive responses following bioactivation with the liver microsomal system. The results suggest that the Ames mutagenicity test may be of some value in initial evaluations for potential toxic effects of plants consumed by animals and man.     

Genotoxicity assessment through the Ames test of medicinal plants commonly used in Brazil

Ten medicinal herbs commonly used as popular medicine in Brazil—Bauhinia forficata L., Bauhinia variegata L., Cymbopogon citratus D.C. Stapf, Echinodorus macrophyllum (Kunth) Micheli, Hidrocotyle asiatica L, Matricaria chamomila L., Pfaffia iresinoides (Kunth) Sprengel, Plaffia paniculata (Martius) Kuntze, Phyllanthus tenellus Roxb, and Solidago microglossa D.C.—were tested for mutagenicity by the Ames test using Salmonella typhimurium TA 97a, TA 98, TA 100, and TA 104 strains, with and without metabolic activation. The genotoxicity assessment of these medicinal plants was performed in aqueous extracts 1:5. Seventy percent of these herbs presented mutagenic effects with at least one of the Ames strains used in this study. Bauhinia variegata L., E. macrophyllum K., and M. chamomilla L. showed no mutagenic activity. The mutagenic effects were detected mainly with the strains TA 98 related to frameshift mutations. The higher mutagenicity ratio was obtained with S. microglossa D.C. (known as arnica-do-Brazil) when TA 98 strain was used with metabolic activation (MR = 6.55) and with TA 97a strain with and without the addition of S9. Medicinal plants are now used by all the segments of the population, more intensively in the last years. These results indicate the need to establish rules to assess the safety of the use of medicinal herbs. © 1994 by John Wiley & Sons, Inc..     

N,N-diethylphenylacetamide, an insect repellent: absence of mutagenic response in the in vitro Ames test and in vivo mouse micronucleus test

N,N-diethylphenylacetamide (DEPA), a promising new insect repellent, was tested for mutagenicity in the in vitro Ames Salmonella/microsome mutagenicity test and the in vivo mouse micronucleus test. For the Ames test, DEPA was assayed both in the presence and absence of Aroclor 1254-induced rat-liver S-9 mix (5 and 20% S-9 fraction), using five tester strains of Salmonella typhimurium--TA97a, TA98, TA100, TA102 and TA104. For the micronucleus test, mice were exposed to DEPA through ip injection for 2 and 5 days in separate experiments, and bone marrow and peripheral blood were sampled 6 and 48 hr after the final injection, respectively. DEPA did not induce a mutagenic response in the Ames test, and mouse bone marrow and peripheral blood micronucleus tests. DEPA was not considered cytotoxic, as a depression of the percentage PCE was not observed at any dose in the range of 1 to 100 mg/kg body weight with either treatment protocol of the micronucleus test.     

Screening of medicinal plants used in South African traditional medicine for genotoxic effects

Dichloromethane and 90% methanol extracts from 51 South African medicinal plants were evaluated for potential genotoxic effects using the bacterial Ames and VITOTOX tests with and without metabolic activation. Dichloromethane extracts from bulbs of Crinum macowanii showed mutagenicity in strain TA98 with and without metabolic activation, whereas extracts from leaves of Chaetacme aristata and foliage of Plumbago auriculata showed mutagenicity and/or toxicity. Extracts from the leaves of Catharanthus roseus and twigs of Combretum mkhzense were mutagenic with metabolic activation only. The only 90% methanol extracts that were mutagenic in strain TA98 were from the leaves of C. roseus and Ziziphus mucronata in the presence of metabolic activation. No genotoxic effects were found in strain TA100 or in the VITOTOX test.     

Detection of genotoxicity and mutagenicity of chlorthiophos using micronucleus,chromosome aberration,sister chromatid exchange,and Ames tests

Potential mutagenic and genotoxic effects of Chlorthiophos, an organophosphate pesticide, were evaluated using four standard assays. Five different concentrations of the pesticide were tested by an Ames test using Salmonella typhimurium strains TA97, TA98, TA100, and TA102, with and without S9 metabolic activation. No concentrations of Chlorthiophos showed mutagenic activity on the TA97, TA100, and TA102 strains, with and without S9 fraction, but were all mutagenic to the TA98 strain without S9. Sister chromatid exchange (SCE), chromosome aberration (CA), and micronucleus (MN) tests were used to investigate the genotoxic effects of Chlorthiophos in human peripheral lymphocytes treated with 25, 50, 100, and 200 µg/mL concentrations of Chlorthiophos for 24 and 48 h. The nuclear division index (NDI), replication index (RI), and mitotic index (MI) were also calculated to determine the cytotoxicity of Chlorthiophos. No increase in SCE frequency was seen for any treatment period or concentration, but Chlorthiophos at 200 µg/mL increased the frequency of CAs. Increases in MN formation were only observed at Chlorthiophos concentrations of 200 µg/mL following 24 and 48 h treatments. Chlorthiophos treatment reduced the MI and NDI significantly, but had no effect on the RI. © 2014 Wiley Periodicals, Inc. Environ Toxicol 30: 937–945, 2015.     

Antigenotoxic, antimutagenic and ROS scavenging activities of a Rhoeo discolor ethanolic crude extract.

Rhoeo discolor is a legendary plant used for treatment of superficial mycoses in Mexican traditional medicine. Despite its extended use, it is not known whether it has side-effects. An ethanolic crude extract from Rhoeo discolor was prepared, its mutagenic capacity was investigated by the Ames test, and its genotoxic activity in primary liver cell cultures using the unscheduled DNA synthesis assay. This extract was not mutagenic when tested with Salmonella typhimurium strains TA97, TA98 and TA100, and it did not elicit unscheduled DNA synthesis in hepatocyte cultures. In addition, we explored the antimutagenic and antigenotoxic activities of the extract and its ROS scavenger behaviour. Our results show that Rhoeo extract is antimutagenic for S. typhimurium strain TA102 pretreated with ROS-generating mutagen norfloxacin in the Ames test, and protects liver cell cultures against diethylnitrosamine induction of unscheduled DNA synthesis even at 1.9 ng per dish, which was the lowest dose tested. A free radical scavenging test was used in order to explore the antioxidant capacity of Rhoeo extract, as compared with three commercial well-known antioxidants quercetin, ascorbic acid and tocopherol. Rhoeo extract showed less radical scavenging effect than quercetin, but similar to that of alpha-tocopherol and more than ascorbic acid. It is important to note that this extract was neither mutagenic in S. typhimurium nor genotoxic in liver cell culture, even at concentrations as high as four- and 166-fold of those needed for maximal antimutagenic or chemoprotective activities, respectively.     

Monitoring sãto paulo state rivers in brazil for mutagenic activity using the ames test

Organic extracts of raw water from 11 water courses of São Paulo State, Brazil, were collected during one year bimonthly and tested for mutagenicity using the Ames test, with strains TA98 and TA100 of Salmonella typhimurium with and without metabolic activation. The samples were extracted with XAD₂ resin and eluted with methanol and methylene chloride. From the 75 samples analyzed, 14 showed positive responses and 8 were considered marginal, making up 29% of mutagenic samples. The percentage of mutagenic samples in October (spring) was 9%, increasing to 64% in February (summer), and decreased to 9% again in August (winter). Paraiba do Sul river showed the higher percentage of mutagenic samples (67%) and Capivari river the highest mutagenic sample (1787 and 3265 revertants per liter for TA98 without and with S9, respectively). The amplitude of the mutagenic response was 39–3265 revertants per liter for TA98 and 83–467 for TA100. The mutagenic samples showed direct and indirect mutagens, and TA98 detected the majority of responses, indicating prevalence of frameshift mutagens in these samples. © 1993 John Wiley & Sons, Inc.     

In silico screening of chemicals for bacterial mutagenicity using electrotopological E-state indices and MDL QSAR software

Quantitative structure–activity relationship (QSAR) software offers a rapid, cost effective means of prioritizing the mutagenic potential of chemicals. MDL QSAR models were developed using atom-type E-state indices and non-parametric discriminant analysis. Models were developed for Salmonella typhimurium gene mutation, combining results from strains TA97, TA98, TA100, TA1535, TA1536, TA1537, and TA1538 (n = 3228), and Escherichia coli gene mutation tests WP2, WP100, and polA (n = 472). Composite microbial mutation models (n = 3338) were developed combining all Salmonella, E. coli, and the Bacillus subtilis rec spot test study results. The datasets contained 74% non-pharmaceuticals and 26% pharmaceuticals. Salmonella and microbial mutagenesis external validation studies included a total of 1444 and 1485 compounds, respectively. The average specificity, sensitivity, positive predictivity, concordance, and coverage of Salmonella models was 76, 81, 73, 78, and 98%, respectively, with similar performance for the microbial mutagenesis models. MDL QSAR and discriminant analysis provides rapid and highly automated mutagenicity screening software with good specificity, sensitivity, and coverage that is simpler and requires less user intervention than other similar software. MDL QSAR modules for microbial mutagenicity can provide efficient and cost effective large scale screening of compounds for mutagenic potential for the chemical and pharmaceutical industry.     

Effect of pyrolysis temperature on the mutagenicity of tobacco smoke condensate.

Tobacco smoke aerosols with fewer mutagens in the particulate fraction may present reduced risk to the smoker. The objective of this study was to test the hypothesis that the temperature at which tobacco is pyrolyzed or combusted can affect the mutagenicity of the particulate fraction of the smoke aerosol. Tobacco smoke aerosol was generated under precisely controlled temperature conditions from 250 to 550 degrees C by heating compressed tobacco tablets in air. The tobacco aerosols generated had a cigarette smoke-like appearance and aroma. The tobacco smoke aerosol was passed through a Cambridge filter pad to collect the particulate fraction, termed the smoke condensate. Although condensates of tobacco smoke and whole cigarette mainstream smoke share many of the same chemical components, there are physical and chemical differences between the two complex mixtures. The condensates from smoke aerosols prepared at different temperatures were assayed in the Ames Salmonella microsome test with metabolic activation by rat liver S9 using tester strains TA98 and TA100. Tobacco smoke condensates were not detectably mutagenic in strain TA98 when the tobacco smoke aerosol was generated at temperatures below 400 degrees C. Above 400 degrees C, condensates were mutagenic in strain TA98. Similarly, condensates prepared from tobacco smoke aerosols generated at temperatures below 475 degrees C were not detectably mutagenic in strain TA100. In contrast, tobacco tablets heated to temperatures of 475 degrees C or greater generated smoke aerosol that was detectably mutagenic as measured in TA100. Therefore, heating and pyrolyzing tobacco at temperatures below those found in tobacco burning cigarettes reduces the mutagenicity of the smoke condensate. Highly mutagenic heterocyclic amines derived from the pyrolysis of tobacco leaf protein may be important contributors to the high temperature production of tobacco smoke Ames Salmonella mutagens. The relevance of these findings regarding cancer risk in humans is difficult to assess because of the lack of a direct correlation between mutagenicity in the Ames Salmonella test and carcinogenicity.     

Investigation of extracts from (Tunisian) Cyperus rotundus as antimutagens and radical scavengers

This study evaluates mutagenic and antimutagenic effects of aqueous, total oligomers flavonoïds (TOF), ethyl acetate and methanol extracts from aerial parts of Cyperus rotundus with the Salmonella typhimurium assay system.The different extracts showed no mutagenicity when tested with Salmonella typhimurium strains TA98, TA100, TA1535 and TA1538 either with or without the S9 mix. On the other hand, our results showed that all extracts have antimutagenic activity against Aflatoxin B1 (AFB1) in TA100 and TA98 assay system, and against sodium azide in TA100 and TA1535 assay system. TOF, ethyl acetate and methanol extracts exhibited the highest inhibition level of the Ames response induced by the indirect mutagen AFB1. Whereas, ethyl acetate and methanol extracts exhibited the highest level of protection towards the direct mutagen, sodium azide, induced response. In addition to antimutagenic activity, these extracts showed an important free radical scavenging activity towards the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical. TOF, ethyl acetate and methanol extracts showed IC₅₀ value of 15, 14 and 20 μg/ml, respectively.Taken together, our finding showed that C. rotundus exhibits significant antioxidant and antimutagenic activities.     

苦荞降糖胶囊的致突变性研究

目的研究苦荞降糖胶囊的致突变性。方法分别采用Ames试验、小鼠骨髓嗜多染红细胞微核试验和小鼠精子畸形试验对基因水平和细胞水平的遗传损伤进行检测。结果该胶囊在0.1、0.5、1.0、2.0和5.0mg/皿的剂量下对TA97、TA98、TA100和TA102四株试验菌株均未引起自发回变菌落数增加;在1250和5000mg/kg体重剂量下均未引起小鼠骨髓嗜多染红细胞微核率和小鼠精子畸形率升高(字2检验,P>0.05)。结论该胶囊在基因水平和细胞水平均不具有致突变性。