Some substrates and inhibitors of cytosolic epoxide hydrolase induce sister-chromatid exchanges in mammalian cells, but do not induce gene mutations in Salmonella typhimurium and V79 cells

Trans-stilbene oxide, trans-β-methylstyrene, 7,8-oxide, trans-β-ethylstyrene, 7,8-oxide, trans-β-propylstyrene 7,8-oxide and 4-fluorochalcone oxide were investigated for genotoxic activity in bacterial and mammalian cells, in the absence of external xenobiotic-metabolising systems. All compounds strongly enhanced the frequency of sister-chromatid exchanges (SCE) in cultured human lymphocytes. None of them was mutagenic in Salmonella typhimurium (reversion of the his⁻ strains TA98, TA100 and TA104). The limit of detection was 1/20,000 to 1/10⁶ of the activity of the positive control, benzo[a]pyrene 4,5-oxide, depending on the compound and the bacterial strain. Trans-β-methylstyrene 7,8-oxide and 4-fluorochalcone oxide were additionally tested for induction of SCE and gene mutations in the same target cells, namely Chinese hamster V79 cells. Their influence on the level of SCE was similar to that observed in human lymphocytes, whilst gene mutations (at the hprt locus) were not induced. The four investigated styrene oxide derivatives are known to be excellent substrates for a mammalian enzyme, cytosolic epoxide hydrolase (cEH). 4-Fluorochalcone oxide is a potent selective inhibitor of this enzyme and is structurally similar to the investigated styrene oxide derivatives. These properties of the test compounds however cannot explain the observed discrepancies in the results, since the genetic end point (SCE versus gene mutations) was decisive, and SCE were induced in cEH-proficient human lymphocytes as well as in cEH-deficient V79 cells.     

Mutagenic and genotoxic effects of Anilofos with micronucleus,chromosome aberrations,sister chromatid exchanges and Ames test

We aimed to evaluate the mutagenic effect of Anilofos, organophosphate pesticide, by using Ames/Salmonella/microsome test. Its cytotoxic and genotoxic effects were also determined by chromosome aberration (CA), sister chromatid exchange (SCE) and micronucleus (MN) test in human peripheral blood lymphocytes. In the Ames test, five different concentrations of Anilofos were examined on TA97, TA98, TA100 and TA102 strains in the absence and presence of S9 fraction. According to the results all concentrations of this pesticide have not shown any mutagenic activity on TA97, TA100 and TA102 strains in the absence and presence of S9 fraction. But, 10, 100 and 1000 µg/plate concentrations of Anilofos were determined to be mutagenic on TA98 strain without S9 fraction. Lymphocytes were treated with various concentrations (25, 50, 100 and 200 µg/ml) of Anilofos for 24 and 48 h. The results of the assays showed that Anilofos did not induce SCE frequency, replication index and MN formation at all concentrations for both treatment periods. Anilofos significantly increased CA frequency at 100 and 200 µg/ml concentrations at 24 h treatment periods and at 50, 100 and 200 µg/ml concentrations in 48 h treatment periods. Additionally, it was determined that this pesticide decreased mitotic index and nuclear division index significantly. It was concluded that Anilofos has genotoxic and cytotoxic effects in human peripheral lymphocytes.     

Mutagenicity and genotoxicity of dicapthon insecticide

Mutagenic and genotoxic effects of dicapthon were investigated by using the bacterial reverse mutation assay in Salmonella typhimurium TA97, TA98, TA100 and TA102 strains with or without metabolic activation system (S9 mix), and chromosome aberrations (CAs), sister chromatid exchanges (SCEs), and micronucleus (MN) tests in human peripheral blood lymphocytes in vitro. Dicapthon was dissolved in dimethyl sulfoxide for all test systems. 0.1, 1, 10 and 100 μg/plate doses of dicapthon were found to be weakly mutagenic on S. typhimurium TA 98 without S9 mix. The human peripheral lymphocytes were treated with four experimental concentrations of dicapthon (25, 50, 100, and 200 μg/mL) for 24 and 48 h. Dicapthon increased the frequency of SCE only at the 100 μg/mL concentration for the 24 and 48 h applications. Dicapthon also induced abnormal cell frequency, CA/cell ratio and frequency of MN dose dependently for 24 and 48 h. Dicapthon showed a statistically significant cytotoxic effect by decreasing the mitotic index in all concentrations and a cytostatic effect by decreasing nuclear division index in 100 and 200 μg/mL concentrations for both treatment periods when compared with both untreated and solvent controls. These values decreased also in a dose dependent manner.     

The influence of automobile exhausts on mutagenicity of soils: contamination with, fractionation, separation, and preliminary identification of mutagens in the Salmonella/reversion assay and effects of solvent fractions on the sister-chromatid exchanges in human lymphocyte cultures and in the in vivo mouse bone marrow micronucleus assay

To test the assumption that automobile exhausts contribute to soil mutagenicity, two soils with low levels of mutagenic activities were exposed to traffic exhausts at a heavily charged junction of German motorways (Autobahnen) for 3, 7, 10, 13, 17, 21, and 26 weeks. Indeed, in the presence of a metabolic activation system from rat liver (S9), an average increase of 8 and 9 (4 and 12) revertants per gram per week was found in Salmonella typhimurium TA 98 (TA 100). In the absence of S9, meaningful measurements were impossible on account of a concurrent dose dependent increase of toxicity. No correlation between the increase of mutagenicity and the contents of polycyclic aromatic hydrocarbons (PAH) could be detected. In another series, soils sampled at the roadside and at distances of 10 and 50 m of five roads near Mainz expressed 10–20-fold higher mutagenicity (revertants per gram) under identical test conditions as compared with the average of agricultural soils. Toxic effects, however, again confounded the results and no correlation between the distance from roads and the levels of mutagenicity could be demonstrated. Subsequently, Soxhlet-extraction with the solvent sequence dichloromethane, acetone, and toluene/diethylketone was found to be an optimum procedure for soils at roadsides. The mass balance of solvent fractionation of such soils revealed that <2% each belonged to organic acids and bases, 4% to fractions designed polar neutrals, 8% to polar aromatics, 7% to dichloromethane solubles, and 79% to cylohexane solubles, among them 63% acetone soluble compounds. The major part of mutagenicity (55–65%) was present in the fraction of polar aromatics, followed by polar neutrals and the acetone subfraction of cyclohexane solubles (10% each) summarizing the results obtained with S. typhimurium TA 98, TA 98NR, YG 1021, YG 1024, TA 100, YG 1026, and YG 1029 with and without addition of S9. The modified tester strains, either deficient in nitroreductase (TA 98NR) or overproducing nitroreductase (YG 1021, 1026) or O-acetyl-transferase (YG 1024, 1026), indicated a major contribution of nitroarenes to soil mutagenicity. With respect to mutagenic PAH, high pressure liquid chromatography (HPLC) revealed that >90% of dibenz[a,h]anthracene (4.18 mg/kg soil), benzo[a]pyrene (1.96 mg), benzofluoranthenes (0.14 mg), and benz[a]anthracene (0.18 mg) were present in the acetone subfraction of cyclohexane solubles. Concentrations and mutagenic activities, however, did not correlate. Additional preparative and analytical HPLC of the solvent fractions of polar neutrals and polar aromatics, resulted in the tentative identification of 2-nitrofluorene. Analysis of the vertical profile of soil revealed an increase of mutagenicity per gram from the surface to a maximum at 5–15 cm depth and a subsequent decrease with very little activity remaining deeper than 35 cm. In human lymphocyte cultures, the fraction of polar aromatics, 0.01–0.3 μg/ml, induced 11.27±4.76–20.70±6.19 sister-chromatid exchanges (SCE) per cell in the absence of S9 (solvent control: 10.16±4.83 SCE per cell) and 12.77±6.53–17.87±4.93 SCE per cell in the presence of S9 (solvent control: 8.37±3.92 SCE per cell). However, no activities could be detected in the fractions of polar neutrals and non-polar neutrals. Again, negative results were obtained in the in vivo mouse bone marrow micronucleus assay at 2000 mg/kg p.o. with all fractions.     

Antimutagenic activity of soybeans fermented with basidiomycetes in Ames/Salmonella test

Soybeans fermented with either Phellinus igniarius or Agrocybe cylindracea inhibited the mutagenicity of the directly-acting mutagens: 4-nitro-o-phenylenediamine on Salmonella typhimurium strain TA 98 and NaN₃ on S. typhimurium strain TA 100; and indirectly-acting mutagens, 2-aminofluorene using strain TA 98 and benzo[a]pyrene using strain TA 100, in the presence of a supernatant solution from mammalian hepatic microsomes.     

Reduction in Ames Salmonella mutagenicity of mainstream cigarette smoke condensate by tobacco protein removal

The mutagenic activity of cigarette smoke condensates (CSC) made from tobacco before and after removal of protein was assessed by the Ames Salmonella assay in bacterial strains TA98 and TA100. Removal of protein and peptides from flue-cured tobacco via water extraction followed by protease digestion reduced the mutagenicity of the resultant CSC by 80% in the TA98 strain and 50% in the TA100 strain. Similarly, reductions of 81% in TA98 and 54% in TA100 were seen following water extraction and protease digestion of burley tobacco. The significant reductions in Ames mutagenicity following protein removal suggest that protein pyrolysis products are a principal contributor to the genotoxicity of CSC as measured in this assay.     

Genotoxic evaluation of extracts from Aplysina fulva, a Brazilian marine sponge

A range of biologically active secondary metabolites with pharmacological application has been reported to occur in marine sponges. The present study was undertaken to provide a set of data on the safety of a hydro-alcoholic extract (ALE) and an aqueous fraction (AQE) from Aplysina fulva Pallas, 1766 (Aplysinidae, Verongida, Porifera). Salmonella typhimurium strains TA97, TA98, TA100 and TA102, Escherichia coli strains PQ65, OG40, OG100, PQ35 and PQ37 and Balb/c 3T3 mouse fibroblasts were used to detect induction of DNA lesions by ALE and AQE. Assays used for these analyses were a bacterial (reverse) mutation assay (Ames test), the SOS-chromotest and the comet assay. Both extracts presented identical infrared 2-oxazolidone spectra. ALE treatment induced a higher frequency of type-4 comets, indicative of increasing DNA migration, in the alkaline comet assay. ALE also induced a weak genotoxic effect, as expressed by the induction factor (IF) values in the test with E. coli strain PQ35 (IF = 1.5) and by cytotoxic effects in strains PQ35, PQ65 and PQ37. Positive SOS induction (IF = 1.7) was detected in strain PQ37 treated with diluted AQE. No genotoxic effects were observed in strains PQ35, PQ65, OG40 and OG 100 after treatment with AQE dilutions. Using the bacterial (reverse) mutation test and survival assays with or without S9 mix, after 60 min of pre-incubation, we observed for strain TA97 treated with ALE a weak mutagenic response (MI = 2.2), while cytotoxic effects were seen for strains TA98, TA100 and TA102. AQE did not show mutagenic activity in any of the strains tested, but a weak cytotoxic effect was noted in strain TA102. Our data suggest that both ALE and AQE from A. fulva induce DNA breaks leading to cytotoxicity and mutagenicity under the conditions used.     

A comparative study on the antimutagenicity of atorvastatin and lovastatin against directly acting mutagens

Elevated levels of oxidative DNA lesions have been noted in many tumors and such damage is strongly implicated in the etiology of cancer. The cumulative risk of cancer increases with the fourth power of age and is associated with an accumulation of oxidative DNA damage. Many agents, synthetic or natural, that can inhibit mutation have been depicted as cancer chemopreventive agents. Antimutagenicity of the 3-hydroxy-3-methylgutaryl-CoA (HMG-CoA) reductase inhibitors atorvastatin and lovastatin was studied using the Ames Salmonella typhimurium assay. Directly acting mutagens, sodium azide (NaN₃) and 4-nitro-o-phenylenediamine (NPDA), were used to induce mutation in Salmonella strains TA98 and TA100. The antimutagenicity of lovastatin and atorvastatin was found to be significant (p < 0.01) and dose-dependent. The percentage inhibition of a 3 mg lovastatin-treated plate was found to be 79.9% and 61.8% against NPDA- and NaN₃-induced mutation to TA98 and TA100, respectively. Atorvastatin (0.5 mg/plate) inhibited NPDA-and NaN₃-induced mutation to TA98 and TA100 by 78.6% and 45.5%, respectively. Atorvastatin showed antimutagenic activity at lower concentrations than lovatstatin. The results of the present study regarding the antimutagenic activity of atorvastatin and lovastatin suggested their therapeutic application as cancer chemopreventive agents.     

Mutagenicity of ptaquiloside, the carcinogen in bracken, and its related illudane-type sesquiterpenes I. Mutagenicity in Salmonella typhimurium

Ptaquiloside, a potent carcinogen of an illudane-type sesquiterpene glycoside isolated from Pteridium aquilium, and its related compounds, hypolosides having the same nucleus isolated from the Pteridaceae, exhited marked mutagenicity in the modified Ames test with Salmonella typhimurian TA98 and A100 using a preincubation at pH 8.5 Illudins M and S, sesquiterpenes of the same illudane type from basidiomycetes, also exhibited mutagenicity. The structural requirements for mutagenicity are discussed.     

Comparative chemical analysis,mutagenicity, and genotoxicity of Petroleum refinery wastewater and its contaminated river using prokaryotic and eukaryotic assays

Concern on the toxicity of final wastewater generated by the petroleum refining industry has increased in recent years due to the potential health threats associated with their release into the waterways. This study determined the mutagenic and genotoxic potential of petroleum refinery wastewater and a receiving river using the Ames fluctuation test on Salmonella typhimurium strains TA100 and TA98, SOS chromotest on Escherichia coli PQ37, and piscine peripheral micronucleus (MN) assay. Analyses of the physicochemical parameters, heavy metal, and organic contents of the samples were also performed. Ames test result showed that the two tested samples were mutagenic with TA100 strain as the more responsive strain for both the refinery wastewater and the river sample in terms of the calculated mutagenic index. A similar result was obtained in the SOS chromotest; however, the E. coli PQ37 system recorded a slightly higher sensitivity for detecting genotoxins than the Salmonella assay in the two samples. MN data showed induction of a concentration-dependent significant (p < 0.05) increase in the frequency of MN by both samples when compared with the negative control. Generally, the refinery wastewater induced the highest mutagenicity and genotoxicity compared to the river sample in the three assays used. Haemoglobin, platelets, red blood cells, mean corpuscular volume, total white blood cells, heterophils, haematocrit, and eosinophils reduced significantly with increased lymphocytes, basophils, mean corpuscular haemoglobin, and mean corpuscular haemoglobin concentration in fishes exposed to both samples. Total petroleum hydrocarbon, benzene, toluene, phenol index, polycyclic aromatic hydrocarbons, cadmium, mercury, nickel, lead, and vanadium contents analysed in the samples were believed to be responsible for the observed genotoxicity and mutagenicity. The findings of this study revealed that petroleum refinery wastewater is a potential mutagenic and genotoxic risk to the environment.

     

Genotoxicity assessment of new synthesized acridine derivative--3,6-diamino-10-methyl-9,10-dihydroacridine.

A new synthesized acridine derivative, 3,6-diamino-10-methyl-9, 10-dihydroacridine (AcrH), was tested for in vitro reverse mutations with Salmonella TA strains, chromosome aberrations and sister chromatid exchanges (SCE) in human lymphocytes, and for in vivo chromosome aberrations in bone marrow of mice. Using the classic plate incorporation method, mutagenicity of AcrH in bacterial cells (TA97a, TA98, TA100 and TA102) was observed in the experiments performed with, and without, rat liver S9 metabolic activation. The reverse mutation assay showed no difference in mutagenic activity between AcrH and acriflavine (Acr(+)) in the test with TA97. The results of in vitro chromosome aberrations assay revealed potential clastogenicity. The test using macroculture of human lymphocytes induced mainly chromatid gaps. The experiments with human lymphocytes revealed SCE-inducing effect of AcrH and Acr(+). In an in vivo study, AcrH given intraperitoneally to Balb/c mice did not cause any significant increase in the percentage of cells with aberrations compared to the negative control.     

Genotoxicity Evaluation of Irrigative Wastewater from Shijiazhuang City in China

In the present study, the wastewater sample collected from the Dongming discharging river in Shijiazhuang city was analysed using both chemical analysis and biological assays including the Salmonella mutagenicity test, micronucleus test and single-cell gel electrophoresis. Chemical analysis of the sample was performed using gas chromatography mass spectrometry and inductively coupled plasma mass spectrometry. The Salmonella mutagenicity test was performed on Salmonella typhimurium TA97, TA98, TA100 and TA102 strains with and without S9 mixture. The mice received the wastewater in natura through drinking water at concentrations of 25%, 50%, and 100%. One group of mice was exposed for 2 consecutive days, and the other group of mice was exposed for 15 consecutive days. To establish the levels of primary DNA damage, single-cell gel electrophoresis was performed on treated mouse liver cell. The concentrations of chromium and lead in the sample exceeded the national standard (GB20922-2007) by 0.78 and 0.43-fold, respectively. More than 30 organic compounds were detected, and some of the detected compounds were mutagens, carcinogens and environmental endocrine disrupters. A positive response for Salmonella typhimurium TA98 strain was observed. Mouse exposure via drinking water containing 50% and 100% of wastewater for 15 consecutive days caused a significant increase of MN frequencies in a dose-response manner. Mouse exposure via drinking water containing 50% and 100% of wastewater for 15 consecutive days caused a significant increase of the Olive tail moments in a dose-response manner. All the results indicated that the sample from the Dongming discharging river in Shijiazhuang city exhibited genotoxicity and might pose harmful effects on the local residents.     

Genotoxicity and DNA adduct formation of incense smoke condensates: comparison with environmental tobacco smoke condensates

Indoor air pollution has now been recognized as a potentially important problem for public health, since people spend most of their day in closed environments. Incense burning is possibly associated with elevated risks of leukemia and brain tumor in children from the epidemiological studies. Thus, evaluation of the genotoxicity of smoke condensates from incense burning is needed. We examined the genotoxicity of incense smoke condensates (ISC) using the Ames test in S. typhimurium strains with different mutagenic specificity and level of metabolic enzyme, the SOS chromotest in E. coli PQ37, and sister chromatid exchange assay in Chinese hamster ovary cells (SCE/CHO). The genotoxicity of environmental tobacco smoke condensates (TSC) was also evaluated by the three assays to compare with the genotoxicity of ISC, ISC showed a positive response in TA98, but not in TA100. It suggested that ISC only contained frame shift mutagens. The mutagenicity of ISC in both strains of TA98NR with deficient nitroreductase and TA98/1,8-DNP₆ with deficient O-acetyl-transferase was markedly decreased compared to that in TA98 strain. However, the mutagenicity was enhanced in YG1024 with overexpression of O-acetyltransferase activity. Thus, nitroarenes seemed to be responsible in part for the mutagenicity of ISC. Interestingly, all of the four ISC and two TSC samples showed a dose-dependent genotoxic response in the SOS chromotest with E. coli PQ37 but a low SCE induction of those samples were observed in CHO cells. When the genotoxicity was analyzed based on the condensates per one gram of original samples, the genotoxicity of two TSC condensates in prokaryotic cells was higher than that of four ISC samples except for the genotoxicity of TSC-2 in TA98 strain. However, the genotoxicity of certain ISC in eukaryotic cells based on the SCE/CHO assay was higher than that of TSC. To compare the covalent binding of DNA reactive intermediates of ISC and TSC to S. typhimurium TA98, the DNA adducts were evaluated by the ³²P-postlabeling method with butanol extraction version. Similar diagonal radioactive zone (DRZ) was observed between ISC and CSC. However, DNA adduct levels induced by TSC were much greater than that of ISC.     

Inhibitory effect of Teucrium ramosissimum extracts on aflatoxin B1, benzo[a]pyrene, 4-nitro-o-phenylenediamine and sodium azide induced mutagenicity: Correlation with antioxidant activity

The mutagenic potential of total oligomers flavonoids (TOF), ethyl acetate (EA) and petroleum ether (PE) extracts from aerial parts of Teucrium ramosissimum was assessed using Ames Salmonella tester strains TA98, TA100 and TA1535 with and without metabolic activation (S9). None of the different extracts produced a mutagenic effect. Likewise, the antimutagenicity of the same extracts was tested using the “Ames test”. Our results showed that T. ramosissimum extracts possess antimutagenic activity against all the tested genotoxicants (aflatoxin B₁, benzo[a]pyrene, 4-nitro-o-phenylenediamine and sodium azide) in the Salmonella assay systems used in this study. In addition, all extracts showed important free radical scavenging activity toward the radicals DPPH and ABTS except the PE extract.     

Kinetic study of monophenol and o-diphenol binding to oxytyrosinase

The complex reaction mechanism of tyrosinase involves three enzymatic forms, two overlapping catalytic cycles and a dead-end complex. The deoxytyrosinase form binds oxygen with a high degree of affinity, μM. The mettyrosinase and oxytyrosinase forms bind monophenols and o-diphenols, although the former is inactive on monophenols. Analytical expressions for the catalytic and Michaelis constants of tyrosinase towards phenols and o-diphenols have been derived. Thus, the Michaelis constant of tyrosinase towards monophenols and o-diphenols are related with the catalytic constants for monophenols and o-diphenols , respectively, and with the binding rate constants of the oxytyrosinase form with these substrates (k₊₄ and k₊₆, respectively), by means of the expressions and . From these expressions, we calculate the values of the binding rate constant of oxytyrosinase to the substrates (monophenols and o-diphenols) for tyrosinases from different biological sources, and reveal that the o-diphenols bind more rapidly to oxytyrosinase than the monophenols. In addition, a new kinetic constant (the Michaelis constant for o-diphenol in the monophenolase activity), is derived and determined. Thus, it has been shown that tyrosinase has apparently higher affinity towards o-diphenols in its monophenolase than in its diphenolase activity.     

Retinol (vitamin A) inhibition of dimethylnitrosamine (DMN) and diethylnitrosamine (DEN) induced sister-chromatid exchanges in V79 cells and mutations in Salmonella/microsome assays

When the Chinese hamster cell line V79 and the tester strain of Salmonella typhimurium TA100 were treated with the precarcinogens dimethylnitrosamine (DMN) or diethylnitrosamine (DEN) in the presence of S9 mix, a dose-dependent increase of sister-chromatid exchanges (SCE) in V79 cells and His+ revertants in TA100 resulted. DMN was a far more efficient SCE inducer than DEN, while DEN was a more efficient inducer of His+ revertants than DMN. Retinol (Rol) effectively inhibited DMN and DEN induced SCE in V79 cells and His+ revertants in TA100. Concurrent treatment of V79 cells with Rol at various doses and one dose of DMN or DEN in the presence of S9 mix caused a significant reduction of SCE as compared to SCE induced by DMN or DEN without Rol. Rol inhibition of DMN-induced SCE was dose-dependent. Rol was less efficient in inhibiting DEN-induced SCE, and no consistent dose-dependent inhibition was observed. At all doses, Rol significantly inhibited DMN and DEN induced mutation frequencies in TA100. At the highest dose of Rol (40 micrograms/plate), the inhibition of DMN and DEN induced His+ revertants reached about 90% and 60%, respectively. The possibility that Rol exerts its antimutagenic activities by inhibiting certain forms of the cytochrome P-450 isoenzymes required for activation of precarcinogens such as DMN and DEN is discussed.     

Effects of vanillin and o-vanillin on induction of DNA-repair networks: modulation of mutagenesis in Escherichia coli

Vanillin and its isomer o-vanillin have an effect on the adaptive and SOS responses, as well as mutagenesis, induced in Escherichia coli by N-methyl-N-nitrosourea (MNU) and UV irradiation, potentiating in some cases and suppressing in others. o-Vanillin markedly inhibited the MNU-induced adaptive response, while both vanillins potentiated the UV-induced SOS response. These phenomena appear to be responsible for the comutagenic or antimutagenic role of these chemicals in MNU and UV mutagenesis.     

Use of Salmonella typhimurium TA 98, YG 1024 and YG 1021 and deconjugating enzymes for evaluating the mutagenicity from smokers'' urine

Four smokers were chosen for their different smoking habits, and their declared cigarette consumption confirmed by urinary measurement of nicotine and its metabolites. The promutagenicity of their urine was evaluated by the Ames test, modified according to Kado et al. (Mutation Res., 31 (1983) 25–32) after extraction on XAD2 Amberlite resin. The different Salmonella typhimurium strains TA 98, YG 1021 and YG 1024 were compared to determine the presence of amino aromatic compounds in the urine of smokers of blond and black tobacco. The strain YG 1024 shows higher mutagenicity than TA 98 for extracts from the smoker's urine and more particularly from black tobacco smokers. In addition, the pretreatment of urine by external enzymatic systems (β-glucuronidase or arylsulfatase) reveals the presence in the urine of glucurono- and sulfoconjugated forms of promutagens, including amino aromatic compounds.     

In vitro cytogenetic effects of Andrographis paniculata (kalmegh) on arsenic

In vitro effects of arsenic in human peripheral lymphocytes (HPL) at three different doses – 3.6×10⁻⁴, 1.4×10⁻³ and 0.72×10⁻³ μM for 24 h before harvesting on sister chromatid exchanges (SCE), Cell cycle proliferative index/replicative index (CCPI/RI), %M₁, %M₂ and %M₃, population doubling time (PDT) and average generation time (AGT) were examined. Andrographis paniculata (commonly referred to as ‘kalmegh’) has been used for centuries in traditional Indian and Chinese herbal medicine as a safe, natural folk remedy for assorted health concerns. In the present study, kalmegh (0.01 μg/7 ml culture media) was used along with the highest dose of arsenic; the results showed that arsenic induced increase in these genotoxic endpoints were fairly diminished by kalmegh. In addition, mutagenic in vitro effect of ethyl methanesulphonate (EMS) was used as a positive control in this study. It is thus concluded from this study that Andrographis has a protective role in arsenic toxicity.