Sister Chromatid Exchange Test Research Articles

In vitro genotoxic and antigenotoxic effects of an exopolysaccharide isolated from Lactobacillus salivarius KC27L

Exopolysaccharide isolated from Lactobacillus salivarius (new genus name Ligilactobacillus) KC27L strain (EPSKC27L) exhibits antioxidant properties with 1,1-diphenyl-2-picrylhydrazase (DPPH) radical and superoxide anion radical (O2-.) scavenging effect and iron ion (Fe2+) chelating activity. This study aimed to investigate the in vitro genotoxic effects of EPSKC27L alone (12.50, 25.00, 50.00, and 100.00 μg/mL) and its antigenotoxic activity against DNA damage induced by mitomycin-C (MMC; 0.20 μg/mL), methyl methanesulfonate (MMS; 5.00 μg/mL), and hydrogen peroxide (H2O2; 100 μM). For this purpose, chromosome aberration (CA), sister chromatid exchange (SCE), micronucleus (MN), and comet assays were performed in human peripheral lymphocytes. In addition, the structure of EPSKC27L was investigated in the scanning electron microscope (SEM). EPSKC27L alone did not cause a significant genotoxic effect in CA, SCE, MN, and comet tests. EPSKC27L significantly decreased the frequency of CA, SCE, and MN induced by MMC and MMS. EPSKC27L also significantly reduced DNA damage induced by H2O2. This study showed that the EPSKC27L alone has no genotoxic risk at these concentrations and shows antigenotoxic activity against MMC, MMS, and H2O2. Consequently, EPSKC27L was found to exhibit chemopreventive activity against genotoxic agents. This effect is believed to be due to the antioxidant properties of EPSKC27L.

Cytotoxic, genotoxic, oxidative, and irritant effects of zinc pyrithione in vitro

Zinc pyrithione is an organometallic compound with antimicrobial activity used in many industrial products. In this study, cytotoxicity (cell viability, lactate dehydrogenase release, proliferation rate, and mitotic index) and genotoxicity (sister chromatid exchange and micronucleus test) of zinc pyrithione on human lymphocytes were determined. Intracellular zinc concentrations were determined by inductively coupled plasma-optical emission spectrometry. Intracellular antioxidant/oxidant status was evaluated by total antioxidant capacity and total oxidative status assays. Its irritation potential was investigated using the hen’s egg test chorioallantoic membrane model. Up to the highest concentration of 1000 nmol/L, ZnPT did not cause genotoxicity and did not change the proliferation index. Above 500 nmol/L, zinc pyrithione caused an increase in lactate dehydrogenase, oxidative stress, and intracellular zinc levels, while decreasing cell viability and mitotic index level. At 1000 nmol/L, zinc pyrithione caused slight irritation. These results suggest that zinc pyrithione may exert toxic effects via increased oxidative stress on human cellular systems.

Novel polymeric microspheres: Synthesis, enzyme immobilization, antimutagenic activity, and antimicrobial evaluation against pathogenic microorganisms.

New polymeric microspheres containing azomethine (1a-1c and 2a-2c) were synthesized by condensation to compare the enzymatic properties of the enzyme glucose oxidase (GOx) and to investigate antimutagenic and antimicrobial activities. The polymeric microspheres were characterized by elemental analysis, infrared spectra (FT-IR), proton nuclear magnetic resonance spectra, thermal gravimetric analysis, and scanning electron microscopy analysis. The catalytic activity of the glucose oxidase enzyme follows Michaelis-Menten kinetics. Influence of temperature, reusability, and storage capacity of the free and immobilized glucose oxidase enzyme were investigated. It is determined that immobilized enzymesexhibit good storage stability and reusability. After immobilization of GOx in polymeric supports, the thermal stability of the enzyme increased and the maximum reaction rate (Vmax ) decreased. The activity of the immobilized enzymes was preserved even after 5 months. The antibacterial and antifungal activity of the polymeric microspheres were evaluated by well-diffusion method against some selected pathogenic microorganisms. The antimutagenic properties of all compounds were also examined against sodium azide in human lymphocyte cells by micronuclei and sister chromatid exchange tests.

Anticancer and antiangiogenesis activities of novel synthesized 2-substitutedbenzimidazoles molecules

In this study, novel 2-substituted benzimidazoles molecules having triazole, thiadiazole, and oxadiazole rings were synthesized and were evaluated by anticancer, antioxidant/oxidant status, genotoxicity, and antiangiogenesis assays. Anticancer activity of the compounds was determined by MTT (0.5, 5, and 50 $\mu $g/mL) and lactate dehydrogenase (LDH) release assays against human prostate and breast cancer cells. Oxidative status of cells was elicited by total oxidative stress and total antioxidant capacity methods. Chick chorioallantoic membrane assay was used to evaluate the antiangiogenic activity. Genotoxicity was evaluated by the sister chromatid exchange (SCE) and micronucleus (MN) tests in lymphocyte cultured human blood. Our results showed that some of the compounds synthesized had significant antiproliferative activity against both cancer cell lines (between 4.54 $\pm $ 0.35 and 20.17 $\pm $ 3.15 $\mu $g/mL), with higher inhibition of the breast cancer, and caused inhibition of LDH release with a linear correlation to MTT results. Moreover, the 5 $\mu $g/mL dose of these molecules led to an increase in antioxidant levels. Compounds had antiangiogenic effectiveness in a dose-dependent manner. Additionally, all of the compounds did not affect SCE and MN levels compared to controls. In conclusion, these newly synthesized molecules can be a resource of new anticancer agents with their nongenotoxic, antiproliferative, and antiangiogenic properties.

Synthesis, antimicrobial and antimutagenic effects of novel polymeric-Schiff bases including indol

Herein, the synthesis and characterization of three new polymeric-Schiff bases including indol (L1, L2, L3) were reported. The antibacterial and antifungal activity of all compounds were investigated by the well-diffusion method against some selected microorganisms as potential antimicrobial agents. In addition, the anti-genotoxic properties of these polymeric-Schiff bases were examined against sodium azide in human lymphocyte cells by micronuclei (MN) and sister chromatid exchange (SCE) tests.

Assessment of genome stability in various breeds of cattle.

Chromosomal instability is a type of genome instability involving changes in genetic information at the chromosomal level. The basic tests used to identify this form of instability are sister chromatid exchange (SCE) tests and identification of fragile sites (FS). SCE is the process by which sister chromatids become fragmented as a result of DNA strand breakage and reassembly, followed by exchange of these fragments. FS can be observed in the form of breaks, gaps or constrictions on chromosomes, which often result from multiple nucleotide repeats in DNA that are difficult to replicate. The research material was the peripheral blood of ten breeds of cattle raised in Poland, including four native breeds covered by a genetic resources conservation programme, i.e. Polish Red, Polish Red-and-White, White-Backed, and Polish Black-and-White, as well as Polish Holstein-Friesian, Simmental, Montbéliarde, Jersey, Limousine and Danish Red. Two tests were performed on chromosomes obtained from in vitro cultures: SCE and FS. The average frequency of SCE was 5.08 ± 1.31, while the incidence of FS was 3.45 ± 0.94. Differences in the incidence of SCE and FS were observed between breeds. The least damage was observed in the Polish Red and White-Backed breeds, and the most in Polish Holstein-Friesians. The most damage was observed in the interstitial part of the chromosomes. Age was shown to significantly affect the incidence of SCE and FS. Younger cows showed less damage than older ones (SCE: 4.84 ± 1.25; 5.34 ± 1.24; FS: 3.10 ± 0.88, 3.80 ± 0.92).

In vitro cytotoxic and genotoxic effects of newly synthesised boron ionic liquids

In this study, new molecules containing boron were added to the family of ionic organic compounds, in particular, ionic liquids with a cationic center. This study aimed to determine the cytotoxic and genetic effects of a total of four newly synthesised borenium and borinium compounds on human peripheral lymphocytes in vitro. Human peripheral lymphocytes were obtained from heparinised blood samples collected from healthy females aged between 29 and 32 years, with no history of exposure to toxic agents. The cytotoxicity was assayed via the MTT (3-(4.5-dimethylthiazole- 2-yl)-2.5-diphenyltetrazolium-bromide) and LDH (lactate dehydrogenase) tests; the genotoxicity and cytotoxicity, via the micronucleus (MN) and sister chromatid exchange (SCE) tests. The results showed that the borenium compounds did not exhibit cytotoxic activity in the MTT and LDH tests even in high concentrations, the borinium compound did not exhibit cytotoxic effects in lower concentrations in vitro. The borenium compounds did not show genotoxic effects in SCE and MN tests. However, at a high concentration, borinium increased the micronucleus rate in comparison to the negative control group. The obtained results suggest that these newly synthesised cationic boron compounds can be used reliably in health, cosmetics or other industries, taking into consideration their types and concentrations.

Genotoxic risk evaluation of cleaning workers

Background and Aim: Cleaning agents are used in large quantities by millions of people throughout the world for disinfection and surface maintenance. Although there is a complex pattern of exposure to cleaning agents and resulting health problems among cleaners, genotoxic risks of cleaners as an occupational group are uncertain. In the present study, possible genotoxic effects of exposing to cleaning agents in peripheral lymphocytes of cleaners were investigated. Materials and Methods: In this study, possible genotoxic risks of cleaning workers were investigated by sister chromatid exchange (SCE) and chromosomal aberrations (CAs) tests. The frequencies of SCE and CA were determined in peripheral blood samples taken from 32 cleaning workers exposed to cleaning agents and 20 healthy controls as the control group. Cell kinetic parameters of mitotic index (MI) and proliferation index (PI) were also detected for determining the possible cytotoxic effects. Data analysis was perfomed using SPSS (17.0) package program. Results: A significant SCE formation was found in the peripheral blood of cleaners in comparison with the control group (P 0.05). The CA values were correlated with both the working period and the ages of the cleaning workers. No marked differences were detected concerning PI and MI indices between the workers and controls. Conclusion: The results of this study suggest that cleaning workers may have weak genotoxic risk due to occupational exposure.

Importance of the Toxicological Tests in the Application and Safety of Ozone Therapy

Until today, there is not any official registry of the different routes of systemic ozone therapy. With the aim to prove the safety of this therapy, several ways of ozone (O3) applications were evaluated, such as rectal insufflation (RI), major autohemotherapy (M-AHT) and intraperitoneal application (IP). For RI, some toxicological tests were performed such as: acute, sub-chronic, mutagenic (bone marrow chromosomic aberrations and micronucleus), teratogenic and irritation studies (at 40 mg/L and 10 mL during 15 days). For M-AHT, acute toxicological (in rats with 21, 47 and 64 mg/L and a volume of 2 mL with daily evaluation up to 15 days) and mutagenic (chromosomal aberration analysis, micronucleus assay and sister chromatid exchange test) studies were performed. For IP application, subchronic (O3 was administered during 15 days in mice at concentrations of 11, 29 and 35 mg/L and volumes of 80 mL/kg) and genotoxic (cytotoxic and clastogenic activity) studies were evaluated. All the toxicological studies performed for the O3 RI fulfilled the requirements established for an official registry (no deleterious effects were observed). However, more toxicological studies must be done with respect to M-AHT and IP O3 applications in order to prove the complete safety of these ways.

4,4’- Isopropylidenediphenol – inhalable fraction. Documentation of proposed values of occupational exposure limits (OELs)

4,4’- Isopropylidenediphenol – inhalable fraction. Documentation of proposed values of occupational exposure limits (OELs)

Cytogenetic investigation in two endangered pig breeds raised in Southern-Italy: Clinical and environmental aspects

Representative groups of animals of two endangered local pig breeds (Casertana and Nero Siciliano, both with black skin and raised in Southern-Italy) were cytogenetically investigated and compared to check for the presence of chromosomal abnormalities and to test their chromosome stability by sister chromatid exchange (SCE) test, in their normal breeding conditions. Forty-two Casertana pigs (22 males and 20 females, raised in 3 farms) and 39 Nero Siciliano pigs (19 males and 20 female, raised in 3 farms) were investigated. All animals showed normal CBA- and RBA-banded karyotypes (2n = 38), except for two Nero Siciliano boars (both from the same farm) which showed 2n = 37 being heterozygous carrier of rob (15;17). The translocation was confirmed by FISH-mapping with specific BAC-clones. Both animals were probably hybrids from crosses with the wild pig (2n = 36) present in the Nebrodi mountains where Nero Siciliano is reared with extensive or semi-extensive systems. SCE-test applied on all studied animals revealed no statistical differences between the SCE-mean number of Casertana (7.13 ± 3.20) and Nero Siciliano (6.87 ± 3.12) breeds. Statistical differences were found between SCEs mean values of males (7.26 ± 3.38) and females (6.59 ± 2.90) of Nero Siciliano breed, as well as between females of Casertana (7.24 ± 3.26) and Nero Siciliano (6.59 ± 2.90) breeds, while no statistical differences were found between SCE mean values of males of Casertana (6.98 ± 3.10) and Nero Siciliano (6.45 ± 2.97) breeds, as well as between males and females of Casertana breed.

In vitro genotoxic and cytotoxic effects of some paraben esters on human peripheral lymphocytes

Parabens (PBs) are p-hydroxybenzoic acid ester compounds commonly employed as antimicrobial preservatives, mainly in food, cosmetic, and pharmaceutical products. The aim of the present study was to investigate the genotoxic and cytotoxic effects of some paraben esters (butyl paraben, propyl paraben, isobutyl paraben, and isopropyl paraben) on human peripheral lymphocytes, using in vitro sister chromatid exchange (SCE), chromosome aberration (CA), and cytokinesis-block micronucleus (CBMN) tests. Lymphocyte cultures were treated with four concentrations of PBs (100, 50, 25 and 10 µg/mL) for 24 and 48 h. Paraben esters significantly induced MN formations as compared to solvent control. Furthermore, butyl paraben and propyl paraben increased MN formations a concentration-dependent manner at 24 and 48 h. PBs increased the CA at 24 and 48 h. However, this increase was not meaningful for butyl paraben and isopropyl paraben at 48 h when compared with solvent control. Butyl, isobutyl, and isopropyl paraben significantly increased the SCE at 24 and 48 h. However, propyl paraben did not induce SCE meaningfully in both treatment periods. A significant decrease in the cytokinesis-block proliferation index and mitotic index was observed in cells exposed to all concentrations of PBs at 24 and 48 h. However, proliferation index was not affected at all concentrations of PBs after 24 h treatment, although it was decreased at the highest concentration of PBs at 48 h. It is concluded that all of the paraben esters used in this study have highly genotoxic and cytotoxic effects on human lymphocytes cells in vitro.

Evaluación del efecto genotóxico y mutagénico en linfocitos humanos expuestos a nanotubos de carbono modificados

Objetivo: evaluar efecto genotóxico y mutagénico en linfocitos humanos expuestos a nanotubos de carbono (NTC) prístinos y dopados con Nitrógeno. Métodos: linfocitos humanos fueron expuestos a NTC dopados y prístinos (0.08, 0.09, 0.1mg/mL), se evaluó alteraciones cromosómicas e intercambio de cromátidas hermanas (ICH). Resultados: se presentaron rupturas cromatídicas y cromosómicas en linfocitos expuestos a 0.1mg/mL y 0.08mg/mL de NTC prístinos. NTC dopados, indujeron cromosomas dicéntricos y anillos cromosómicos. Se presentó diferencia significativa en el porcentaje de ICH de células tratadas con NTC dopados versus control negativo y NTC prístinos (p<0.0001). Conclusión: la concentración más alta de NTC prístinos indujo daños cromatídicos y cromosómicos; aunque el porcentaje de la población con daño fue inferior al 10%, se consideran perjudiciales para las células. Linfocitos tratados con NTC dopados presentaron menores porcentajes de AC y altos valores en ICH, lo que muestra mayor reparación de material genético con estos compuestos.

Evaluation of teratogenicity and genotoxicity induced by kramecyne (KACY)

Kramecyne (KACY), a polymer isolated from Krameria cytisoides Cav, has anti-inflammatory, anti-nociceptive, anti-arthritic and anti-ulcerogenic properties. As a part of standard preclinical safety tests, the present study sought to determine potential developmental toxicity (in female rats) and genotoxicity (in male mice) of KACY. Pregnant female rats were divided into six groups: the negative control (vehicle), the positive control (250 mg/kg of acetylsalicylic acid (ASA)), and four experimental groups (50, 250, 500 and 1000 mg/kg of KACY). To evaluate genotoxicity by in vivo micronuclei (MN) and sister chromatid exchange (SCE) tests, male mice were divided into five groups: the negative control (vehicle), the positive control (1.5 and 2.5 mg/kg of doxorubicin for MN and SCE, respectively), and three experimental groups (50, 500 and 1000 mg/kg of KACY). All treatments were administered by oral gavage. A slight maternal toxicity was evidenced by lower weight gain for rats receiving 500 and 1000 mg/kg of KACY, but no fetal malformations were found. However, there were less live fetuses/litter and greater post-implantation loss/litter at these two doses. Manifestations of developmental toxicity were limited to a higher rate of skeletal alterations. The MN tests did not evidence genotoxicity or cytotoxicity. KACY caused a slightly but significantly increased frequency of SCE. Although KACY-treated rats had skeletal alterations, these apparently were not caused by a mechanism of genotoxicity. Furthermore, the same administration in adult male mice did not produce genotoxicity. Hence, KACY herein proved to be safe for rats during the period of organogenesis.

Anti-mutagenic and Anti-oxidant Potencies of Cetraria Aculeata(Schreb.) Fr.,Cladonia Chlorophaea(Flörke ex Sommerf.) Spreng. andCetrelia olivetorum(Nyl.) W.L. Culb. & C.F. Culb.).

In this study, the mutagenic and anti-mutagenic effects of methanol extract of three lichen species (Cetraria aculeata, Cladonia chlorophaea and Cetrelia olivetorum) were investigated by using E. coli-WP2, Ames-Salmonella (TA1535 and TA1537) and sister chromatid exchange (SCE) test systems. The results obtained from bacterial test systems demonstrated that methanol extracts of three lichen species have strong anti-mutagenic potencies on TA1535, TA1537 strains and to a lesser extent on E. coli-WP2 strain. The anti-oxidant level of human lymphocytes cells was determined in order to clarify the mechanism underlying the anti-mutagenic effects of these lichen species. Co-treatments of 5, 10 and 20 µg/mL concentrations of these three lichen species with AFB decreased the frequencies of SCE and the level of MDA and increased the amount of SOD, GSH and GPx which decreased by aflatoxin. The findings of this work have clearly demonstrated that Cetraria aculeata, Cladonia chlorophaea and Cetrelia olivetorum have significant anti-mutagenic effects which are thought to be partly due to the anti-oxidant activities and the interaction capability of lichen extracts with mutagen agents (Sodium azide, acridin, N-methyl-N'-nitro-N-nitrosoguanidine and aflatoxin B1).

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 1000µg/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 200µg/ml) of Anilofos for 24 and 48h. 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 200µg/ml concentrations at 24h treatment periods and at 50, 100 and 200µg/ml concentrations in 48h 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.

Genotoxic effects of 4-methylimidazole on human peripheral lymphocytes in vitro

4-Methylimidazole (4-MEI), a heterocyclic organic chemical compound, is widely found in many foods and consumed by people worldwide. In this research, we aimed to investigate the cytotoxic and genotoxic effects of 4-MEI on human lymphocytes. For this purpose, human peripheral blood lymphocytes were treated with four concentrations of 4-MEI (300, 450, 600 and 750 μg/ml) for 24 h and 48 h periods and in vitro sister chromatid exchange (SCE), chromosome aberration (CA) and micronucleus (MN) tests were used. 4-MEI induced SCE in human peripheral lymphocytes at three highest concentrations (450, 600 and 750 μg/ml) in 48 h treatment period. CA and MN were induced in human peripheral lymphocytes at two highest concentrations of 4-MEI (600 and 750 μg/ml) in 24 h and 48 h treatment periods. The highest concentration of 4-MEI (750 μg/ml) induced MN formation more than the positive control MMC in 24 h treatment period. In addition, 4-MEI led to a decrease in MI at the highest concentration (750 μg/ml) in 24 h treatment period and at all concentrations in 48 h treatment period. 4-MEI reduced PI at all concentrations in 24 h treatment period and at all concentrations (expect the lowest) for 48 h treatment period. 4-MEI reduced nuclear division index (NDI) at 24 and 48 h treatment periods, even at the highest two concentrations, decreased more than the positive control MMC. Our results showed that 4-MEI pose a genotoxic and cytotoxic effects for human peripheral lymphocytes.

Oxcarbazepine-induced cytotoxicity and genotoxicity in human lymphocyte cultures with or without metabolic activation

There has been considerable debate about the relationship between epilepsy and cancer. Oxcarbazepine (OXC) is used for treating certain types of seizures in patients with epilepsy. There have been no detailed investigations about genotoxicity of OXC and its metabolites. Therefore, the aim of this study is to investigate the cytotoxic and genotoxic effects of OXC and its metabolites on cultured human lymphocytes. The cytotoxicity and genotoxicity of OXC on human peripheral blood lymphocytes were examined in vitro by sister chromatid exchange (SCE), chromosomal aberration (CA) and micronucleus (MN) tests. Cultures were treated with 125, 250 and 500 μg/ml of OXC in the presence (3 h treatment) and absence (24 h and 48 h treatment) of a metabolic activator (S9 mix). Dimethyl sulfoxide (DMSO) was used as a solvent control. OXC showed cytotoxic activities due to significant decreases in mitotic index (MI), proliferation index (PI) and nuclear division index (NDI) in the absence of S9 mix when compared with solvent control. Metabolites of OXC also significantly reduced MI and PI in cultures with S9 mix. OXC significantly increased the CAs, aberrant cells, SCE and MN values in the presence and absence of S9 mix. Our results indicated that both OXC and its metabolites have cytotoxic, cytostatic and genotoxic potential on human peripheral blood lymphocyte cultures under the experimental conditions. Further studies are necessary to elucidate the relationship between cytotoxic, cytostatic and genotoxic effects, and to make a possible risk assessment in patients receiving therapy with this drug.

Ziprasidone induces cytotoxicity and genotoxicity in human peripheral lymphocytes

It has been stated that some antipsychotic drugs might cause genotoxic and carcinogenic effects. Ziprasidone (ZIP) is commonly used an antipsychotic drug. However, its genotoxicity and carcinogenicity data are very limited. The cytotoxicity and genotoxicity of ZIP on human peripheral blood lymphocytes were examined in vitro by sister chromatid exchange (SCE), chromosome aberration (CA) and micronucleus (MN) tests in this study. Lymphocyte cultures were treated with 50, 75 and 100 μg/ml of ZIP in the presence and absence of a metabolic activator (S9 mix). Dimethylsulfoxide was used as a solvent control. While the cells were treated with ZIP for 24 h and 48 h in cultures without S9 mix, the cultures with S9 mix were exposed to ZIP for 3 h. ZIP and its metabolites can exert cytotoxic activities due to significant decreases in mitotic index, proliferation index and nuclear division index in the presence and absence of S9 mix. Statistically significant increases in CAs, aberrant cells and MN values in the presence and absence of S9 mix were found in cultures treated with ZIP. While ZIP significantly increased the SCE values in the absence of S9 mix at all concentrations, increased SCE values in cultures with S9 mix were not found to significantly at all concentrations tested. Our results indicated that both ZIP and its metabolites have cytotoxic, cytostatic and genotoxic potential on lymphocyte cultures under the experimental conditions. Further studies are necessary to make a possible risk assessment in patients receiving therapy with this drug.

Antioxidant and antigenotoxic potencies of Sempervivum armenum on human lymphocytes in vitro.

In this research, the genotoxic and antigenotoxic effects of methanol extract of Sempervivum armenum (MSA) were studied using micronucleus (MN) test and sister chromatid exchange (SCE) test systems in cultured human peripheral blood cells. According to the SCE and MN tests results, MSA reduced the genotoxic effects of aflatoxin B1. In order to explain the reason for the antigenotoxic effects of MSA, antioxidants levels were determined. Cotreatments of 5, 10, 20mg/mL concentrations of MSA with aflatoxin B1 decreased the frequencies of SCE, MN and the malondialdehyde level and increased the amount of superoxide dismutase, glutathione and glutathione peroxidase which were decreased by aflatoxin. The results of this experiment showed that MSA has strong antioxidative and antigenotoxic effects and this antigenotoxic activities of MSA can be due to the antioxidant activities.