Anticlastogenicity in cultured mammalian cells

Protective Effects of Fullerene C60 Nanoparticles and Virgin Olive Oil against Genotoxicity Induced by Cyclophosphamide in Rats

The potential effects of the fullerene C₆₀ nanoparticle (C₆₀) as well as virgin olive oil (VOO) against the cyclophosphamide- (CP-) induced cytotoxic and mutagenic effects were evaluated by two main methods: molecular intersimple sequence repeat (ISSR) assay and cytogenetic biomarkers. Thirty adult male rats were divided to five groups (control, CP, C₆₀, CP + C₆₀, and CP + VOO). CP was i.p. injected with a single dose of 200 mg/kg; C₆₀ and VOO were given orally (4 mg/kg dissolved in VOO and 1 ml, resp.) in alternative days for 20 days. The ISSR analysis revealed an increased in the DNA fragmentation level for liver and heart tissues represented by 21.2% and 32.6%, respectively, in the CP group. The DNA polymorphism levels were modulated and improved in CP + C₆₀ (8.9% and 12%) and CP + VOO (9.8% and 12.7%) for hepatic and cardiac tissues, respectively. The bone marrow cytogenetic analysis revealed that C₆₀ and VOO had significantly decreased the frequency of CP-induced chromosomal aberrations (chromosomal ring, deletion, dicentric chromosome, fragmentation, and polyploidy). Fullerene C₆₀ and VOO have ability to reduce DNA damage and decrease chromosomal aberrations. In conclusion, fullerene C₆₀ and VOO have protective effects against the CP-induced mutagenicity and genotoxicity. Fullerene C₆₀ and VOO open an interesting field concerning their potential antigenotoxic agents against deleterious side effects of chemotherapeutics.

Amelioration of the cyclophosphamide induced genotoxic damage in mice by the ethanolic extract of Equisetum arvense

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Plants like E. arvense posess not only nutritional value but therapeutic value as well.

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CPA is an important chemotherapeutic agent but is associated with various mutagenic and other toxic side effects.

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Ethanolic extract of the plant has immense protective effect against the genotoxic damage induced by the cyclophosphamide.

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GC–MS analysis of the extract shows various important phyto components which may be associated with its antimutagenic property.

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Plant can be used in cancer as a chemopreventive agent or even as a coadjuvant to chemotherapy to reduce the side effects associated with it.

In the present study, we evaluated the potential of the plant E. arvense against the cytotoxic and mutagenic effects induced by cyclophosphamide (chemotherapeutic agent) in the bone marrow cells of mice using the Chromosome assay (CA) and Mitotic index (MI) in vivo as the biomarkers. The study was performed following 3 protocols: pre-treatment, simultaneous treatment and post-treatment with the ethanolic extract of the plant. The results demonstrated that the plant extract was not cytotoxic and mutagenic and has a protective effect against the mutagenicity induced by cyclophosphamide in pre, simultaneous and post treatments and against its cytotoxicity as well. Because of its ability to prevent chromosomal damage, E. arvense is likely to open an interesting field concerning its possible use in clinical applications, most importantly in cancer as a chemopreventive agent or even as a coadjuvant to chemotherapy to reduce the side effects associated with it.

Antigenotoxic Effect of Trametes spp. Extracts against DNA Damage on Human Peripheral White Blood Cells

Trametes species have been used for thousands of years in traditional and conventional medicine for the treatment of various types of diseases. The goal was to evaluate possible antigenotoxic effects of mycelium and basidiocarp extracts of selected Trametes species and to assess dependence on their antioxidant potential. Trametes versicolor, T. hirsuta, and T. gibbosa were the species studied. Antigenotoxic potentials of extracts were assessed on human peripheral white blood cells with basidiocarp and mycelium extracts of the species. The alkaline comet test was used for detection of DNA strand breaks and alkali-labile sites, as well as the extent of DNA migration. DPPH assay was used to estimate antioxidative properties of extracts. Fruiting body extracts of T. versicolor and T. gibbosa as well as T. hirsuta extracts, except that at 20.0 mg/mL, were not genotoxic agents. T. versicolor extract had at 5.0 mg/mL the greatest antigenotoxic effect in both pre- and posttreatment of leukocytes. The mycelium extracts of the three species had no genotoxic activity and significant antigenotoxic effect against H2O2-induced DNA damage, both in pre- and posttreatment. The results suggest that extracts of these three species could be considered as strong antigenotoxic agents able to stimulate genoprotective response of cells.

Antimutagenic activity of ipriflavone against the DNA-damage induced by cyclophosphamide in mice

In the present study we evaluated the potential of ipriflavone against the cytotoxic and mutagenic effects induced by cyclophosphamide chemotherapeutic agent in bone marrow cells of mice, using the micronucleus assay in vivo on cells of bone marrow. The study was performed following three protocols: pre-treatment, simultaneous treatment and post treatment. The results demonstrated that ipriflavone has a protective effect against mutagenicity induced by cyclophosphamide in the pre-treatment and post-treatment and against the cytotoxicity in all treatments. There was variation between the genders in some of the experimental groups. To evaluate their possible mechanisms of action, it was performed the DPPH assay, which showed no ability to donate hydrogens, suggesting that it acts through other mechanisms. Due to its ability to prevent chromosomal damage, ipriflavone is likely to open an interest field concerning its possible the use in clinical applications.

Antigenotoxic effect of lipoic acid against mitomycin-C in human lymphocyte cultures

Antitumor agents are used in therapy against many forms of human cancer. One of these is mitomycin-C (MMC). As with many agents, it can interact with biological molecules and can induce genetic hazards in non-tumor cells. One of the possible approaches to protect DNA from this damage is to supply antioxidants that can remove free radicals produced by antitumor agents. Lipoic acid (LA) is known as one of the most powerful antioxidants. The aim of this study was to investigate antigenotoxic effects of LA against MMC induced chromosomal aberrations (CA), sister chromatid exchanges (SCE) and micronucleus (MN) formation in human lymphocytes. Lymphocytes were treated with 0.2 μg MMC/heparinized mL for 48 h. Three different concentrations (0.5, 1, 2 μg/mL) of LA were used together with MMC in three different applications; 1 h pre-treatment, simultaneous treatment and 1 h post-treatment. A negative, a positive and a solvent control were also included. In all the cultures treated with MMC + LA, the frequency of abnormal cells and CA/cell significantly decreased compared to MMC. Statistically significant reduction was also observed in SCE/cell and MN frequencies in all treatments. These results demonstrated anticlastogenic and antimutagenic effects of LA against MMC induced genotoxicity. LA showed the most efficient effect during 1 h pretreatment. On the other hand, MMC + LA treatments induced significant reduction in mitotic index than that of MMC treatment alone. These results are encouraging that LA can be a possible chemopreventive agent in tumorigenesis in both cancer patients and in health care persons handling anti-cancer drugs.

Curcumin attenuates acrylamide-induced cytotoxicity and genotoxicity in HepG2 cells by ROS scavenging

Acrylamide (AA), a proven rodent carcinogen, has recently been discovered in foods heated at high temperatures. This finding raises public health concerns. In our previous study, we found that AA caused DNA fragments and increase of reactive oxygen species (ROS) formation and induced genotoxicity and weak cytotoxicity in HepG2 cells. Presently, curcumin, a natural antioxidant compound present in turmeric was evaluated for its protective effects. The results showed that curcumin at the concentration of 2.5 microg/mL significantly reduced AA-induced ROS production, DNA fragments, micronuclei formation, and cytotoxicity in HepG2 cells. The effect of PEG-catalase on protecting against AA-induced cytotoxicity suggests that AA-induced cytotoxicity is directly dependent on hydrogen peroxide production. These data suggest that curcumin could attenuate the cytotoxicity and genotoxicity induced by AA in HepG2 cells. The protection is probably mediated by an antioxidant protective mechanism. Consumption of curcumin may be a plausible way to prevent AA-mediated genotoxicity.

Anticlastogenic and antigenotoxic effects of selenomethionine on doxorubicin-induced damage in vitro in human lymphocytes

The use of antioxidants during chemotherapy has been shown to reduce or prevent the undesirable effects experienced by healthy cells. Micronutrient selenium is well known for its antioxidant properties; however, selenium exhibits a bimodal nature in that both its beneficial and toxic properties lie within a limited and narrow dose range. The present study investigated the possible protective effects of selenomethionine (SM) on the cytotoxicity, genotoxicity and clastogenicity of the chemotherapic doxorubicin (DXR), a key chemotherapic used in cancer treatment. Human peripheral lymphocytes were treated in vitro with varying concentrations of SM (0.25 microM, 0.5 microM, 1.0 microM and 2.0 microM), tested in combination with DXR (0.15 microg/mL). SM alone was not cytotoxic and when combined with DXR treatment, reduced the DNA damage index significantly, the frequency of chromosomal aberrations, the number of aberrant metaphases and the frequency of apoptotic cells. The mechanism of chemoprotection of SM may be related to its antioxidant properties as well as its ability to interfere with DNA repair pathways. Therefore this study showed that SM is effective in reducing the genetic damage induced by the antitumoral agent DXR.

Curcumin-induced genotoxicity and antigenotoxicity in HepG2 cells

Curcumin, a polyphenolic yellow pigment found in turmeric, is commonly used as a coloring agent in foods, drugs, and cosmetics. In our previous study, we found that low levels of curcumin did not increase the reactive oxygen species (ROS) formation and caused no damage to DNA in human hepatoma G2 (HepG2) cells, but at high doses, curcumin imposed oxidative stress and damaged DNA. In the present study, we are determined to investigate the genotoxic and antigenotoxic effects of curcumin using HepG2 cell line, a relevant in vitro model to detect the cytoprotective, antigenotoxic, and cogenotoxic agents. The results of micronucleus (MN) assays showed that, on one hand, curcumin at the high tested concentrations (8 and 16 microg/ml) displayed a small but significant increase in the frequency of MN, and on the other hand, it was observed that the low tested concentration (2 microg/ml) significantly reduced the MN formation induced by the chemotherapeutic agent cyclophosphamide. The present results indicate that curcumin shows both genotoxicity and antigenotoxicity depending on its concentration.

Evaluation of the clastogenicity and anticlastogenicity of vitamin B6 in human lymphocyte cultures

Insufficient intakes of many micronutrients found in fruits and vegetables, such as folic acid, vitamins C and B6 may lead to DNA damage, cancer, and degenerative disease. The investigation of dietary antioxidants is a field of great interest for elucidating mechanisms of mutagenesis/carcinogenesis. The present study was undertaken to investigate the effects of vitamin B6 on the induction of chromosomal aberrations in cultured human lymphocytes and to examine the possible anticlastogenic effect of this vitamin on chromosomal damage induced by the antitumor drug doxorubicin. The results showed that when the cultures treated with vitamin B6 were compared with the untreated control in terms of total chromosomal damage and abnormal metaphases, pre- and simultaneous treatment with this vitamin showed no significant differences. In the post-treatment, average and above average concentrations of vitamin B6 alone showed a clastogenic effect. In the simultaneous protocol, this vitamin (15, 90 and 120 microg/mL) was effective in inhibiting chromosomal aberrations induced by doxorubicin (p<0.05), with a reduction of 33.1% with the highest concentration tested. However, in the post-treatment, the associations of vitamin B6 and doxorubicin exerted a more evident clastogenic effect than that observed in the cultures exposed only to the antitumor drug. In the present investigation, the inability of vitamin B6 to decrease chromosomal damage induced by doxorubicin in the pre- and post-treatments could be justified by the instability of this vitamin as a free radical scavenger. In conclusion, the results from this study confirmed that vitamin B6 is protective against chromosomal damage induced by doxorubicin in cultured human lymphocytes, but that the effects depend on concentration and form of treatment.

Shiitake (Lentinula edodes (Berkeley) Pegler) extracts as a modulator of micronuclei induced in HEp-2 cells

Shiitake (Lentinula edodes (Berkeley) Pegler) is one of the most consumed mushrooms, for both therapeutic purposes and as food, therefore, the study of its biological properties is of great interest for producers and consumers. Aqueous extracts of the shiitake mushroom (L. edodes (Berkeley) Pegler) were evaluated by the micronucleus test (MN) in HEp-2 cells in vitro, to analyze their possible mutagenic and antimutagenic activities. None of the three extract concentrations tested (0.5, 1.0 and 1.5mg/mL) presented mutagenicity at any of the preparation temperatures (4 degrees C, 22+/-2 degrees C and 60 degrees C). In the antimutagenicity evaluation, all extract concentrations at all preparation temperatures presented a strong protective activity for the HEp-2 cells in response to the alkylating agent methyl methanesulfonate (MMS) in the different treatment protocols: pre-treatment, simultaneous treatment and post-treatment. The extracts prepared at 22+/-2 degrees C presented the lowest frequencies of MN in the evaluations of mutagenicity and antimutagenicity, indicating these as the best option for potential therapeutic use.

Anticlastogenic effect of Vitamin C on cisplatin induced chromosome aberrations in human lymphocyte cultures

Vitamin C (ascorbic acid) is an antioxidant that can scavenge free radicals and protect cellular macromolecules, including DNA, from oxidative damage induced by different agents. The protective effect of Vitamin C on cisplatin induced chromosome aberrations has been determined in the human peripheral lymphocyte chromosome aberration test in vitro. The results of treatments with Vitamin C indicated that it statistically significantly decreases the number of chromosome aberrations and number of metaphases with aberrations induced with cisplatin, but it can not completely protect cells from damage. The test concentrations of Vitamin C (10 and 100 microg/ml) had a limited antimutagen effect on cisplatin (0.5 microg/ml), which can cause genetic damage through free radical mechanisms. The antimutagen effect included the anticlastogenic effect of Vitamin C and its ability to decrease the number of aneuploid mitoses. Vitamin C showed the most efficient anticlastogenic effect during simultaneous treatment with cisplatin. Also, Vitamin C reduced cell toxicity of cisplatin during simultaneous treatment.

Comparative study of the effects of vitamin C and bleomycin on smokers' and non-smokers' lymphocytes in clastogenicity assays

Free radicals are products of metabolic reactions and of external factors that can injure different biological molecules. However, different antioxidant agents can prevent the action of these reactive species and the damage they cause. Vitamin C (VC) is an important micronutrient found in the diet, which presents defense mechanisms against the free radicals that challenge the cells of the organism. The objective of the present study was to investigate the effect of VC as a modulator of the damage induced in DNA by bleomycin (BLM) in lymphocytes from smokers and non-smokers. The difference in response to the mutagenic potential of BLM between smokers and non-smokers was also investigated. Peripheral blood lymphocyte cultures were treated simultaneously with BLM (20 microg/ml) and/or VC (100, 200, and 400 microg/ml) in the G2 phase of the cell cycle. The results obtained did not demonstrate a statistically significant difference in the response to the antitumor agent BLM between smokers and non-smokers. The data also showed that VC had no significant modulating effect on the frequency of chromosome aberrations induced by BLM in the cells of smokers and non-smokers under the experimental conditions used.

Dietary supplements of antioxidants reduce hprt mutant frequency in splenocytes of aging mice

The level of spontaneous and gamma-radiation-induced mutations in the hypoxanthine-guanine phosphoribosyl-transferase (hprt) locus as well as the decrease in frequency of these mutations in mice of various age pretreated with dietary supplements of an antioxidant mixture (vitamins C, E, beta-carotene, rutin, selenium, zinc) were studied in splenocytes of young (8-14-week-old) and aged (102-110-week-old) male C57BL/6 mice. The frequency of spontaneous mutations in splenocytes of 102-110-week-old mice was higher by 68-88% than that in mice aged 8-14 weeks. On gamma-irradiation (0.5-5.0 Gy) of mice, the frequency of radiation-induced mutations (Vf assay) in aged mice was 2.3 to 3.6 times (depending on dose) higher than in young ones. Daily supplements of an antioxidant mixture to the diet of mice prior to irradiation showed an antimutagenic effect. The values of mutant frequency reduction factor (MFRF) for 14-110-week-old mice fed with dietary antioxidants during 6 weeks prior to gamma-irradiation with doses of 2.0 and 5.0 Gy were 5.4 and 3.7, respectively. The frequency of radiation-induced mutations prevented or not prevented by antioxidants was much higher in aged mice than in young ones.

The anticlastogenicity of beta-carotene evaluated on human hepatoma cells

The efficiency of beta-carotene as a modulatory agent against clastogenicity induced by cyclophosphamide (CPA), an indirect-acting mutagen, and mitomycin C (MMC), a direct-acting mutagen, was evaluated in human hepatoma cells (Hep G2) using three different treatment regimes. Six doses of beta-carotene, 0.25, 0.5, 1.0, 2.0, 4.0 and 6.0 microM, were tested as pre-treatment, simultaneous treatment and pre- + simultaneous treatment. Since these cells are able to activate mutagens without any exogenous metabolizing system (S9 mix), some problems related to the use of S9 mix were eliminated. The data obtained show a statistically significant decrease in the frequency of micronuclei (MN) induced by CPA when the cells were treated with beta-carotene, for all treatments, and no effect of this provitamin on the clastogenicity of MMC was found. These results reinforce the anticlastogenicity of beta-carotene showing that its action is independent of the treatment regime used. On the other hand, the fact that beta-carotene had a protective action only on CPA-induced MN suggests an effect on activation of the promutagen and emphasizes the important utility of cell lines capable of metabolizing chemical mutagens, in such basic studies.

Modification of genotoxicity by naturally occurring flavorings and their derivatives

The number of studies in the research field of antimutagenesis is increasing. The aims of many of these studies are preventing genetic hazards from environmental mutagens and elucidating the process of mutagenesis. Some naturally occurring flavorings such as vanillin, cinnamaldehyde, and coumarin have been reported to inhibit mutagenesis induced by mutagens in bacterial and mammalian cells. These flavorings are considered to act as antimutagens by modifying DNA replication and/or DNA repair systems after cellular DNA was damaged by mutagens. A factor that suppresses mutagenicity in a given situation, however, sometimes exerts enhancing effects when the endpoints investigated or the test conditions used are varied. This makes the evaluation of antimutagenic factors complicated. Different modifying effects of the above-mentioned flavorings observed in various test systems for genotoxicity are discussed, based on their proposed mechanisms.