Lokman Alpsoy

Protective role of methanol extract of Cetraria islandica (L.) against oxidative stress and genotoxic effects of AFB1 in human lymphocytes in vitro

In this study, the antigenotoxic and antioxidant effects of Cetraria islandica methanol (CME) extract were determined by using sister chromatid exchange (SCE), micronuclei (MN) assays and superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities and malondialdehyde (MDA) levels against effects of aflatoxin B1 (AFB 1) induced oxidative stress and genotoxicity in human lymphocytes in vitro. The results showed that the frequencies of SCE, MN and MDA level decreased, SOD and GPx activities increased when 5 μg/mL and 10 μg/mL doses of CME were added to AFBı-treated cultures. Also, the present results indicate that CME has strong antioxidative and the antigenotoxicity mechanisms of CME are associated with its antioxidant nature.

Key Roles of Vitamins A, C, and E in Aflatoxin B1-Induced Oxidative Stress

Aflatoxins (Aspergillus flavus toxins) are one of the natural toxic molecules which are produced by a group of fungi called Aspergillus. Foods and drinks contaminated with aflatoxins cause global health and environmental problems. Today in many developing countries, these toxins are leading cause of some liver cancers and serious gastrointestinal problems. Aflatoxins, which are well known to be mutagenic, carcinogenic, hepatotoxic, and immunosuppressive, exert inhibitory effects on biological processes including DNA synthesis, DNA-dependent RNA synthesis, DNA repair, and protein synthesis. Aflatoxins B(1) (AFB(1)) is the most widespread oxidative agent of the aflatoxins. Numerous diverse compounds and extracts have been reported to reduce the aflatoxins induced oxidative stress in the body. Most of these inhibitors including phenylpropanoids, terpenoids, alkaloids, and vitamins are originally derived from plants. Among these, being essential biomolecules, vitamins are used as coenzymes in very significant biological reactions. They also function as nonenzymatic antioxidative agents protecting the cells from oxidative stress-induced toxicity and transformation. This chapter reviews the mechanism of AFB(1)-induced oxidative stress and focuses on the protective effects of vitamins A, C, and E on reducing this stress.

An electrochemical immunosensor for sensitive detection of Escherichia coli O157:H7 by using chitosan, MWCNT, polypyrrole with gold nanoparticles hybrid sensing platform

An electrochemical immunosensor for the common food pathogen Escherichia coli O157:H7 was developed. This novel immunosensor based on the PPy/AuNP/MWCNT/Chi hybrid bionanocomposite modified pencil graphite electrode (PGE). This hybrid bionanocomposite platform was modified with anti-E. coli O157:H7 monoclonal antibody. The prepared bionanocomposite platform and immunosensor was characterized by using cyclic voltammetry (CV). Under the optimum conditions, the results have shown the order of the preferential selectivity of the method is gram negative pathogenic species E. coli O157:H7. Concentrations of E. coli O157:H7 from 3×101 to 3×107cfu/mL could be detected. The detection limit was ∼30cfu/mL in PBS buffer. Briefly, we developed a high sensitive electrochemical immunosensor for specific detection of E. coli O157:H7 contamination with the use of sandwich assay evaluated in this study offered a reliable means of quantification of the bacteria. For the applications in food quality and safety control, our immunosensor showed reproducibility and stability.

Protective role of methanol extracts of two lichens on oxidative and genotoxic damage caused by AFB1 in human lymphocytes in vitro

In this study, the antigenotoxic and antioxidant effects of Umbilicaria vellea (UME) and Xantho somloensis (XME) extracts were determined using sister chromatid exchange (SCE), micronuclei (MN) assays, and superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities and malondialdehyde (MDA) levels against the effects of aflatoxin B1 (AFB1)-induced oxidative stress and genotoxicity in human lymphocytes in vitro. The results showed that the frequencies of SCE, MN, and MDA level decreased, but the activities of SOD and GPx increased when 5 μg/mL and 10 μg/mL doses of UME and XME were added to AFB1-treated cultures. Also the present results indicate that strong antioxidative and the antigenotoxicity mechanisms of UME and XME are associated with its antioxidant nature.

Anti-oxidative and anti-genotoxic effects of methanolic extract of Mentha pulegium on human lympocyte culture

In the present work, methanolic extract of Mentha pulegium from Erzurum, Turkey, was used in order to report the results of anti-oxidant capacity, anti-oxidant activity and anti-genotoxic effects. The total antioxidant capacity and total phenolic content were measured by using CUPRAC, ABTS and Folin—Ciocalteu colorimetric methods. The total phenolic content was higher than the total antioxidant capacity (for the results of both the CUPRAC and ABTS methods) of methanolic extract of M pulegium (ME). Also, we evaluated the anti-oxidant enzyme activity such as superoxide dismutase (SOD) and glutation peroxidase, total glutation (GSH) and malondialdehyde (MDA) in human lymphocyte culture. In CCI4-treated group, the activity of SOD, glutathione peroxidase (GPx) and GSH decreased significantly and the level of MDA increased significantly. A significant increase in the activity of SOD, GPx and the level of GSH were seen when supplemented with ME to CCI4-treated group. Furthermore, a significant decrease in the level of MDA was observed when compared with CCI4 alone treated group. In addition, anti-genotoxic effect of ME was studied by using sister chromatid exchange (SCE) method. As a result, ME has shown anti-genotoxic effect depend on anti-oxidative effect on human lymphocyte culture.

Determination of the antigenotoxic potencies of some luteolin derivatives by using a eukaryotic cell system, Saccharomyces cerevisiae.

In this study, we aimed to examine the mutagenic and antimutagenic potencies of three luteolin derivatives (luteolin-7-O-glucoside, luteolin-7-O-rutinoside and luteolin-7-O-glucuronide) by using a eukaryotic cell system, Saccharomyces cerevisiae (RS112). In the antimutagenicity assays, these luteolin derivatives showed antimutagenic effects in deletion and intrachromosomal recombination events against ethyl methanesulfonate and acridine mutagen agents. In deletion events, the highest inhibition rates for luteolin-7-O-glucoside, luteolin-7-O-rutinoside and luteolin-7-O-glucuronide against ethyl methanesulfonate were 57.6%, 58.3% and 62.5%, respectively. Likewise, the highest inhibition rates for luteolin-7-O-glucoside, luteolin-7-O-rutinoside and luteolin-7-O-glucuronide against acridin were 21.8%, 22.4% and 23.6%, respectively. Our findings showed that these luteolin derivatives have stronger antimutagenic properties against ethyl methanesulfonate compared to the acridine mutagen agent.

The protective role of zinc and calcium in Vicia faba seedlings subjected to cadmium stress

The aim of the present study was to evidence the possible antagonistic effect of Zinc (Zn2+) and Calcium (Ca2+) against cadmium (Cd2+)-induced DNA damage by using random amplification of polymorphic DNA (RAPD) and metabolic activities in Vicia faba. The results showed that all doses of Cd2+ (10 -3 M, 10-5 M) caused an increase in polymorphism value and a decrease in genomic template stability (GTS %). In addition, when 10 -4-10-6 M Ca2+, 10-6 M Zn2+ were added together with 10-3 M, 10-4 M, 10-5 M of Cd2+, polymorphism value decreased besides GTS, total protein and chlorophyll content increased. Results suggested that Zn2+ and Ca2+ have an antagonistic effect against Cd2+. The order of the antagonisms of Ca2+, Zn2+ against Cd2+ toxicity was Ca2+ > Zn2+. Especially, the degree of antagonistic effect of Zn2+ against Cd2+ is probably related to its concentration ratio.

Anti-oxidative and anti-genotoxic effects of carnosine on human lymphocyte culture.

The aim of this study was to investigate the effects of carnosine, a biological antioxidant, on the oxidative stress and genotoxicity by a single dose of carbon tetrachloride (CCl4; 5 mM) in the human lymphocyte culture. We studied the anti-genotoxic effects of carnosine by using sister chromatid exchange (SCE) test system. Also, the anti-oxidative effects of carnosine were evaluated by using superoxide dismutase (SOD), glutathione peroxidase (GPx), total glutathione (GSH) and malondialdehyde (MDA) assay. The SCE frequency was increased when treated with CCl4. Carnosine at 10 and 20 mM reduced SCE frequency in the human lymphocyte (p < 0.001). In addition, CCl4 treatment significantly depleted the level of GSH, reduced the activity of SOD and GPx and elevated the level of MDA (p < 0.001). Carnosine treatment led to significant attenuation of CCl4-induced oxidative stress by normalization of the activities of SOD and GPx and the level of GSH and MDA (p < 0.05 or 0.001). These results suggest that carnosine could provide anti-oxidative and anti-genotoxic protection for the oxidative and genotoxic agents that cause many diseases including cancer and neurodegenerative disease.

Evaluation of antioxidant, enzyme inhibition, and cytotoxic activity of three anthraquinones (alizarin, purpurin, and quinizarin).

Objective: The aim of this work was to investigate the cytotoxic, antioxidative, and enzyme inhibition effects of alizarin, quinizarin, and purpurin, which are anthraquinones (AQ). Methods: Cytotoxic effects were evaluated with cell inhibition rate by 3-(4,5-dimethylthiazol- 2-yl)-2,5-diphenyltetrazolium bromide assay. Different chemical assays, including free radical scavenging activity (1,1-diphenyl-2-picrylhydrazyl and 2,2-azino-bis(3-ethylbenzothiazloine-6-sulfonic acid)), phosphomolybdenum and reducing power (ferric reducing antioxidant power and cupric ion reducing activity), were used to evaluate the antioxidant properties. Moreover, enzyme inhibitory activities were analyzed against acetylcholinesterase, butrylcholinesterase, tyrosinase, α-amylase, and α-glucosidase. Results: These components have antioxidant and enzyme inhibition activity. Especially, purpurin showed the strongest antioxidant and good enzyme inhibitory effects. According to our cytotoxicity results, alizarin, purpurin, and quinizarin induced dose- and time-dependent cell proliferation. Furthermore, when we applied AQs with mitomycin C (MC) on L929 cell line, we demonstrated that cell proliferation in MC-AQ groups compared with MC group was increased. The most effective component was alizarin at 100 µM concentration. These AQs showed positive effects on L929 cell lines with high half-maximal inhibitory concentration values. Conclusion: Our results demonstrate that AQs may be used as antioxidative compounds in food and medicinal applications.

Genotoxic effects of catmint (Nepeta meyeri Benth.) essential oils on some weed and crop plants

This study investigates the genotoxicity of the essential oils extracted from the aerial parts of catmint (Nepeta meyeri Benth.) against two weeds (Bromus danthoniae and Lactuca serriola) and two crop plants (Brassica napus and Zea mays). The essential oils of N. meyeri analyzed by gas chromatography–mass spectrometry contained 14 compounds, with 4aα, 7α, 7aβ-nepetalactone (83.4%), 4aα, 7α, and 7aα-nepetalactone (8.83%) as the major components. The oils were diluted (25, 50, 100, and 150 ppm) and the solutions were applied to seeds or leaves of these plants. The study compared the germination percentage and random amplified polymorphic DNA (RAPD) results with the control group. The results showed that the oils had a strong inhibitory activity and caused a change in RAPD profiles in terms of variation in band intensity, loss of bands, and appearance of new bands compared with the control group. The results suggested that RAPD analysis could be applied as a suitable biomarker assay for the detection of genotoxic effects of plant allelochemicals. This study indicates the genotoxical potential of N. meyeri essential oils on weed and crop plants.