DNA Damage In Human Lymphocytes Research Articles

Methanolic fraction of Cassia fistula L. bark exhibits potential to combat oxidative stress and possess antiproliferative activity

ABSTRACT Cassia fistula L. is well known for its traditional medicinal properties as an anti-inflammatory, hepatoprotective, antifungal, antibacterial, antimutagenic, and wound healing agent. The aim of the present study was to determine antioxidant, genoprotective, and cytotoxic potential of different fractions of C. fistula bark including hexane (CaMH), chloroform (CaMC), ethyl acetate (CaME), and methanol (CaMM). Among all the fractions studied, CaMM exhibited maximal radical scavenging activity in antioxidant DPPH assay, Superoxide anion radical scavenging assay and nitric oxide radical scavenging assay displayed an IC50 value of 18.95, 29.41, and 13.38 µg/ml, respectively. CaMM fraction possessed the highest phenolic (130.37 mg gallic acid equivalent/g dry weight of extract) and flavonoid (36.96 mg rutin equivalent/g dry weight of fraction) content. Data demonstrated significant positive correlation between polyphenol levels and radical scavenging activity. Single cell gel electrophoresis (Comet assay) exhibited genoprotective potential of C. fistula bark fractions against DNA damage induced by hydrogen peroxide (H2O2) in human lymphocytes. CaMM fraction displayed highest protective ability against H2O2 induced-toxicity as evidenced by significant decrease in % tail DNA content from 30 to 7% at highest concentration (200 µg/ml). CaMM was found to be rich in catechin, gallic acid, chlorogenic acid, and kaempferol. The phenolic content and antioxidant ability of the fractions was markedly negatively correlated with H2O2- induced DNA damage in human lymphocytes. Cytotoxic potential was evaluated against dermal epidermoid carcinoma (A431), pancreatic (MIA PaCa-2) and brain glioblastoma (LN-18) cancer cell lines using MTT assay. Results showed that C. fistula bark fractions possessed highest toxicity against the skin carcinoma cells. CaMM fraction reduced over 50% cell growth at the concentration of 76.72 µg/ml in A431 cells. These findings suggest that fractions of C. fistula bark exhibit potential to be considered as therapeutic agents in various carcinomas.

Ratio-dependent effects of photoactivated hypericin and manumycin A on their genotoxic and mutagenic potential

Natural compounds originated from plants and microorganisms and their combinations are currently being investigated as a possible treatment for several diseases including cancer. Hypericin (photodynamically-active pigment from Hypericum perforatum L.) and manumycin A (inhibitor of farnesyltransferase from Streptomyces parvulus) belong to the chemicals potentially applicable in clinical practice. In this study we evaluated potential cytotoxic (via trypan blue exclusion test), genotoxic (via DNA-topology and comet assays), and mutagenic effects (via bacterial reverse mutation test) of these compounds and their combinations considering the molecular mechanism of their action in cell-free and cellular systems. Our results did not reveal neither cytotoxic nor mutagenic activities of tested compounds and their combinations. Regarding the genotoxic potential, no damage of plasmid DNA in cell-free system was detected. On the other hand, photoactivated hypericin and manumycin A were able to induce primary DNA damage in human lymphocytes analyzed by comet assay. The possible antagonistic interactions between these two metabolites were estimated using SynergyFinder software analysis and experimental data obtained from comet assay. Our findings indicate that not only the presence of substances, but also their ratio plays an important role in resulting effects of the combined treatment in cellular system.

Flavonoids of the Heartwood of Cotinus coggygria Scop. Showing Protective Effect on Human Lymphocyte DNA

In continuation of our study on Cotinus coggygria from Serbia, 10 known flavonoids (1-10) were isolated from the methylene chloride/methanol extract of the heartwood. They were tested for in vitro protective effect against chromosome aberrations in peripheral human lymphocytes, using the cytokinesis-block micronucleus assay. All tested compounds (in minimal doses of 1 μg/mL) exerted a beneficial effect by decreasing DNA damage of human lymphocytes in the range of 24.2% to 54.5%, better than the radio protectant control, amifostine. Functional groups, such as 3′,4′-dihydroxyphenyl (catechol), 5-OH, 3-OH, and 4-keto in flavonoids (3-keto in aurones), which play a key role in antioxidant activity, are proposed to be responsible for the DNA protective activity of the tested compounds.

Cytogenetic Damage of Human Lymphocytes in Humanized Mice Exposed to Neutrons and X Rays 24 h After Exposure

Detonation of an improvised nuclear device highlights the need to understand the risk of mixed radiation exposure as prompt radiation exposure could produce significant neutron and gamma exposures. Although the neutron component may be a relatively small percentage of the total absorbed dose, the large relative biological effectiveness (RBE) can induce larger biological DNA damage and cell killing. The objective of this study was to use a hematopoietically humanized mouse model to measure chromosomal DNA damage in human lymphocytes 24 h after in vivo exposure to neutrons (0.3 Gy) and X rays (1 Gy). The human dicentric and cytokinesis-block micronucleus assays were performed to measure chromosomal aberrations in human lymphocytes in vivo from the blood and spleen, respectively. The mBAND assay based on fluorescent in situ hybridization labeling was used to detect neutron-induced chromosome 1 inversions in the blood lymphocytes of the neutron-irradiated mice. Cytogenetics endpoints, dicentrics and micronuclei showed that there was no significant difference in yields between the 2 irradiation types at the doses tested, indicating that neutron-induced chromosomal DNA damage in vivo was more biologically effective (RBE ∼3.3) compared to X rays. The mBAND assay, which is considered a specific biomarker of high-LET neutron exposure, confirmed the presence of clustered DNA damage in the neutron-irradiated mice but not in the X-irradiated mice, 24 h after exposure.

Intercomparison of Conventional and QuickScan Dicentric Scoring for the Validation of Individual Biodosimetry Analysis in Taiwan

Purpose The dicentric chromosome assay (DCA), the gold standard for radiation biodosimetry, evaluates an individual absorbed radiation dose by the analysis of DNA damage in human lymphocytes. The conventional (C-DCA) and QuickScan (QS-DCA) scoring methods are sensitive for estimating radiation dose. The Biodosimetry Laboratory at Institute of Nuclear Energy Research (INER), Taiwan, participated in intercomparison exercises conducted by Health Canada (HC) in 2014, 2015 and 2018 to validate the laboratory’s accuracy and performance. Material and Methods Blood samples for the conventional dose response curve for Taiwan were irradiated with 0, 0.25, 0.5, 1, 2, 3, 4 and 5 Gy. Ten blind blood samples were provided by HC. Either or both of two methods of conventional (C) or QuickScan (QS) scoring could be chosen for the HC’s intercomparison. For C-DCA triage scoring, only cells with 46 centromeres were counted and each scorer recorded the number of dicentrics in the first 50 metaphases or stopped scoring when 30 dicentrics were reached. Scorers also recorded how much time it took to analyze 10, 20, and 50 cells. Subsequently, the data were entered into the Dose Estimate software (DoseEstimate_v5.1) and dose estimates were calculated. With QS-DCA scoring, a minimum of 50 metaphase cells (or 30 dicentrics) were scored in apparently complete metaphases without verification of exactly 46 centromeres. Results For the blinded blood samples irradiated at HC and shipped to INER, the mean absolute deviation (MAD) derived after scoring 50 cells for C-DCA and QS-DCA was <0.5 Gy for all three intercomparisons, meeting the criteria for acceptance. Conclusion The results indicated that the Biodosimetry Laboratory at INER can provide reliable dose estimates in the case of a large-scale radiation accident.

Mitochondrial, lysosomal and DNA damages induced by acrylamide attenuate by ellagic acid in human lymphocyte.

Acrylamide (AA), is an important contaminant formed during food processing under high temperature. Due to its potential neurotoxicity, reproductive toxicity, hepatotoxicity, immunotoxicity, genotoxicity and carcinogenicity effects, this food contaminant has been recognized as a human health concern. Previous studies showed that acrylamide-induced toxicity is associated with active metabolite of acrylamide by cytochrome P450 enzyme, oxidative stress, mitochondrial dysfunction and DNA damage. In the current study, we investigated the role of oxidative stress in acrylamide's genotoxicity and therapeutic potential role of ellagic acid (EA) in human lymphocytes. Human lymphocytes were simultaneously treated with different concentrations of EA (10, 25 and 50 μM) and acrylamide (50 μM) for 4 h at 37°C. After 4 hours of incubation, the toxicity parameters such cytotoxicity, ROS formation, oxidized/reduced glutathione (GSH/GSSG) content, malondialdehyde (MDA) level, lysosomal membrane integrity, mitochondria membrane potential (ΔΨm) collapse and 8-hydroxy-2'-deoxyguanosine (8-OHdG) were analyzed using biochemical and flow cytometry evaluations. It has been found that acrylamide (50 μM) significantly increased cytotoxicity, ROS formation, GSH oxidation, lipid peroxidation, MMP collapse, lysosomal and DNA damage in human lymphocytes. On the other hand, cotreatment with EA (25 and 50 μM) inhibited AA-induced oxidative stress which subsequently led to decreasing of the cytotoxicity, GSH oxidation, lipid peroxidation, MMP collapse, lysosomal and DNA damage. Together, these results suggest that probably the co-exposure of EA with foods containing acrylamide could decrease mitochondrial, lysosomal and DNA damages, and oxidative stress induced by acrylamide in human body.

Protective effects of (-)-epigallocatechin gallate and curcumin against acrylamide toxicity

Human lymphocytes as well as zebrafish embryos were used to study the toxicity of acrylamide, and the intervention effects of the dietary antioxidants (-)-epigallocatechin gallate and curcumin have been examined. The alkaline comet assay revealed that acrylamide (1, 5, 10 mmol/L) had dose-response effects on basic DNA damage and oxidative DNA damage in human lymphocytes. Exposure of zebrafish embryos to acrylamide resulted in decrease of hatching rate, and in increases of mortality and teratogenicity. (-)-Epigallocatechin gallate and curcumin reduced DNA damage and protected zebrafish embryos in the growth and development.

DNA protective activity of triterpenoids isolated from medicinal mushroom Fomitopsis betulina

Eleven 31-methylenlanostane triterpenoids, i.e., seven 21- and four 26-oic acids, as well as a lupane triterpenoid betulin, isolated from the fruiting bodies of the mushroom Fomitopsis betulina, were tested for in vitro protective effect on chromosome aberrations in peripheral human lymphocytes using cytochalasin-B blocked micronucleus (CBMN) assay. Most of the tested compounds showed a beneficial effect by reducing DNA damage of human lymphocytes more effectively than amifostine, a radioprotective agent, used as a positive control. All the tested compounds decreased MN frequency in the concentration dependent manner, with the concentration of 2.0 ?g mL-1 being the most effective ? with increase of the concentration the activity slightly decreases. The structure?activity relationship (SAR) studies indicated that the lanostanes containing a conjugated 7,9 (11)-diene system exhibit lower activity than ?8-analogues. It was also demonstrated that the DNA protective activities within the ?8-lanostane-26-oic acid group are affected by the substitution in position 3 pattern. In the ?8 series the oxygenation at C-12 or 16 as well as 21- or 26-oic acid functionality proved beneficial for in vitro protective effect on chromosomal aberrations. Betulin exhibited the lowest protective activity, but it is still comparable to that of amifostine.

Primary screening for the toxicity of marine cyanobacteria Lyngbya bouillonii (Cyanophyceae: Oscillatoriales) recorded for the first time from Indian Ocean

Climate change has triggered an increased incidence of cyanobacterial blooms in the marine ecosystem. While most bloom-forming species cause widespread algal blooms, Lyngbya bouillonii, a benthic marine cyanobacteria forms localized blooms. This cyanobacteria, reported only from the tropical Pacific Ocean, has gained immense biomedical interest owing to an array of bioactive secondary metabolites it produces. While studying the occurrence and distribution of marine cyanobacteria across Andaman Nicobar Islands we encountered this species forming tenacious mats, attached to corals and quite often forming extensive localized blooms. Accordingly, L. bouillonii is being reported for the first time from the Indian Ocean. The symbiotic, snapping shrimp Alpheus frontalis was found to coexist within these cyanobacterial mats. Our initial toxicity studies showed L. bouillonii to possess toxins, causing mortality of brine shrimps with a LC50 of 0.8 mg/ml and causing DNA damage in human lymphocytes in vitro at concentrations as low as 1 ng/ml of crude cyanobacterial extract. Preliminary investigation revealed the presence of chlorinated fatty acid amides, fatty acid esters and benzazepine derivatives in the extract. Furthermore, how this cyanobacteria initially reached Indian waters and whether this is a bio-invasion is still being ascertained.

Inhibitory effect of carnosine and anserine on DNA oxidative damage induced by Fe 2+, Cu 2+ and H 2O 2 in lymphocytes

The effects of carnosine and anserine on oxidative DNA damage in human lymphocytes induced by Fe 2+, Cu 2+ or H 2O 2 were investigated using single cell gel electrophoresis (comet assay). Carnosine and anserine induced a slight DNA damage in human lymphocytes after incubation with cells for 30 min. Carnosine and anserine caused a tail DNA % from 4.7% to 7.3% and 6.1% to 10.0% respectively, at a concentration of 5-100 mM. The cell viability of carnosine and anserine to human lymphocytes was more than 85%. Fe 2+ and Cu 2+ caused a marked cytotoxicity and DNA damage in human lymphocytes with a concentration dependent manner. At a concentration of 100 μM, carnosine and anserine possessed 60-70% inhibitory effect on DNA damage in human lymphocytes when they reacted with Fe 2+ or Cu 2+ for 30 min before incubated with human lymphocytes. Fe 2+, Cu 2+, and H 2O 2-induced DNA damage in human lymphocytes were inhibited by carnosine and anserine in a concentration dependent manner (5-100 μM). However, the inhibitory effect of carnosine and anserine on oxidative DNA damage in human lymphocyte was 46.4% and 49.3%, respectively, when reacted simultaneously with H 2O 2. Carnosine and anserine possessed more marked inhibitory effect on oxidative DNA damage in human lymphocyte induced by Fe 2+ and Cu 2+ than that induced by H 2O 2. This result might be due to carnosine and anserine did not possess significantly scavenging effect on H 2O 2, thus, H 2O 2 entered the cell and caused DNA damage.

Leaf-surface guaianolides from Amphoricarpos neumaeyri showing protective effect on human lymphocytes DNA

Analysis of composition of CH2Cl2 surface extract of leaves of Amphoricarpos neumayeri Vis. revealed 16 sesquiterpene lactones with guaianolide skeleton, so called amphoricarpolides, typical for this genus. Four of them, 13–16, were new derivatives and their structures were elucidated by detailed analyses of IR, NMR and MS data. Amphoricarpolide (9), its 15-O-acetyl derivative (5), and two 9β-hydroxyamphoricarpolides, 3,15-di-O-acetyl- and 3-O-acetyl-15-O-isovaleroyl derivatives (3 and 6, respectively) were tested for in vitro protective effect on chromosome aberrations in peripheral human lymphocytes using cytochalasin-B blocked micronucleus (CBMN) assay. The tested compound exerted a beneficial effect by decreasing DNA damage of human lymphocytes.

Wiskott-Aldrich syndrome protein senses irradiation-induced DNA damage to coordinate the cell-protective Golgi dispersal response in human T and B lymphocytes

Wiskott-Aldrich syndrome (WAS) is an X-linked primary immune deficiency disorder resulting from Wiskott-Aldrich syndrome protein (WASp) deficiency. Lymphocytes from patients with WAS manifest increased DNA damage and lymphopenia from cell death, yet how WASp influences DNA damage-linked cell survival is unknown. Arecently described mechanism promoting cell survival after ionizing radiation (IR)-induced DNA damage involves fragmentation and dispersal of the Golgi apparatus, known as the Golgi-dispersal response (GDR), which uses the Golgi phosphoprotein 3 (GOLPH3)-DNA-dependent protein kinase (DNA-PK)-myosin XVIIIA-F-actin signaling pathway. We sought to define WASp's role in the DNA damage-induced GDR and its disruption as a contributor to the development of radiosensitivity-linked immunodeficiency in patients with WAS. In human TH and B-cell culture systems, DNA damage-induced GDR elicited by IR or radiomimetic chemotherapy was monitored in the presence or absence of WASp or GOLPH3 alone or both together. WASp deficiency completely prevents the development of IR-induced GDR in human TH and B cells, despite the high DNA damage load. Loss of WASp impedes nuclear translocation of GOLPH3 and its colocalization with the DNA-dependent protein kinase catalytic subunit (DNA-PKcs). Surprisingly, however, depletion of GOLPH3 alone or depolymerization of F-actin in WASp-sufficient TH cells still allows development of robust GDR, suggesting that WASp, but not GOLPH3, is essential for GDR and cell survival after IR-induced DNA-damage in human lymphocytes. The study identifies WASp as a novel effector of the nucleus-to-Golgi cell-survival pathway triggered by IR-induced DNA damage in cells of the hematolymphoid lineage and proposes an impaired GDR as a new cause for development of a "radiosensitive" form of immune dysregulation in patients with WAS.

Aberrant Function of the C-Terminal Tail of HIST1H1E Accelerates Cellular Senescence and Causes Premature Aging

Histones mediate dynamic packaging of nuclear DNA in chromatin, a process that is precisely controlled to guarantee efficient compaction of the genome and proper chromosomal segregation during cell division and to accomplish DNA replication, transcription, and repair. Due to the important structural and regulatory roles played by histones, it is not surprising that histone functional dysregulation or aberrant levels of histones can have severe consequences for multiple cellular processes and ultimately might affect development or contribute to cell transformation. Recently, germline frameshift mutations involving the C-terminal tail of HIST1H1E, which is a widely expressed member of the linker histone family and facilitates higher-order chromatin folding, have been causally linked to an as-yet poorly defined syndrome that includes intellectual disability. We report that these mutations result in stable proteins that reside in the nucleus, bind to chromatin, disrupt proper compaction of DNA, and are associated with a specific methylation pattern. Cells expressing these mutant proteins have a dramatically reduced proliferation rate and competence, hardly enter into the S phase, and undergo accelerated senescence. Remarkably, clinical assessment of a relatively large cohort of subjects sharing these mutations revealed a premature aging phenotype as a previously unrecognized feature of the disorder. Our findings identify a direct link between aberrant chromatin remodeling, cellular senescence, and accelerated aging.

Phorate triggers oxidative stress and mitochondrial dysfunction to enhance micronuclei generation and DNA damage in human lymphocytes.

Herein, we studied phorate for its toxicological effects in human lymphocytes. Phorate treatment for 3 h has induced significant increase in the lymphocytic DNA damage. Compared to control, comet data from highest concentration of phorate (1000 µM) showed 8.03-fold increase in the Olive tail moment (OTM). Cytokinesis blocked micronucleus (CBMN) assay revealed 6.4-fold increase in binucleated micronucleated (BNMN) cells following the exposure with phorate (200 µM) for 24 h. The nuclear division index (NDI) in phorate (200 µM) treated cells reduced to 1.8 vis-à-vis control cells showed NDI of 1.94. Comparative to untreated control, 60.43% greater DCF fluorescence was quantitated in lymphocytes treated with phorate (500 µM), affirming reactive oxygen species (ROS) generation and oxidative stress. Flow cytometric data of phorate (200 µM) treated lymphocytes showed 81.77% decline in the fluorescence of rhodamine 123 (Rh123) dye, confirming the perturbation of mitochondrial membrane potential (ΔΨm). Calf thymus DNA (ct-DNA) treated with phorate (1000 µM) exhibited 2.3-fold higher 8-Hydroxy-2′-deoxyguanosine (8-oxodG) DNA adduct formation, signified the oxidative DNA damage. The alkaline unwinding assay revealed 4.0 and 6.5 ct-DNA strand breaks when treated to phorate and phorate-Cu (II) complex. Overall, the data unequivocally suggests the cyto- and genotoxic potential of phorate in human lymphocytes, which may induce comparable toxicological consequences in persons occupationally or non-occupationally exposed to insecticide phorate.

Eggplant fruits protect against DNA damage and mutations

Eggplant belongs to the Solanaceae family, and it has an important antioxidant capability that has been shown to counteract oxidation, which is harmful to health and many diseases. In this present study, we evaluated the antigenotoxic effects of six eggplants ((Solanum aculeatissimum Jacq. ‘Ma-khuea-lueang’; ML), (Solanum aculeatissimum Jacq. ‘Ma-khuea-pro’; MP), (Solanum aculeatissimum Jacq. ‘Ma-khuea-sawoei’; MS), (Solanum melongena Linn. ‘Ma-khuea-khai-tao’; MKT), (Solanum melongena Linn. ‘Ma-khuea-muang klom’; MM) and (Solanum torvum Sw. ‘Ma-khuea-phuang’; MPH)) against urethane-induced somatic mutation and recombination test (SMART) in Drosophila melanogaster and hydrogen peroxide-induced oxidative DNA damage in human lymphocytes. First, we determined all of the eggplant extracts of their antioxidant properties including radical scavenging activities, reducing antioxidant power and total phenolic contents, surprisingly ML extract showed the highest level of activity. In SMART, larvae were fed with each lyophilized eggplant. The results revealed that no sample was mutagenic. Interestingly, we found that all six eggplants had a potent inhibitory effect against urethane-induced mutagenicity. Moreover, the protective effect of each eggplant extract against oxidative DNA damage in human lymphocytes was investigated using the single-cell gel electrophoresis (comet) assay. The treatment cells with six eggplant extracts prevented DNA human lymphocytes in response to hydrogen peroxide, especially ML extract exhibited higher an inhibition percentage than other samples. This study demonstrated that these eggplants seem to be safe for consumption and their extracts could protect against DNA damage. Thus, these eggplants have the potential to provide health benefits associated with prevention or reduced risk of developing chronic diseases, such as cancer.

Effect of Ascorbic Acid (Vitamin C) on H2O2 Induced Oxidative DNA Damage in Human Lymphocytes Estimated by Comet Assay

Effect of Ascorbic Acid (Vitamin C) on H2O2 Induced Oxidative DNA Damage in Human Lymphocytes Estimated by Comet Assay

An evaluation of DNA damage in human lymphocytes and sperm exposed to methyl methanesulfonate involving the regulation pathways associated with apoptosis

Exposure to DNA-damaging agents produces a range of stress-related responses. These change the expression of genes leading to mutations that cause cell cycle arrest, induction of apoptosis and cancer. We have examined the contribution of haploid and diploid DNA damage and genes involved in the regulation of the apoptotic process associated with exposure, The Comet assay was used to detect DNA damage and quantitative RT-PCR analysis (qPCR) to detect gene expression changes in lymphocytes and sperm in response to methyl methanesulfonate. In the Comet assay, cells were administered 0–1.2 mM of MMS at 37 °C for 30 min for lymphocytes and 32 °C for 60 min for sperm to obtain optimal survival for both cell types. In the Comet assay a significant increase in Olive tail moment (OTM) and % tail DNA indicated DNA damage at increasing concentrations compared to the control group. In the qPCR study, cells were treated for 4 h, and RNA was isolated at the end of the treatment. qPCR analysis of genes associated with DNA stress responses showed that TP53 and CDKN1A are upregulated, while BCL2 is downregulated compared with the control. Thus, MMS caused DNA damage in lymphocytes at increasing concentrations, but appeared not to have the same effect in sperm at the low concentrations. These results indicate that exposure to MMS increased DNA damage and triggered the apoptotic response by activating TP53, CDKN1A and BCL2. These findings of the processing of DNA damage in human lymphocytes and sperm should be taken into account when genotoxic alterations in both cell types are produced when monitoring human exposure.

Prevention of γ-Radiation-Induced DNA Damage in Human Lymphocytes Using a Serine-Magnesium Sulfate Mixture.

Ionising radiation has deleterious effects on human cells. N-acetylcysteine (NAC) and cysteine, the active metabolite of NAC, are well-known radioprotective agents. Recently, a serine-magnesium sulfate combination was proposed as an antidote for organophosphate toxicity. This study aimed to investigate the use of a serine-magnesium sulfate mixture in the prevention of γ-radiation-induced DNA damage in human lymphocytes as compared to NAC and cysteine. This study was carried out at the Iran University of Medical Sciences, Tehran, Iran, between April and September 2016. Citrated blood samples of 7 mL each were taken from 22 healthy subjects. Each sample was divided into 1 mL aliquots, with the first aliquot acting as the control while the second was exposed to 2 Gy of γ-radiation at a dose rate of 102.7 cGy/minute. The remaining aliquots were separately incubated with 600 μM concentrations each of serine, magnesium sulfate, serine-magnesium sulfate, NAC and cysteine before being exposed to 2 Gy of γ-radiation. Lymphocytes were isolated using a separation medium and methyl-thiazole-tetrazolium and comet assays were used to evaluate cell viability and DNA damage, respectively. The serine-magnesium sulfate mixture significantly increased lymphocyte viability and reduced DNA damage in comparison to serine, magnesium sulfate, NAC or cysteine alone (P <0.01 each). The findings of the present study support the use of a serine-magnesium sulfate mixture as a new, non-toxic, potent and efficient radioprotective agent.

Possible benefits of tomato juice consumption: a pilot study on irradiated human lymphocytes from healthy donors

BackgroundReactive oxygen species (ROS) mediate much of the DNA damage caused by ionizing radiation. Among carotenoids, lycopene and β-carotene, present in tomato juice, are known to be strong radical scavengers. The aim of the study was to investigate the effect of tomato juice intake on the levels of DNA damage and oxidative stress in human whole blood induced by in vitro exposure to X-rays.MethodsTen healthy adults were asked to drink 190 g of tomato juice, containing 17 mg lycopene and 0.25 mg β-carotene, per day for 3 weeks and then refrain from drinking it for 3 weeks. Peripheral whole blood samples were collected before and after the intake period of tomato juice and after the washout period. The blood samples were exposed in vitro to X-ray doses of 0, 0.1, 0.5, and 2 Gy. Cytogenetic damage was measured using the cytokinesis-block micronucleus (CBMN) assay and the dicentrics (DIC) assay. The level of oxidative stress was determined using serum 8-oxo-7, 8-dihydro-2-deoxyguanosine (8-oxo-dG) and plasma reactive oxygen metabolite-derived compounds (d-ROMs). The concentration of carotenoids in plasma was measured at the three time points.ResultsThe levels of 8-oxo-dG tended to decrease during the intake period and increase during the washout period. A non-significant inverse correlation was noted between the plasma concentration of lycopene plus β-carotene and the level of 8-oxo-dG (P = 0.064). The radiation-induced MN and DIC frequencies increased in a dose-dependent manner, and when compared at the same dose, the MN and DIC frequencies decreased during the intake period compared with those at baseline and then increased during the washout period. The results suggest that continuous tomato juice consumption non-significantly decreases extracellular 8-oxo-dG, d-ROMs, and MN. Tomato juice intake had minimal or no effect on radiation-induced 8-oxo-dG and d-ROMs. For most radiation doses, continuously tomato juice intake lowered the levels of MN and DIC.ConclusionTomato juice consumption may suppress human lymphocyte DNA damage caused by radiation, but further examination is required.Trial registration2014-001 and 2014-R06.

Antioxidant and Genotoxic Properties of Hispidin Isolated from the Velvet-Top Mushroom, Phaeolus schweinitzii (Agaricomycetes).

Antioxidant and genotoxic properties of hispidin isolated from the Phaeolus schweinitzii mushroom were evaluated with various assays. Hispidin demonstrated strong free radical scavenging, oxygen radical absorbance capacity, and ferric-reducing antioxidant power; in all applied assays, hispidin exhibited antioxidant capacity similar to or higher than that of the reference antioxidant Trolox. Genotoxic activity of hispidin was assessed using different end points: chromosome aberrations, micronuclei, sister chromatid exchanges, and primary DNA damage (detected by the comet assay) in human lymphocytes in vitro, and gene mutations in the Salmonella/microsome test. Hispidin did not increase the frequency of chromosome aberrations, micronuclei, or primary DNA damage in human lymphocytes in vitro and did not produce reverse mutation in bacterial cells. However, we identified in human lymphocytes a statistically significant dose-dependent increase in sister chromatid exchange frequency and a decrease in replication index and nuclear division index values.