The Effect of Green and Black Tea Polyphenols on BRCA2 Deficient Chinese Hamster Cells by Synthetic Lethality through PARP Inhibition.

Tea polyphenols are known antioxidants presenting health benefits due to their observed cellular activities. In this study, two tea polyphenols, epigallocatechin gallate, which is common in green tea, and theaflavin, which is common in black tea, were investigated for their PARP inhibitory activity and selective cytotoxicity to BRCA2 mutated cells. The observed cytotoxicity of these polyphenols to BRCA2 deficient cells is believed to be a result of PARP inhibition induced synthetic lethality. Chinese hamster V79 cells and their BRCA2 deficient mutant V-C8, and V-C8 with gene complemented cells were tested against epigallocatechin gallate and theaflavin. In addition, Chinese hamster ovary (CHO) wild-type cells and rad51D mutant 51D1 cells were used to further investigate the synthetic lethality of these molecules. The suspected PARP inhibitory activity of epigallocatechin and theaflavin was confirmed through in vitro and in vivo experiments. Epigallocatechin gallate showed a two-fold increase of cytotoxicity to V-C8 cells compared to V79 and gene complimented cells. Compared to CHO wild type cells, 51D1 cells also showed elevated cytotoxicity following treatment with epigallocatechin gallate. Theaflavin, however, showed a similar increase of cytotoxicity to VC8 compared to V79 and gene corrected cells, but did not show elevation of cytotoxicity towards rad51D mutant cells compared to CHO cells. Elevation of sister chromatid exchange formation was observed in both tea polyphenol treatments. Polyphenol treatment induced more micronuclei formation in BRCA2 deficient cells and rad51D deficient cells when compared against the respective wild type cells. In conclusion, tea polyphenols, epigallocatechin gallate, and theaflavin may present selective cytotoxicity to BRCA2 deficient cells through synthetic lethality induced by PARP inhibition.

Protective effect of Teucrium polium on carbon tetrachloride induced genotoxicity and oxidative stress in rats.

This study aimed to investigate the protective effects of Teucrium polium (TP) on carbon tetrachloride (CCl4) induced spleen, erythrocyte's oxidative stress, and genotoxicity in rats. TP was found to contain large amounts of polyphenols (150 mg GAE/G of dry plant) and flavonoids (60 mg QE/g of quercetin dry plant). The CCl4 (0.5 ml/kg) treated rats exhibited significant reductions in serum vitamin A (VA), vitamin E (VE) and total antioxidant status (TAS). Thiobarbituric acid reactive substances (TBARS) and conjugated dienes (CD) were significantly high in the CCl4 group compared to controls. Superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) were significantly decreased in CCl4 rats. Cytogenetic trials revealed remarkable increases in the frequency of chromosomal aberrations (CAs) and sister chromatid exchange (SCE) following CCl4 administration. Pretreatment with TP prevented damages caused by CCl4. Spleen characterised by necrosis was detected in CCl4 as compared to controls. Pretreatment with TP considerably decreased the perturbation.

Molecular and cytogenetic effects of Thai royal jelly: modulation through c-MYC, h-TERT, NRF2, HO-1, BCL2, BAX and cyclins in human lymphocytes in vitro.

Royal jelly (RJ) is widely used as a food supplement for anti-aging and beauty. However, its use has been linked to asthma and hemorrhagic colitis. Since its mechanisms of toxicity have not been fully identified, we conducted an investigation to elucidate its molecular and cytogenetic effects. Using human lymphocytes in vitro, treatments with RJ (0.0005-5 mg/ml) for 3 h did not induce sister chromatid exchanges until 5 mg/ml was used. Treatments for 24 h showed a dose-dependent reduction in BCL2/BAX, c-MYC/BAX and HO-1/BAX ratios. The exception was the NRF2/BAX ratio, showing a dose-dependent reduction at low doses, but a marked increase at the highest dose. The hTERT/BAX ratio was maintained at approximately a 1.2-fold increase but decreased to nearly normal at the highest dose. Our findings indicated that the lowest dose of RJ treatment provided maximum benefits, mainly through hTERT activation relating to prolonged lifespan. The highest dose of RJ inhibited cell survival, cell proliferation and an antioxidative enzyme; nevertheless, it still activated an antioxidative response through NRF2 and maintained telomeres during cell crisis. RJ treatment at 0.05 mg/ml increased cyclin E, BCL2 and BAX to maximum levels indicating that throughout the active cell cycle, both cell survival and cell apoptosis increased. Using the gene expression ratios over BAX, similar to BCL2/BAX, provided more informative data than using individual protein levels alone. With these informative ratios, our results confirm the potential benefits of RJ in enhancing lifespan and activation antioxidative power. Further, in vivo mechanistic studies will be useful in validating these results.

Absence of toxicity and genotoxicity in an extract of Rubus coriifolius.

Rubus coriifolius Focke is a wild plant from the Rosaceae family. It grows in both Guatemala and Mexico. The polar extract of the aerial parts of this plant has antibacterial, anti-inflammatory, and anti-protozoal activities. These properties may explain the traditional use of this plant. In vivo and in vitro assays were used to assess the genotoxic and toxic effects of an ethanol extract of the aerial parts of R. coriifolius. Three groups of rats were orally administered the R. coriifolius extract diluted in ethanol (5%) at doses of 1.89 mg/kg body weight (low dose), 4.72 mg/kg body weight (medium dose), and 9.44 mg/kg body weight (high dose) for 3 weeks. Genotoxic/cytotoxic effects induced by the R. coriifolius ethanol extract were evaluated in vivo by a micronuclei (MN) test in rat's bone marrow cells and in vitro by MN and sister chromatid exchange (SCE) in human lymphocyte cultures. In vivo genotoxicity analyses revealed that the average number of micronucleated polychromatic erythrocytes and the polychromatic erythrocyte/red blood cell ratio at all doses were not significantly different from those of the negative control. In vitro genotoxicity analyses showed that MN, SCE, and proliferative index frequencies in a human lymphocyte cell culture were not significantly different from those of the negative control. These results demonstrate that the ethanol extract of R. coriifolius aerial parts is not toxic or mutagenic (in vitro and in vivo) and does not affect cell proliferation at the concentrations analyzed.

The genotoxic effects of anti-cancer drug gossypol on human lymphocytes and its mitigation by melatonin.

PURPOSE OF STUDY: To determine melatonin as a potential natural antioxidant to mitigate the genotoxic effects of promising anti-cancer drug gossypol in human lymphocytes. INTRODUCTION: Gossypol, is a polyphenolic compound naturally occurring in cotton seed, was originally identified as a male contraceptive but it has several proposed clinical applications. Gossypol has anti-proliferative effects on cancer cell lines. However, its genotoxic effects on normal cells are not much studied. Hence, there is a paucity of data available. Hence, the study was conducted to investigate gossypol-induced genotoxic effects on lymphocytes. METHODS: Peripheral blood lymphocyte cultures (PBLC) were done and exposed by two different doses of an anti-cancer drug, gossypol (0.274 mM, 1.645 mM) to check genotoxic effects. Melatonin (0.2 mM) is used as an antioxidant. Genotoxic indices such as sister chromatid exchanges (SCEs), cell cycle proliferative index (CCPI), average generation time (AGT), population doubling time (PDT) were assayed in the cultures. RESULT: Gossypol-treated groups indicated significant increases in frequency of SCEs calculated for SCE/plate and SCE/chromosome. Furthermore, CCPI showed a remarkable reduction and increased AGT and PDT levels were found in exposed cultures. When the higher dose of gossypol cultures was treated along with melatonin, these indices were found to be declined and comparable to control. CONCLUSION: Gossypol, an anti-cancer drug, induces genotoxicity on lymphocyte cells and co-supplementation of melatonin antioxidant ameliorates these toxic effects of gossypol.

Argemone oil induces genotoxicity in mice.

CONTEXT: Argemone mexicana L. is native to Mexico and the plant extracts are used in traditional medicine in India and South American countries. Argemone oil (AO) is a common adulterant of mustard oil in India and causes serious pathophysiological consequences leading to outbreaks of epidemic dropsy among consumers. In vivo cytogenetic studies on the toxicological effects of AO and its component alkaloids are limited. OBJECTIVE: The present study was undertaken to evaluate the safety of AO by assessment of their in vivo genotoxic potential in bone marrow cells of mice. MATERIALS AND METHODS: AO mixed in corn oil in the proportions of 0.01, 0.1, and 1 ml AO/kg body weight in a total volume of 10 ml/kg body weight and a single undiluted dose of AO (10 ml/kg body weight) were administered intraperitoneally in separate groups of male Swiss Albino mice for 24 h. In addition, a single concentration of sanguinarine (SG) (50 mg/kg body weight) was also administered. Genotoxicity was evaluated by chromosome aberration (CA) and sister chromatid exchange (SCE) tests. Bromodeoxyuridine (BrdU) differential technique was used to study the effect on cell replication by the calculation of average generation time (AGT). RESULTS: The minimum effective concentrations that produced significant frequencies of CA and SCE were 0.1 and 0.01 ml/kg, respectively. AO and SG induced an insignificant increase of AGT indicating that they are non-cytotoxic in the concentrations tested. DISCUSSION AND CONCLUSION: Our results confirm that AO is genotoxic even at low concentrations and its usage should be checked.

Evaluation of genotoxic and apoptotic potential of Hypericum adenotrichum Spach. in vitro.

Hypericum adenotrichum Spach. is an endemic plant from Turkey that is also used in folk medicine. In this study, following analyses of its chemical composition, the genotoxic/antigenotoxic effects of the methanol extract of H. adenotrichum in human lymphocyte culture were investigated using in vitro sister chromatid exchange, micronucleus and comet assays. In addition, the anti-growth effect of the extract was investigated in human breast cancer cell lines (MCF-7 and MDA-MB-231) using MTT and ATP viability assays. The mode of cell death was determined using fluorescence microscopy and biochemical methods. We found that the H. adenotrichum extract demonstrated cytotoxic and genotoxic effects in a cell type-dependent manner. At selected doses (125-500 µg/ml), the H. adenotrichum extract exhibited significant genotoxic activity in human lymphocytes, whereas it showed anti-growth effects on cancer cell lines between 0.2 and 100 µg/ml concentrations. The mode of cell death in cancer cells was shown to be apoptosis due to the presence of pyknotic nuclei, the cleavage of poly-(ADP-ribose) polymerase (PARP) and/or the activation of caspase-3. These results suggest that H. adenotrichum might show both cytotoxic and genotoxic effects depending on the cell type. This should be taken into account in its use for therapeutic purposes.

Synergistic Genotoxic Effects and Modulation of Cell Cycle by Ginger Ethanolic Extracts in Adjunct to Doxorubicin in Human Lymphocytes In Vitro.

BACKGROUND: Several natural phytochemicals are increasingly used, as an adjunct to chemotherapy, to reduce drug adverse effects. Zingiber officinale rhizome (ginger) product has been reported to be effective against nausea and vomiting in patients receiving emetogenic chemotherapy such as cisplatin/doxorubicin (DXR). In addition, its ethanolic extract of Zingiber officinale rhizome (EEZOR) has been reported to possess anticarcinogenic properties. However, the mechanism for anticancer activity of ginger especially when used in combination with chemotherapy has not well elucidated, one of its possible mechanisms might involve its genotoxicity. OBJECTIVE: To investigate genotoxic and cytotoxic potentials of EEZOR alone and EEZOR pretreatments followed by 0.1 mcg/ ml DXR, a genotoxic chemotherapeutic agent in human lymphocytes by sister chromatid exchange (SCE) assay in vitro. The effect on cell cycle kinetics was also explored. MATERIAL AND METHOD: Human lymphocytes were treated with EEZOR alone at 25-500 mcg/ml and EEZOR pretreated at 12.5-200 mcg/ml followed by 0.1 mcg/ml DXR. SCE levels and cell cycle kinetics were evaluated. RESULTS: EEZOR significantly induced biphasic SCE at 50 and 400 mcg/ml (p < 0.05). However, cytotoxicity manifested at 500 mcg/ml. All EEZOR pretreatments at 12.5, 25, 50, and 100 mcg/ml, except at 200 mcg/ml, prior to DXR, moderately enhanced DXR-induced genotoxicity by 1.3 times (p < 0.05). Both EEZOR alone and EEZOR prior to DXR at certain concentrations delayed cell cycle. CONCLUSION: At specific doses, EEZOR could induce genotoxicity and in pretreatments could moderately enhance DXR-induced genotoxicity and delay cell cycle. This finding suggests that dosage use of EEZOR needs to be adjusted for long-term safety. In addition, EEZOR in adjunct to DXM might have potential benefits not only as an emetic agent but also in chemotherapy. Further in vivo animal and human studies to support this evidence is essentially needed.

In vitro enhancement of doxorubicin genotoxic activities and interference with cell cycle delay by Plumbago indica root ethanolic extract in human lymphocytes.

BACKGROUND: Combinations of modern medicines with herbal medicines are being developedfor more effectiveness. Data on the safety and drug-herb interactions are needed to be clarified. Ethanolic extract of Plumbago indica root (EEPIR) is medicinally usedfor cancer treatment in Asian traditional medicine. However its mechanism of action is still inconclusive. Our previous study demonstrated that EEPIR was genotoxic and induced cell cycle delay in human lymphocytes in vitro. OBJECTIVE: To investigate genotoxic potency and interference with cell cycle of EEPIR in combination with doxorubicin (DXR), a standard chemotherapeutic agent, in human lymphocytes by in vitro sister chromatid exchange (SCE) assay. MATERIAL AND METHOD: Human lymphocytes were pretreated with EEPIR at 6.25-100 mcg/mlfollowed by DXR (0.1 mcg/ml). SCE levels and cell cycle kinetics were evaluated. RESULTS: EEPIR pretreatments (6.5-50 mcg/ml) significantly enhanced genetic damage induced by DXR (p<0. 05). Delaying of the cell cycle was detected and related to EEPIR concentration. EEPIR at 100 mcg/ml, on the contrary, did not enhance DXR-induced genotoxicity but tended to lower genotoxicity compared to DXR treatment alone. It significantly delayed cell cycle the most (p<0.05). CONCLUSION: EEPIR pretreatments at proper doses enhanced genotoxic damage induced by DXR in human lymphocytes. Delaying cell cycle by EEPIR could lower that potency. Usage of EEPIR, therefore, should be adjusted for safety. Combination of EEPIR with DXR might be usefulfor more efficient cancer treatment with less DXR toxicity. Further in vivo study is needed to support this in vitro evidence.

Ameliorative effect of certain antioxidants against mercury induced genotoxicity in peripheral blood lymphocytes.

Various antioxidants play an important role in reducing the reactive oxygen species (ROS) by scavenging them directly or indirectly. Mercury (Hg) is one of the known hazardous genotoxicant, induces the genotoxicity by enhancing the ROS. In the present study, three structurally different bioactive compounds such as melatonin (0.2 mM), curcumin (3.87 µM) and andrographolide (0.4 µM) were evaluated against the genotoxic effect of mercury. All the experiments were conducted using the peripheral blood lymphocytes In Vitro. The cultures were exposed to different doses (2.63 µM; 6.57 µM; 10.52 µM) of mercury salt (HgCl2) for studying various genotoxic indices. All three antioxidant compounds, alone and in combination with high dose of mercury, were added to the cultures with controls. For ascertaining genotoxicity, sister chromatid exchanges (SCEs), cell cycle proliferative index/replicative index (CCPI/RI), average generation time (AGT), population doubling time (PDT), %M1, %M2 and %M3 were assessed and analyzed using suitable statistical analysis. The results revealed a dose dependent increase in SCEs, AGT and PDT, with a concomitant reduction in CCPI values after treatment of mercury. Supplementation of these three antioxidant compounds effectively negated these genotoxic endpoints in treated cultures with improvement in the cell cycle kinetics i.e. CCPI. The antimutagenic activity of these compounds on mercury induced genotoxicity was in the following order: melatonin > curcumin > andrographolide. In conclusion, these compounds have ameliorated mercury induced increase in genotoxic indices due to their excellent antioxidant properties and the combination seems to be effective.

Genotoxic and antigenotoxic potentials of two Usnea species.

For ages, lichens have long been investigated popularly for biological roles, mainly antitumor, antimicrobial and antioxidant activities. Many positive results were obtained in these previous research. Thus, in this study, we aimed to determine whether extracts of Usnea articulata (UAE) and Usnea filipendula (UFE) possessing a protection against aflatoxin B1 (AFB1)-induced genotoxic and oxidative damage. The results of our studies showed that 5 µM concentrations of AFB1 increased the frequencies of sister chromatid exchange (SCE) and the level of malondialdehyde (MDA) and decreased the activities of superoxide dismutase (SOD), glutathione (GSH) and glutathione peroxidase (GPx). However, when 5, 10 and 20 µg/mL concentrations of UAE and UFE was added to AFB1, the frequencies of SCE and MDA level were decreased and SOD, GSH and GPx level were increased. The Ames (Salmonella typhimurium TA1535, TA1537) and WP2 (Escherichia coli) test systems carried out evinced that UAE and UFE possess any mutagenicity, but have antimutagenic effects. Consequently, the results of this experiment have clearly shown that UAE and UFE have strong antioxidative and antigenotoxic effects that are associated with its antioxidant nature. A detailed study can be performed to determine the antioxidant properties of each compound that will extend the use of lichen extracts in food and pharmacy industries.

Studying the effect of antioxidants on cytogenetic manifestations of solvent exposure in the paint industry.

OBJECTIVE: To investigate the antioxidant role in reversing cytogenetic changes caused by solvent exposure in paint industry. SUBJECTS AND METHODS: A prospective controlled clinical trial was performed on 39 workers exposed to solvents and 39 workers not exposed to solvents by supplying a mixture of antioxidant vitamins (A, C, E and selenium) and the after effects of such regimen were analyzed. Environmental monitoring was carried out for air concentrations of different solvents at workplace. Exposed group was cytogenetically tested before and after giving the mixture of antioxidant vitamins for 1 month duration. RESULTS: Frequency of chromosomal aberrations (CAs) and the mean of sister chromatid exchanges (SCEs) were statistically significantly higher among exposed workers than among controls. After the supplementation of antioxidants, there was a statistically significant decrease in the frequency of CAs, and 88% abnormal levels of SCEs were back to normal levels. CONCLUSION: Antioxidant supplementation decreases the frequency of CAs and SCEs among exposed workers.

Antagonistic effects of Satureja hortensis essential oil against AFB1 on human lymphocytes in vitro.

Satureja hortensis L. (Lamiaceae) has been used as a folk remedy to treat various such as cramps, muscle pains, nausea, indigestion, diarrhea, and infectious diseases. In this study, the antagonistic effects of essential oil of S. hortensis (SHE) were studied against aflatoxin B1 (AFB1) in human lymphocytes in vitro. The analysis of the essential oil was performed by using Gas chromatography-mass spectrometry (GC-MS). Anti-genotoxic effects of the SHEs was evaluated using sister chromatid exchange (SCE), micronuclei (MN) tests against AFB1. Also level of malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities used to determine the anti-oxidative effects of the SHEs. This result showed AFB1 (5 microM) increased the frequencies of SCE, MN and the level of MDA. AFB1 at the same concentration decreased the activities of SOD and GPx. However, different concentrations of SHE with AFB1 decreased the frequency of SCE and MN and level of MDA and also increased the activities of SOD and GPx significantly. Especially, the 1.0, 1.5, 2.0 microL dose of SHE are more effective than other doses. The results of this experiment have clearly shown that SHE has strong antioxidative and antigenotoxic effects, these biological activities of SHEs can be due to its component.

The genotoxic and antigenotoxic effects of Salvia fruticosa leaf extract in human blood lymphocytes.

The aim of this study was to investigate the genotoxic and antigenotoxic effects of Salvia fruticosa (Sf) leaf extract with the absence and presence of S9 mix using sister chromatid exchange (SCE), chromosome aberration (CA) and micronucleus (MN) formation test systems in human peripheral blood lymphocytes (HPBLs) that were treated with 1.5-, 3.0- and 6.0-µL/mL concentrations for 24- and 48-hour treatment periods. The cytotoxicity of Sf leaf extract was also investigated by calculating the mitotic index (MI), proliferation index (PI) and nuclear division index (NDI). In the absence of S9 mix, Sf leaf extract alone increased SCE frequency at the 48-hour treatment period; however, it induced the CA and MN at all concentrations and at all treatment periods. Sf plus MMC (mitomycin C) synergically induced SCE and CA, except the highest concentration of Sf leaf extract and MMC on induction of SCE. In addition, Sf leaf extract induced the effect of MMC on MN frequency for 24 hours, but it significantly decreased the effect of MMC on MN frequency for the 48-hour treatment period. Sf leaf extract showed a cytotoxic effect by decreasing the MI; however, it did not decrease the PI and NDI. In the presence of S9 mix, Sf leaf extract did not increase the SCE, when compared to solvent control, whereas it reduced the effect of cyclophosphamide (Cyp). Sf leaf extract induced the CA and MN, but could not increase the effect of Cyp on CA and MN formation. Sf leaf extract had no cytotoxic effect; however, it induced the cytotoxicity of Cyp.

Genotoxicity and interference with cell cycle activities by an ethanolic extract from Thai Plumbago indica roots in human lymphocytes in vitro.

In Thai traditional medicine, Plumbago indica or Jetamul-Pleung-Dang in Thai is known to have health benefit especially for anti-inflammatory, antibacterial, and antitumor activities. However, the mechanisms of its action are still uncertain. One of which might be genotoxic effects. In the present study, we investigated the genotoxicity of an ethanolic extract of Plumbago indica root (EEPIR) by sister chromatid exchange (SCE) assay in human lymphocytes. Results have shown that all treatments with EEPIR (12.5-100 µg/ml) could induce cell cycle delay as shown by significant increase in the number of metaphase cells in the first cell cycle but neither in the second nor the third cell cycle. Only at concentrations of 25, 50, and 100 µg/ml were SCE levels significantly increased above that of the control (p<0.05) . EEPIR at a concentration of 500 µg/ml induced cell death as few mitotic cells were shown. Accordingly, EEPIR (25-100 µg/ml) is genotoxic in human lymphocytes and cytotoxic at concentrations of ≥ 500 µg/ml in vitro. Therefore, these activities of the EEPIR could serve its potential therapeutic effects, especially as an anticancer agent. Further study of EEPIR in vivo is now needed to support this in vitro evidence.

Aluminium phosphide-induced genetic and oxidative damages in vitro: attenuation by Laurus nobilis L. leaf extract.

OBJECTIVE: The present investigation was undertaken to assess the protective effect of Laurus nobilis leaf extract (LNE) against aluminum phosphide (AIP)-induced genotoxic and oxidative damages stress in cultured human blood cells in the presence of a metabolic activator (S9 mix). MATERIALS AND METHODS: Sister chromatid exchange (SCE) and chromosome aberration (CA) assays were used to assess AlP-induced genotoxicity and to establish the protective effects of LNE. In addition, we determined total antioxidant capacity (TAC) and total oxidative status (TOS) levels in AlP and LNE treated cultures for biomonitoring the oxidative alterations. RESULTS: There was significant increases (P < 0.05) in both SCE and CA frequencies of cultures treated with AlP as compared to controls. Our results also showed that AlP (58 mg/l) caused oxidative stress by altering TAC and TOS levels. However, co-application of LNE (25, 50, 100 and 200 mg/l) and AlP resulted in decreases of SCE, CA rates and TOS level and increases of TAC level as compared to the group treated with AlP alone. CONCLUSION: The preventive role of LNE in alleviating AlP-induced DNA and oxidative damages was indicated for the first time in the present study.

Evaluation of the biological activity of naturally occurring 5,8-dihydroxycoumarin.

5,8-Dihydroxycoumarin (5,8-DHC) was isolated from aerial parts of sweet grass (Hierochloë odorata L.) and screened for antioxidant and genotoxic activities. A clear linear dependency of radical scavenging capacity in DPPH• and ABTS•+ assays was determined. 5,8-DHC was very efficient in retarding rapeseed oil oxidation (Oxipress test). TPC (total phenols content) and FRAP (the ability to reduce ferric ion to ferrous ion) assays revealed a somewhat lower antioxidant capacity of 5,8-DHC as compared with gallic acid. Genotoxic activity was tested using different genetic end-points: chromosome aberrations (CAs) and micronuclei (MN) in Wistar rat bone marrow in vivo, CAs and sister chromatid exchanges (SCEs) in human lymphocytes in vitro, and somatic mutations and recombination in Drosophila melanogaster wing cells in vivo. 5,8-DHC did not increase frequency of CAs in rat bone marrow cells, but induced a significant increase of MN. It was slightly mutagenic in the Drosophila melanogaster assay after 120 h of treatment, but not after 48 h of treatment. 5,8-DHC induced both CAs and SCEs in vitro in human lymphocytes in a clear dose-dependent manner. Thus, 5,8-DHC may be classified as weakly genotoxic both in vivo and in vitro.

Genotoxic and cytotoxic effects of storax in vitro.

The aim of this study is to investigate the effects of the storax balsam, which is a kind of sweet gum obtained from the Liquidambar orientalis Mill trees, on cell viability, cytotoxicity and genotoxicity in human lymphocyte in vitro. We studied the genotoxic effects of the extract of storax balsam (SE) using sister chromatid exchange (SCE) test system. Also the cytotoxic and inhibitory effects on cell proliferation of SE were evaluated using lactate dehydrogenase (LDH) assay and cell proliferation (WST-1) assay. The SCE frequency was increased when the cells were treated with 1.6 and 4.0 µg/mL SE concentrations (p < 0.05). Moreover, treatment of the cells with the same concentrations significantly depleted the cell number at 24th and 48th hours and elevated the LDH levels (p < 0.05) at 48th hour. These results suggest that SE can be used as an alternative antibacterial and antipathogenic agent due to its cytotoxic and genotoxic effects.

Aqueous extracts of Lippia turbinata and Aloysia citriodora (Verbenaceae): assessment of antioxidant capacity and DNA damage.

The aim of the present work was to make a contribution to the knowledge of aqueous extracts of Lippia turbinata and Aloysia citriodora (Verbenaceae; infusion and decoction) in relation with the establishment of its antioxidant activity and lack of DNA damage, for its potential use in therapeutics. The cytogenotoxic profile was evaluated through genotoxic biomarkers such as mitotic index, cellular proliferation kinetics, sister chromatid exchanges, single-cell gel electrophoresis assay, and micronucleus test in human peripheral blood lymphocyte cultures. No statistical differences were found (P > .05) between control and exposed cultures, even between both aqueous extracts. The total antioxidant capacity was shown to be higher in the decoction than in the infusion and both aqueous extracts protected against protein carbonylation and lipid peroxidation, the decoction being more efficient than the infusion (P < .005). These results suggest the safe use of these medicinal plants as chemoecologic agents in therapeutics.

The effects of taurine on permethrininduced cytogenetic and oxidative damage in cultured human lymphocytes.

Permethrin (PM) is a common pyrethroid pesticide used to control pests in agriculture, forestry, horticulture, health care, homes, and textile industry. It is confirmed as a strong mutagen in animals and humans. Taurine (TA) is an amino acid found in mammalian tissues that protects the cell against DNA damage. In this study, we investigated whether supplementation of human lymphocyte cultures with TA (in the concentrations of 25 µg mL-1, 50 µg mL-1 and 100 µg mL-1) provided any protection against PM toxicity applied in the concentration of 200 µg mL-1. Genotoxicity was assessed using the micronucleus (MN) and sister chromatid exchanges (SCE) tests. In addition, we measured the total antioxidant capacity (TAC) and total oxidative stress (TOS) levels in the plasma to determine oxidative effects. PM increased SCE and MN levels and altered TAC and TOS levels. TA alone did not affect SCE and MN levels compared to controls, regardless of the concentration applied. In addition, it increased TAC levels without changing TOS levels. Moreover, it significantly buffered the negative cytogenetic and oxidative effects induced by PM in a clear dose-dependent manner. In conclusion, this study is the first to evidence the beneficial effects of TA against PM-induced DNA and oxidative damages in vitro.