Possible involvement of oxidative stress in potassium bromate-induced genotoxicity in human HepG2 cells

Yttrium oxide nanoparticles ameliorates calcium hydroxide and calcium titanate nanoparticles induced genomic DNA and mitochondrial damage, ROS generation and inflammation

Calcium hydroxide (Ca(OH)2NPs), calcium titanate (CaTiO3NPs) and yttrium oxide (Y2O3NPs) nanoparticles are prevalent in many industries, including food and medicine, but their small size raises concerns about potential cellular damage and genotoxic effects. However, there are very limited studies available on their genotoxic effects. Hence, this was done to investigate the effects of multiple administration of Ca(OH)2NPs, CaTiO3NPs or/and Y2O3NPs on genomic DNA stability, mitochondrial membrane potential integrity and inflammation induction in mouse brain tissues. Mice were orally administered Ca(OH)2NPs, CaTiO3NPs or/and Y2O3NPs at a dose level of 50 mg/kg b.w three times a week for 2 weeks. Genomic DNA integrity was studied using Comet assay and the level of reactive oxygen species (ROS) within brain cells was analyzed using 2,7 dichlorofluorescein diacetate dye. The expression level of Presenilin-1, tumor necrosis factor-alpha (TNF-α) and Interleukin-6 (IL-6) genes and the integrity of the mitochondrial membrane potential were also detected. Oral administration of Ca(OH)2NPs caused the highest damage to genomic DNA and mitochondrial membrane potential, less genomic DNA and mitochondrial damage was induced by CaTiO3NPs administration while administration of Y2O3NPs did not cause any remarkable change in the integrity of genomic DNA and mitochondrial membrane potential. Highest ROS generation and upregulation of presenilin-1, TNF-α and IL-6 genes were also observed within the brain cells of mice administrated Ca(OH)2NPs but Y2O3NPs administration almost caused no changes in ROS generation and genes expression compared to the negative control. Administration of CaTiO3NPs alone slightly increased ROS generation and the expression level of TNF-α and IL-6 genes. Moreover, no remarkable changes in the integrity of genomic DNA and mitochondrial DNA potential, ROS level and the expression level of presenilin-1, TNF-α and IL-6 genes were noticed after simultaneous coadministration of Y2O3NPs with Ca(OH)2NPs and CaTiO3NPs. Coadministration of Y2O3NPs with Ca(OH)2NPs and CaTiO3NPs mitigated Ca(OH)2NPs and CaTiO3NPs induced ROS generation, genomic DNA damage and inflammation along with restoring the integrity of mitochondrial membrane potential through Y2O3NPs scavenging free radicals ability. Therefore, further studies are recommended to study the possibility of using Y2O3NPs to alleviate Ca(OH)2NPs and CaTiO3NPs induced genotoxic effects.

Chia seeds and coenzyme Q10 alleviate iron overload induced hepatorenal toxicity in mice via iron chelation and oxidative stress modulation

Iron overload (IOL) can cause hepatorenal damage due to iron-mediated oxidative and mitochondrial damage. Remarkably, combining a natural iron chelator with an antioxidant can exert greater efficacy than monotherapy. Thus, the present study aimed to evaluate the efficacy of Chia and CoQ10 to chelate excess iron and prevent hepatorenal oxidative damage in IOL mice. Male Swiss albino mice (n = 49) were randomly assigned to seven groups: control, dietary Chia, CoQ10, IOL, IOL + Chia, IOL + CoQ10, and IOL + Chia + CoQ10. Computational chemistry indicates that the phytic acid found in the Chia seeds is stable, reactive, and able to bind to up to three iron ions (both Fe2+ and Fe3+). IOL induced a significant (P < 0.05) increase in serum iron, ferritin, transferrin, TIBC, TSI, RBCs, Hb, MCV, MCH, WBCs, AST, ALT, creatinine, and MDA. IOL causes a significant (P < 0.05) decrease in UIBC, platelets, and antioxidant molecules (GSH, SOD, CAT, and GR). Also, IOL elicits mitochondrial membrane change depolarization, and DNA fragmentation and suppresses mitochondrial DNA copies. Furthermore, substantial changes in hepatic and renal tissue, including hepatocellular necrosis and apoptosis, glomerular degeneration, glomerular basement membrane thickening, and tubular degeneration, were observed in the IOL group. Dietary Chia and CoQ10 induced significant (P < 0.05) amelioration in all the mentioned parameters. They can mostly repair the abnormal architecture of hepatic and renal tissues induced by IOL, as signified by normal sinusoids, normal central veins, and neither glomerular damage nor degenerated tubules. In conclusion, the combined treatment with Chia + CoQ10 exerts more pronounced efficacy than monotherapy in hepatorenal protection via chelating excess iron and improved cellular antioxidant status and hepatorenal mitochondrial function in IOL mice.

Hepatoprotective effect of p-Coumaric acid against KBrO3 -induced apoptosis in HepG2 cells

In the present study, we investigated the effect of the p-Coumaric acid (PCA), a phenolic acid, on potassium bromate (KBrO3 ) induced oxidative damage, Ras/Raf/MEK signaling, and apoptosis in HepG2 cells. Our findings showed that PCA-treated cells prevented cytotoxicity compared with KBrO3- treated cells. Furthermore, KBrO3 -induced oxidative stress and lipid peroxidation was attenuated by PCA and it also increased the antioxidant levels such as SOD, CAT, and GPX. Additionally, PCA inhibited the KBrO3 -induced DNA damage in HepG2 cells. Moreover, PCA treatment suppressed the activation of Ras/Raf/MEK signaling and increased the expression of PRDX-1. In addition, PCA prevented the KBrO3 -induced apoptosis cascade by altering the expression of proapoptotic, Bax, caspase-3, and antiapoptotic, Bcl-2 proteins. The present study proves that PCA inhibited the KBrO3 -induced oxidative stress, DNA damage, and apoptotic signaling cascade in HepG2 cells.

Estimation of genomic and mitochondrial DNA integrity in the renal tissue of mice administered with acrylamide and titanium dioxide nanoparticles

The Kidneys remove toxins from the blood and move waste products into the urine. However, the accumulation of toxins and fluids in the body leads to kidney failure. For example, the overuse of acrylamide and titanium dioxide nanoparticles (TiO2NPs) in many food and consumer products increases human exposure and risks; however, there are almost no studies available on the effect of TiO2NPs coadministration with acrylamide on the integrity of genomic and mitochondrial DNA. Accordingly, this study was conducted to estimate the integrity of genomic and mitochondrial DNA in the renal tissue of mice given acrylamide and TiO2NPs. To achieve this goal, mice were administrated orally TiO2NPs or/and acrylamide at the exposure dose levels (5 mg/kg b.w) and (3 mg/kg b.w), respectively, five times per week for two consecutive weeks. Concurrent oral administration of TiO2NPs with acrylamide caused remarkable elevations in the tail length, %DNA in tail and tail moment with higher fragmentation incidence of genomic DNA compared to those detected in the renal tissue of mice given TiO2NPs alone. Simultaneous coadministration of TiO2NPs with acrylamide also caused markedly high elevations in the reactive oxygen species (ROS) production and p53 expression level along with a loss of mitochondrial membrane potential and high decreases in the number of mitochondrial DNA copies and expression level of β catenin gene. Therefore, from these findings, we concluded that concurrent coadministration of acrylamide with TiO2NPs augmented TiO2NPs induced genomic DNA damage and mitochondrial dysfunction through increasing intracellular ROS generation, decreasing mitochondrial DNA Copy, loss of mitochondrial membrane potential and altered p53 and β catenin genes expression. Therefore, further studies are recommended to understand the biological and toxic effects resulting from TiO2NPs with acrylamide coadministration.

Salidroside protect Chinese hamster V79 cells from genotoxicity and oxidative stress induced by CL-20

Hexanitrohexaazaisowurtzitane (CL-20) is a high-energy elemental explosive widely used in chemical and military fields. CL-20 harms environmental fate, biosafety, and occupational health. However, there is little known about the genotoxicity of CL-20, in particular its molecular mechanisms. Therefore, this study was framed to investigate the genotoxic mechanisms of CL-20 in V79 cells and evaluate whether the genotoxicity could be diminished by pretreating the cells with salidroside. The results showed that CL-20-induced genotoxicity in V79 cells primarily through oxidative damage to DNA and mitochondrial DNA (mtDNA) mutation. Salidroside could significantly reduce the inhibitory effect of CL-20 on the growth of V79 cells and reduce the levels of reactive oxygen species (ROS), 8-hydroxy-2 deoxyguanosine (8-OHdG), and malondialdehyde (MDA). Salidroside also restored CL-20-induced superoxide dismutase (SOD) and glutathione (GSH) in V79 cells. As a result, salidroside attenuated the DNA damage and mutations induced by CL-20. In conclusion, oxidative stress may be involved in CL-20-induced genotoxicity in V79 cells. Salidroside could protect V79 cells from oxidative damage induced by CL-20, mechanism of which may be related to scavenging intracellular ROS and increasing the expression of proteins that can promote the activity of intracellular antioxidant enzymes. The present study for the mechanisms and protection of CL-20-mediated genotoxicity will help further to understand the toxic effects of CL-20 and provide information on the therapeutic effect of salidroside in CL-20-induced genotoxicity.

Theobroma cacao fortified-feed ameliorates potassium bromate-induced oxidative damage in male Wistar rat

Some therapeutic and beneficial health properties of the Theobroma cacao leaf have been documented. This study evaluated the ameliorative effect of Theobroma cacao-fortified feed against potassium bromate-induced oxidative damage in male Wistar rats. Thirty rats were randomly grouped into A-E. Except for E (the negative control), the rats in the other groups were administered 0.5 ml of 10 mg/kg body weight of potassium bromate daily using oral gavage and then allowed access to feed and water ad libitum. Groups B, C, and D were fed with 10 %, 20 %, and 30 % leaf-fortified feed respectively, while the negative and positive control (A) was fed with commercial feed. The treatment was carried out consecutively for fourteen days. In the liver and kidney, there was a significant increase (p < 0.05) in total protein concentration, a significant decrease (P < 0.05) in MDA level, and SOD activity in the fortified feed group compared to the positive control. Furthermore, in the serum, there was a significant increase (p < 0.05) in the albumin concentration, and ALT activity, and a significant decrease (p < 0.05) in urea concentration in the fortified feed groups compared to the positive control. The histopathology of the liver and kidney in the treated groups showed moderate cell degeneration compared to the positive control group. Antioxidant activity due to the presence of flavonoids and metal chelating activity of fiber in Theobroma cacao leaf could be responsible for the ameliorative effect of the fortified feed against potassium bromate-induced oxidative damage.

Toxicity assessment of potassium bromate and the remedial role of grape seed extract

In this study, the multiple toxic effects of potassium bromate were investigated in Allium cepa L., an indicator test material. In addition, the toxicity-reducing effects of grape seed extract (GSE) were tested. The toxicity was investigated by some physiological (germination percentage, root length, weight gain, relative injury rate), cytogenetic [mitotic index (MI), micronucleus (MN), and chromosomal abnormalities (CAs)], biochemical [malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), glutathione (GSH) levels] and anatomical parameters. A. cepa bulbs were divided into 6 groups as control and five treatment groups (Group II: 465 mg/L GSE, Group III: 930 mg/L GSE, Group IV: 100 mg/L potassium bromate, Group V: 100 mg/L potassium bromate + 465 mg/L GSE, Group VI: 100 mg /L potassium bromate + 930 mg/L GSE). The bulbs were germinated for 72 h and at the end of the period the bulbs were subjected to routine preparations and made ready for analysis and measurements. As a result, potassium bromate exposure caused statistically significant (p < 0.05) decreases in all physiological parameter values. Potassium bromate application decreased MI by 41.6%, and increased the MN and CAs frequencies. CAs such as fragment, sticky chromosome, and vagrant chromosome, unequal distribution of chromatin, reverse polarization, nuclear bud and disordered mitosis were induced in root meristem cells. The mechanism of potassium bromate genotoxicity has been associated with DNA-potassium bromate interaction supported by spectral shift. Potassium bromate caused a decrease in GSH levels and an increase in MDA, SOD and CAT levels, thereby disrupting the antioxidant/oxidant balance in root tip cells. GSE administration in two different doses together with potassium bromate reduced the toxic effects and caused improvements in all parameters examined. The most significant reduction in toxicity was in group VI, which received 930 mg/L GSE, and there was an improvement about 18% in MI levels and an improvement about 44% in GSH levels in this group. While GSE application increased physiological parameters and GSH levels, it decreased MDA, SOD, CAT levels, MN and CAs frequencies. As a result, it has been determined that potassium bromate causes multi-directional toxicity at high doses and A. cepa is a very reliable indicator in determining this toxicity. In addition, GSE extract has been found to have a strong role in reducing the toxicity induced by potassium bromate.

Alleviation of Cadmium Chloride-Induced Acute Genotoxicity, Mitochondrial DNA Disruption, and ROS Generation by Chocolate Coadministration in Mice Liver and Kidney Tissues

Increased human exposure to cadmium compounds through ingesting contaminated food, water, and medications causes negative long-term health effects, which has led to the focus of recent researches on finding natural antioxidants to mitigate cadmium-induced toxicity. Therefore, the current study was undertaken to estimate the possible ameliorative effect of chocolate coadministration on acute cadmium chloride (CdCl₂)-induced genomic instability and mitochondrial DNA damage in mice liver and kidney tissues. Concurrent administration of chocolate with CdCl₂ dramatically decreased the DNA damage level and the number of apoptotic and necrotic cells compared to mice given CdCl₂ alone. Extra-production of reactive oxygen species and increased expression of inducible nitric oxide synthase and heat shock proteins genes caused by CdCl₂ administration were also highly decreased after chocolate coadministration. Conversely, chocolate coadministration restored the integrity of the mitochondrial membrane potential disrupted by CdCl₂ administration, as well as the mitochondrial DNA copy number and expression level of heme oxygenase-1 gene were significantly upregulated after chocolate coadministration with CdCl₂. Thus, it was concluded that the coadministration of chocolate alleviated CdCl₂-induced genomic instability and mitochondrial DNA damage through its antioxidative and free radical scavenging capabilities, making chocolate a promising ameliorative product and recommended for inclusion in the daily human diet.

Potassium bromate-induced oxidative stress, genotoxicity and cytotoxicity in the blood and liver cells of mice

Potassium bromate (KBrO₃) is an oxidising agent that is extensively used as a food additive, it is also a product of cosmetic and pharmaceutical relevance. The objective of this study was to evaluate the oxidative stress, genotoxicity, and apoptosis induced by KBrO₃ in an experimental animal model. To study the toxic effects and oxidative stress, different doses of KBrO₃ below LD₅₀ (The half maximal lethal dose, 50, 100 and 150 mg/kg body weight) were given intraperitoneally to the mice for multiple time periods (24, 48, and 72 h). The results showed that KBrO₃ significantly induces oxidative damage by increasing the levels of reactive oxygen species (ROS) and lipid peroxidase and depleted the levels of catalase (CAT), superoxide dismutase (SOD) and glutathione (GSH) enzymes in the serum and liver. Moreover, a significant increase of chromosomal aberrations in bone marrow cells and an elevated incidence of micronuclei in the peripheral blood of mice were observed. KBrO₃ induces 3 ´ -OH end double-strand DNA breaks, which was evident in liver sections of the treated mice, and increases the percentage of apoptotic cells, as observed in TUNEL assays and flow cytometry analysis. The present findings indicate that KBrO₃ induces oxidative stress, genotoxicity, and cytotoxicity in a dose- and time-dependent manner in mice.

New aspects in deriving health-based guidance values for bromate in swimming pool water

Bromate, classified as a EU CLP 1B carcinogen, is a typical by-product of the disinfection of drinking and swimming pool water. The aim of this study was (a) to provide data on the occurrence of bromate in pool water, (b) to re-evaluate the carcinogenic MOA of bromate in the light of existing data, (c) to assess the possible exposure to bromate via swimming pool water and (d) to inform the derivation of cancer risk-related bromate concentrations in swimming pool water. Measurements from monitoring analysis of 229 samples showed bromate concentrations in seawater pools up to 34 mg/L. A comprehensive non-systematic literature search was done and the quality of the studies on genotoxicity and carcinogenicity was assessed by Klimisch criteria (Klimisch et al., Regul Toxicol Pharmacol 25:1–5, 1997) and SciRAP tool (Beronius et al., J Appl Toxicol, 38:1460–1470, 2018) respectively. Benchmark dose (BMD) modeling was performed using the modeling average mode in BMDS 3.1 and PROAST 66.40, 67 and 69 (human cancer BMDL₁₀; EFSA 2017). For exposure assessment, data from a wide range of sources were evaluated for their reliability. Different target groups (infants/toddlers, children and adults) and exposure scenarios (recreational, sport-active swimmers, top athletes) were considered for oral, inhalation and dermal exposure. Exposure was calculated according to the frequency of swimming events and duration in water. For illustration, cancer risk-related bromate concentrations in pool water were calculated for different target groups, taking into account their exposure using the hBMDL₁₀ and a cancer risk of 1 in 100,000. Convincing evidence was obtained from a multitude of studies that bromate induces oxidative DNA damage and acts as a clastogen in vitro and in vivo. Since statistical modeling of the available genotoxicity data is compatible with both linear as well as non-linear dose–response relationships, bromate should be conservatively considered to be a non-threshold carcinogen. BMD modeling with model averaging for renal cancer studies (Kurokawa et al., J Natl. Cancer Inst, 1983 and 1986a; DeAngelo et al., Toxicol Pathol 26:587–594, 1998) resulted in a median hBMDL₁₀ of 0.65 mg bromate/kg body weight (bw) per day. Evaluation of different age and activity groups revealed that top athletes had the highest exposure, followed by sport-active children, sport-active adults, infants and toddlers, children and adults. The predominant route of exposure was oral (73–98%) by swallowing water, followed by the dermal route (2–27%), while the inhalation route was insignificant (< 0.5%). Accepting the same risk level for all population groups resulted in different guidance values due to the large variation in exposure. For example, for an additional risk of 1 in 100,000, the bromate concentrations would range between 0.011 for top athletes, 0.015 for sport-active children and 2.1 mg/L for adults. In conclusion, the present study shows that health risks due to bromate exposure by swimming pool water cannot be excluded and that large differences in risk exist depending on the individual swimming habits and water concentrations.

Health Effect of N-Nitroso Diethylamine in Treated Water on Gut Microbiota Using a Simulated Human Intestinal Microbiota System

Chlorination disinfection byproducts (CDBPs) can exert adverse human health effects. Many toxicology-based studies confirmed the health hazards of CDBPs, but little research has been done on gut microbiome. We explored the effect of CDBPs on intestinal microbiota in the Simulator of the Human Intestinal Microbial Ecosystem (SHIME). The results showed that CDBPs slightly inhibited the production of short-chain fatty acids, and the abundance of Actinobacteria decreased in the transverse colon and descending colon. The abundance of Proteobacteria increased in the ascending colon and descending colon, while it decreased in the transverse colon. The abundance of Firmicutes decreased in both the ascending colon and descending colon. In particular, the abundance of Lachnospiraceae members, Bilophila, Oscillospira, Parabacteroides, Desulfovibrio, and Roseburia increased in the ascending colon, while the abundance of Sutterella, Bacteroides, Escherichia, Phascolarctobacterium, Clostridium, Citrobacter, and Klebsiella increased in the descending colon. The Shannon index differed significantly in both the ascending colon and descending colon before and after exposure. Overall, we demonstrate the feasibility of applying the SHIME model to studying the effects of intestinal toxicity on health of chlorinated by-products. The findings of this study improve our understanding of the health impact of CDBPs on the intestinal microbiota and better control of CDBPs in treated water is recommended.

Analysis of the suspected cancer-causing potassium bromate additive in bread samples available on the market in and around Dhaka City in Bangladesh

Bread is one of the most popular foods consumed worldwide. It is a very popular foodstuff consumed in almost every house in Bangladesh as breakfast. Bread is prepared predominantly from flour to meet the daily carbohydrate demand and enhances its overall nutrition value using various ingredients. Potassium bromate (KBrO3) is an alluring additive to improve bread quality by bread makers. But due to the well-known toxic and carcinogenic effect, certain levels of KBrO3 residue are not suitable for bread, and it is therefore forbidden in many countries. The key objective of this study is to evaluate the safety status of bread in Dhaka City and its proximity to Bangladesh. Twenty-one randomly collected bread samples were tested in this study from different bakeries or shops in and around Dhaka City. The levels of KBrO3 were analyzed spectrophotometrically, and the maximum concentration found in the bread sample was 9.29 μg/g. A total of 67% of collected bread samples showed elevated levels of KBrO3 relative to the allowable amount prescribed by various Food and Drug Administration worldwide. KBrO3 is toxic to consumers and could endanger their health over continuous regular consumption and thus need to be monitored strictly.

Protective Effect of Capparis spinosa Extract against Potassium Bromate Induced Oxidative Stress and Genotoxicity in Mice

Despite the commercial value of potassium bromate (KBrO3), it has been linked to many diseases including cancer. Capparis spinosa possesses exceptional ethnobotanical, pharmaceutical, and economic prominence by virtue of its bioactive components. The present study was designed to explore the protective role and antioxidant potential of ethanolic leaves extract of C. spinosa against the oxidative stress, genotoxicity, and apoptosis induced by KBrO3 in an experimental animal model. The results of the study revealed remarkable diminution in the levels of oxidative stress in all the treatment groups. C. spinosa extract attenuated the toxic effects of KBrO3 significantly (p < 0.05) in a time- and dose-dependent manner by restoring the normal levels of ROS and antioxidative enzymes in serum and liver tissues. The extract also abolished the oxidative DNA damage as it was evident in decreased frequency of micronuclei. A marked increase in viable cells was observed in annexin-V apoptosis assay. In conclusion, the findings of the present study demonstrate that ethanolic leaves extract of C. spinosa has considerable protective effects against KBrO3-induced toxicity in experimental mice which is attributed to its antioxidant activity. Therefore, leaves of C. spinosa could be used as a potential source of natural antioxidant and bioactive compounds.

Propolis prevents inhibition of apoptosis by potassium bromate in CCD 841 human colon cell

Previously, we demonstrated that biotransformation of propolis by some special strains of Lactobacillus plantarum might decrease the allergenic molecules in propolis. In this study, we aimed to investigate the effect of biotransformation of propolis on its antioxidant effect and its protective effect against potassium bromate-induced cancer in human colon cell line. Propolis samples were treated with different solutions (ethanol, polyethylene glycol, and water), and ultrasonication was applied at 40 Hz (5, 10, and 15 minutes) in order to facilitate solvation of solid samples. Fermentations were performed by L. plantarum strains (ISLG-2, ATCC-8014, and Visbyvac). The phenolic content of propolis was determined with liquid chromatography-mass spectrometry/mass spectrometry (LCMS/MS). The antioxidant activity (antioxidant enzymes, lipid peroxidation) and apoptosis markers (caspase 3,8,9, cytochrome-c, tumour necrosis factor-related apoptosis-inducing ligand-R1 and R2 [TRAIL], and apoptosis protease activating factor-1 [APAF-1] levels) were determined in CCD 841-human colon cell line after induction of oxidative stress by potassium bromate. All propolis samples in different solvents induced apoptosis and 4 biotransformed (by L. plantarum ISL-2 strain and L. plantarum ATCC 8014 strain) propolis samples with low allergenic molecules demonstrated similar inductions of apoptosis in CCD841 cell line. In conclusion, reduction of allergenic molecules in propolis via biotransformation did not change the antioxidant and protective effects of propolis, and it is suggested as a potential therapeutic molecule in prevention of colon cancer caused by oxidative stress for all patients. SIGNIFICANCE OF THE STUDY: This study is the first investigation that shows protective effect of propolis against potassium bromate toxicity by means of decreasing lipid peroxidation and reversing the main molecule levels in intrinsic and extrinsic pathway of apoptosis. Biotransformed propolis samples by L. plantarum ISL-2 and ATCC 8014 strain with low allergen molecule content has also the same effect in potassium bromate toxicity in CCD841 colon cell. Our data contributed that propolis as a natural compound might be a good candidate due to its minimal toxicity and lack of any adverse effects to prevent carcinogenic effect of potassium bromate.

Potassium bromate: Effects on bread components, health, environment and method of analysis: A review

Potassium bromate, is an oxidizing agent and one of the best and cheapest dough improvers in the baking industry. Due to its positive effects it plays a major role in the bread-making industry. Potassium bromate has significant effect on food biomolecules, such as starch and protein, as it affects the extent of gelatinization, viscosity, swelling characteristics as well as gluten proteins; it removes the sulfhydryl group and leads to the formation of disulfide linkages and thus improves the bread properties. However, there are many reports elucidating its negative impact on human health. It is deemed as a potential human carcinogen by IARC and classified under class 2B. Due to this, countries across world have either partially or completely banned it. Numerous techniques have evolved to determine the concentration of potassium bromate in bread. This review explains in detail, the effects of potassium bromate on biomolecules, human health, environment and various methods of analysis.

Hydroxyl Group Difference between Anthraquinone Derivatives Regulate Different Cell Death Pathways via Nucleo-Cytoplasmic Shuttling of p53

BACKGROUND

Despite a number of measures having been taken for cancer management, it is still the second leading cause of death worldwide. p53 is the protein principally being targeted for cancer treatment. Targeting p53 localization may be an effective strategy in chemotherapy as it controls major cell death pathways based on its cellular localization. Anthraquinones are bioactive compounds widely being considered as potential anticancer agents but their mechanism of action is yet to be explored. It has been shown that the number and position of hydroxyl groups within the different anthraquinones like Emodin and Chrysophanol reflects the number of intermolecular hydrogen bonds which affect its activity. Emodin contains an additional OH group at C-3, in comparison to Chrysophanol and may differentially regulate different cell death pathways in cancer cell.

OBJECTIVE

The present study was aimed to investigate the effect of two anthraquinones Emodin and Chrysophanol on induction of different cell death pathways in human lung cancer cells (A549 cell line) and whether single OH group difference between these compounds differentially regulate cell death pathways.

METHODS

The cytotoxic effect of Emodin and Chrysophanol was determined by the MTT assay. The expression of autophagy and apoptosis marker genes at mRNA and protein level after treatment was checked by the RT-PCR and Western Blot, respectively. For cellular localization of p53 after treatment, we performed immunofluorescence microscopy.

RESULTS

We observed that both compounds depicted a dose-dependent cytotoxic response in A549 cells which was in concurrence with the markers associated with oxidative stress such as an increase in ROS generation, decrease in MMP and DNA damage. We also observed that both compounds up-regulated the p53 expression where Emodin causes nuclear p53 localization, which leads to down-regulation in mTOR expression and induces autophagy while Chrysophanol inhibits p53 translocation into nucleus, up-regulates mTOR expression and inhibits autophagy.

CONCLUSION

From this study, it may be concluded that the structural difference of single hydroxyl group may switch the mechanism from one pathway to another which could be useful in the future to improve anticancer treatment and help in the development of new selective therapies.

Oral administration of a potassium bromate dosage: Determination and evaluation of accumulated bromate on the liver of male mice

In this work, we developed a simple spectrophotometric strategy for BrO₃^- ions determination as a major water disinfection constituents in the mice's liver tissues by using pararosaniline (PRA). Mice were divided into seven main groups (6 doses): lowest dose KBrO₃ (G₁ 0.01 mg L^-1, G₂ 0.025 mg L^-1 and G₃ 0.1 mg L^-1), highest dose KBrO₃ (G₄ 1 mg L^-1, G₅ 10 mg·L^-1 and G₆ 30 mg L^-1) and control. All these groups maintained a dose-specific feeding for one month, just before the bromate assessment in mice's liver samples. The results revealed that groups of exposure to lower doses of drinking water did not detect the presence of BrO₃^- accumulated in the liver tissue during the study period (1-2 months). While, the BrO₃^- was detected in higher dosages for samples analyzed in first, second, third, fourth and fifth weeks (W₁, W₂, W₃, W₄, and W₅). These results confirmed that the higher BrO₃^- dosages (1, 10, and 30 mg L^-1) were fatal if introduced in drinking water and could accumulate in the liver tissues both for mice and for human. Detection the accuracy of the method for recovery of bromate ions in liver samples (N = 5) was found to be more than 95%. Relative standard deviations (RSDs) were found to be less than 2.0% confirming the reproducibility of the assay technique.

Ethanol extract of Curcuma longa rhizome mitigates potassium bromate-induced liver changes in the Wistar rat: Histological, histochemical and immunohistochemical assessments

The effects of Curcuma longa rhizome on hepatic cells, glycogen, connective tissue fibres and filamentous cytoskeleton were evaluated following KBrO₃-induced liver injury in Wistar rats. Thirty-five male rats were randomly divided into seven groups (n=5). Group 1 were normal saline treated rats. Hepatic injury was induced in groups 2 to 7 by oral administration of 100mg/kg KBrO₃ for 2 weeks. Following induction, rats in group 2 were sacrificed while groups 3, 4, 5 were given oral dose of EECLOR at 100, 200, 400mg/kg respectively. Group 6 rats were treated with silymarine while group 7 rats were left untreated. The rats were sacrificed and the liver sections were stained with H&E, Masson trichrome, Gordon and Sweets, PAS, Feulgen reaction, anti-vimentin antibody for demonstration of general histoarchitecture, elastic fibre, collagen fibre; glycogen, nuclear DNA and filamentous cytoskeleton respectively. Groups 2, 3, 7 developed intranuclear vacuolation, plasma coagulation, plamolysis, karyopyknosis, karyorrhexis and karyolysis, hyperchromatism, DNA fading and pleomorphism. Immunohistochemical study revealed near negative immunoreaction for vimentin. These pathological changes were ameliorated in EECLOR-treated groups in a manner comparable to silymarine-treated group. The study concluded that ameliorative effects of EECLOR in KBrO₃-induced liver injury could be due to its vimentin stabilization property.

Anticancer Potential of Green Synthesized Silver Nanoparticles Using Extract of Nepeta deflersiana against Human Cervical Cancer Cells (HeLA)

In this study, silver nanoparticles (AgNPs) were synthesized using aqueous extract of Nepeta deflersiana plant. The prepared AgNPs (ND-AgNPs) were examined by ultraviolet-visible spectroscopy, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscope (SEM), and energy dispersive spectroscopy (EDX). The results obtained from various characterizations revealed that average size of synthesized AgNPs was 33 nm and in face-centered-cubic structure. The anticancer potential of ND-AgNPs was investigated against human cervical cancer cells (HeLa). The cytotoxic response was assessed by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT), neutral red uptake (NRU) assays, and morphological changes. Further, the influence of cytotoxic concentrations of ND-AgNPs on oxidative stress markers, reactive oxygen species (ROS) generation, mitochondrial membrane potential (MMP), cell cycle arrest and apoptosis/necrosis was studied. The cytotoxic response observed was in a concentration-dependent manner. Furthermore, the results also showed a significant increase in ROS and lipid peroxidation (LPO), along with a decrease in MMP and glutathione (GSH) levels. The cell cycle analysis and apoptosis/necrosis assay data exhibited ND-AgNPs-induced SubG1 arrest and apoptotic/necrotic cell death. The biosynthesized AgNPs-induced cell death in HeLA cells suggested the anticancer potential of ND-AgNPs. Therefore, they may be used to treat the cervical cancer cells.

Oxidative stress mediated cytotoxicity of tin (IV) oxide (SnO2) nanoparticles in human breast cancer (MCF-7) cells

Due to unique optical and electronic properties tin oxide nanoparticles (SnO₂ NPs) have shown potential for various applications including solar cell, catalyst, and biomedicine. However, there is limited information concerning the interaction of SnO₂ NPs with human cells. In this study, we explored the potential mechanisms of cytotoxicity of SnO₂ NPs in human breast cancer (MCF-7) cells. Results demonstrated that SnO₂ NPs induce cell viability reduction, lactate dehydrogenase leakage, rounded cell morphology, cell cycle arrest and low mitochondrial membrane potential in dose- and time-dependent manner. SnO₂ NPs were also found to provoke oxidative stress evident by generation of reactive oxygen species (ROS), hydrogen peroxide (H₂O₂) and lipid peroxidation, while depletion of glutathione (GSH) level and lower activity of several antioxidant enzymes. Remarkably, we observed that ROS generation, GSH depletion, and cytotoxicity induced by SnO₂ NPs were effectively abrogated by antioxidant N-acetylcycteine. Our data have shown that SnO₂ NPs induce toxicity in MCF-7 cells via oxidative stress. This study warrants further research to explore the genotoxicity of SnO₂ NPs in different types of cancer cells.

Copper doping enhanced the oxidative stress-mediated cytotoxicity of TiO2 nanoparticles in A549 cells

Physicochemical properties of titanium dioxide nanoparticles (TiO₂ NPs) can be tuned by doping with metals or nonmetals. Copper (Cu) doping improved the photocatalytic behavior of TiO₂ NPs that can be applied in various fields such as environmental remediation and nanomedicine. However, interaction of Cu-doped TiO₂ NPs with human cells is scarce. This study was designed to explore the role of Cu doping in cytotoxic response of TiO₂ NPs in human lung epithelial (A549) cells. Characterization data demonstrated the presence of both TiO₂ and Cu in Cu-doped TiO₂ NPs with high-quality lattice fringes without any distortion. The size of Cu-doped TiO₂ NPs (24 nm) was lower than pure TiO₂ NPs (30 nm). Biological results showed that both pure and Cu-doped TiO₂ NPs induced cytotoxicity and oxidative stress in a dose-dependent manner. Low mitochondrial membrane potential and higher caspase-3 enzyme (apoptotic markers) activity were also observed in A549 cells exposed to pure and Cu-doped TiO₂ NPs. We further observed that cytotoxicity caused by Cu-doped TiO₂ NPs was higher than pure TiO₂ NPs. Moreover, antioxidant N-acetyl cysteine effectively prevented the reactive oxygen species generation, glutathione depletion, and cell viability reduction caused by Cu-doped TiO₂ NPs. This is the first report showing that Cu-doped TiO₂ NPs induced cytotoxicity and oxidative stress in A549 cells. This study warranted further research to explore the role of Cu doping in toxicity mechanisms of TiO₂ NPs.

Cobalt iron oxide nanoparticles induce cytotoxicity and regulate the apoptotic genes through ROS in human liver cells (HepG2)

Cobalt iron oxide (CoFe₂O₄) nanoparticles (CIO NPs) have been one of the most widely explored magnetic NPs because of their excellent chemical stability, mechanical hardness and heat generating potential. However, there is limited information concerning the interaction of CIO NPs with biological systems. In this study, we investigated the reactive oxygen species (ROS) mediated cytotoxicity and apoptotic response of CIO NPs in human liver cells (HepG2). Diameter of crystalline CIO NPs was found to be 23nm with a band gap of 1.97eV. CIO NPs induced cell viability reduction and membrane damage, and degree of induction was dose- and time-dependent. CIO NPs were also found to induce oxidative stress revealed by induction of ROS, depletion of glutathione and lower activity of superoxide dismutase enzyme. Real-time PCR data has shown that mRNA level of tumor suppressor gene p53 and apoptotic genes (bax, CASP3 and CASP9) were higher, while the expression level of anti-apoptotic gene bcl-2 was lower in cells following exposure to CIO NPs. Activity of caspase-3 and caspase-9 enzymes was also higher in CIO NPs exposed cells. Furthermore, co-exposure of N-acetyl-cysteine (ROS scavenger) efficiently abrogated the modulation of apoptotic genes along with the prevention of cytotoxicity caused by CIO NPs. Overall, we observed that CIO NPs induced cytotoxicity and apoptosis in HepG2 cells through ROS via p53 pathway. This study suggests that toxicity mechanisms of CIO NPs should be further investigated in animal models.

Evidence of ATP assay as an appropriate alternative of MTT assay for cytotoxicity of secondary effluents from WWTPs

Biological tests are effective and comprehensive methods to assess toxicity of environmental pollutants to ensure the safety of reclaimed water. In this study, the canonical MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay was performed to evaluate the cytotoxicity of dissolved organic matters (DOMs) of secondary effluents from wastewater treatment plants (WWTPs). It was surprising that most concentrated DOMs treated HepG2 cells yielded much higher signal compared with vehicle control regardless of difference of treatment technologies and seasons. However, there was actually no obvious enhancement of the cell proliferation by microscopy. In order to find out potential reason for the discrepancy, another three assays were performed. The results of ATP assay and flow cytometry showed expected toxicity, which was consistent with microscopy and previous studies, while DNA assay did not exhibit apparent change in treated cells. The possible mechanisms of abnormal MTT signal could be that some materials in secondary effluents isolated by solid extraction with HLB resin directly reacted with MTT and/or enhanced the activity of mitochondrial dehydrogenase. Therefore, the MTT assay is not suitable to assess cytotoxicity of complex mixtures such as secondary effluents, while ATP assay is an optional sensitive method. This study also suggests the importance of choosing both suitable extraction methods and detection assays for toxicity evaluation of component-unknown environmental samples.

Zinc ferrite nanoparticle-induced cytotoxicity and oxidative stress in different human cells

Background

Zinc ferrite nanoparticles (NPs) have shown potential to be used in biomedical field such as magnetic resonance imaging and hyperthermia. However, there is limited information concerning the biological response of zinc ferrite NPs. This study was designed to evaluate the cytotoxicity of zinc ferrite NPs in three widely used in vitro cell culture models: human lung epithelial (A549), skin epithelial (A431) and liver (HepG2) cells. Zinc ferrite NPs were characterized by electron microscopy and dynamic light scattering. Cell viability, cell membrane damage, reactive oxygen species (ROS), glutathione (GSH), mitochondrial membrane potential (MMP), transcriptional level of apoptotic genes were determined in zinc ferrite NPs exposed cells.

Results

Zinc ferrite NPs were almost spherical shaped with an average size of 44 nm. Zinc ferrite NPs induced dose-dependent cytotoxicity (MTT and LDH) and oxidative stress (ROS and GSH) in all three types of cells in the dosage range of 10–40 µg/ml. Transcriptional level of tumor suppressor gene p53 and apoptotic genes (bax, caspase-3 and caspase-9) were up-regulated while the anti-apoptotic gene bcl-2 was down-regulated in cells after zinc ferrite NPs exposure. Furthermore, higher activity of caspase-3 and caspase-9 enzymes was also observed in zinc ferrite NPs treated cells. ROS generation, MMP loss and cell death in all three types of cells were abrogated by N-acetyl cysteine (ROS scavenger), which suggests that oxidative stress might be one of the plausible mechanisms of zinc ferrite NPs cytotoxicity. It is worth mentioning that there was marginally difference in the sensitivity of three cell lines against zinc ferrite NPs exposure. Cytotoxicity of zinc ferrite NPs were in following order; A549 > HepG2 > A431.

Conclusion

Altogether, zinc ferrite NPs induced cytotoxicity and oxidative stress in A549, A431 and HepG2 cells, which is likely to be mediated through ROS generation. This study warrants further investigation to explore the potential mechanisms of toxicity of zinc ferrite NPs in normal cells as well as in animal models.

Comparative cytotoxic response of nickel ferrite nanoparticles in human liver HepG2 and breast MFC-7 cancer cells

Nickel ferrite nanoparticles (NPs) have received much attention for their potential applications in biomedical fields such as magnetic resonance imaging, drug delivery and cancer hyperthermia. However, little is known about the toxicity of nickel ferrite NPs at the cellular and molecular levels. In this study, we investigated the cytotoxic responses of nickel ferrite NPs in two different types of human cells (i.e., liver HepG2 and breast MCF-7). Nickel ferrite NPs induced dose-dependent cytotoxicity in both types of cells, which was demonstrated by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazoliumbromide (MTT), neutral red uptake (NRU) and lactate dehydrogenase (LDH) assays. Nickel ferrite NPs were also found to induce oxidative stress, which was evident by the depletion of glutathione and the induction of reactive oxygen species (ROS) and lipid peroxidation. The mitochondrial membrane potential due to nickel ferrite NP exposure was also observed. The mRNA levels for the tumor suppressor gene p53 and the apoptotic genes bax, CASP3 and CASP9 were up-regulated, while the anti-apoptotic gene bcl-2 was down-regulated following nickel ferrite NP exposure. Furthermore, the activities of apoptotic enzymes (caspase-3 and caspase-9) were also higher in both types of cells treated with nickel ferrite NPs. Cytotoxicity induced by nickel ferrite was efficiently prevented by N-acetyl cysteine (ROS scavenger) treatment, which suggested that oxidative stress might be one of the possible mechanisms of nickel ferrite NP toxicity. We also observed that MCF-7 cells were slightly more susceptible to nickel ferrite NP exposure than HepG2 cells. This study warrants further investigation to explore the potential mechanisms of different cytotoxic responses of nickel ferrite NPs in different cell lines.

Protective effect of Lepidium sativum seed extract against hydrogen peroxide-induced cytotoxicity and oxidative stress in human liver cells (HepG2)

CONTEXT

Garden cress [Lepidium sativum (Brassicaceae)] has been widely used to treat a number of ailments in traditional medicine. The pharmacological and preventive potential of Lepidium sativum, such as anti-inflammatory, antipyretic, antihypertensive, anti-ashthamatic, anticancer, and anti-oxidant, are well known.

OBJECTIVE

The present investigation was designed to study the protective effects of chloroform extract of Lepidium sativum seed (LSE) against oxidative stress and cytotoxicity induced by hydrogen peroxide (H2O2) in human liver cells (HepG2).

MATERIALS AND METHODS

Cytotoxicity of LSE and H2O2 was identified by (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT), neutral red uptake (NRU) assays, and morphological changes in HepG2. The cells were pre-exposed to biologically safe concentrations (5-25 μg/ml) of LSE for 24 h, and then cytotoxic (0.25 mM) concentration of H2O2 was added. After 24 h of the exposures, cell viability by MTT, NRU assays, and morphological changes in HepG2 were evaluated. Further, protective effects of LSE on reactive oxygen species (ROS) generation, mitochondrial membrane potential (MMP), lipid peroxidation (LPO), and reduced glutathione (GSH) levels induced by H2O2 were studied.

RESULTS

Pre-exposure of LSE significantly attenuated the loss of cell viability up to 48% at 25 µg/ml concentration against H2O2 (LD50 value = 2.5 mM). Results also showed that LSE at 25 µg/ml concentration significantly inhibited the induction of ROS generation (45%) and LPO (56%), and increases the MMP (55%) and GSH levels (46%).

DISCUSSION AND CONCLUSION

The study suggests the cytoprotective effects of LSE against H2O2-induced toxicity in HepG2. The results also demonstrate the anti-oxidative nature of LSE.

Concentration-dependent induction of reactive oxygen species, cell cycle arrest and apoptosis in human liver cells after nickel nanoparticles exposure

Due to advent of nanotechnology, nickel nanoparticles (Ni NPs) are increasingly recognized for their utility in various applications including catalysts, sensors and electronics. However, the environmental and human health effects of Ni NPs have not been fully investigated. In this study, we examined toxic effects of Ni NPs in human liver (HepG2) cells. Ni NPs were prepared and characterized by X-ray diffraction, transmission electron microscopy and dynamic light scattering. We observed that Ni NPs (size, ∼28 nm; concentration range, 25-100 μg/mL) induced cytotoxicity in HepG2 cells and degree of induction was concentration-dependent. Ni NPs were also found to induce oxidative stress in dose-dependent manner evident by induction of reactive oxygen species and depletion of glutathione. Cell cycle analysis of cells treated with Ni NPs exhibited significant increase of apoptotic cell population in subG1 phase. Ni NPs also induced caspase-3 enzyme activity and apoptotic DNA fragmentation. Upregulation of cell cycle checkpoint gene p53 and bax/bcl-2 ratio with a concomitant loss in mitochondrial membrane potential suggested that Ni NPs induced apoptosis in HepG2 cells was mediated through mitochondrial pathway. This study warrants that applications of Ni NPs should be carefully assessed as to their toxicity to human health.

Molybdenum nanoparticles-induced cytotoxicity, oxidative stress, G2/M arrest, and DNA damage in mouse skin fibroblast cells (L929)

The present investigation was aimed to study the cytotoxicity, oxidative stress, and genotoxicity induced by molybdenum nanoparticles (Mo-NPs) in mouse skin fibroblast cells (L929). Cells were exposed to different concentrations (1-100 μg/ml) of Mo-NPs (size 40 nm) for 24 and 48 h. After the exposure, different cytotoxicity assays (3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide, MTT; neutral red uptake, NRU; and cellular morphology) and oxidative stress markers (lipid peroxidation, LPO; glutathione, GSH; and catalase) were studied. Further, Mo-NPs-induced intracellular reactive oxygen species (ROS) generation, mitochondrial membrane potential (MMP), cell cycle arrest, and DNA damage were also studied. L929 cells treated with Mo-NPs showed a concentration- and time-dependent decrease in cell viability and a loss of the normal cell morphology. The percentage cell viability was recorded as 25%, 42%, and 58% by MTT assay and 24%, 46%, and 56% by NRU assay at 25, 50, and 100 μg/ml of Mo-NPs, respectively after 48 h exposure. Furthermore, the cells showed a significant induction of oxidative stress. This was confirmed by the increase in LPO and ROS generation, as well as the decrease in the GSH and catalase levels. The decrease in MMP also confirms the impaired mitochondrial membrane. The cell cycle analysis and comet assay data revealed that Mo-NPs induced G2/M arrest and DNA damage in a concentration-dependent manner. Our results demonstrated, for the first time, Mo-NPs induced cytotoxicity, oxidative stress and genotoxicity in L929 cells. Thus, data suggest the potential hazardous nature of Mo-NPs.

Nickel nanoparticle-induced dose-dependent cyto-genotoxicity in human breast carcinoma MCF-7 cells

Despite the widespread application of nickel nanoparticles (Ni NPs) in industrial, commercial, and biomedical fields, their response to human cells has not been clearly elucidated. In the study reported here, Ni NPs with a 28 nm diameter were used to study their interaction with human breast carcinoma (MCF-7) cells. Dose-dependent decreased cell viability and damaged cell membrane integrity showed the cytotoxic potential of the Ni NPs. We further found that Ni NPs induce oxidative stress in a dose-dependent manner, as evidenced by glutathione depletion and reactive oxygen species (ROS) generation. Comet assay indicated the dose-dependent induction of DNA damage due to Ni NP exposure. The level of messenger RNA, as well as activity of caspase-3 enzyme, was higher in MCF-7 cells exposed to Ni NPs than in control cells. Moreover, we observed statistically significant correlations of ROS with cell viability (R²=0.984), DNA damage (% tail DNA) (R²=0.982), and caspase-3 enzyme activity (R²=0.991). To the best of our knowledge, this is the first study on human breast cancer cells to have shown the cyto-genotoxicity of Ni NPs, which seems to be mediated through ROS.

Potassium bromate causes cell lysis and induces oxidative stress in human erythrocytes

In the present study, we have studied the effect of KBrO3 on human erythrocytes under in vitro conditions. Erythrocytes were isolated from the blood of healthy nonsmoking volunteers and incubated with different concentrations of KBrO3 at 37°C for 60 min. This resulted in marked hemolysis in a KBrO3 -concentration dependent manner. Lysates were prepared from KBrO3 -treated and control erythrocytes and assayed for various parameters. KBrO3 treatment caused significant increase in protein oxidation, lipid peroxidation, hydrogen peroxide levels, and decrease in total sulfhydryl content, which indicates induction of oxidative stress in human erythrocytes. Methemoglobin levels and methemoglobin reductase activity were significantly increased while the total antioxidant power of lysates was greatly reduced upon KBrO3 treatment. Intracellular production of reactive oxygen species increased in a dose dependent manner. Exposure of erythrocytes to KBrO3 also caused decrease in the activities of catalase, glutathione peroxidase, thioredoxin reductase, glucose 6-phosphate dehydrogenase and glutathione reductase whereas the activities of Cu-Zn superoxide dismutase and glutathione-S-transferase were increased. These results show that KBrO3 induces oxidative stress in human erythrocytes through the generation of reactive oxygen species and alters the cellular antioxidant defense system.

Rotenone-induced oxidative stress and apoptosis in human liver HepG2 cells

Rotenone, a commonly used pesticide, is well documented to induce selective degeneration in dopaminergic neurons and motor dysfunction. Such rotenone-induced neurodegenration has been primarily suggested through mitochondria-mediated apoptosis and reactive oxygen species (ROS) generation. But the status of rotenone induced changes in liver, the major metabolic site is poorly investigated. Thus, the present investigation was aimed to study the oxidative stress-induced cytotoxicity and apoptotic cell death in human liver cells-HepG2 receiving experimental exposure of rotenone (12.5-250 μM) for 24 h. Rotenone depicted a dose-dependent cytotoxic response in HepG2 cells. These cytotoxic responses were in concurrence with the markers associated with oxidative stress such as an increase in ROS generation and lipid peroxidation as well as a decrease in the glutathione, catalase, and superoxide dismutase levels. The decrease in mitochondrial membrane potential also confirms the impaired mitochondrial activity. The events of cytotoxicity and oxidative stress were found to be associated with up-regulation in the expressions (mRNA and protein) of pro-apoptotic markers viz., p53, Bax, and caspase-3, and down-regulation of anti-apoptotic marker Bcl-2. The data obtain in this study indicate that rotenone-induced cytotoxicity in HepG2 cells via ROS-induced oxidative stress and mitochondria-mediated apoptosis involving p53, Bax/Bcl-2, and caspase-3.

Copper oxide nanoparticles induced mitochondria mediated apoptosis in human hepatocarcinoma cells

Copper oxide nanoparticles (CuO NPs) are heavily utilized in semiconductor devices, gas sensor, batteries, solar energy converter, microelectronics and heat transfer fluids. It has been reported that liver is one of the target organs for nanoparticles after they gain entry into the body through any of the possible routes. Recent studies have shown cytotoxic response of CuO NPs in liver cells. However, the underlying mechanism of apoptosis in liver cells due to CuO NPs exposure is largely lacking. We explored the possible mechanisms of apoptosis induced by CuO NPs in human hepatocellular carcinoma HepG2 cells. Prepared CuO NPs were spherical in shape with a smooth surface and had an average diameter of 22 nm. CuO NPs (concentration range 2–50 µg/ml) were found to induce cytotoxicity in HepG2 cells in dose-dependent manner, which was likely to be mediated through reactive oxygen species generation and oxidative stress. Tumor suppressor gene p53 and apoptotic gene caspase-3 were up-regulated due to CuO NPs exposure. Decrease in mitochondrial membrane potential with a concomitant increase in the gene expression of bax/bcl2 ratio suggested that mitochondria mediated pathway involved in CuO NPs induced apoptosis. This study has provided valuable insights into the possible mechanism of apoptosis caused by CuO NPs at in vitro level. Underlying mechanism(s) of apoptosis due to CuO NPs exposure should be further invested at in vivo level.

Hepatoprotective potential of Lavandula coronopifolia extracts against ethanol induced oxidative stress-mediated cytotoxicity in HepG2 cells

The present investigations were carried out to study the protective potential of four extracts (namely petroleum ether extract (LCR), chloroform extract (LCM), ethyl acetate extract (LCE), and alcoholic extract (LCL)) of Lavandula coronopifolia on oxidative stress-mediated cell death induced by ethanol, a known hepatotoxin in human hapatocellular carcinoma (HepG2) cells. Cells were pretreated with LCR, LCM, LCE, and LCL extracts (10-50 μg/ml) of L. coronopifolia for 24 h and then ethanol was added and incubated further for 24 h. After the exposure, cell viability using (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) and neutral red uptake assays and morphological changes in HepG2 cells were studied. Pretreatment with various extracts of L. coronpifolia was found to be significantly effective in countering the cytotoxic responses of ethanol. Antioxidant properties of these L. coronopifolia extracts against reactive oxygen species (ROS) generation, lipid peroxidation (LPO), and glutathione (GSH) levels induced by ethanol were investigated. Results show that pretreatment with these extracts for 24 h significantly inhibited ROS generation and LPO induced and increased the GSH levels reduced by ethanol. The data from the study suggests that LCR, LCM, LCE, and LCL extracts of L. coronopifolia showed hepatoprotective activity against ethanol-induced damage in HepG2 cells. However, a comparative study revealed that the LCE extract was found to be the most effective and LCL the least effective. The hepatoprotective effects observed in the study could be associated with the antioxidant properties of these extracts of L. coronopifolia.

Oral administration of potassium bromate, a major water disinfection by-product, induces oxidative stress and impairs the antioxidant power of rat blood

Potassium bromate (KBrO(3)) is a widely used food additive, a water disinfection by-product and a known nephrotoxic agent. The effect of KBrO(3) on rat blood, especially on the anti-oxidant defense system, was studied in this work. Animals were given a single oral dose of KBrO(3) (100 mg/kg body weight) and sacrificed 12, 24, 48, 96 and 168 h after this treatment. Blood was collected from the animals and separated into plasma and erythrocytes. KBrO(3) administration resulted in increased lipid peroxidation, protein oxidation, hydrogen peroxide levels and decreased the reduced glutathione content indicating the induction of oxidative stress in blood. Methemoglobin levels and methemoglobin reductase activity were significantly increased while the total anti-oxidant power was greatly reduced upon KBrO(3) treatment. Nitric oxide levels were enhanced while vitamin C concentration decreased in KBrO(3) treated animals. The activities of major anti-oxidant enzymes were also altered upon KBrO(3) treatment. The maximum changes in all these parameters were 48 h after the administration of KBrO(3) and then recovery took place. These results show for the first time that KBrO(3) induces oxidative stress in blood and impairs the anti-oxidant defense system. Thus impairment in the anti-oxidant power and alterations in the activities of major anti-oxidant enzymes may play an important role in mediating the toxic effects of KBrO(3) in the rat blood. The study of such biochemical events in blood will help elucidate the molecular mechanism of action of KBrO(3) and also for devising methods to overcome its toxic effects.