Isolation of a novel quercetin derivative from Terminalia chebula and RT-PCR-assisted probing to investigate its DNA repair in hepatoma cells.

Background and purpose: DNA damage can lead to carcinogenesis if replication proceeds without proper repair. This study focused on the purification of a novel quercetin derivative present in Terminalia chebula fruit and studied its protective role in hepatoma cells due to H2O2-DNA damage. Experimental approach: The pure compound obtained from the silica gel column was subjected to structural characterization using spectroscopic techniques. MTT assay was employed to select a non-toxic concentration of the isolated compounds on HepG2 and Chang liver cells. The antigenotoxic property of the compound on HepG2 and Chang liver cells was carried out by alkaline comet assay. Analyses of expression levels of mRNA for two DNA repair enzymes, OGG1 and NEIL1, in HepG2 and Chang liver cells, were carried out using the RT-PCR method. Findings/Results: The pure compound obtained from the fraction-5 of diethyl ether extract was identified as a novel quercetin derivative and named 7-(but-2-en-1-yloxy)-2-(4(but-2-en-1-yloxy)-3-hydroxyphenyl)-3- (hexa-2,4-dien-1-yloxy)-6-hydroxy-4H-chromen-4-one. This compound recorded modest toxicity at the highest concentration tested (percentage cell viability at 100 µg/mL was 64.71 ± 0.38 for HepG2 and 45.32 ± 0.07 for Chang liver cells). The compound has demonstrated noteworthy protection against H2O2-induced DNA damage in both cell lines. Analyses of mRNA expression levels for enzymes OGGI and NEIL1 enzymes in HepG2 and Chang liver cells asserted the protective role of the isolated compound against H2O2-induced DNA damage. Conclusion and implication: The protective effect of a novel quercetin derivative isolated from T. chebula in the hepatoma cells is reported here for the first time.

Toxicity Assessment of Wild Mushrooms from the Western Ghats, India: An in Vitro and Sub-Acute in Vivo Study.

Background: Poisoning by different kinds of toxic mushrooms is unfortunately becoming an increasingly important medical problem, evident from the growing number of reports worldwide since the 1950s. Mycetism being a health concern, deserves scientific attention. In this perspective, the present study aims to assess the potential effects of ingesting the selected wild mushrooms from regions of the Western Ghats, India. Methods: The preliminary cytotoxicity of the selected mushrooms was studied in vitro on the intestinal NCM460 and the Chang's liver cell lines on the basis of cell viability. Further, the hepatotoxicity was assessed by measuring biologically relevant endpoints such as membrane integrity, mitochondrial stress and oxidative status. A 28 day sub-acute toxicity study was carried out by orally administering the mushroom extracts to mice at 250 and 500 mg/kg body weight. The hematological and serum analysis as well as histological examinations were carried out to evaluate their in vivo toxicity. GC-MS analysis of the mushrooms facilitated the identification of their volatile chemical profile. Result: The in vitro intestinal cytotoxicity exhibited by these wild mushrooms in comparison to the edible mushroom indicated their potential gastrointestinal toxicity. The pathological findings in small intestine on exposure to Chlorophyllum molybdites and Agaricus endoxanthus also validates the speculations about their intestinal toxicity. The toxic insult to the hepatocytes due to Amanita angustilamellata, Entoloma crassum, and Clarkeinda trachodes was predictive of the observed in vivo hepatotoxicity which was also accompanied by renal toxicity at the higher dose of 500 mg/kg bwt. Conclusion: The potential toxicity exhibited by these representative mushrooms from the wild warrants caution about their consumption. The present work could also have broader implications for global mycetism.

Silymarin nanoemulsion against human hepatocellular carcinoma: development and optimization.

OBJECTIVE: Nanoemulsion of silymarin was developed and optimized. MATERIALS AND METHODS: Nanoemulsion was made by aqueous titration method. Sefsol 218 (5.8% v/v), Kolliphor RH40 and polyethylene glycol 400 (Smix; 2:1; 28.99% v/v) were used as oil phase, surfactant and co-surfactant while distilled water (65.22% v/v) acted as an aqueous phase. Nanoemulsion was characterized on the basis of particle size, viscosity, electrical conductivity and refractive index. Further, in vitro release, in vivo pharmacokinetic study, stability study and cancer cell line studies were also performed. RESULTS AND DISCUSSION: The optimized formulation (NE9) with mean particle size of 21.24 nm showed a minimum viscosity of 9.59 cps, maximum drug release (97.75%) in 24 h. The NE9 formulation also showed higher AUC (p < .01) and Cmax (p < .01) and shorter Tmax (p < .05) compared with conventional and standard suspensions of silymarin. The stability study also showed considerably stable formulations at refrigerator temperature as compared with room temperature (p > .05). The cancer cell line studies also confirmed that silymarin nanoemulsion reduced the cell viability and increased ROS intensity and chromatin condensation (p < .05). CONCLUSION: Our results concluded that nanoemulsion may be an efficient carrier for oral delivery of silymarin against human hepatocellular carcinoma without damaging normal cells.

Protective effects of quercetin on hepatic cell damage induced by oxidative stress / 天津医药

Objective To explore the protective effects of quercetin on damage induced by oxidative stress and to clari?fy its molecular mechanism. Methods Chang liver cell cultures were randomly divided into control groups, H2O2 group and 3 doses of quercetin groups. Cell survival rate was detected with MTT. Cell apoptotic rate was measured by FACS(Fluores?cence-activated cell sorting). Intracellular reactive oxygen species (ROS) level in Chang liver cells were tested by flow cy?tometer. The DCF fluorescence intensity of DCFH-DA-stained intracellular ROS was observed by fluorescence microscope. The levels of malondialdehyde (MDA), superoxide dismutase(SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) were determined in liver cells using commercial available kits. The expression of Nrf2 were detected by Western blot. Re?sults Compared with control, cell survival rate and levels of SOD, CAT and GSH-Px decreased significantly in H2O2 group (P < 0.05 ),while cell appotosis rate, content of MDA and mean fluorescence intensity(MFI) increased in H2O2 group (P <0.05). In comparison with H2O2, expression of Nrf2 protein was higher in all three quercetin treatment groups (P<0.05). Con?clusion Quercetin protected Chang liver cells from H2O2-induced oxidative stress, which may be caused by the increased ex?pressions of down stream antioxidant genes via activating the Nrf2-ARE signaling pathway.

Cytotoxicity of three South African medicinal plants using the Chang liver cell line.

BACKGROUND: Arctotis arctotoides, Gasteria bicolor and Pittosporum viridiflorum are commonly used in the Eastern Cape, South Africa by traditional healers for the treatment of opportunistic fungal infections in HIV/AIDS patients. Unfortunately, there is a dearth of published data regarding the toxicity of the selected plants, despite the fact that experimental screening of toxicity is crucial to guarantee the safety of the users. MATERIALS AND METHODS: Therefore, it was decided to evaluate the cytotoxicity of the hexane and acetone extracts of the medicinal plants against the Chang Liver cell line using the in vitro MTT assay. Different concentrations of the extracts were added into 24-hour cultured cells and incubated for 72 hours under specific condition (37 °C, 5% CO2). Cell survival was evaluated using the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. RESULTS: Depending on the dosage and duration of treatment, the cytotoxic effects of Gasteria bicolor and Pittosporum viridiflorum were considered relatively weak (but not entirely absent) and less of a toxicity risk. Arctotis arctotoides extracts were the most toxic both in terms of IC50 values as well as the steeper slope of the dose response curve. The IC50 values for the acetone and hexane extracts of this plant were 17.4 and 12.4 µg/ml respectively. CONCLUSION: These relatively low values raise concern for potential hepatotoxic effects and deserve further investigation or at least a warning to potential users.

Evaluation of Oxidative DNA Damage Using an Alkaline Single Cell Gel Electrophoresis (SCGE) Comet Assay, and the Protective Effects of N-Acetylcysteine Amide on Zearalenone-induced Cytotoxicity in Chang Liver Cells.

Zearalenone (ZEN) is a non-steroidal estrogenic mycotoxin produced by several species of Fusarium that are found in cereals and agricultural products. ZEN has been implicated in mycotoxicosis in farm animals and in humans. The toxic effects of ZEN are well known, but the ability of an alkaline Comet assay to assess ZEN-induced oxidative DNA damage in Chang liver cells has not been established. The first aim of this study was to evaluate the Comet assay for the determination of cytotoxicity and extent of DNA damage induced by ZEN toxin, and the second aim was to investigate the ability of N-acetylcysteine amide (NACA) to protect cells from ZEN-induced toxicity. In the Comet assay, DNA damage was assessed by quantifying the tail extent moment (TEM; arbitrary unit) and tail length (TL; arbitrary unit), which are used as indicators of DNA strand breaks in SCGE. The cytotoxic effects of ZEN in Chang liver cells were mediated by inhibition of cell proliferation and induction of oxidative DNA damage. Increasing the concentration of ZEN increased the extent of DNA damage. The extent of DNA migration, and percentage of cells with tails were significantly increased in a concentration-dependent manner following treatment with ZEN toxin (p < 0.05). Treatment with a low concentration of ZEN toxin (25 µM) induced a relatively low level of DNA damage, compared to treatment of cells with a high concentration of ZEN toxin (250 µM). Oxidative DNA damage appeared to be a key determinant of ZEN-induced toxicity in Chang liver cells. Significant reductions in cytolethality and oxidative DNA damage were observed when cells were pretreated with NACA prior to exposure to any concentration of ZEN. Our data suggest that ZEN induces DNA damage in Chang liver cells, and that the antioxidant activity of NACA may contribute to the reduction of ZEN-induced DNA damage and cytotoxicity via elimination of oxidative stress.

Cytotoxicity and the induction of the stress protein Hsp 70 in Chang liver cells in response to zearalenone-induced oxidative stress.

Zearalenone (ZEN) has been implicated in several cases of mycotoxicosis in farm animals and humans. The toxic effects of ZEN have been well characterized, but little is known regarding the mechanisms of ZEN toxicity, including the involvement of the oxidative stress pathway. Using Chang liver cells as a model, the aim of this study was to determine if ZEN could elevate the expression of the heat shock protein Hsp 70, induce cytotoxicity and modulate the levels of glutathione (GSH) and thiobarbituric acid reactive substance (TBARS). In addition, the cytoprotective effects of N-acetylcysteine amide (NACA) pre-treatment were assessed. Finally, the involvement of oxidative stress in ZEN-induced toxicity was confirmed. The results of this study demonstrated that ZEN-induced Hsp 70 expression in a dose- and time-dependent manners. This effect occurred at low-ZEN concentrations, and could therefore be considered a biomarker of ZEN-induced toxicity. The cytotoxicity was reduced when Chang liver cells were exposed to sub-lethal heat shock prior to ZEN treatment, demonstrating a cytoprotective effect of Hsp 70. This cytoprotective effect suggested that Hsp 70 might play a key role in the cellular defense mechanism. When cells were pre-treated with NACA prior to ZEN treatment, the cells were also protected from toxicity. This NACA cytoprotective effect suggested the involvement of oxidative stress in ZEN-induced toxicity, and this mechanism was supported by reduced Hsp 70 expression, inhibited cytolethality, increased GSH levels and decreased TBARS formation when cells were pre-treated with NACA prior to ZEN exposure. Our data clearly demonstrated that ZEN induced cytotoxicity in Chang liver cells by inhibiting cell proliferation, decreasing GSH levels and increasing TBARS formation in a dose-dependent manner. ZEN also, induced Hsp 70 expression, and the side effects of ZEN were significantly alleviated by pre-treatment with NACA. Oxidative stress is likely to be one of the primary pathways of ZEN toxicity. This oxidative stress may contribute, at least in part, to the mechanism of ZEN-induced cytotoxicity.

Evaluation of Oxidative DNA Damage Using an Alkaline Single Cell Gel Electrophoresis (SCGE) Comet Assay, and the Protective Effects of N-Acetylcysteine Amide on Zearalenone-induced Cytotoxicity in Chang Liver Cells

Zearalenone (ZEN) is a non-steroidal estrogenic mycotoxin produced by several species of Fusarium that are found in cereals and agricultural products. ZEN has been implicated in mycotoxicosis in farm animals and in humans. The toxic effects of ZEN are well known, but the ability of an alkaline Comet assay to assess ZEN-induced oxidative DNA damage in Chang liver cells has not been established. The first aim of this study was to evaluate the Comet assay for the determination of cytotoxicity and extent of DNA damage induced by ZEN toxin, and the second aim was to investigate the ability of N-acetylcysteine amide (NACA) to protect cells from ZEN-induced toxicity. In the Comet assay, DNA damage was assessed by quantifying the tail extent moment (TEM; arbitrary unit) and tail length (TL; arbitrary unit), which are used as indicators of DNA strand breaks in SCGE. The cytotoxic effects of ZEN in Chang liver cells were mediated by inhibition of cell proliferation and induction of oxidative DNA damage. Increasing the concentration of ZEN increased the extent of DNA damage. The extent of DNA migration, and percentage of cells with tails were significantly increased in a concentration-dependent manner following treatment with ZEN toxin (p < 0.05). Treatment with a low concentration of ZEN toxin (25 microM) induced a relatively low level of DNA damage, compared to treatment of cells with a high concentration of ZEN toxin (250 microM). Oxidative DNA damage appeared to be a key determinant of ZEN-induced toxicity in Chang liver cells. Significant reductions in cytolethality and oxidative DNA damage were observed when cells were pretreated with NACA prior to exposure to any concentration of ZEN. Our data suggest that ZEN induces DNA damage in Chang liver cells, and that the antioxidant activity of NACA may contribute to the reduction of ZEN-induced DNA damage and cytotoxicity via elimination of oxidative stress.

Active effect of hemeoxygenase-1 expression on Chang liver cell induced by inorganic arsenic / 中国地方病学杂志

Objective To observe whether sodium arsenite(NaAsO2)can activate the expressions of hemeoxygenase-1(HO-1)of normal human liver cell line named Chang liver.Methods Chang liver cells were exposed to NaAsO2 at 10 μmoL/L,0(contml),2,6,12,24 h and at 0(control),5,10,25,50 μmol/L in 12 h, followed by the measuring of the expressions of HO-1 protein in ceUs with western blot.Results In 10 μmol/L groups Chang liver cells exposed for 6,12,24 h cultured in vitro,the expressions of HO-l protein(3.97±0.72, 12.92±2.98,23.29±3.82)was significantly higher than that of control(1.00±0.00),and compared with the control, the difference being statistically significant(F=85.83,P＜0.01;t=-9.42,-8.95,-13.83,respectively,P＜ 0.05 or＜0.01).In 12 h,5,10,25 and 50 μmol/L groups cultured in vitro,the expressions of HO-1(16.34±0.25, 7.75±0.39,7.93±0.14,12.48±0.35)was significantly higher than that of control(1.00±0.00).and compared with the control,the difference being statistically significant(F=85.83,P＜0.01;t=-36.25,-30.19,-86.40, -56.40,respectively,all P＜0.01).Conclusion Inorganic arsenic call induce the activation of HO-1,promote the expression of protein in a time-and dose-dependent manner.

Involvement of ROS and JNK1 in selenite-induced a poptosisin Chang liver cells

Selenium is a dietary essential trace nutrient with important biological roles. Selenocompounds were reported to induce apoptosis in many types of tumor cells. In this study, we investigated the signaling pathway involved in the selenite-induced apoptosis using Chang liver cells as a non-malignant cell model. The Chang liver cell apoptosis induced by selenite (10 mM) was confirmed by DNA fragmentation and typical apoptotic nuclear changes. Treatment of selenite increased intracellular reactive oxygen species (ROS) level and c-Jun N-terminal kinase1 (JNK1) phosphorylation. The selenite-induced cell death was attenuated by SP600125, a specific inhibitor of JNK, and by dominant negative JNK1 (DN-JNK1). Antioxidants such as glutathione (GSH), N-acetyl cysteine (NAC), curcumin, epigallocatechin gallate (EGCG) and epicatechin (EC) inhibited selenite-induced intracellular ROS elevation and JNK1 phosphorylation. Our results suggest that selenite-induced apoptosis in Chang liver cells was preceded by the ROS generation and JNK1 activation.