Differential Apoptotic Effects of Bee Product Mixtures on Normal and Cancer Hepatic Cells.

Most effective anticancer drugs normally generate considerable cytotoxicity in normal cells; therefore, the preferential activation of apoptosis in cancer cells and the reduction of toxicity in normal cells is a great challenge in cancer research. Natural products with selective anticancer properties used as complementary medicine can help to achieve this goal. The aim of the present study was to analyze the effect of the addition of bee products [propolis (PR) or royal jelly (RJ) or propolis and royal jelly (PR+RJ), 2-10%] to thyme (TH) and chestnut honeys (CH) on the differential anticancer properties, mainly the cytotoxic and pro-apoptotic effects, in normal and cancer hepatic cells. The cytotoxic effects of samples were analyzed using the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay (0-250 mg/mL) and the effects on apoptosis were analyzed using cell cycle analysis, TdT-dUTP terminal nick-end labeling (TUNEL) assay, DR5 (Death Receptor 5) and BAX (BCL-2-Associated X) activation, and caspases 8, 9, and 3 activities. Both honey samples alone and honey mixtures had no or very little apoptotic effect on normal cells. Antioxidant honey mixtures enhanced the apoptotic capacity of the corresponding honey alone via both extrinsic and intrinsic pathways. Of all the samples, chestnut honey enriched with 10% royal jelly and 10% propolis (sample 14, CH+10RJ+10PR) showed the highest apoptotic effect on tumor liver cells. The enrichment of monofloral honey with bee products could be used together with conventional anticancer treatments as a dietary supplement without side effects. On the other hand, it could be included in the diet as a natural sweetener with high added value.

Protective Effect of Thyme and Chestnut Honeys Enriched with Bee Products against Benzo(a)pyrene-Induced DNA Damage.

The aim of the present study was to validate the cytotoxicity, genotoxicity, and preventive potential against benzo(a)pyrene (BaP)-induced DNA damage of nine samples of thyme and chestnut honeys enriched with bee products (royal jelly and propolis, 2-10%). Cell viability was determined by the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay (0-250 mg/mL) to select nontoxic concentrations, and DNA damage (0.1-10 µg/mL) was evaluated by the alkaline single-cell gel electrophoresis or comet assay. Treatment with honey samples or royal jelly and propolis did not affect the viability of HepG2 cells up to 100 and 50 mg/mL, respectively. Treatment with 100 µM BaP significantly increased (p ≤ 0.001) the levels of the DNA strand breaks. None of the tested concentrations (0.1-10 µg/mL) of the honey samples (thyme and chestnut), royal jelly, and propolis caused DNA damage per se. All tested samples at all the concentrations used decreased the genotoxic effect of BaP. In addition, all mixtures of thyme or chestnut honeys with royal jelly or propolis showed a greater protective effect against BaP than the samples alone, being the thyme and chestnut honey samples enriched with 10% royal jelly and 10% propolis the most effective (70.4% and 69.4%, respectively). The observed protective effect may be associated with the phenolic content and antioxidant capacity of the studied samples. In conclusion, the thyme and chestnut honey samples enriched with bee products present potential as natural chemoprotective agents against the chemical carcinogen BaP.

Enhancement of the Antioxidant Capacity of Thyme and Chestnut Honey by Addition of Bee Products.

Honey consumption and imports have increased in recent years, and it is considered by consumers to be a healthy alternative to more commonly used sweeteners. Honey contains a mixture of polyphenols and antioxidant compounds, and the botanical origin and geographical area of collection play an important role on its chemical composition. The present study investigated the physicochemical properties, total phenolic content and antioxidant capacity of Spanish thyme honey and chestnut honey, and their mixtures with royal jelly (2% and 10%) and propolis (2% and 10%). The analysis of the physicochemical parameters of both honey samples showed values within the established limits. Propolis showed the highest value of total phenolic content (17.21-266.83 mg GAE/100 g) and antioxidant capacity (DPPH, ORAC and ABTS assays; 0.63-24.10 µg eq. Tx/g, 1.61-40.82 µg eq. Tx/g and 1.89-68.54 µg eq. Tx/g, respectively), and significantly reduced ROS production in human hepatoma cells. In addition, mixtures of honey with 10% of propolis improved the results obtained with natural honey, increasing the value of total phenolic content and antioxidant capacity. A significant positive correlation was observed between total phenolic compounds and antioxidant capacity. Therefore, the antioxidant capacity could be attributed to the phenolic compounds present in the samples, at least partially. In conclusion, our results indicated that thyme and chestnut honey supplemented with propolis can be an excellent natural source of antioxidants and could be incorporated as a potential food ingredient with biological properties of technological interest, added as a preservative. Moreover, these mixtures could be used as natural sweeteners enriched in antioxidants and other bioactive compounds.

Validation of coffee silverskin extract as a food ingredient by the analysis of cytotoxicity and genotoxicity.

The aim of the present study was to validate the food safety of CSE, by studying its effect on cytotoxicity (100-20000µg/ml) and genotoxicity (10, 100 and 1000µg/ml) and also to investigate its preventive potential (1, 10 and 100µg/ml) against B(a)P induced DNA damage. Prior to analyses, the antioxidant capacity and the microbiological quality of CSE were tested. DNA damage (strand breaks and oxidized purines/pyrimidines) was evaluated by the alkaline single-cell gel electrophoresis or comet assay. HepG2 cells were pre-treated with CSE (1, 10 and 100µg/ml) for 24h followed by the addition of 100µM B(a)P in presence of CSE for other 24h. Detection of oxidized purines and pyrimidines was carried out using Formamidopyrimidine DNA glycosylase or Endonuclease III enzymes, respectively. Chlorogenic acid (CGA), the major antioxidant present in coffee, was used as a control. Treatment with 100 µM B(a)P significantly increased (p<0.05) levels of DNA strand breaks and oxidized purine and pyrimidine bases. Treatment of HepG2 cells with CSE did not induce either cytotoxicity or genotoxicity. CSE significantly inhibited (p<0.05) genotoxicity induced by B(a)P and the observed effect may be associated to its antioxidant capacity. CGA alone at the concentration present in CSE was effective against B(a)P. Thus, CGA seems to be a contributor to the preventive effect of CSE against B(a)P induced DNA damage in HepG2 cells. In conclusion, CSE presents potential as a natural sustainable chemoprotective agent against the chemical carcinogen B(a)P.

Interactions of manufactured silver nanoparticles of different sizes with normal human dermal fibroblasts.

Silver compounds have been used for their medicinal properties for centuries. At present, silver nanoparticles (AgNPs) are reemerging as a viable topical treatment option for infections encountered in burns, open wounds and chronic ulcers. This study evaluated the in vitro mechanisms of two different sizes of AgNPs (4·7 and 42 nm) toxicity in normal human dermal fibroblasts. The toxicity was evaluated by observing cell viability and oxidative stress parameters. In all toxicity endpoints studied (MTT and lactate dehydrogenase assays), AgNPs of 4·7 nm were much more toxic than the large AgNPs (42 nm). The cytotoxicity of both AgNPs was greatly decreased by pre-treatment with the antioxidant N-acetyl-L-cysteine. The oxidative stress parameters showed significant increase in reactive oxygen species levels, depletion of glutathione level and slight, but not statistically significant inactivation of superoxide dismutase, suggesting generation of oxidative stress. Thus, AgNPs should be used with caution for the topical treatment of burns and wounds, medical devices etc, because their toxicity depends on the size, the smaller NPs being much more cytotoxic than the large.

Oxidative stress contributes to gold nanoparticle-induced cytotoxicity in human tumor cells.

Due to their exceptional properties, gold nanoparticles (AuNPs) have shown promising medical and technological applications in the treatment of cancer and the development of antimicrobial packaging and time-temperature indicators in the food sector. However, little is known about their cytotoxicity when they come into contact with biological systems. The aim of this work was to compare the effects of three commercially available AuNPs of different sizes (30, 50 and 90 nm) on human leukemia (HL-60) and hepatoma (HepG2) cell lines. AuNP-induced cytotoxicity was dose and time-dependent, with IC50 values higher than 15 µg/mL. Nanoparticle (NP) size and cell line slightly influenced on the cytotoxicity of AuNPs, although HL-60 cells proved to be more sensitive to the cytotoxic response than HepG2. N-Acetyl-L-cysteine (NAC) protected HL-60 and HepG2 cells only against treatment with 30 nm AuNPs. In both cell types, glutathione (GSH) content was drastically depleted after 72 h of incubation with the three AuNPs (less than 30% in all cases), while the reduction of superoxide dismutase activity (SOD) activity depended on cell line. HepG2, but not HL-60 cells, exhibited a decrease of SOD activity (∼ 45% of activity). The three AuNPs also caused a two-fold elevation of reactive oxygen species (ROS) production in both cell lines. Thus, protective effect of NAC, depletion of GSH and increase of ROS appear to be determined by NP size and indicate that oxidative stress contributes to cytotoxicity of AuNPs.

Nanopartículas de oro: aplicaciones y citotoxicidad in vitro / Gold nanoparticles: Applications and in vitro cytotoxicity

En los últimos años, la evolución en el desarrollo de productos elaborados a partir de nanotecnología ha experimentado un espectacular crecimiento. En particular, las nanopartículas de oro han despertado gran interés en los sectores biomédico y alimentario, donde se ha descrito su utilización en el tratamiento frente al cáncer o como parte integrante de envases resistentes a la abrasión, con propiedades antimicrobianas. Por tanto, se cree que la exposición humana a las nanopartículas de oro aumentará considerablemente en los próximos años, pudiendo tener esto repercusiones sobre la salud. En este marco, el estudio de la toxicología de las nanopartículas ha revelado que su toxicidad depende de multitud de factores. Además, en la bibliografía hay cierta controversia en torno a los posibles efectos citotóxicos inducidos por las nanopartículas de oro. Diversos estudios de exposición in vitro han destacado su inocuidad en algunas líneas celulares, mientras que otros trabajos demostraron respuesta citotóxica. La siguiente revisión tiene por objeto describir las propiedades más relevantes de las nanopartículas de oro considerando sus potenciales aplicaciones en medicina y en la industria de los alimentos, así como examinar su posible toxicidad, con especial énfasis en los estudios de citotoxicidad in vitro disponibles hasta el momento.

In the recent years, the development of nanotechnology-based products has experienced a spectacular growth. Especially, gold nanoparticles have awoken a great interest in the biomedical and food sector, where their applications in cancer treatment as well as their incorporation in abrasion resistant and antimicrobial packaging have been described. Therefore, it is believed that human exposure to gold nanoparticles will increase considerably in the next few years, which may arise possible human health hazards. Hence, toxicology studies on nanoparticles revealed that their toxicity depends on various factors. Furthermore, there is some controversy regarding to gold nanoparticle-induced cytotoxicity. Several in vitro studies have reported that gold nanoparticles are innocuous, while some investigations have demonstrated a cytotoxic response after the exposure to these. The aim of this review is to describe the most relevant properties of gold nanoparticles according to their possible applications in medicine and in food industry, as well as to provide information about their possible toxic effects, taking into account the cytotoxic in vitro studies published at present.

Nanopartículas de oro: aplicaciones y citotoxicidad in vitro / Gold nanoparticles: Applications and in vitro cytotoxicity

En los últimos años, la evolución en el desarrollo de productos elaborados a partir de nanotecnología ha experimentado un espectacular crecimiento. En particular, las nanopartículas de oro han despertado gran interés en los sectores biomédico y alimentario, donde se ha descrito su utilización en el tratamiento frente al cáncer o como parte integrante de envases resistentes a la abrasión, con propiedades antimicrobianas. Por tanto, se cree que la exposición humana a las nanopartículas de oro aumentará considerablemente en los próximos años, pudiendo tener esto repercusiones sobre la salud. En este marco, el estudio de la toxicología de las nanopartículas ha revelado que su toxicidad depende de multitud de factores. Además, en la bibliografía hay cierta controversia en torno a los posibles efectos citotóxicos inducidos por las nanopartículas de oro. Diversos estudios de exposición in vitro han destacado su inocuidad en algunas líneas celulares, mientras que otros trabajos demostraron respuesta citotóxica. La siguiente revisión tiene por objeto describir las propiedades más relevantes de las nanopartículas de oro considerando sus potenciales aplicaciones en medicina y en la industria de los alimentos, así como examinar su posible toxicidad, con especial énfasis en los estudios de citotoxicidad in vitro disponibles hasta el momento.(AU)

In the recent years, the development of nanotechnology-based products has experienced a spectacular growth. Especially, gold nanoparticles have awoken a great interest in the biomedical and food sector, where their applications in cancer treatment as well as their incorporation in abrasion resistant and antimicrobial packaging have been described. Therefore, it is believed that human exposure to gold nanoparticles will increase considerably in the next few years, which may arise possible human health hazards. Hence, toxicology studies on nanoparticles revealed that their toxicity depends on various factors. Furthermore, there is some controversy regarding to gold nanoparticle-induced cytotoxicity. Several in vitro studies have reported that gold nanoparticles are innocuous, while some investigations have demonstrated a cytotoxic response after the exposure to these. The aim of this review is to describe the most relevant properties of gold nanoparticles according to their possible applications in medicine and in food industry, as well as to provide information about their possible toxic effects, taking into account the cytotoxic in vitro studies published at present.(AU)

Selective apoptotic effects of piceatannol and myricetin in human cancer cells.

Numerous studies have shown the potential of dietary polyphenols as anticarcinogenic agents. The aim of the present study was to evaluate the apoptotic effects of piceatannol and myricetin, naturally occurring polyphenols in red wine, alone or in combination, in two human cell lines: HL-60 (leukemia) and HepG2 (hepatoma). Apoptotic cells were identified by chromatin condensation, poly(ADP-ribose) polymerase cleavage and flow cytometry analysis. Results from TUNEL assay showed that piceatannol or myricetin alone induced apoptotic cell death in a concentration- and time-dependent manners in HL-60 cells. Furthermore, in combined treatment the percentage of apoptotic HL-60 cells was significantly higher. Nevertheless, the percentage of TUNEL positive HepG2 cells only was significant after piceatannol treatment and in combined treatment was even lower than in cells treated with piceatannol alone. Moreover, we also studied the relative reactive oxygen species (ROS) production. Our results indicate that apoptosis induced by piceatannol or myricetin occurs through an ROS-independent cell death pathway. In conclusion, piceatannol and myricetin synergistically induced apoptosis in HL-60 cells but not in HepG2 cells. These findings suggest that the potential anticarcinogenic properties of dietary polyphenols depend largely on the cell line used. The relevance of these data needs to be verified in human epidemiological studies.

N-Nitrosopiperidine and N-Nitrosodibutylamine induce apoptosis in HepG2 cells via the caspase dependent pathway.

The human hepatoma cell line (HepG2) exhibited a dose and time-dependent apoptotic response following treatment with N-Nitrosopiperidine (NPIP) and N-Nitrosodibutylamine (NDBA), two recognized human carcinogens. Our results showed a significant apoptotic cell death (95%) after 24h treatment with NDBA (3.5 mM), whereas it was necessary to use high doses of NPIP (45 mM) to obtain a similar percentage of apoptotic cells (86%). In addition, both extrinsic (caspase-8) and intrinsic pathway (caspase-9) could be implicated in the N-Nitrosamines-induced apoptosis. This study also addresses the role of reactive oxygen species (ROS) as intermediates for apoptosis signaling. A significant increase in ROS levels was observed after NPIP treatment, whereas NDBA did not induce ROS. However, N-acetylcysteine (NAC) did not block NPIP-induced apoptosis. All these findings suggest that NPIP and NDBA induce apoptosis in HepG2 cells via a pathway that involves caspases but not ROS.

Antiapoptotic effects of dietary antioxidants towards N-nitrosopiperidine and N-nitrosodibutylamine-induced apoptosis in HL-60 and HepG2 cells.

The aim of this work was to determine the effect of vitamin C, diallyl disulfide (DADS) and dipropyl disulfide (DPDS) towards N-nitrosopiperidine (NPIP) and N-nitrosodibutylamine (NDBA)-induced apoptosis in human leukemia (HL-60) and hepatoma (HepG2) cell lines using the terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay. None of the vitamin C (5-50 microm), DADS and DPDS (1-5 microm) concentrations selected induced a significant percentage of apoptosis. In simultaneous treatments, vitamin C, DADS and DPDS reduced the apoptosis induced by NPIP and NDBA in HL-60 and HepG2 cells (around 70% of reduction). We also investigated its scavenging activities towards reactive oxygen species (ROS) produced by NPIP and NDBA using 2',7'-dichlorodihydrofluorescein diacetate in both cell lines. ROS production induced by both N-nitrosamine was reduced to control levels by vitamin C (5-50 microm) in a dose-dependent manner. However, DADS (5 microm) increased ROS levels induced by NPIP and NDBA in HL-60 (40 and 20% increase, respectively) and HepG2 cells (18% increase), whereas DPDS was more efficient scavenger of ROS at the lowest concentration (1 microm) in both HL-60 (52 and 25% reduction, respectively) and HepG2 cells (24% reduction). The data demonstrated that the scavenging ability of vitamin C and DPDS could contribute to inhibition of the NPIP- and NDBA-induced apoptosis. However, more than one mechanism, such as inhibition of phase I and/or induction of phase II enzymes, could be implicated in the protective effect of dietary antioxidants towards NPIP- and NDBA-induced apoptosis in HL-60 and HepG2 cells.

Inhibition by vitamin C of apoptosis induced by N-nitrosamines in HepG2 and HL-60 cells.

The aim of this study was to evaluate the effect of vitamin C towards N-nitrosopyrrolidine (NPYR)- and N-nitrosodimethylamine (NDMA)-induced apoptosis in human hepatoma (HepG2) and leukemia (HL-60) cell lines using flow cytometry analysis and the terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling assay (TUNEL). None of the vitamin C concentrations tested (1-100 microM) caused cytotoxicity in HepG2 cells. However, there were significant losses of HL-60 cells viability, measured by MTT assay, 72 h after treatment with 50 and 100 microM vitamin C (29 and 46%, respectively). Moreover, an increase of lactate dehydrogenase release was significant with 50 microM at 72 h (28%) and with 100 microM of vitamin C at 48 and 72 h (27 and 36%, respectively). Also, the percentage of apoptotic HL-60 cells found in TUNEL assay increased to 21% when they were treated with 100 microM vitamin C for 72 h. Thus, in subsequent simultaneous treatments with NPYR (30 and 50 mM) or NDMA (27 and 68 mM) and vitamin C, concentrations of 5-50 microM vitamin C were used. Our results revealed that vitamin C, at all concentrations and times tested, reduced the apoptosis induced by NPYR and NDMA in both cell lines, showing a similar effect in HepG2 and HL-60 cells towards NPYR (50 mM)--65 and 63% of reduction, respectively--whereas towards NDMA (27 mM) the inhibition was higher in HL-60 than in HepG2 cells--75 and 57%, respectively. Therefore, our findings suggest that inhibition of apoptosis may be one of the mechanisms by which vitamin C exerts its protective effect.

Protective effects of isothiocyanates alone or in combination with vitamin C towards N-nitrosodibutylamine or N-nitrosopiperidine-induced oxidative DNA damage in the single-cell gel electrophoresis (SCGE)/HepG2 assay.

The aim of this study was to investigate the protective effect of isothiocyanates alone or in combination with vitamin C towards N-nitrosodibutylamine (NDBA) or N-nitrosopiperidine (NPIP)-induced oxidative DNA damage in the single cell gel electrophoresis (SCGE)/HepG2 assay. Phenethyl isothiocyanate (PEITC) and indole-3-carbinol (I3C) alone showed a weak protective effect towards NDBA (0.1 microm, 26-27%, respectively) or NPIP (1 microm, 26-28%, respectively)-induced oxidative DNA damage. Allyl isothiocyanate (AITC) alone did not attenuate the genotoxic effect provoked by NDBA or NPIP. In contrast, HepG2 cells simultaneously treated with PEITC, I3C and AITC in combination with vitamin C showed a stronger inhibition of oxidative DNA-damage induced by NDBA (0.1 microm, 67%, 42%, 32%, respectively) or NPIP (1 microm, 50%, 73%, 63%, respectively) than isothiocyanates (ITCs) alone. One feasible mechanism by which ITCs alone or in combination with vitamin C exert their protective effects towards N-nitrosamine-induced oxidative DNA damage could be by the inhibition of their cytochrome P450 dependent bioactivation. PEITC and I3C strongly inhibited the p-nitrophenol hydroxylation (CYP2E1) activity (0.1 microm, 66-50%, respectively), while the coumarin hydroxylase (CYP2A6) activity was slightly reduced (0.1 microm, 25-37%, respectively). However, the ethoxyresorufin O-deethylation (CYP1A1) activity was only inhibited by PEITC (1 microm, 55%). The results indicate that PEITC and I3C alone or PEITC, I3C and AITC in combination with vitamin C protects human-derived cells against the oxidative DNA damaging effects of NDBA and NPIP, two food carcinogenic compounds.

Induction of apoptosis and reactive oxygen species production by N-nitrosopiperidine and N-nitrosodibutylamine in human leukemia cells.

N-nitrosopiperidine (NPIP) and N-nitrosodibutylamine (NDBA) belong to a group of N-nitrosamines that are widely distributed in foodstuffs and the occupational environment. In the present study, the human promyelocytic leukemia cell line HL-60, was used to characterize the apoptotic effects of N-nitrosamines, and to examine the production of reactive oxygen species (ROS). Apoptotic cells were identified by (i) chromatin condensation (ii) flow cytometry analysis and (iii) poly(ADP-ribose) polymerase (PARP) cleavage. NPIP and NDBA induced morphological changes consistent with apoptotic events in HL-60 cells. Flow cytometry analysis showed that both N-nitrosamines induced apoptotic cell death in a concentration and time dependent-manner. It was observed that NDBA was stronger than NPIP, since it induced a significant apoptotic cell death after 18 h starting from a concentration of 2 mm, whereas NPIP was effective at 10 mm. Furthermore, PARP was markedly cleaved with 0.5 mm of NDBA and 5 mm of NPIP after treatments for 3 and 18 h, respectively. Finally, the ROS level was found to be elevated after 0.5 h of treatment with both N-nitrosamines. Antioxidant N-acetylcysteine (NAC) completely inhibited the ROS production induced by NPIP and NDBA. However, this action seems not to be associated with the apoptosis because NAC did not block N-nitrosamines-induced apoptosis. The data demonstrate that NPIP and NDBA induce apoptosis and ROS production in HL-60 cells.

Protective effect of vitamin C towards N-nitrosamine-induced DNA damage in the single-cell gel electrophoresis (SCGE)/HepG2 assay.

The aim of this study was to investigate the protective effect of vitamin C towards N-nitrosamine-induced DNA damage in the single-cell gel electrophoresis (SCGE)/HepG2 assay. None of the vitamin C concentrations tested (1-10 microM) in presence or absence of formamidopyrimidine-DNA glycosylase (Fpg enzyme) caused DNA damage per se. HepG2 cells simultaneously treated with vitamin C and N-nitrosodimethylamine (NDMA), N-nitrosopyrrolidine (NPYR), N-nitrosodibutylamine (NDBA) or N-nitrosopiperidine (NPIP) reduced the genotoxic effects of the N-nitrosamines in a dose-dependent manner. At concentrations of 1-5 microM vitamin C, the protective effect was higher towards NPYR-induced oxidative DNA damage (78-79%) than against NDMA (39-55%), NDBA (12-14%) and NPIP (3-55%), in presence of Fpg enzyme. However, a concentration of 10 microM vitamin C led to a maximum reduction in NDBA (94%), NPYR (81%), NPIP (80%) and NDMA (61%)-induced oxidative DNA damage, in presence of Fpg enzyme. The greatest protective effect of vitamin C (10 microM) was higher towards NDBA-induced oxidative DNA damage. One feasible mechanism by which vitamin C exerted its protective effect is that may interact with the enzyme systems catalyzing the metabolic activation of the N-nitrosamines, blocking the production of genotoxic intermediates. Vitamin C (10 microM) strongly reduced the coumarin hydroxylase (82%) activity. However, the p-nitrophenol hydroxylase and the ethoxyresorufine O-deethylation activities were slightly and weakly reduced (32-19%), respectively.

Protective effects of isothiocyanates towards N-nitrosamine-induced DNA damage in the single-cell gel electrophoresis (SCGE)/HepG2 assay.

The aim of this study was to investigate the protective effect of isothiocyanates towards N-nitrosamine-induced DNA damage in the single-cell gel electrophoresis (SCGE)/HepG2 assay. None of the isothiocyanates (ITCs) concentrations tested in the presence or absence of formamidopyrimidine-DNA glycosylase (Fpg), caused DNA damage per se. Combined treatments of HepG2 cells with phenethyl isothiocyanate (PEITC), allyl isothiocyanate (AITC) or indol-3-carbinol (I3C) and N-nitrosopyrrolidine (NPYR) or N-nitrosodimethylamine (NDMA) reduced the genotoxic effects of the N-nitrosamines in a dose-dependent manner. The protective effect of the three ITCs tested was higher towards NPYR-induced oxidative DNA damage than against NDMA. The greatest protective effect towards NPYR-induced oxidative DNA damage was shown by I3C (1 microm, 79%) and by PEITC (1 microm, 67%) and I3C (1 microm, 61%) towards NDMA (in the presence of Fpg enzyme). However, in the absence of Fpg enzyme, AITC (1 microm, 72%) exerted the most drastic reduction towards NPYR-induced oxidative DNA damage, and PEITC (1 microm, 55%) towards NDMA. The results indicate that ITCs protect human-derived cells against the DNA damaging effect of NPYR and NDMA, two carcinogenic compounds which occur in the environment.

Protective effects of isothiocyanates towards N-nitrosamine-induced DNA damage in the single-cell gel electrophoresis (SCGE)/HepG2 assay.

The aim of this study was to investigate the protective effect of isothiocyanates towards N-nitrosamine-induced DNA damage in the single-cell gel electrophoresis (SCGE)/HepG2 assay. None of the isothiocyanates (ITCs) concentrations tested in the presence or absence of formamidopyrimidine-DNA glycosylase (Fpg) caused DNA damage per se. Combined treatments of HepG2 cells with phenethyl isothiocyanate (PEITC), allyl isothiocyanate (AITC) or indol-3-carbinol (I3C) and N-nitrosopyrrolidine (NPYR) or N-nitrosodimethylamine (NDMA) reduced the genotoxic effects of the N-nitrosamines in a dose-dependent manner. The protective effect of the three ITCs tested was higher towards NPYR-induced oxidative DNA damage than against NDMA. The greatest protective effect towards NPYR-induced oxidative DNA damage was shown by I3C (1 microM, 79%) and by PEITC (1 microM, 67%) and I3C (1 microM, 61%) towards NDMA (in presence of Fpg enzyme). However, in absence of Fpg enzyme, AITC (1 microM, 72%) exerted the most drastic reduction towards NPYR-induced oxidative DNA damage, and PEITC (1 microM, 55%) towards NDMA. Our results indicate that ITCs protect human-derived cells against the DNA damaging effect of NPYR and NDMA, two carcinogenic compounds that occur in the environment.

Use of a Monoclonal Antibody and Two Enzyme-Linked Immunosorbent Assay Formats for Detection and Quantification of the Substitution of Caprine Milk for Ovine Milk.

A stable hybridoma cell line (B2B) has been produced that secretes a monoclonal antibody (MAb) specific for goat's milk αS2-casein. The MAb B2B was used in two enzyme-linked immunosorbent assay (ELISA) formats for the detection and quantification of the presence of goat's milk in ewe's milk. In the indirect ELISA format the limit of detection was 0.5 to 15% (vol/vol) substitution of goat's milk for ewe's milk. Afterwards, a competitive indirect ELISA was successfully developed for the detection of 0.25 to 15% (vol/vol) of goat's milk in ewe's milk. This competitive indirect ELISA is a very sensitive assay; it can be performed in less than 5 h and is not influenced by the heat treatment of milk.

Immunostick ELISA for Detection of Cow's Milk in Ewe's Milk and Cheese Using a Monoclonal Antibody against Bovine ß-Casein.

An immunostick enzyme-linked immunosorbent assay (ELISA) has been developed for the rapid detection of cow's milk in ewe's milk or cheese. The assay uses a monoclonal antibody (AH4) produced against bovine ß-casein for the detection of cow's milk or cheese bound to the paddles of immunostick tubes. This immunostick ELISA allows the visual identification of ewe's milk containing more than 1% of cow's milk or cheese samples containing more than 0.5% of cow's cheese.