Photodegradation enhances the toxic effect of anthracene on skin.

Anthracene, a polycyclic aromatic hydrocarbon (PAH), is a widespread environmental pollutant that poses potential risks to human health. Exposure to anthracene can result in various adverse health effects, including skin-related disorders. Photo exposure sufficiently removes the anthracene from the environment but also generates more degradation products which can be more toxic. The goal of this study was to assess the change in anthracene dermotoxicity caused by photodegradation and understand the mechanism of this change. In the present study, over 99.99% of anthracene was degraded within 24 h of sunlight exposure, while producing many intermediate products including 9,10-anthraquinone and phthalic acid. The anthracene products with different durations of photo exposure were applied to 2D and 3D human keratinocyte cultures. Although the non-degraded anthracene significantly delayed the cell migration, the cell viability and differentiation decreased dramatically in the presence of the photodegraded anthracene. Anthracene photodegradation products also altered the expression patterns of a number of inflammation-related genes in comparison to the control cells. Among these genes, il1a, il1b, il8, cxcl2, s100a9, and mmp1 were upregulated whereas the tlr4 and mmp3 were downregulated by the photodegraded anthracene. Topical deliveries of the photodegraded and non-degraded anthracene to the dorsal skin of hairless mice showed more toxic effects by the photodegraded anthracene. The 4-hour photodegradation products of anthracene thickened the epidermal layer, increased the dermal cellularity, and induced the upregulation of inflammatory markers, il1a, il1b, s100a9, and mmp1. In addition, it also prevented the production of a gap junction protein, Connexin-43. All the evidence suggested that photodegradation enhanced the toxicities of anthracene to the skin. The 4-hour photodegradation products of anthracene led to clinical signs similar to acute inflammatory skin diseases, such as atopic and contact dermatitis, eczema, and psoriasis. Therefore, the potential risk of skin irritation by anthracene should be also considered when an individual is exposed to PAHs, especially in environments with strong sunlight.

Emodin-8-O-ß-D-glucopyranoside-induced hepatotoxicity and gender differences in zebrafish as revealed by integration of metabolomics and transcriptomics.

BACKGROUND: Emodin-8-O-ß-D-glucopyranoside (Em8G) is an active ingredient of traditional Chinese medicine Rhei Radix et Rhizoma and Polygonum multiflorum Thunb.. And it caused hepatotoxicity, while the underlying mechanism was not clear yet. PURPOSE: We aimed to explore the detrimental effects of Em8G on the zebrafish liver through the metabolome and transcriptome integrated analysis. STUDY DESIGN AND METHODS: In this study, zebrafish larvae were used in acute toxicity tests to reveal the hepatotoxicity of Em8G. Adult zebrafish were then used to evaluate the gender differences in hepatotoxicity induced by Em8G. Integration of transcriptomic and metabolomic analysis was used further to explore the molecular mechanisms underlying gender differences in hepatotoxicity. RESULTS: Our results showed that under non-lethal concentration exposure conditions, hepatotoxicity was observed in Em8G-treated zebrafish larvae, including changes in liver transmittance, liver area, hepatocyte apoptosis and hepatocyte vacuolation. Male adult zebrafish displayed a higher Em8G-induced hepatotoxicity than female zebrafish, as demonstrated by the higher mortality and histopathological alterations. The results of transcriptomics combined with metabolomics showed that Em8G mainly affected carbohydrate metabolism (such as TCA cycle) in male zebrafish and amino acid metabolism (such as arginine and proline metabolism) in females, suggesting that the difference of energy metabolism disorder may be the potential mechanism of male and female liver toxicity induced by Em8G. CONCLUSIONS: This study provided the direct evidence for the hepatotoxicity of Em8G to zebrafish models in vivo, and brought a new insight into the molecular mechanisms of Em8G hepatotoxicity, which can guide the rational application of this phytotoxin. In addition, our findings revealed gender differences in the hepatotoxicity of Em8G to zebrafish, which is related to energy metabolism and provided a methodological reference for evaluating hepatotoxic drugs with gender differences.

The safety evaluation of Shenze Shugan capsule and mechanism of apoptosis induced by five potentially nephrotoxic components.

ETHNOPHARMACOLOGICAL RELEVANCE: Shenze Shugan capsule is a prescription of traditional Chinese medicine for nonalcoholic steatohepatitis treatment. It includes Rhei Radix et Rhizoma (RR), Cassiae Semen (CS) and Alismatis Rhizoma(AR), which widely contains rhein, emodin, aurantio-obtusin, alisol A and alisol B 23-monoacetate. AIM OF THE STUDY: In this study, we aimed to explore the safety of the medicine, and further elucidate the mechanism of apoptosis induction in HK-2 cells by five components, including rhein, emodin, aurantio-obtusin, alisol A and alisol B 23-monoacetate. MATERIALS AND METHODS: We investigated the nephrotoxicity of Shenze Shugan capsule, including RR, CS, AR and mixed herbs given for two months in rats. Superoxide dismutase (SOD) in kidney tissues, urea nitrogen (BUN) and creatinine (CRE) in serum were detected, and renal pathology analysis was performed. In cell experiments, the apoptotic rate and cell cycle distribution of HK-2 cells were tested by flow cytometry. The levels of mitochondrial membrane potential (ΔΨm) and related protein expression in mitochondrial pathway were measured as well. RESULTS: We confirmed that two months of administering high doses(60 times the dose for clinical use in adults) of RR, CS or mixed herbs upregulated the levels of CRE and RUN, inhibited SOD activity, and increased the degree of tubular degeneration and glomerular dilatation, but Shenze Shugan capsule has no significant differences in renal structure or renal function. In addition, we found that five components all concentration-dependently inhibited HK-2 cells proliferation and induced apoptosis, especially aurantio-obtusin as the novel nephrotoxic component. Rhein and emodin significantly induced S/M accumulation, but aurantio-obtusin, alisol A and alisol B 23-monoacetate significantly induced G1/M accumulation in HK-2 cells. Similarly, they could induce Caspase3 activation, loss of mitochondrial membrane potential (ΔΨm), and down-regulation of Bcl-2 and up-regulation of Bax. CONCLUSIONS: Through a two-month subchronic toxicity study in rats, our preliminary determination is that this formulation is safe and reliable for long-term use. Interestingly, the potentially toxic herbs such as RR, CS, AR can reduce toxicity by drug compatibility. When further exploring the mechanism of action of toxic herbs, we found that mitochondrial pathway is involved in the apoptosis of HK -2 cells induced by rhein, emodin, aurantio-obtusin, alisol A and alisol B 23-monoacetate. Our findings provide new ideas for safety studies of Shenze Shugan capsule.

Genetic and prenatal developmental evaluation of anthraquinone.

Anthraquinone is a recently identified contaminant present in teas globally, and its potential teratogenic and genotoxic impacts have yet to be fully comprehended. Hence, this study's objective was to determine anthraquinone's genotoxicity using various studies such as the Ames test, Mammalian erythrocyte micronucleus test, and in-vitro mammalian chromosome aberration study. Additionally, the study assessed its effects on maternal gestational toxicity and the fetus's teratogenicity through prenatal developmental toxicity research in rats. Results indicated that anthraquinone did not manifest mutagenic effects on Salmonella typhimurium histidine-deficient, did not cause chromosomal aberrations in Chinese hamster ovary cell subclone CHO-K1, and did not exhibit a genotoxic effect on mouse bone marrow erythrocytes. However, in the prenatal developmental toxicity study, administering anthraquinone orally to pregnant rats from day 5 to day 19 of gestation resulted in decreased body weight and food consumption of pregnant rats, along with a higher number of visceral malformations in the fetuses in the highest dose group (217.6 mg/kg BW). Additionally, two pregnant rats died in this group. The study has established the no observed adverse effect level (NOAEL) as 21.76 mg/kg BW, while the lowest observed adverse effect level (LOAEL) was 217.6 mg/kg BW.

Is natural better? An ecotoxicity study of anthraquinone dyes.

The concept of sustainability has gained prominence in recent years, enhancing the need to develop products that are less harmful to the environment. Dyes are used by various industrial sectors and have a lot of market value; they are used on a large scale mainly by the textile industry that uses large volumes of water and is one of the main contributors to the contamination of water bodies. Some natural compounds, especially anthraquinones are re-emerging as possible alternatives to synthetic dyes, some of which are known for their toxic and/or mutagenic effects. The BioColour project (https://biocolour.fi/) which is interested in promoting the development of new alternative molecules to synthetic dyes, provided us highly purified anthraquinone dyes dermocybin and dermorubin (>98% purity) extracted from a specie of fungus Cortinarius sanguineus. Dyes were tested for their acute and chronic toxicity using different aquatic organisms. Dermorubin was not toxic to any of the organisms tested for the highest test concentration of 1 mg L-1 and it was the most promising dye. Dermocybin was toxic to Daphnia similis (EC50 = 0.51 mg L-1), Ceriodaphnia dubia (IC10 = 0.13 mg L-1) and Danio rerio embryos (extrapolated LC50 = 2.44 mg L-1). A safety limit, i.e, predicted no-effect concentration (PNEC) of 0.0026 mg L-1 was derived based on the toxicity of dermocybin. The PNEC value can be used to provide hazard information for future application in commercial dyeing processes. Then, we compared the toxicity of dermocybin and dermorubin with ecotoxicity data available in the literature on other anthraquinone dyes of natural and synthetic origin. Some natural dyes can be as toxic as synthetic ones, or more toxic when chronic effects are considered. Despite natural dyes being used since centuries past, there are few ecotoxicological studies available. This study is designed to help develop a more comprehensive understanding of their toxicological properties.

Impact of Reactive Oxygen Species Scavenging on the Intermediate Production of Anthracene and Anthraquinone in Fresh versus Saltwater Environments.

While salinity can alter the photodegradation of hydrophobic organic compounds (HOCs), the cause of their altered kinetics in seawater is not well understood. Because HOC intermediate photoproducts are often more toxic than their parent compounds, characterizing the generation of intermediates in saline environments is needed to accurately predict their health effects. The present study investigated the influence of salinity on the generation of anthraquinone through the photolysis of anthracene and the generation of anthrone and 1-hydroxyanthraquinone from the photolysis of anthraquinone as well as their reactivities with hydroxyl radicals. This was conducted by measuring the photolysis rates of anthracene and anthraquinone and characterizing their product formation in buffered deionized water, artificial seawater, individual seawater halides (bromide, chloride, and iodide), dimethyl sulfoxide, furfuryl alcohol, and solutions of hydrogen peroxide. Salinity enhanced the persistence of anthraquinone by a factor >10 and altered its product formation, including the generation of the suspected carcinogen 1-hydroxyanthraquinone. In part, this was attributed to reactive oxygen species (ROS) scavenging by the seawater constituents chloride and bromide. In addition, anthraquinone and its hydroxylated products were found to be moderately to highly reactive with hydroxyl radicals, further illustrating their tendency to react with ROS in aqueous environments. The present study emphasizes the importance of considering the effects of salinity on organic contaminant degradation; it can significantly enhance the persistence of HOCs and alter their intermediate formation, subsequently impacting chemical exposure times and potential toxic effects on estuarine/marine organisms. Environ Toxicol Chem 2023;42:1721-1729. © 2023 SETAC.

Acute and Subchronic Oral Toxicity of Anthraquinone in Sprague Dawley Rats.

Objective: This study was conducted to evaluate the acute and subchronic toxicity of anthraquinone. An acute toxicity test was performed in female Sprague Dawley (SD) rats, and the oral median lethal dose (LD50) of anthraquinone was estimated to be >5000 mg/kg body weight (BW). In the subchronic study, groups of 10 male and 10 female rats were dosed with anthraquinone by gavage at 0, 1.36, 5.44, 21.76, and 174.08 mg/kg BW, 7 days/week for 90 days followed by a recovery period of 28 days. No appreciable toxic-related changes were observed in the 1.36 mg/kg BW group. When the animals received 5.44 mg/kg BW or more of anthraquinone, hyaline droplet accumulation in the renal tubules was observed in both the male and female rats, and anemia was observed in the females. When the anthraquinone dose reached 174.08 mg/kg BW, mild hepatocellular hypertrophy around the central vein of the hepatic lobule and hypothyroidism were observed in the female rats. During the recovery period, changes in clinical symptoms and parameters were considerably alleviated. Based on the results of this study, the no observed adverse effect level (NOAEL) for anthraquinone in rats was set at 1.36 mg/kg BW, and the lowest observed adverse effect level (LOAEL) was 5.44 mg/kg BW.

Rhein activated Fas-induced apoptosis pathway causing cardiotoxicity in vitro and in vivo.

Rhein, one of the main active components of rhubarb (Dahuang) and Polygonum multiflorum (Heshouwu), has a wide range of effective pharmacological effects. Recently, increasing studies have focused on its potential hepatorenal toxicity, but the cardiotoxicity is unknown. In this study, we found that the IC50 of rhein to H9c2 cells at 24 h and 48 h were 94.5 and 45.9µmol/L, respectively, with positive correlation of dose-toxicity and time-toxicity. After the treatment of rhein (106, 124 and 132µmol/L), the number of H9c2 cells decreased significantly, and the morphology of H9c2 cells showed atrophy, round shape and wall detachment. Moreover, the proportion of apoptotic cells in H9c2 cells treated with rhein was significantly increased in a dose-dependent manner. And rhein induced S phase arrest of H9c2 cells and inhibited cell proliferation. Rhein up-regulated ROS, LDH levels and low MMP but down-regulated SOD content in H9c2 cells. Additionally, the results showed that the cardiac function LVEF and LVFS of rhein high-medium-low dose groups (350, 175, 87.5 mg/kg) were significantly reduced. And the contents of Ca2+, cTnT, CK and LDH in serum of KM mice were significantly up-regulated by rhein. Furthermore, western blot results suggested that rhein the above effects via promoting Fas-induced apoptosis pathway in vitro and in vivo. In general, rhein may cause cardiotoxicity via Fas-induced apoptosis pathway in vivo and in vitro, which provides reference for the safe use of medicinal plant containing rhein and its preparations.

Acute and subchronic toxicity studies of rhein in immature and d-galactose-induced aged mice and its potential hepatotoxicity mechanisms.

Rhein is a key ingredient in many herbal remedies and is widely used. However, herbs containing rhein are frequently associated with poisoning incidents, especially in elderly subjects. Acute and subchronic toxicity of rhein in Kunming mice (KM) was investigated in this experiment. Acute toxicity tests showed a 40% lethality at a given rhein dose of 4000 mg/kg, and the LD50 of rhein was calculated by the bliss method to be greater than 2185.6 mg/kg. In subchronic toxicity, d-gal-induced aged and immature animals were randomized into three groups that were exposed to rhein of 0, 175, and 375 mg/kg/d for 75 days, respectively. No mortality was observed in immature mice group, whereas 55.5% (5/9) subjects in aged mice groups died in the high dosage group. AST, ALT, IL-6, TNF-α levels and typical histopathological changes indicate that rhein causes liver injury. In addition, our investigation explored possible hepatotoxic mechanisms of rhein and experimental results showed increased ROS production, NRF-2 and MDA levels and decreased SOD levels, demonstrating that rhein causes oxidative stress. MMP and mitochondrial swelling levels were able to assess the impact of rhein on mitochondrial function. Furthermore, the effect of rhein on apoptosis can be detected by flow cytometry. Our studies suggested that rhein induces oxidative stress leading to mitochondria dysfunction and apoptotic activation. Multidrug resistance protein (MRP) is an efflux transporter protein and is capable of transporting cellular oxidative stress-related substances. To further clarify the role of MRP in rhein induced oxidative stress, we examined MRP expression in the liver. However, the expression of MRP has no statistical significance.

Detection and toxicity modeling of anthraquinone dyes and chlorinated side products from a colored smoke pyrotechnic reaction.

"Green" pyrotechnics seek to remove known environmental pollutants and health hazards from their formulations. This chemical engineering approach often focuses on maintaining performance effects upon replacement of objectionable ingredients, yet neglects the chemical products formed by the exothermic reaction. In this work, milligram quantities of a lab-scale pyrotechnic red smoke composition were functioned within a thermal probe for product identification by pyrolysis-gas chromatography-mass spectrometry. Thermally decomposed ingredients and new side product derivatives were identified at lower relative abundances to the intact organic dye (as the engineered sublimation product). Side products included chlorination of the organic dye donated by the chlorate oxidizer. Machine learning quantitative structure-activity relationship models computed impacts to health and environmental hazards. High to very high toxicities were predicted for inhalation, mutagenicity, developmental, and endocrine disruption for common military pyrotechnic dyes and their analogous chlorinated side products. These results underscore the need to revise objectives of "green" pyrotechnic engineering.

Aurantio-obtusin induces hepatotoxicity through activation of NLRP3 inflammasome signaling.

Aurantio-obtusin (AO) is a major anthraquinone (AQ) compound derived from Cassiae semen (CS). Although pharmacological studies have shown that the CS extracts can serve as effective agents in preclinical and clinical practice, AQ-induced hepatotoxicity in humans has attracted widespread attention. To explore whether AO induces hepatotoxicity and its underlying mechanisms, we exposed larval zebrafish and mice to AO. We found that AO delayed yolk sac absorption, and increased liver area and inflammation in the larval zebrafish. This inflammation was manifested as an increase in liver neutrophils and the up-regulated mRNA expression of interleukin-6 (Il-6) and tumor necrosis factor-α (Tnf-α) in the larval zebrafish. Furthermore, a pharmacokinetics study showed that AO was quickly absorbed into the blood and rapidly metabolized in the mice. Of note, AO induced hepatotoxicity in a gender-dependent manner, characterized by liver dysfunction, increased hepatocyte necrosis with inflammatory infiltration, and up-regulated mRNAs of Il-6, Tnf-α and monocyte chemotactic protein 1(Mcp1) in the female mice after 28-day oral administration. It also highlighted that AO triggered NOD-like receptor protein (NLRP) signaling in the female mice, as evidenced by the increased NLRP3, Caspase-1, pro-IL-1ß, IL-1ß and IL-18. Finally, we found that AO led to a significant increase in potassium calcium-activated channel, subfamily N, member 4 (KCNN4) and reactive oxygen species (ROS) levels, along with decreased nuclear factor kappa B p65 (NF-κB p65), in the female mouse livers. In conclusion, AO induced hepatotoxicity by activating NLRP3 inflammasome signaling, at least in part, through increased KCNN4 and ROS production, and NF-κB inhibition.

Inhibition of CYP3A4 enhances aloe-emodin induced hepatocyte injury.

Aloe-emodin (AE) is a natural hydroxyanthraquinone derivative that was found in many medicinal plants and ethnic medicines. AE showed a wide array of pharmacological activities including anticancer, antifungal, laxative, antiviral, and antibacterial effects. However, increasing number of published studies have shown that AE may have some hepatotoxicity effects but the mechanism is not fully understood. Studies have shown that the liver injury induced by some free hydroxyanthraquinone compounds is associated with the inhibition of some metabolic enzymes. In this study, the CYP3A4 and CYP3A1 were found to be the main metabolic enzymes of AE in human and rat liver microsomes respectively. And AE was metabolized by liver microsomes to produce hydroxyl metabolites and rhein. When CYP3A4 was knocked down in L02 and HepaRG cells, the cytotoxicity of AE was increased significantly. Furthermore, AE increased the rates of apoptosis of L02 and HepaRG cells, accompanied by Ca2+ elevation, mitochondrial membrane potential (MMP) loss and reactive oxygen species (ROS) overproduction. The mRNA expression of heme oxygenase-1 in L02 and HepaRG cells increased significantly in the high-dose of AE (40 µmol/L) group, and the mRNA expression of quinone oxidoreductase-1 was activated by AE in all concentrations. Taken together, the inhibition of CYP3A4 enhances the hepatocyte injury of AE. AE can induce mitochondrial injury and the imbalance of oxidative stress of hepatocytes, which results in hepatocyte apoptosis.

Impact evaluation of marking Salmo trutta with Alizarin Red S produced by different manufacturers.

Fish otolith marking with the alizarin dye is a commonly used tool in sustainable fishery management. However, the reported effects of this dye on fish health are rather controversial and are possibly linked to differences in the composition of different brands of Alizarin red S (ARS). Laboratory experiments designed to elucidate effects of different concentrations of theoretically the same ARS as indicated by the CAS (Chemical Abstracts Service) number on fish at different development stages were carried out. The acute toxicity of ARS to Salmo trutta was found to be concentration- and fish developmental stage-dependant. Our study results showed that S. trutta sensitivity to ARS varies depending on its developmental stages as follows: fry (50-days after hatching) > alevins (30-days after hatching) > alevins (1-day after hatching). One of the tested ARS brands (purchased from VWR International LLC (Matsonford Road, USA)) was found to be several times more toxic to fish than another (purchased from Sigma-Aldrich (St. Louis, USA)), although according to the certificates of analysis, the tested substances were identical. Survival and growth of the S. trutta fry, which was marked with different ARS brands and stocked in the same natural stream, was investigated for two consecutive years. The results obtained indicate remarkable differences (p < 0.05) in the effects produced by the tested ARS brands, thus confirming our laboratory findings. The performed elemental analysis of the tested ARS dyes revealed significant differences in chemical impurities that these dyes contain. This study has, for the first time, expressed concern about the probable long-term impact of some ARS brands on the marked fish and their potential to bias the results of the studies dealing with ARS-marked fish.

Mutagenicity of Tectona grandis Wood Extracts and Their Ability to Improve Carbohydrate Yield for Kraft Cooking Eucalyptus Wood.

Considering the toxicity of the impurities of synthesized anthraquinone, this study clarified new catalytic compounds for kraft cooking with improved carbohydrate yield and delignification and less mutagenicity, which are important for ensuring the safety of paper products in contact with food. The 2-methylanthraquinone contents of teak (Tectona grandis) woods were 0.18-0.21%. Acetone extracts containing 2-methylanthraquinone from Myanmar and Indonesia teak woods as additives improved lignin removal during kraft cooking of eucalyptus wood, which resulted in kappa numbers that were 2.2-6.0 points lower than the absence of additive. Myanmar extracts and 2-methylanthraquinone improved carbohydrate yield in pulps with 1.7-2.2% yield gains. Indonesia extracts contained more deoxylapachol and its isomer than 2-methylanthraquinone. The residual content of 2-methylanthraquinone in the kraft pulp was trace. Although Ames tests showed that the Indonesia and Myanmar extracts were mutagenic to Salmonella typhimurium, 2-methylanthraquinone was not. The kraft pulp obtained with the additives should be safe for food-packaging applications, and the addition of 0.03% 2-methylanthraquinone to kraft cooking saves forest resources and fossil energy in industries requiring increased pulp yield.

Molecular mechanisms underlying the effect of diacerein on trichloroacetic acid-induced hepatic pre-neoplastic lesions in rats.

CONCLUSION: IL-1ß mediates angiogenesis indirectly, as it has been shown to induce hypoxia-inducible factor-1α (HIF-1α) which upregulates VEGF.

Marine Anthraquinones: Pharmacological and Toxicological Issues.

The marine ecosystem, populated by a myriad of animals, plants, and microorganisms, is an inexhaustible reservoir of pharmacologically active molecules. Among the multiple secondary metabolites produced by marine sources, there are anthraquinones and their derivatives. Besides being mainly known to be produced by terrestrial species, even marine organisms and the uncountable kingdom of marine microorganisms biosynthesize anthraquinones. Anthraquinones possess many different biological activities, including a remarkable antitumor activity. However, due to their peculiar chemical structures, anthraquinones are often associated with toxicological issues, even relevant, such as genotoxicity and mutagenicity. The aim of this review is to critically describe the anticancer potential of anthraquinones derived from marine sources and their genotoxic and mutagenic potential. Marine-derived anthraquinones show a promising anticancer potential, although clinical studies are missing. Additionally, an in-depth investigation of their toxicological profile is needed before advocating anthraquinones as a therapeutic armamentarium in the oncological area.

Aloe-emodin, a hydroxyanthracene derivative, is not genotoxic in an in vivo comet test.

Aloe-emodin, one of the molecules belonging to the group of hydroxyanthracene derivatives, was recently described as genotoxic in vivo. Indeed, the EFSA judged that aloe-emodin, together with other similar molecules (emodin and danthron) and extracts from the leaf of Aloe species containing hydroxyanthracene derivatives, could represent a risk factor for colorectal cancer mediated by a genotoxic effect. Given the marked uncertainty regarding the conclusions in the opinion of the EFSA ANS Panel and conflicts in the epidemiological data on which the opinion is based, a new in vivo study (in vivo alkaline comet assay in mice - OECD 489) was conducted to test the potential genotoxicity of aloe-emodin at doses of 250, 500, 1000 and 2000 mg/kg bw/day on preparations of single cells from the kidney and colon of treated male mice. Following treatment with the test item, no clinical signs were observed in animals in any treatment group. Slight body-weight loss was randomly observed in all groups treated with the test item and was more evident in the groups dosed at 1000 and 2000 mg/kg bw/day. Under these experimental conditions, aloe-emodin showed no genotoxic activity. Possible oxidative damage to colon tissues could not be excluded based on the results obtained after repair enzyme treatment.

Versicolorin A enhances the genotoxicity of aflatoxin B1 in human liver cells by inducing the transactivation of the Ah-receptor.

Aflatoxins are a group of mycotoxins that have major adverse effects on human health. Aflatoxin B1 (AFB1) is the most important aflatoxin and a potent carcinogen once converted into a DNA-reactive form by cytochrome P450 enzymes (CYP450). AFB1 biosynthesis involves the formation of Versicolorin A (VerA) which shares structural similarities with AFB1 and can be found in contaminated commodities, often co-occurring with AFB1. This study investigated and compared the toxicity of VerA and AFB1, alone or in combination, in HepG2 human liver cells. Our results show that both toxins have similar cytotoxic effects and are genotoxic although, unlike AFB1, the main genotoxic mechanism of VerA does not involve the formation of DNA double-strand breaks. Additionally, we show that VerA activates the aryl hydrocarbon receptor (AhR) and significantly induce the expression of the CYP450-1A1 (CYP1A1) while AFB1 did not induce AhR-dependent CYP1A1 activation. Combination of VerA with AFB1 resulted in enhanced genotoxic effects, suggesting that AhR-activation by VerA influences AFB1 genotoxicity by promoting its bioactivation by CYP450s to a highly DNA-reactive metabolite. Our results emphasize the need for expanding the toxicological knowledge regarding mycotoxin biosynthetic precursors to identify those who may pose, directly or indirectly, a threat to human health.

Chrysophanol Attenuates Manifestations of Immune Bowel Diseases by Regulation of Colorectal Cells and T Cells Activation In Vivo.

Inflammatory bowel disease (IBD) is an immune disorder that develops due to chronic inflammation in several cells. It is known that colorectal and T cells are mainly involved in the pathogenesis of IBD. Chrysophanol is an anthraquinone family member that possesses several bioactivities, including anti-diabetic, anti-tumor, and inhibitory effects on T cell activation. However, it is unknown whether chrysophanol suppresses the activity of colorectal cells. In this study, we found that chrysophanol did not induce cytotoxicity in HT-29 colorectal cells. Pre-treatment with chrysophanol inhibited the mRNA levels of pro-inflammatory cytokines in tumor necrosis factor-α (TNF-α)-stimulated HT-29 cells. Western blot analysis revealed that pre-treatment with chrysophanol mitigates p65 translocation and the mitogen-activated protein kinase (MAPK) pathway in activated HT-29 cells. Results from the in vivo experiment confirmed that oral administration of chrysophanol protects mice from dextran sulfate sodium (DSS)-induced IBD. Chrysophanol administration attenuates the expression of pro-inflammatory cytokines in colon tissues of the DSS-induced IBD model. In addition, we found that oral administration of chrysophanol systemically decreased the expression of effector cytokines from mesenteric lymph nodes. Therefore, these data suggest that chrysophanol has a potent modulatory effect on colorectal cells as well as exhibiting a beneficial potential for curing IBD in vivo.

Cytotoxicity and antigenotoxicity evaluation of acetylshikonin and shikonin.

Shikonin (SH) is used as a red pigment for food coloring and cosmetics, and has cytotoxic activity towards cancer cells. However, due to strong toxicity SH has limited potential as an anticancer drug. Acetylshikonin (ASH) is one of the SH derivatives with promising anticancer potential. In present study, we attempted to evaluate and compare the cytotoxicity of SH and ASH towards a normal cell line (V79) and in addition to evaluate their antigenotoxic activity. The evaluation was made with the use of the set of cytotoxicity assays with V79 line and the micronucleus test in vitro performed using clinafloxacin (CLFX), ethyl methanesulfonate (EMS) as direct genotoxins and cyclophosphamide (CPA) as indirect genotoxin. For CPA and EMS the simultaneous protocol was used and for CLFX three different variants were performed: pretreatment, simultaneous, and post-treatment. A higher cytotoxic effect was observed for SH. The EC50 values obtained for SH were approximately twofold lower compared to that of ASH. Moreover, ASH exhibited an antigenotoxic potential against CPA-induced genotoxicity, whereas SH has no activity. However, ASH increased the EMS-induced genotoxicity, when SH exhibited no effect. Both compounds decreased the genotoxicity of CLFX in pretreatment and simultaneous protocol. Based on the results of the present study it can be concluded that ASH is less cytotoxic than SH to normal cells and has comparable antigenotoxic potential.