Multi-level toxicity assessment of the antidepressant venlafaxine in embryos/larvae and adults of zebrafish (Danio rerio).

The toxic effects of venlafaxine (VLX) on aquatic organisms have already been verified and therefore are a proven matter of concern. Herein, we evaluated zebrafish embryos/adults after acute exposure to VLX. Embryos/larvae were exposed to different concentrations of VLX (100-1000 mg/L; 1.33 as a dilution factor), to evaluate mortality/developmental changos and to analyze biomarkers (0.002-100 mg/L). For adults, mortality, genotoxicity, and biomarkers were assessed in five different concentrations of VLX (1-100 mg/L). The median lethal concentration (LC50-168h) was 274.1 mg/L for embryos/larvae, and >100 mg/L for adults (LC50-96h). VLX decreased the heart rate frequency and caused premature hatching and lack of equilibrium in embryos/larvae exposed to different concentrations ranging from 100 to 562.5 mg/L. The activity of acetylcholinesterase (AChE) was inhibited in larvae exposed to 1, 25 and 100 mg/L. Glutathione-S-transferase (GST) activity was reduced in both larvae and adults after exposure to different concentrations, mainly at 25 mg/L. For both larvae and adults, lactate dehydrogenase (LDH) activity increased after 100 mg/L of VLX exposure. No DNA damage was observed in peripheral erythrocytes. Exposure to VLX may cause adverse effects on zebrafish in their early and adult life stages, interfering with embryo-larval development, and can induce physiological disturbances in adults.

In the screening of alternative insecticides to control Aedes aegytpti larvae 2-methylanthraquinone showed no genotoxicity and low toxicity to zebrafish (Danio rerio).

The threats posed by insecticide resistance to Aedes aegypti in the context of controlling dengue have led to an urgent search for an environmentally safer alternative chemical with more effective larvicidal properties. Among many molecules tested, 2-methylanthraquinone showed the lowest LC50 for A. aegypti in a previous study and the highest LC50 for zebrafish embryos. Embryos were exposed at concentrations of 1.0, 2.19, 4.78, 10.46, 22.87, 50.0 and 100.0 mg/L, and malformations and mortality were significantly observed only at the highest exposures of 50 and 100 mg/L after 96 h. Micronucleus test and comet assay in zebrafish adults were both negative after exposures at 6.25, 12.5, 25.0, 50.0 and 100.0 mg/L for 96 h. Several biochemical biomarkers were analyzed in adults, and 2-methylanthraquinone did not interfere with acetylcholinesterase activity. The lactate dehydrogenase activity was higher at concentrations of 25 and 100 mg/L. Glutathione-S-Transferase (GST) activities were tested in the gill and body (muscle tail). The gill was more sensitive than body for GST activity after exposure to 2-methylanthraquinone, showing the highest activities, and 2-methylanthraquinone showed low toxicity to a non-target organism.

Neuromotor activity inhibition in zebrafish early-life stages after exposure to environmental relevant concentrations of caffeine.

Caffeine (CAF), a neuroactive compound, has been found in surface waters at concentrations ranging from few nanograms up to micrograms and may induce adverse effects in aquatic vertebrates. Thus, the aim of this study was to evaluate the potential of CAF in affecting fish early-life stages in a wide concentration range, including occurring levels in surface waters. Specimens of zebrafish in early-life stages were exposed to CAF for 168 h and survival, developmental alterations, locomotor activity and acetylcholinesterase activity were evaluated. CAF induced mortality in embryos unable to hatch or in larvae after hatching (LC50 - 168 h = 283.2 mg/L). Tail deformities were observed in organisms exposed to concentrations ≥ 40 mg/L, while edemas were found at concentrations of 100 mg/L. CAF also decreased the total swimming time and distance moved of exposed organisms (LOEC = 0.0006 mg/L). Locomotor inhibition may be associated with an acetylcholinesterase inhibition observed at concentration ≥ 0.0088 mg/L. Therefore, the hazard of CAF for fish populations deserves further attention since unexpected effects on neuro-behavioral parameters occurs at concentrations often detected in natural aquatic ecosystems.

Steroid androgen 17 alpha methyltestosterone used in fish farming induces biochemical alterations in zebrafish adults.

The 17 alpha methyltestosterone (MT) hormone is fed to Oreochromis niloticus larvae in fish farms with the purpose of inducing sex reversal. The aim of this study was to evaluate the toxicity and sub-lethality of MT (99.9% purity) and cMT (a commercial MT with 90% purity) in zebrafish (Danio rerio) adults, where the animals were exposed to concentrations of 0, 4, 23, 139, 833 and 5000 µg/L for 96 hours. Genotoxicity was evaluated by micronucleus test (MN), nuclear abnormalities (NA) and comet assay. A low genotoxic potential of MT was showed, inducing micronucleus, nuclear abnormalities and DNA damage in Danio rerio, depending on the use of MT or cMT, gender and tested concentrations. In the sub-lethality trials, there was a basal difference in the activity of the enzymatic biochemical markers for males and females, while the Glutatione S transferase (GST) activity decreased in all analyzed tissues, and for males the enzymatic activity decreased only in the intestine. Results suggest that MT has a toxic potential to fish because it alters enzymatic metabolic pathways and may pose a risk to the ecosystems.

Why pesticides with mutagenic, carcinogenic and reproductive risks are registered in Brazil.

Brazil is the biggest market for pesticides in the world. In the registration process, a pesticide must be authorized by the Institute of the Environment, Health Surveillance Agency and Ministry of Agriculture. Evaluations follow a package of toxicological studies submitted by the companies and also based on the Brazilian law regarding pesticides. We confronted data produced by private laboratories, submitted to the Institute of the Environment for registration, with data obtained from scientific databases, corresponding to mutagenicity, carcinogenicity and teratogenicity of pesticides. All studies submitted by the companies were carried out by private laboratories. From 247 pesticide formulations analyzed, none showed positive results for mutagenicity, carcinogenicity or teratogenicity. From 574 articles in the scientific literature, 84% published by public laboratories showed positive results, while 79% of those showing negative results came from private laboratories. There is an ethical concern about a conflict of interest between public/independent laboratories and private laboratories that produce data for registering pesticides. We demonstrated that there is a clear contradiction between public and private laboratories. Brazilian regulatory authorities have approved the registration of pesticides based almost exclusively on the monographs provided by the pesticide industry, because the use of scientific articles or information from the independent literature is strongly belittled by the industry. Pesticide companies argue that scientific articles cannot be trusted. Also, according to the industry, pesticide registration cannot be refused based on results from scientific articles. Thus, the registration of pesticides with mutagenic, carcinogenic and teratogenic risks has been approved in Brazil.

Chronic effects of carbamazepine on zebrafish: Behavioral, reproductive and biochemical endpoints.

Carbamazepine (Cbz), one of the most prescribed pharmaceuticals in the world is often detected in surface waters and sediments. However, few studies addressed its chronic effects in fish. In the present study, Danio rerio adults were exposed for 63 days to Cbz (0 - control, 10 µg L-1 - concentration found in effluents, and 10,000 µg L-1 - 5% of LC50 at 72 h). Assessed endpoints were: feeding behavior, growth rate, number of eggs produced and their viability, histological alterations in female gonads, and biochemical biomarkers associated with antioxidant defenses (catalase - CAT, and glutathione S-transferase - GST activities), neurotransmission (acetylcholinesterase activity - AChE) and metabolism (lactate dehydrogenase - LDH). Cbz exposure increased the total time for food intake but did not affect D. rerio growth. Although the total number of eggs was not affected by Cbz exposure, the eggs viability was significantly impaired. Exposure to Cbz caused alterations in the female gonads follicular stages. In terms of biochemical endpoints, CAT activity in liver and gills, was sensitive to the pharmaceutical exposure presenting a decreased activity. AChE activity was induced in the head (both concentrations) and muscle (10,000 µg L-1). GST activity was increased in gills (both concentrations) but inhibited in the intestine. Concerning LDH, enzymatic activity was increased in the liver and decreased in muscle and gills. Several of the above-mentioned effects can be directly linked with effects at population level (e.g. feeding behavior) and occurred at environmental concentrations (the lowest concentration tested), thus serious concerns regarding risks posed by Cbz residues to fish populations arise with this study.

The pequi pulp oil (Caryocar brasiliense Camb.) provides protection against aging-related anemia, inflammation and oxidative stress in Swiss mice, especially in females.

Continued exposure to reactive oxygen species and inflammation are the rationale behind aging theories and associated diseases. Scientific evidence corroborates the ethnomedicinal use of the oil of pequi (Caryocar brasiliense Camb.), a typical Brazilian Cerrado fruit, against oxidative damage to biomolecules and inflammation. We aimed to investigate in vivo the antioxidant and anti-inflammatory effects of pequi oil on hemogram and DNA damage in healthy young adult and older middle-aged Swiss mice of both genders. Animals, aged 6-7 and 11-12 months, were orally treated for 15 days with pequi oil at 30 mg/day. Blood samples were used for hemogram and comet assay, and bone marrow for micronucleus test. Female controls of 11-12 months had significantly lower haemoglobin and hematocrit than those of 6-7 months. Treatment with pequi oil improved this state, removing the differences. Pequi oil had no genotoxic or clastogenic effects and significantly increased lymphocytes and decreased neutrophils+monocytes in females of 11-12 months, removing the significant differences observed between controls of 6-7 and 11-12 months. The results suggest that dietary supplementation with pequi oil could protect against anemia, inflammation and oxidative stress related to aging, helping to prevent aging-related chronic degenerative diseases, mainly for females.

Hematotoxicity and genotoxicity evaluations in Swiss mice intraperitoneally exposed to Bacillus thuringiensis (var kurstaki) spore crystals genetically modified to express individually Cry1Aa, Cry1Ab, Cry1Ac, or Cry2Aa.

Bacillus thuringiensis (Bt) has been widely used in foliar sprays as part of integrated pest management strategies against insect pests of agricultural crops. Since the advent of genetically modified plants expressing Bt δ-endotoxins, the bioavailability of Cry proteins has increased, and therefore for biosafety reasons their adverse effects should be studied, mainly for nontarget organisms. We evaluated, in Swiss mice, the hematotoxicity and genotoxicity of the genetically modified strains of Bt spore crystals Cry1Aa, 1Ab, 1Ac, or 2Aa at 27 mg/kg, and Cry1Aa, 1Ab and 2Aa also at 136 and 270 mg/kg, administered with a single intraperitoneal injection 24 h before euthanasia. Controls received filtered water or cyclophosphamide. Blood samples collected by cardiac puncture were used to perform hemogram, and bone marrow was extracted for the micronucleus test. Bt spore crystals presented toxicity for lymphocytes when in higher doses, which varied according to the type of spore crystal studied, besides promoting cytotoxic and genotoxic effects for the erythroid lineage of bone marrow, mainly at highest doses. Although the profile of such adverse side effects can be related to their high level of exposure, which is not commonly found in the environment, results indicated that these Bt spore crystals were not harmless to mice. This suggests that a more specific approach should be taken to increase knowledge about their toxicological properties and to establish the toxicological risks to nontarget organisms. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 970-978, 2016.

Association between interleukin 6 -174 G/C promoter gene polymorphism and runners' responses to the dietary ingestion of antioxidant supplementation based on pequi (Caryocar brasiliense Camb.) oil: a before-after study.

Exercise is a double-edged sword: when practiced in moderation, it increases the expression of antioxidant enzymes, but when practiced strenuously it causes oxidative stress and cell damage. In this context, polymorphisms in the interleukin (IL)-6 gene should be investigated better because they can influence performance, at least in exercise that generates oxidative stress and leads to muscular injuries with consequent inflammation. In this work, we investigated the influence of IL-6 -174 G/C polymorphism on tissue damage and inflammation markers, lipid peroxidation, hemogram and lipid profile of runners before and after ingestion of 400 mg of pequi oil in capsules supplied daily for 14 consecutive days. The IL-6 genotypes were associated with significant differences in lipid peroxidation, with the CC mutant having lower values. There were also significant differences among these genotypes in the response to supplementation with pequi oil, exercise-induced damage and C-reactive protein (CRP) levels. The best protection against damage was observed with the heterozygous genotype. Although the CC genotype showed an increase in CRP levels after supplementation, the lack of a positive correlation between triglycerides and high-sensitivity CRP in this mutant genotype after supplementation indicated a protective effect of pequi. These findings deserve further investigation, particularly with regard to the quantification of circulating IL-6 concentrations.

The lipidome, genotoxicity, hematotoxicity and antioxidant properties of andiroba oil from the Brazilian Amazon.

Andirobeira is an Amazonian tree, the seeds of which produce a commercially valuable oil that is used in folk medicine and in the cosmetic industry. Andiroba oil contains components with anti-inflammatory, cicatrizing and insect-repellant actions. However, virtually nothing is known of the safety of this oil for humans. The aim of this work was therefore to investigate the hematotoxicity, genotoxicity and mutagenicity of andiroba oil using the comet and micronucleus assays, and to assess its antioxidant properties and lipidome as a means of addressing safety issues. For the experiments, andiroba oil was administered by gavage for 14 consecutive days in nulliparous female Swiss mice randomly distributed in four groups: negative control and three doses of oil (500, 1000 and 2000 mg/kg/day). These doses were chosen based on recommendations of the OECD guideline no. 474 (1997). GC/MS was used to investigate the free fatty acid, cholesterol and triterpene content of andiroba oil in a lipidomic analysis. No clinical or behavioral alterations were observed throughout the period of treatment, and exposure to andiroba oil at the doses and conditions used here did not result in hematotoxic, genotoxic or mutagenic effects. Tests in vitro showed that oil sample 3 from southwestern of Brazilian Amazon had a high antioxidant capacity that may protect biological systems from oxidative stress, although this activity remains to be demonstrated in vivo.

Haptoglobin and myeloperoxidase (- G463A) gene polymorphisms in Brazilian sickle cell patients with and without secondary iron overload.

We aimed to investigate the influence of haptoglobin (Hp) and myeloperoxidase (MPO - G463A; dbSNP rs2333227) gene polymorphisms on 78 sickle cell patients of a public hospital in the Federal District/Brazil with and without iron overload, to evaluate a possible association between these polymorphisms and clinical variability, response to treatment and prognosis. Data were obtained through laboratory tests, questionnaires, research in medical records and analyses of polymorphisms using PCR-based methods. Positive correlations were found between Hp and ferritin levels, hydroxyurea treatment, hospitalisation for and sequelae from stroke; and between MPO and number of hospitalizations in the past 12 months and splenectomy. Significant associations of specific Hp genotypes with comorbidities were also found, while results suggested that MPO AA homozygosis could increase effects of asplenia. Deviation from Hardy-Weinberg equilibrium, compatible with heterozygous deficit, was observed for Hp polymorphism. Odds ratio suggested the possibility that increased chance of hospitalisation for stroke (OR = 6.346; IC 95% = 1.56-25.79; p = 0.005) and sequelae of stroke (OR = 6.556; IC 95% = 1.578-27.237; p = 0.005) could be associated with lower frequency of 1S-2 than expected. In the interaction analyses, significant effects between subjects were shown only in the group without overload for Hp polymorphism in hs-CRP levels (p = 0.000) and number of transfusions (p = 0.018), and for MPO polymorphism (p = 0.000) and the interaction Hp/MPO (p = 0.000) in hs-CRP values. Results corroborate others indicating biological differences between Hp*1 alleles and highlight the importance of this study in understanding the biological significance of Hp and MPO polymorphisms in clinical variability and response to treatment of sickle cell patients.

Evaluation of carbon nanotubes network toxicity in zebrafish (Danio rerio) model.

This is a detailed in vivo study of the biological response to carbon nanotubes network as probed by the zebrafish model. First, we prepared pristine carbon nanotubes (CNTs) by methanol chemical vapor deposition in the presence of Mn and Co as catalysts, followed by purification in acid, which furnished curved tubes with diameters lying between 10 and 130 nm. The CNT network consisted of pristine CNTs dispersed in water in the presence of a surfactant. The CNT network pellets corresponded to agglomerated multi-walled CNTs with an average diameter of about 500 nm. Although the same pristine CNTs had been previously found to exert genotoxic effects in vitro, here we verified that the CNT network was not genotoxic in vivo. Indeed, Raman spectroscopy and microscopy conducted in the intestine of the zebrafish revealed complete clearance of the CNT network as well as minimal disturbances, such as aneurysms, hyperemia, and reversible inflammatory focus in the zebrafish gills.

Multilevel assessment of carbamazepine effects: An integrative approach using zebrafish early-life stages.

Carbamazepine (CBZ) is the most commonly used drug in epilepsy treatment, and its metabolites are commonly detected among persistent pharmaceuticals in the aquatic environment. This study aimed to investigate CBZ effects on early-life-stage zebrafish (Danio rerio) (from 2 to 168 hpf) by employing of an integrative approach linking endpoints from molecular to individual level: (i) development; (ii) locomotor activity; (iii) biochemical markers (lactate dehydrogenase, glutathione-S-transferase, acetylcholinesterase and catalase) and (iv) transcriptome analysis using microarray. A 168 h - LC50 of 73.4 mg L-1 and a 72 h - EC50 of 66.8 mg L-1 for hatching were calculated while developmental effects (oedemas and tail deformities) were observed at CBZ concentrations above 37.3 mg L-1. At the biochemical level, AChE activity proved to be the most sensitive parameter, as evidenced by its decrease across all concentrations tested (∼25% maximum reduction, LOEC (lowest observed effect concentration) < 0.6 µg L-1). Locomotor behaviour seemed to be depressed by CBZ although this effect was only evident at the highest concentration tested (50 mg L-1). Molecular analysis revealed a dose-dependent effect of CBZ on gene expression. Although only 25 genes were deregulated in organisms exposed to CBZ when compared to controls, both 0.6 and 2812 µg L-1 treatments impaired gene expression related to development (e.g. crygmxl1, org, klf2a, otos, stx16 and tob2) and the nervous system (e.g. Rtn3, Gdf10, Rtn3), while activated genes were associated with behavioural response (e.g. prlbr and taar). Altogether, our results indicate that environmentally relevant CBZ concentrations might affect biochemical and genetic traits of fish. Thus, the environmental risk of CBZ cannot be neglected, especially in a realistic scenario of constant input of domestic effluents into aquatic systems.

Enhancing photocatalytic tetracycline degradation through the fabrication of high surface area CeO2 from a cerium-organic framework.

Water pollution is a global environmental issue, and the presence of pharmaceutical compounds, such as tetracyclines (TCs), in aquatic ecosystems has raised growing concerns due to the potential risks to both the environment and human health. A high surface area CeO2 was prepared via atmospheric thermal treatment of a metal-organic framework of cerium and benzene-1,3,5-tricarboxylate. The effects of calcination temperature on the morphology, structure, light absorption properties and tetracycline removal efficiency were studied. The best activity of the photocatalysts could be achieved when the heat treatment temperature is 300 °C, which enhances the photocatalytic degradation performance towards tetracycline under visible light. The resulting CeO2 particles have high capacity for adsorbing TCs from aqueous solution: 90 mg g-1 for 60 mg L-1 TCs. As a result, 98% of the initial TC can be removed under simulated sunlight irradiation. The cooperation of moderate defect concentration and disordered structure showed tetracycline removal activity about 10 times higher than the initial Ce-MOF. An embryotoxicity assessment on zebrafish revealed that treatment with CeO2 particles significantly decreased the toxicity of TC solutions.

Profile of micronucleus frequencies and nuclear abnormalities in different species of electric fishes (Gymnotiformes) from the Eastern Amazon.

The frequency of spontaneous micronucleus (MN) formation in fish species needs to be determined to evaluate their usefulness for genotoxic biomonitoring. The definition of a good bioindicator takes into account the current knowledge of its metabolic traits as well as other factors including its feeding behavior and relationship to the environment. In this study, we compared the basal frequencies of micronucleated erythrocytes and nuclear abnormalities (NA) among different species of the fish Order Gymnotiformes (Rhamphichthys marmoratus, Steatogenys elegans, Sternopygus macrurus, Parapteronotus hasemani, Gymnotus mamiraua, Gymnotus arapaima, Brachyhypopomus beebei, Brachyhypopomus n. sp. BENN) sampled in several localities of the Eastern Amazon. A baseline of MN and NA frequency in these fish was determined, enabling the identification of potentially useful species as models for genotoxicity studies. Only one impacted sample collected at a site in the River Caripetuba showed a significant number of NAs, which may be due to the release of wastewater by neighbouring mining industries and by the burnt fuel released by the small boats used by a local community. Our results may provide support for further studies in areas of the Eastern Amazon affected by mining, deforestation and other anthropogenic activities.

Mutagenicity and genotoxicity in gill erythrocyte cells of Poecilia reticulata exposed to a glyphosate formulation.

Poecilia reticulata were exposed to herbicide Roundup Transorb(®) for micronucleus test, nuclear abnormalities and comet assay. The exposure-concentrations were based on CL50-96 h following 0, 1.41, 2.83, 4.24 and 5.65 µL L(-1) for 24 h. Micronucleus and comets were significantly increased in the gill erythrocyte cells after herbicide exposure compared with the non-exposed group. Results showed a gradual increase in the number of damaged cells, indicating a concentration-dependent effect and that this herbicide was mutagenic and genotoxic to P. reticulata and this effect could be attributed to a combination of compounds contained in the formulation with the active ingredient glyphosate.

Bioavailability assessment of metals from a nickel mining residue in the gastrointestinal tract of Oreochromis niloticus in vivo.

Mining to obtain ferronickel by the pyrometallurgical process involves a calcination stage that generates a highly metallic solid dust. This study evaluated the bioavailability of metals from calcination dust after being ingested by Oreochromis niloticus. Chemical analysis was performed on the whole body and histological analysis was performed on the gills and gastrointestinal tract of fish to evaluate potential bioaccumulation. After 96 h of exposure to the dust, gill tissue contained a small amount of particulate matter, while the gastrointestinal tract was filled with the material, generating high values of metals in the fish whole body chemical analysis. However, after 15 and 30 days in clean water, both the gills and gastrointestinal tract were nearly devoid of particles and metal concentrations in the fish whole body had largely returned to baseline levels.

Multilevel Toxicity Evaluations of Polyethylene Microplastics in Zebrafish (Danio rerio).

Microplastics in freshwater environments pose a serious threat to living beings. Polyethylene microplastics (PE-MP) are the type most used around the world as microbeads in personal care products, and they have been found in aquatic organisms. The behavior and toxicity of fluorescent PE-MP spheres with an average diameter of 58.9 µm were studied in adult, juvenile and embryo zebrafish (Danio rerio). The adults were studied for genotoxicity, cytotoxicity, histology and biochemical markers. Juveniles underwent a follow-up in the gastrointestinal (GI) tract with histologic observations, and embryos were studied for embryotoxicity with the FET-test. In adults, micronucleus test and comet assays found neither genotoxicity after acute exposure for 96 h at concentrations of 0.0, 12.5, 50 and 100 mg.L-1, nor cytotoxicity through the nuclear abnormalities test. Acetylcholinesterase (AChE), Glutathione-S-Transferase (GST) and Lactate Dehydrogenase (LDH) activities were measured in adults exposed for 96 h. The AChE and GST activities were significantly changed, while no changes occurred for LDH. In conclusion, these PE-MP spheres did not cause serious toxic effects in zebrafish because there was no internalization. The observed biochemical changes in AChE and GST may be associated with GI microbiological dysbiosis, previously reported. The PE-MP spheres in the intestine of juveniles remained present for 12-15 days on average after the post-exposure clearance study, showing a slow depuration. The histological analysis, in adults, found no internalization of these microbeads, with complete depuration. The PE-MP spheres did not cross the chorion barrier, showing no embryotoxic effects after exposures at 0.0, 6.25, 12.5, 50.0 or 100.0 mg.L-1 for 96 h.

Effects of environmental concentrations of caffeine on adult zebrafish behaviour: a short-term exposure scenario.

Caffeine (CAF) has been considered an emerging environmental contaminant and its presence indicator of anthropogenic contamination. This study evaluated the effects of environmental concentrations of CAF (0, 0.5, 1.5, and 300 µg. L-1) on the behaviour of adult zebrafish (Danio rerio) after 7 days of exposure. The components of feeding, locomotion, boldness (new tank test), sociability (schooling test), and aggression (mirror test) were analysed. Growth rate and weight were investigated as complementary measures. CAF (0.5, 1.5, and 300 µg. L-1) reduced exploratory behaviour in zebrafish, increased feeding latency time (1.5, and 300 µg. L-1), and decreased growth rate and fish weight (300 µg. L-1). CAF also induced aggressive behaviour (0.5, 1.5, and 300 µg. L-1) and decreased appetence to the shoal (sociability) (0.5, and 1.5 µg. L-1). This study showed that low doses of CAF can induce behavioural effects in zebrafish that may have significant long-term impacts on vital ecological functions.

Toxicological effects of aqueous extract of Genipa americana L. leaves on adult zebrafish (Danio rerio): Chemical profile, histopathological effects and lack of genotoxicity.

Genipa americana is a native plant of Brazil with potential applications in folk medicine. Whereas most of the phytochemical and pharmacological studies on this plant have focused on its fruits, the crude extracts of its leaves contain chemical metabolites that may have toxicity to organisms, which have yet to be investigated. This study aimed to determine the main groups of secondary metabolites in the aqueous extract of the leaves of G. americana by phytochemistry and qualitative HPLC, and to evaluate the possible toxicological effects and histopathological changes caused by this extract in zebrafish (Danio rerio) adults, through micronucleus test, nuclear abnormalities and histopathological analyses of gills and liver. While three metabolites of high intensity (phenolic compounds, flavonoids and triterpenes) were found in the phytochemical evaluation, the HPLC showed results compatible with flavonoids and iridoids, all belonging to common classes for this species and the Rubiaceae family. The acute toxicity test did not induce mortality or genotoxicity in zebrafish, but after exposure for 96 h, it was possible to observe injuries to the fish gill tissue, such as lamellar fusion, vasodilation and telangiectasia; in the liver, necrosis was visualized at 40 mg/L, and at higher concentrations (80 and 100 mg/L) induced sinusoidal widening was identified. In conclusion, the results demonstrated the toxic potential of this plant for aquatic species.