Acute Toxicity Assay Research Articles

Toxicological Response of <i>Poecilia reticulata, Hyla species</i> and <i>Culex species</i> to Leachates from Olusosun Landfill, Lagos State, Nigeria

The effect of leachate samples from Olushosun dumpsite in Ojota, Lagos on the toxicological response of Poecilia reticulata , Hyla and Culex species was investigated using acute and chronic toxicity tests. Physicochemical parameters were analysed in the leachate prior to toxicological assessment against test animals. Computed results showed that pH 7.62 while the acute toxicity assay of leachate sample against test animals revealed a 96hr LC 50 of 71.53ml/L, 58.34ml/L and 60.643ml/L for Poecilia, Hyla and Culex species respectively. On the basis of the 96hr LC 50 values, the leachate was found to be more toxic against Hyla than Poecilia . The exposure of the Poecilia and Hyla species to sub-lethal concentrations (1/10th of 96hrs LC 50 ) of leachate revealed varied biochemical responses over a 28 day period. The activity of Catalase, Superoxide Dismutase (SOD), Malondialdehyde (MDA) and Glutathione-S-Transferase (GST) showed significant increase (p<0.05) when compared to control in Hyla while the activity of GSH, SOD and CAT showed significant increase (p<0.05) when compared to control in Poecilia sp. Results from this study showed that leachate can induce adverse environmental effect on organisms. The acute and chronic toxicological response of the test animals could be incorporated into risk assessment of dumpsite leachate, design and management of landfill sites.

Acute sensitivity of three Cladoceran species to different types of microplastics in combination with thermal stress

Microplastics (<5 mm, MP) are ubiquitously distributed in the environment, causing increasing concern regarding their potential toxicity to organisms. To date, most research has focussed on the impacts of MPs on marine and estuarine organisms, with fewer studies focussing on the effects of microplastics on freshwater ecosystems, especially under different environmental conditions. In the present study, the sensitivity of two temperate Cladoceran species, Daphnia magna and Daphnia pulex, and a smaller tropical species Ceriodaphnia dubia, to primary microplastics (PMP) and secondary (weathered) microplastics (SMP) was assessed. A prolonged acute toxicity assay (up to 72 or 96 h) was performed at 18°, 22°, and 26 °C, to determine the influence of temperature as an additional stressor and survival data were analysed using toxicokinetic-toxicodynamic (TK-TD) model. Acute sensitivity of D. magna and D. pulex to both PMP and SMP increased sharply with temperature, whereas that of C. dubia remained relatively stable across temperatures. C. dubia was the most sensitive species at 18 °C, followed by D. pulex and D. magna, which were of comparable sensitivity. However, this ranking was reversed at 26 °C as could be seen from the No Effect Concentration (NEC) estimates of the TK-TD model. In addition, SMP and PMP had a similar effect on D. magna and D. pulex, but PMP was more toxic to C. dubia. Effects on survival were strongly time-dependent and became substantially more severe after the standard 48 h test period. Our results indicate that sensitivity to microplastics may differ between species for different types of microplastics, and could be drastically influenced by temperature albeit at high exposure concentrations.

Examining Natural Attenuation and Acute Toxicity of Petroleum-Derived Dissolved Organic Matter with Optical Spectroscopy.

Groundwater samples containing petroleum-derived dissolved organic matter (DOMHC) originating from the north oil body within the National Crude Oil Spill Fate and Natural Attenuation Research Site near Bemidji, MN, USA were analyzed by optical spectroscopic techniques (i.e., absorbance and fluorescence) to assess relationships that can be used to examine natural attenuation and toxicity of DOMHC in contaminated groundwater. A strong correlation between the concentration of dissolved organic carbon (DOC) and absorbance at 254 nm ( a254) along a transect of the DOMHC plume indicates that a254 can be used to quantitatively assess natural attenuation of DOMHC. Fluorescence components, identified by parallel factor (PARAFAC) analysis, show that the composition of the DOMHC beneath and adjacent to the oil body is dominated by aliphatic, low O/C compounds ("protein-like" fluorescence) and that the composition gradually evolves to aromatic, high O/C compounds ("humic-/fulvic-like" fluorescence) as a function of distance downgradient from the oil body. Finally, a direct, positive correlation between optical properties and Microtox acute toxicity assays demonstrates the utility of these combined techniques in assessing the spatial and temporal natural attenuation and toxicity of the DOMHC in petroleum-impacted groundwater systems.

Assessment of the Acute Toxicity, Uptake and Biotransformation Potential of Benzotriazoles in Zebrafish ( Danio rerio) Larvae Combining HILIC- with RPLC-HRMS for High-Throughput Identification.

The current study reports on the toxicity, uptake, and biotransformation potential of zebrafish (embryos and larvae) exposed to benzotriazoles (BTs). Acute toxicity assays were conducted. Cardiac function abnormalities (pericardial edema and poor blood circulation) were observed from the phenotypic analysis of early life zebrafish embryos after BTs exposure. For the uptake and biotransformation experiment, extracts of whole body larvae were analyzed using liquid chromatography-high-resolution tandem mass spectrometry (UPLC-Q-TOF-HRMS/MS). The utility of hydrophilic interaction liquid chromatography (HILIC) as complementary technique to reversed phase liquid chromatography (RPLC) in the identification process was investigated. Through HILIC analyses, additional biotransformation products (bio-TPs) were detected, because of the enhanced sensitivity and better separation efficiency of isomers. Therefore, reduction of false negative results was accomplished. Both oxidative (hydroxylation) and conjugative (glucuronidation, sulfation) metabolic reactions were observed, while direct sulfation proved the dominant biotransformation pathway. Overall, 26 bio-TPs were identified through suspect and nontarget screening workflows, 22 of them reported for the first time. 4-Methyl-1- H-benzotriazole (4-MeBT) demonstrated the highest toxicity potential and was more extensively biotransformed, compared to 1- H-benzotriazole (BT) and 5-methyl-1- H-benzotriazole (5-MeBT). The extent of biotransformation proved particularly informative in the current study, to explain and better understand the different toxicity potentials of BTs.

Cardiospermum corindum L. (Sapindaceae) has gastroprotective and antispasmodic effect on rodent model

Aim: To investigate the effects of crude ethanol extract obtained from the aerial parts Cardiospermum corindum (Cc-EtOH) on the ethanol-induced gastric ulcer assay in rats, its oral acute toxicity on mice, and its antispasmodic activity on the isolated rat ileum. Methods: The Cc-EtOH was evaluated on ethanol-induced rat gastric lesions. To verify the safety this extract in vivo, the acute toxicity assay was performed during 14 days in mice. Finally, effects of extract on rat ileum were analyzed. Results: The Cc-EtOH extract (50, 150 and 500 mg/kg) significantly protected the rat gastric mucosa layer (ULA = 210.0 ± 55.8; 119.2 ± 39.3 and 47.7 ± 13.2 mm2, respectively) from lesions induced by ethanol (ULA = 367.5 ± 89.3mm2), as effectively as omeprazole. The histological analyses also corroborated its protective effect. In addition, 60-min treatment with a single dose 2 g/kg p.o. of Cc-EtOH extract promoted mice sedation (n = 5), which reversed after 30 min., without causing neither animal death, nor body mass, water ingestion, or feed alterations, during 14 days thus showing no acute toxicity. The antispasmodic effect of the Cc-EtOH extract was evidenced on the phasic component of the isolated rat ileum contractions elicited by CCh and KCl (IC50 = 236 ± 59 and 201 ± 43mg/ml, respectively). Conclusion: the aereal parts of C. corindum contain chemical compounds which are able to promote effective gastric protection in rats, in the absence of any acute toxicity, combined with the antispasmodic effect in vitro.

Antinociceptive and anti-inflammatory effects of 1,2-bis-(4 methoxyphenylselanyl) styrene in mice: involvement of the serotonergic system.

Pain is one of the most prevalent, costly and disabling conditions that reduces quality of life. Although there are many analgesics available, there is some concern regarding their efficacy, safety and side effects. Organic selenium compounds are attractive targets of various research groups due to their pharmacological properties. The aim of this study was to evaluate the antinociceptive and anti-inflammatory activity of 1,2-bis-(4-methoxyphenylselanyl) styrene (BMOSE) in mice, as well as to investigate the mechanism involved in the antinociceptive effect. The animals were submitted to the formalin and glutamate tests. The assessment of the possible involvement of the serotonergic system in BMOSE antinociceptive activity was performed using the glutamate test. Also, we investigated the possible toxicity of the compound. 1,2-bis-(4-methoxyphenylselanyl) styrene (0.1-50mg/kg, i.g.) was efficient in avoiding nociception induced by glutamate and formalin and also reduced paw oedema. The possible involvement of 5-HT3 serotoninergic receptor antagonist ondansetron blocked the antinociceptive effect of BMOSE. The acute toxicity assays did not show any toxicity related to the administration of BMOSE (200mg/kg). It is possible to conclude that BMOSE has both antinociceptive and anti-inflammatory activity, and the serotoninergic system, more specifically, the 5-HT3 receptor, is involved in the effect.

Synergistic effect and different toxicities of adjuvant components of Realgar–Indigo Naturalis formula

ObjectiveRealgar–Indigo Naturalis formula (RIF) is a well-known arsenic-containing preparation that is used to treat acute promyelocytic leukemia (APL) in China. In recent multicenter clinical trials, complete remission rates in APL patients have ranged from 96.08% to 100%. RIF has a satisfactory therapeutic effect, but its safety is a widespread concern, since the preparation contains arsenic, a wide-ranging and naturally occurring toxicant. In this study, in order to determine the toxic potential of RIF, acute toxicity and sub chronic toxicity assays were performed to evaluate the toxic potential of Realgar and the adjuvant components of RIF in addition to Realgar's synergy with these adjuvant components. MethodsKM mice and Wistar rats were selected for these experiments. To evaluate acute toxicity, the toxic effects of a single dose of a gradient of concentrations of Realgar were firstly determined. Then, the toxic effects of combinations of gradient doses of Realgar and fixed doses of Indigo naturalis and Salvia miltiorrhiza were evaluated. ResultsThe results showed that when Realgar was used alone, the LD50 was 2756.73 mg/kg (equivalent to 23.6 mg/kg As2O3). However, the LD50 dropped to 936.90 mg/kg when Realgarwas used with I. naturalis. By contrast, the LD50 increased to 7538.86 mg/kg when Realgar was used with S. miltiorrhiza. Hence, I. naturalis strengthened the toxicity of Realgar, whereas S. miltiorrhiza displayed the opposite effect. The sub chronic toxicity assessment results revealed a trend that was consistent with acute toxicity. Changes in the levels of different valence states of arsenic were also taken into account. The test results of the effects of in vitro combinations of Realgar and adjuvant components on soluble arsenic dissolution showed that I. naturalis increased the level of soluble arsenic in Realgar extracts and I. naturalis suspensions when theRealgar/I. naturalis ratio was 2, 1.5, and 1.0. However, S. miltiorrhiza did not affect it. ConclusionBased on the collective experimental results presented here, it can be concluded that the toxicity of RIF is the result of the soluble arsenic in Realgar and that the I. naturalis and S. miltiorrhiza in the RIF exert completely opposite effects on the toxicity of Realgar. This maybe an intelligent explanation for the compatibility of this formula, and this RIF study may therefore be viewed as a classic case of traditional Chinese medicine research on compatibility.

Strain-Specific Quantification of Native Probiotic Bacillus spp. and Their Effect on Liver Function and Gut Microflora of Experimental Rats.

Safety and efficacy was investigated for two candidate probiotic B. flexus MCC2427 and B. licheniformis MCC2512 via in vivo studies on albino Wistar rats. In acute toxicity assay, rats were fed with single dose of 1010cfumL-1 of probiotics. The follow-up studies for next 14days did not reveal any toxicity-related criteria indicating the non-toxicity nature of probiotics. In 90-day repeated dosage studies, the cultures were administered in three doses (106, 107, 108cfumL-1). Results showed no overt toxic effect and no drastic treatment-related changes pertaining to histopathology of vital organs. DNA fingerprinting indicated the lack of bacterial translocation. Superoxide dismutase and catalase activity indicated their antioxidant potential. Reduced serum cholesterol with improved HDL-cholesterol specified the cholesterol-reducing ability of the cultures, which was also apparent with increased excretion of cholic acid in feces. Both probiotic cultures positively altered the gut microbial environment, retained lactic acid bacterial effect, and simultaneously reduced pathogenic strains. A sensitive and rapid tool was developed using strain-specific qPCR primers, which facilitated appropriate estimation of test culture in feces. The data strongly advocate the safety of tested probiotics at levels used in the study.

Chemical characterisation of Piper amalago (Piperaceae) essential oil by comprehensive two-dimensional gas chromatography coupled with rapid-scanning quadrupole mass spectrometry (GC×GC/qMS) and their antilithiasic activity and acute toxicity.

Piper amalago has a distribution from Mexico to Brazil; their aerial parts have been used in folk medicine to treat diuretic and kidney diseases. The purpose of this study was to obtain a deeper understanding of the chemical composition of essential oils (EOs) extracted from both the leaves and stems of P. amalago, compare them, and evaluate their antilithiasic activity and acute toxicity. Extraction was performed by hydrodistillation, whereas chemical characterisation by two-dimensional gas chromatography coupled with rapid-scanning quadrupole mass spectrometry (GC×GC/qMS). The antilithiasic activity was evaluated by the effect of the EOs on calcium oxalate crystallisation in vitro. The turbidity index and the number of crystals formed were determined and used as an estimative of the activity. In the acute toxicity assay, the effects of a single oral dose of the EOs in Wistar rats were determined. General behaviour, adverse effects, and mortality were determined. A total of 322 compounds were identified in the EOs. The sesquiterpenes displayed the highest contribution in leaves EOs among which included bicyclogermacrene and δ-cadinene. Sesquiterpenes and oxygenated sesquiterpenes displayed the highest contribution in EOs from stems, among which included bicyclogermacrene and α-cadinol. The EOs demonstrated an excellent action on the crystals growth inhibition, and the oral dose tested did not induce significant changes in the parameters for acute toxicity. The oils have a high chemical complexity, and there are differences between their compositions, which could explain the observed differences in antilithiasic activity. The findings support the use of this plant in folk medicine to treat kidney diseases.

Horseradish peroxidase immobilization by copolymerization into cross-linked polyacrylamide gel and its dye degradation and detoxification potential

Owing to the ever-increasing environmental and health impacts associated with the discharge of dye-based effluents, effective remediation of industrial waste have become a top priority for the industrialists and environmental fraternity, around the world. Plant-based peroxidases represent a suitable bio-remediating agent for the effective treatment of original dyes or dye-based colored wastewater effluents. In the present study, horseradish peroxidase was immobilized by copolymerization into cross-linked polyacrylamide gel and investigated its potential for the degradation and detoxification of an azo dye, methyl orange. In the presence of N, N′-methylenebisacrylamide as a cross-linker, polyacrylamide gel at 10% concentration furnished >80% of immobilization yield. The surface morphology of the control (free enzyme) and immobilized enzyme, i.e., horseradish peroxidase cross-linked polyacrylamide gel was characterized using scanning electron microscopy. The high yielded horseradish peroxidase cross-linked polyacrylamide gel concentration, i.e., 10% was used to develop a packed bed reactor and exploited for dye degradation and detoxification purposes. A noteworthy level (>90%) of dye degradation was recorded after polyacrylamide gel cross-linked horseradish peroxidase-catalyzed reaction in a packed bed bioreactor. The biodegradation was further assessed by Fourier-transform infrared spectral analysis. The acute toxicity assays demonstrated that enzyme-based bio-degradation might be used effectively for large-scale environmental remediation of dyes and dyes containing wastewater effluents.

A systematic investigation of the bio-toxicity of core-shell magnetic mesoporous silica microspheres using zebrafish model

In this work, shearing interface coassembly in biliquid phase systems is employed to synthesize biocompatible core-shell magnetic mesoporous silica microspheres with uniform size of about 600 nm, perpendicular mesopores of 6.0 nm and large pore volume of 0.77 cm3/g. The toxicology assays based on the zebrafish model was conducted to test under a high-throughput manner for the biosafety of Fe3O4@RF@mSiO2 microspheres. The highest no observed toxic effect concentration (NOEC) estimated by the acute toxicity assay for the microspheres was 1.6 mg/mL. The estimated number (measured by ICP-MS) of the penetrated microspheres at this concentration was 2 × 106 per embryo. The results of three different performed toxicity assays show no overall acute toxicity, teratogenicity, or neurotoxicity of the microspheres on zebrafish embryos at any of the tested concentrations (from 0.1 to 1.6 mg/mL) via its multifunctional microstructure. Here, gemcitabine (GEM) as a model of anti-cancer drug was loaded into the mesopores of Fe3O4@RF@mSiO2 microspheres to study their drug release behavior. The microspheres were found to exhibit pH responsive property, which benefits for the GEM release under cancer therapy. Overall, this study offers promising avenue for effective evaluation of magnetic core-shell microspheres for drug delivery and cancer therapy applications.

Uptake and Depuration Kinetics Influence Microplastic Bioaccumulation and Toxicity in Antarctic Krill ( Euphausia superba).

The discarding of plastic products has led to the ubiquitous occurrence of microplastic particles in the marine environment. The uptake and depuration kinetics of ingested microplastics for many marine species still remain unknown despite its importance for understanding bioaccumulation potential to higher trophic level consumers. In this study, Antarctic krill ( Euphausia superba) were exposed to polyethylene microplastics to quantify acute toxicity and ingestion kinetics, providing insight into the bioaccumulation potential of microplastics at the first-order consumer level. In the 10 day acute toxicity assay, no mortality or dose-dependent weight loss occurred in exposed krill, at any of the exposure concentrations (0, 10, 20, 40, or 80% plastic diet). Krill exposed to a 20% plastic diet for 24 h displayed fast uptake (22 ng mg-1 h-1) and depuration (0.22 h-1) rates, but plastic uptake did not reach steady state. Efficient elimination also resulted in no bioaccumulation over an extended 25 day assay, with most individuals completely eliminating their microplastic burden in less than 5 days post exposure. Our results support recent findings of limited acute toxicity of ingested microplastics at this trophic level, and suggest sublethal chronic end points should be the focus of further ecotoxicological investigation.

Progress of research on the toxicology of antibiotic pollution in aquatic organisms

Antibiotics are widely used to improve human and animal health and treat infections. Antibiotics are often used in livestock farms and fisheries to prevent diseases and promote growth. Recently, there has been increasing interest in the presence of antibiotics in aquatic environments. Low levels of antibiotic components are frequently detected in surface water, seawater, groundwater, and even drinking water. Antibiotics are consistently and continually discharged into the natural environment as parent molecules or metabolites, which are usually soluble and bioactive, and this results in a pseudo and persistent pollution. The effects of environmental antibiotic toxicity on non-target organisms, especially aquatic organisms, have become an increasing concern. Although antibiotics have been detected worldwide, their ecological and developmental effects have been poorly investigated, particularly in non-target organisms. This review describes the toxicity and underlying mechanism of antibiotic contamination in aquatic organisms, including the effects on vertebrate development. A considerable number of antibiotic effects on aquatic organisms have been investigated using acute toxicity assays, but only very little is known about the long-term effects. Aquatic photosynthetic autotrophs, such as Pseudokirchneriella subcapitata, Anabaena flos-aquae, and Lemna minor, were previously used for antibiotic toxicity tests because of low cost, simple operation, and high sensitivity. Certain antibiotics show a different degree of potency in algal toxicity tests on the basis of different test algae. Antibiotics inhibit protein synthesis, chloroplast development, and photosynthesis, ultimately leading to growth inhibition; some organisms exhibit growth stimulation at certain antibiotic concentrations. Daphnia magna and other aquatic invertebrates have also been used for checking the toxicity priority of antibiotics. When investigating the acute effect of antibiotics (e.g., growth inhibition), concentrations in standard laboratory organisms are usually about two or three orders of magnitude higher than the maximal concentrations in the aquatic environment, resulting in the underestimation of antibiotic hazards. Vertebrate organisms show a promising potential for chronic toxicity and potentially subtle effects of antibiotics, particularly on biochemical processes and molecular targets. The adverse developmental effects of macrolides, tetracyclines, sulfonamides, quinolones, and other antibiotic groups have been evaluated in aquatic vertebrates such as Danio rerio and Xenopus tropicalis. In acute toxicity tests, low levels of antibiotics have systematic teratogenic effects on fish. The effects of antibiotics on oxidative stress enzymes and cytochrome P450 have been investigated. Cytotoxicity, neurotoxicity, and genotoxicity have been observed for certain antibiotic amounts. However, there are no firm conclusions regarding the chronic toxicity of antibiotics at environmentally relevant levels because of the lack of long-term exposure studies. Herein, future perspectives and challenges of antibiotic toxicology were discussed. Researchers should pay more attention to the following points: chronic toxicity and potentially subtle effects of environmentally relevant antibiotics on vertebrates; effects of toxicity on biochemical processes and mode of action; combined toxicity of antibiotics and other antibiotics, metabolites, and heavy metals; and environmental factors such as temperature and pH.

The semi-synthetic molecule [4″,5″] dihydro-obovatin isolated from Tephrosia Toxicaria pers reduces zymosan-induced temporomandibular joint inflammatory hypernociception in rats

Arthritis possesses inflammatory components and flavonoids of well-known structures exert anti-inflammatory activity. Here, we aim to evaluate the effects of [4″,5″] dihydro-obovatin and three structurally-defined flavonoids from Tephrosia toxicaria Pers roots on the zymosan-induced temporomandibular joint inflammatory hypernociception in rats as well as their toxicity. Rats were pretreated with the flavonoids (1 and 10 mg/kg) and [4″,5″] dihydro-obovatin (0.1 and 1.0 mg/kg) 1 h before intra-articular zymosan injection (2 mg, 40 μL). Von Frey test was used to evaluate the nociceptive threshold at the 4th hour after zymosan injection. Six hours after zymosan injection, synovial lavage was collected for total cell counting. Acute toxicity assay for [4″,5″] dihydro-obovatin (1, 10, and 100 mg/kg) were performed along with the subchronic toxicity assay by administering [4″,5″] dihydro-obovatin (0.01 mg/kg) or saline solution for 14 consecutive days and the rota-rod test was carried out to determine whether [4″,5″] dihydro-obovatin would impair motor functions. The tested flavonoids and [4″,5″] dihydro-obovatin increased nociceptive threshold and reduced the cell counting in the synovial lavage in the temporomandibular joint compared with the zymosan group. [4″,5”] dihydro-obovatin did not induce toxic effects as well as did not alter the motor function in the rota-rod test. The flavonoids and [4″,5″] dihydro-obovatin exerted antinociceptive and anti-inflammatory effects on the zymosan-induced temporomandibular joint inflammatory hypernociception in rats and the latter did not show significant toxic effects. Therefore, [4″,5″] dihydro-obovatin would be a promising anti-inflammatory and antinociceptive agent.

Acute and sub-lethal toxicity of eight essential oils of commercial interest against the filariasis mosquito Culex quinquefasciatus and the housefly Musca domestica

The massive use of synthetic insecticides led to negative effects on the environment and human health. Therefore, researchers looked at natural products as effective alternatives to conventional pesticides. Here, commercially valuable essential oils (EOs) were selected from mint (Mentha x piperita, Mentha spicata), basil (Ocimum basilicum), helichrysum (Helichrysum italicum), yarrow (Achillea ligustica), geranium (Pelargonium odoratissimum), cinnamon (Cinnamomum verum) and ginger grass (Lippia alba). The chemical composition of these EOs assayed was analyzed by GC–MS. Then, we investigated their insecticidal potential in acute and sub-lethal toxicity assays against mosquito vectors of filariasis (Culex quinquefasciatus) and house flies (Musca domestica). Against C. quinquefasciatus 4th instar larvae, the most toxic EO was C. verum (LC50 = 40.7 μl L−1), followed by L. alba (LC50 = 59.6 μl L−1), while against M. domestica adults, the most toxic EOs were C. verum and H. italicum (LD50 = 42 μg adult−1). The exposure of mosquito larvae to a sub-lethal concentration (LC30 = 25 mg L−1) led to a reduction of adult emergence and fertility. Besides, adult flies that survived after exposure to a sub-lethal dose of C. verum EO (LD20 = 10 μg adult−1) showed a marked decrease in male and female longevity, as well as to a reduction in fecundity, fertility, and natality. Overall, C. verum and H. italicum EOs showed a highly promising insecticidal potential on two key insect vectors and pests. The relatively low prices of the selected EOs, their availability on the market and the noteworthy global production of the bulky materials, make them as ideal candidate ingredients to be used in insecticidal formulations.

SYNTHESIS, CHARACTERIZATION, CATALYTIC AND BIOLOGICAL APPLICATIONS OF SILICA SUPPORTED COPPER NANOPARTICLES

Various metal nanoparticles have been synthesized which are used in chemical as well as medicinal industry, but many of them are associated with problems. Hence, there is a need to develop a method for the synthesis of metal nanoparticles with fewer problems. Synthesized Cu/SiO2 nanoparticles have been characterized by XRD, SEM and EDS analysis. Further, their catalytic activity was estimated by various chemical reactions. Antibacterial activity, cytotoxic activity against breast cancer cell lines, acute toxicity and blood biochemical assay were determines. Particles size of Cu/SiO2 was found to be within 20-50nm. Synthesized nanoparticles were catalytically active in performed chemical reactions. Cu/SiO2 was found to be an active antibacterial against gram positive and gram negative bacteria. Acute toxicity and blood biochemical assay help to conclude that the synthesized nanoparticles are non-toxic.

Phytochemical screening, toxicity and antimicrobial action of Solanum paniculatum Linn extract against dental biofilm bacteria

The aims of study were to determine the phytochemical composition of hydroalcoholic extract of Solanum paniculatum Linn (jurubeba) root, to evaluate its in vitro antimicrobial action, as well as to determine the acute toxicity and potential cytotoxic effects of this extract. The extract was characterized by phytochemical screening and thin-layer chromatography. The following oral bacteria were used to determine the minimum inhibitory concentration (MIC): Streptococcus mitis, Streptococcus mutans, Streptococcus sanguinis, Streptococcus oralis, Streptococcus salivarius and Lactobacillus casei. Each assay was carried out in duplicate and the positive control (0.12% chlorhexidine digluconate) was subjected to the same procedure. Results were analyzed by Student t-test or Mann-Whitney test, with the level of significance set at 5%. Preclinical acute toxicity assays were performed using the median lethal dose of the extracts in animals. In addition, the cytotoxic effects of the extracts on human erythrocytes were evaluated. Solanum paniculatum showed MIC values of 7.81 mg/mL. The extract had no acute effects at concentrations of 0.97 to 500 mg/mL. The S. paniculatum extract was only cytotoxic at a concentration of 250 mg/mL. Phytochemical screening revealed predominance of phenolic compounds such as flavonoids and tannins. In conclusion, S. paniculatum Linn showed in vitro antimicrobial activity against bacterial monocultures. No toxicological effects were observed. The predominance of phenols may explain the pharmacological activity of this extract. However, randomized controlled clinical trials should be conducted to evaluate the effect of S. paniculatum added to mouthwash solution. Key words: Microbiology, phytotherapy, chromatography, toxicity, Solanum paniculatum Linn.

A preliminary investigation of the toxic effects of Benzylpenicilloic acid

Benzylpenicilloic acid (BPNLA) is a major cleavage product of benzylpenicillin G (BP) generated after heating treatment. It is found in animal derived products from the unstable residual penicillin. Previous studies have only reported the allergic reaction caused by BPNLA, but not described its toxicity. In this study, the toxicity of BPNLA was evaluated to report the potential public health risk posed by animal derived products using in vivo and in vitro models, including the acute toxicity assays, cytotoxicity assays, apoptosis assays and cell cycle progression assay. The LD50 value for BPNLA was 8.48 g/kg [bw] intraperitoneally. BPNLA showed cytotoxicity and inhibition of cell proliferation on SK-N-SH cells, MRC-5 cells and GC-1 cells. Further, Annexin-v/PI staining and Hoechst 33342 staining showed increased cell apoptosis and nucleus morphological changes with toxic levels of BPNLA. BPNLA arrested cells in G1 phase and reduced cells population in S phase in a dose-dependent manner. This work suggests that BPNLA might be a potential toxic agent and might have public health significance. However, the toxic concentrations of BPNLA are relatively high compared to levels that would result from the degradation of antibiotics residues in meat from animals that have received a therapeutic dose of benzylpenicillin.

Toxicological responses of Laeonereis acuta (Polychaeta, Nereididae) after acute, subchronic and chronic exposure to cadmium

The objective of this study was to analyze the toxicological responses of the estuarine polychaete Laeonereis acuta after acute (96h), subchronic (7 days) and chronic (14 days) exposure to cadmium (Cd). Concentrations of metallothioneins (MT), lipid peroxidation (LPO), total Cd and metal-rich granules (MRG) were evaluated. Seasonal variations of MT and LPO levels in the wild were also measured. Polychaetes were obtained in the Quequén estuary located southeast of Buenos Aires Province, Argentina. For the acute toxicity assay, individuals were exposed to 10; 30, 65; 310; 600; 1300; 2000; 4300; 8100; 16300µgCdL−1, which included levels of environmental relevance and median lethal concentrations (LC50) for related species of polychaete. Based on 96h LC50 values, polychaetes were exposed to sublethal doses of Cd. The concentrations for both subchronic and chronic assays were: 10; 30; 65; 310; 600; 1300; 2000; 4300µgCdL−1. The 96h LC50 value was 8234.9µgL−1, which was within the values reported for other species of polychaete, indicating a high tolerance to Cd. MT induction was not observed for any time exposure. In additoin, LPO levels showed no differences with respect to control levels, which indicated an absence of oxidative damage caused by Cd. However, the total Cd and MRG-Cd concentrations in L. acuta in all tested treatments showed significant differences with respect to control levels. L. acuta were able to accumulate Cd in their tissues in the form of granules which are the main mechanism of Cd detoxification.

Determination of water quality, toxicity and estrogenic activity in a nearshore marine environment in Rio de Janeiro, Southeastern Brazil

Endocrine disrupting compounds (EDCs) can be found in domestic sewage, wastewater treatment plant effluents, natural water, rivers, lakes and in the marine environment. Jurujuba Sound, located in the state of Rio de Janeiro, Southeastern Brazil, receives untreated sewage into its waters, one the main sources of aquatic contamination in this area. In this context, the aim of the present study was to evaluate the estrogenic potential of water sampled from different depths and from areas with differential contamination levels throughout Jurujuba Sound. Water quality was evaluated and acute toxicity assays using Allviibrio fischeri were conducted, while estrogenic activity of the water samples was determined by a Yeast Estrogen Screening assay (YES). Water quality was mostly within the limits established for marine waters by the Brazilian legislation, with only DOC and ammoniacal nitrogen levels above the maximum permissible limits. No acute toxicity effects were observed in the Allivibrio fisheri assay. The YES assay detected moderate estrogenic activity in bottom water samples from 3 sampling stations, ranging from 0.5 to 3.2ngL−1, as well as in one surface water sample. Estrogenic activity was most frequently observed in samples from the bottom of the water column, indicating adsorption of estrogenic compounds to the sediment.