Nematicidal activity of terpenoids

Thirty four phytoterpenoids were evaluated for their nematicidal effect using the model nematode Caenorhabditis elegans. Nematicidal activities of the tested compounds at concentrations of 50 μg/mL showed wide variation in their effects ranging from no effect, weak, moderate and strong effects. Terpenoids exerting 50% or higher mortality at 50 μg/mL were further tested at five different concentrations to calculate the concentration that will kill 50% of the nematode population (LC₅₀). Among the most effective terpenoids were carvacrol, thymol, nerolidol, α-terpinene, geraniol, citronellol, farnesol, limonene, pseudoionone and eugenol in a descending order. These compounds exhibited a dose-dependent effect. The results suggest that the selected monoterpenoids and essential oils with a high concentration of these compounds mayprovide potential natural nematicides and merit further study as botanical nematicides for the control of both plant and animal parasitic nematodes. In general, oxygenated terpenoids and phenolic terpenoids exhibited higher nematicidal activity than hydrocarbons terpenoids.     

Are deep eutectic solvents benign or toxic?

In continuation of investigation for environmentally benign protocol for new solvents termed deep eutectic solvents (DESs), it is herein reported results concerning the toxicity and cytotoxicity of choline chloride (ChCl) based DESs with four hydrogen bond donors including glycerine, ethylene glycol, triethylene glycol and urea. The toxicity was investigated using two Gram positive bacteria Bacillus subtilis and Staphylococcus aureus, and two Gram negative bacteria Escherichia coli and Pseudomonas aeruginosa. The cytotoxicity effect was tested using the Artemia salina leach. It was found that there was no toxic effect for the tested DESs on all of the studied bacteria confirming their benign effects on these bacteria. Nevertheless, it was found that the cytotoxicity of DESs was much higher than their individual components (e.g. glycerine, ChCl) indicating that their toxicological behavior is different. For our best knowledge this is the first time that toxicity and cytotoxicity of DESs were studied. The toxicity and cytotoxicity of DESs varied depending on the structure of components. Careful usage of the terms non-toxicity and biodegradability must be considered. More investigation on this matter is required.     

Adsorption of phenolic compounds from aqueous solutions by a water-compatible hypercrosslinked polymeric adsorbent

A water-compatible hypercrosslinked polymeric adsorbent (NJ-8) for adsorbing and removing phenolic compounds from their aqueous solutions was prepared. This product can be used directly without a wetting process. Its adsorption property toward four phenolic compounds, phenol, p-cresol, p-chlorophenol, and p-nitrophenol was tested using the commercial Amberlite XAD-4 as a reference. The capacities of equilibrium adsorption for all four phenolic compounds on the NJ-8 from their aqueous solutions are around two times as high as that of Amberlite XAD4 within the temperature range 283-323 K, which may contribute to their micropore structure and the partial polarity on the network. Freundlich isotherm equations, as well as relative adsorption capacities and isosteric adsorption enthalpies for the four phenolic compounds, indicate that the adsorption of phenolic compounds on the NJ-8 resin is a physical adsorption process. Mini-column adsorption studies for phenol on Amberlite XAD4 and NJ-8 resins show that the breakthrough adsorption capacities are 0.54 and 0.99 mmol/ml, and the total capacities are 0.62 and 1.37 mmol/ml, while no extra acetone was needed to remove the adsorbed phenol from NJ-8 as from Amberlite XAD4.     

Toxicity of aqueous mixture of phenol and chlorophenols upon photosensitized oxidation initiated by sunlight or vis-lamp

It is well established that aquatic wildlife in marine and freshwater of the European Union is exposed to natural and synthetic endocrine disruptor compounds (EDCs) which are able to interfere with the hormonal system causing adverse effects on the intact physiology of organisms. The traditional wastewater treatment processes are inefficient on the removal of EDCs in low concentration. Moreover, not only the efficiency of treatment must be considered but also toxicological aspects. Taking into account all these aspects, the main goal of the study was to investigate the photochemical decomposition of hazardous phenolic compounds under simulated as well as natural sunlight from the toxicity point of view. The studies were focused on photodegradation of 2,4-dichlorophenol as well as mixture of phenol, 2-chlorophenol and 2,4-dichlorophenol. Photosensitized oxidation process was carried out in homogeneous and heterogeneous system. V. fischeri luminescence inhibition was used to determine the changes of toxicity in mixture during simulated and natural irradiation. The photodegradation was carried out in three kinds of water matrix; moreover, the influence of presence of inorganic matter on the treatment process was investigated. The experiments with natural sunlight proved applicability of photosensitive chitosan for visible-light water pollutant degradation. The results of toxicity investigation show that using photosensitive chitosan for visible-light, the toxicity of reaction mixture towards V. fischeri has significantly decreased. The EC₅₀ was found to increase over the irradiation time; this increase was not proportional to the transformation of the parent compounds.     

Effects-directed analysis of organic toxicants in wastewater effluent from Zagreb, Croatia

The organic toxicants present in the effluent of the main sewer of the city of Zagreb, Croatia were isolated and identified through the use of effects-directed characterisation techniques. At the time of investigation, the wastewater effluent received no treatment and was comprised of a mixture of effluent from domestic and industrial sources. The organic load of the wastewater was isolated by solid phase extraction and toxicity profiles obtained using reverse-phase HPLC. All procedures were evaluated through the analysis of a series of reference compounds of widely differing polarity. Toxicity profiles for EROD activity (CYP1A induction), vitellogenin induction (estrogenic activity), cytotoxicity (membrane stability and metabolic inhibition) were obtained using a rainbow trout (Oncorhynchus mykiss) primary hepatocyte bioassay. The suite of bioassays showed biological responses after exposure to the raw extracts for all the endpoints tested. However, a combination of mixture toxicity and cytotoxicity in the complex raw extract had some masking effect on the sub-lethal responses of vitellogenin and EROD induction. Bioassay testing of the fine fractions obtained by HPLC produced a range of endpoint-specific toxicity profiles for each sample. A number of compounds were identified by the use of GC-MS and LC-MS/MS as responsible for the observed effects. The steroid estrogens 17 beta-estradiol and estriol were identified by LC-MS/MS as estrogen receptor agonists in two of the estrogenic fractions. In addition, GC-MS analysis identified different alkylphenols, benzophenone and methylparaben which also contributed to the estrogenic activity of the sample. Polycyclic aromatic hydrocarbons (PAHs), alkyl substituted PAHs, nitro-polycyclic aromatic compounds (nitro-PACs), carbazoles and alkyl substituted carbazoles and other known CYP1A inducers were identified by GC-MS analysis as responsible for some of the observed EROD activity. Some active compounds remain unidentified.     

Influence of fungicide residues and in vitro gastrointestinal digestion on total antioxidant capacity and phenolic fraction of Graciano and Tempranillo red wines

Abstract

The effect of fenhexamid, mepanipyrim and cyazofamid fungicides on in vitro bioavailability of antioxidant activity and phenolic compounds of Tempranillo and Graciano red wine was studied by simulating the digestive process by dialysis in semipermeable membranes. Determination of antioxidant activity was through reaction with the DPPH ? radical and the measurement of phenolic compounds was made with liquid chromatography with diode detector (HPLC-DAD). Fenhexamid, mepanipyrim and cyazofamid reduce the total polyphenol content in both wines. During dialysis there was a large loss of total polyphenols (80–90%) and of antioxidant activity (> 90%). The bioavailability of the phenolic compounds is lower than that for non-treated wines and the highest dialization percentages were found for stilbenes > 50%. While for the remaining phenolic fraction the order is the following hydroxycinnamic derivatives?>?anthocyanins?>?flavonols.     

酚类化合物对硝化颗粒污泥活性抑制的定量结构-活性相关研究

测定了酚类化合物对硝化颗粒污泥活性抑制的logIC50值,以量子化学参数为自变量,应用偏最小二乘法（PLS）,建立了酚类化合物对硝化颗粒污泥活性抑制的定量结构-活性相关（QSAR）模型。模型所提取的PLS主成分所能解释的因变量总方差的比例Qc2um为0.820,表明模型具有较好的稳定性和预测能力。模型的结果表明,影响酚类化合物对硝化颗粒污泥活性抑制的主要因素是logkow、CCR和Ehomo,酚类化合物对硝化颗粒污泥活性抑制的logIC50随着分子logkow的增大而减小,随着Ehomo和CCR的增大而增大。     

QSAR development and bioavailability determination: The toxicity of chloroanilines to the soil dwelling springtail Folsomia candida

Quantitative structure–activity relationships (QSARs) are an established tool in environmental risk assessment and a valuable alternative to the exhaustive use of test animals under REACH. In this study a QSAR was developed for the toxicity of a series of six chloroanilines to the soil-dwelling collembolan Folsomia candida in standardized natural LUFA2.2 soil. Toxicity endpoints incorporated in the QSAR were the concentrations causing 10% (EC10) and 50% (EC50) reduction in reproduction of F. candida. Toxicity was based on concentrations in interstitial water estimated from nominal concentrations in the soil and published soil–water partition coefficients. Estimated effect concentrations were negatively correlated with the lipophilicity of the compounds. Interstitial water concentrations for both the EC10 and EC50 for four compounds were determined by using solid-phase microextraction (SPME). Measured and estimated concentrations were comparable only for tetra- and pentachloroaniline. With decreasing chlorination the disparity between modelled and actual concentrations increased. Optimisation of the QSAR therefore could not be accomplished, showing the necessity to move from total soil to (bio)available concentration measurements.     

酚类化合物对硝化颗粒污泥活性抑制的定量结构 活性相关研究

测定了酚类化合物对硝化颗粒污泥活性抑制的logIC₅₀值,以量子化学参数为自变量,应用偏最小二乘法（PLS）,建立了酚类化合物对硝化颗粒污泥活性抑制的定量结构活性相关（QSAR）模型。模型所提取的PLS主成分所能解释的因变量总方差的比例Q²_cum为0.820,表明模型具有较好的稳定性和预测能力。模型的结果表明,影响酚类化合物对硝化颗粒污泥活性抑制的主要因素是logkow、CCR和E_homo,酚类化合物对硝化颗粒污泥活性抑制的logIC₅₀随着分子logkow的增大而减小,随着E_homo和CCR的增大而增大。     

Mechanistic insights into the specificity of human cytosolic sulfotransferase 2A1 (hSULT2A1) for hydroxylated polychlorinated biphenyls through the use of fluoro-tagged probes

Determining the relationships between the structures of substrates and inhibitors and their interactions with drug-metabolizing enzymes is of prime importance in predicting the toxic potential of new and legacy xenobiotics. Traditionally, quantitative structure activity relationship (QSAR) studies are performed with many distinct compounds. Based on the chemical properties of the tested compounds, complex relationships can be established so that models can be developed to predict toxicity of novel compounds. In this study, the use of fluorinated analogues as supplemental QSAR compounds was investigated. Substituting fluorine induces changes in electronic and steric properties of the substrate without substantially changing the chemical backbone of the substrate. In vitro assays were performed using purified human cytosolic sulfotransferase hSULT2A1 as a model enzyme. A mono-hydroxylated polychlorinated biphenyl (4-OH PCB 14) and its four possible mono-fluoro analogues were used as test compounds. Remarkable similarities were found between this approach and previously published QSAR studies for hSULT2A1. Both studies implicate the importance of dipole moment and dihedral angle as being important to PCB structure in respect to being substrates for hSULT2A1. We conclude that mono-fluorinated analogues of a target substrate can be a useful tool to study the structure activity relationships for enzyme specificity.     

Assessment of cytotoxicity and toxicity for phosphonium-based deep eutectic solvents

In this work, the cytotoxicity and toxicity of phosphonium-based deep eutectic solvents (DESs) with three hydrogen bond donors, namely glycerine, ethylene glycol, and triethylene glycol were investigated. The cytotoxicity effect was tested using brine shrimp (Artemia salina). The toxicity was investigated using the two Gram positive bacteria Bacillus subtilis and Staphylococcus aureus, and two Gram negative bacteria Escherichia coli and Pseudomonas aeruginosa. The cytotoxicity of tested DESs was much higher than that of their individual components, indicating their toxicological behavior was different. It was also found that there was toxic effect on the studied bacteria, indicating their potential application as anti-bacterial agents. To the best of our knowledge, this is the first time the cytotoxicity and toxicity of phosphonium-based DESs were studied.     

Safening activity of natural hydroxamic acids and analogous compounds against herbicide injury to maize

Abstract

Safening activities of natural compounds DIMBOA, DIBOA, and MBOA, as well as synthetic 1,4‐benzoxazin‐3‐ones were tested against acetochlor and EPTC injuries to maize. No safening activities of natural products and from low to moderate activity of synthetic benzoxazinones were observed. In order to explain inefficacy of natural compounds we studied the influence of these molecules on enzymes participating in metabolic detoxication of acetochlor and EPTC. Pretreatment with DIMBOA elevated maize cytochrome P450 levels. Pretreatments with chemicals containing 1,4‐benzoxazin‐3‐one backbone did not alter glutathione S‐transferase enzyme activities. However, all natural products inhibited glutathione S‐transferase activity of roots and shoots in vitro after addition to the enzyme. Safening ineffectiveness of natural hydroxamic acids may be explained by their inhibitory effects on GST enzymes due to their reaction with sulfhydryl groups on the enzyme.     

Antioxidant activity shown by olive pomace extracts

In this study, the effects of experimental variables such as type of solvent, sample/solvent ratio, and time of extraction have been evaluated to individuate the best results in phenolic recovery by Olive Pomaces (OP) belonging to Carolea and Ottobratica cultivars. Folin–Ciocaulteu procedure and DPPH and ABTS assays were used, respectively, for total phenol quantification and total antioxidant activity of pomace extracts. The ethanol/water mixture was resulted the most efficient extraction solvent for both olive cultivars. The highest amount of phenolic compounds (171 ± 4 mg of gallic acid 100 g^?1 of dry pomace) was obtained after extraction at 120 min with 2:1 solvent/OP (v/w) of Ottobratica Olive Pomace. The recovery of phenol compounds from olive wastes increases the sustainability of sector, allowing obtaining an extract that could be a suitable alternative in the food industry to the use of synthetic antioxidants in order to improve the quality of foods.     

Toxicity of fenamiphos and its metabolites to the cladoceran Daphnia carinata: the influence of microbial degradation in natural waters

The acute toxicity of an organophosphorous pesticide, fenamiphos and its metabolites, fenamiphos sulfoxide, fenamiphos sulfone, fenamiphos phenol, fenamiphos sulfoxide phenol and fenamiphos sulfone phenol, to a cladoceran, Daphnia carinata was studied in both cladoceran culture medium and natural water collected from a local river. The toxicity followed the order: fenamiphos>fenamiphos sulfone>fenamiphos sulfoxide. The hydrolysis products of fenamiphos, F. sulfoxide (FSO) and F. sulfone (FSO(2)) (F. phenol, FSO phenol and FSO(2) phenol) were not toxic to D. carinata up to 500microgl(-1) water, suggesting hydrolysis reaction leads to detoxification. Also the toxicity was reduced in natural water compared to the cladoceran culture medium due to microbial mediated degradation of toxicants in the natural water. Fenamiphos and its metabolites were stable in both cladoceran water and filter-sterilised natural water while these compounds showed degradation in unfiltered natural water implicating the microbial role in degradation of these compounds. To our knowledge this is the first study on acute toxicity of fenamiphos metabolites to cladoceran and this study suggests that the organophosphate pesticides are highly toxic to fresh water invertebrates and therefore pollution with these compounds may adversely affect the natural ecosystems.     

Ecotoxicological and chemical evaluation of phenolic compounds in industrial effluents

The aim of this paper was to evaluate the ecotoxicological response of industrial effluents containing phenolic compounds. All complex effluents collected from a chemical plant and then after both a chemical–physical and biological treatment were characterised with chemical analysis, biodegradability tests and four ecotoxicological tests (Daphnia magna, Artemia salina, Brachionus plicatilis and Vibrio fisheri with Microtox^®). The evaluation of the chemical and ecotoxicological data was useful for predicting the effect of the raw effluent on the treatment plant and the impact of the final treated effluent on the receiving water. Besides the toxicity of the effluent from the chemical plants, the acute toxicity of its main components was also determined. The results of the tests and toxicity data from literature were transformed in Toxic Units (TUs). Effluent toxicity was under- or over-estimated by calculating the sum of the TUs of the individual components, depending on which toxicity data and test organisms were used.     

Enantioselective effects of alpha-hexachlorocyclohexane (HCH) isomers on androgen receptor activity in vitro

Alpha-hexachlorocyclohexane (alpha-HCH), a part of the HCH pesticide mixture, is one of the most widespread persistent organic pollutants. Interestingly, only limited number of studies addressed the toxicity of alpha-HCH and the effects of its individual optical isomers have not been investigated in detail. In the present study we separated two alpha-HCH enantiomers by preparative HPLC and studied their activities towards androgen receptor (AR) using the MDA-kb2 cell line stably transfected with the luciferase reporter gene under the control of AR. There was no direct effect of alpha-HCH on AR but both isomers significantly suppressed the activity of AR in co-exposure with the natural ligand dihydrotestosterone in a concentration-dependent manner. One of the enantiomers appeared to be more active at lower concentration, which was also supported by the molecular modeling calculations with AR that showed a slight difference in estimated free energy of binding and inhibition constant between two enantiomers. Although studies with other pesticides demonstrated strong enantioselective differences in toxicity, the present research shows rather minor differences in modulations of AR by both alpha-HCH enantiomers. For the first time, enantioselective effects of alpha-HCH were demonstrated and the results suggest interaction with multiple regulatory events controlling the AR activity. Full elucidation of the toxicity mechanism will require further research.     

Lactate dehydrogenase activity as an effect criterion in toxicity tests with Daphnia magna straus.

Activity of lactate dehydrogenase (LDH) was used as an effect criterion in toxicity tests with Daphnia magna. In the first part of the work, the conditions for the use of LDH activity in toxicity tests with juveniles and adults of D. magna, were optimized. The influence of parameters such as the number of animals per sample, nutritional status, age and the presence of eggs in the brood chamber were investigated. In the second part of the study, both in vivo and in vitro tests based on the alteration of LDH activity of D. magna were developed and tested using zinc chloride as test substance. The results obtained indicate that LDH activity of D. magna may be used as an indicative parameter in aquatic toxicity tests.