Preliminary hazard assessment of a new nature-inspired antifouling (NIAF) agent

A recently synthesized aminated 3,4-dioxygenated xanthone (Xantifoul2) was found to have promising antifouling (AF) effects against the settlement of the macrofouler Mytilus galloprovincialis larvae. Preliminary assessment indicated that Xantifoul2 has reduced ecotoxicological impacts: e.g., being non-toxic to the marine crustacea Artemia salina (<10 % mortality at 50 μM) and showing low bioconcentration factor in marine organisms. In order to meet the EU Biocidal Product Regulation, a preliminary hazard assessment of this new nature-inspired antifouling (NIAF) agent was accomplished in this work. Xantifoul2 did not affect the swimming ability of the planktonic crustacean Daphnia magna, the growth of the diatom Phaeodactylum tricornutum, and the cellular respiration of luminescent Gram-negative bacteria Vibrio fischeri, supporting the low toxicity towards several non-target marine species. Regarding human cytotoxicity, Xantifoul2 did not affect the cell viability of retinal human cells (hTERT-RPE-1) and lipidomic studies revealed depletion of lipids involved in cell death, membrane modeling, lipid storage, and oxidative stress only at a high concentration (10 μM). Accelerated degradation studies in water were conducted under simulated sunlight to allow the understanding of putative transformation products (TPs) that could be generated in the aquatic ecosystems. Both Xantifoul2 and photolytic-treated Xantifoul2 in the aqueous matrix were therefore evaluated on several nuclear receptors (NRs). The results of this preliminary hazard assessment of Xantifoul2, combined with the high degradation rates in water, provide strong evidence of the safety of this AF agent under the evaluated conditions, and provide the support for future validation studies before this compound can be introduced in the market.

Milligram scale enantioresolution of promethazine and its main metabolites, determination of their absolute configuration and assessment of enantioselective effects on human SY-SY5Y cells

The misuse of pharmaceuticals has significantly increased in recent decades, becoming a major public health concern. The risks associated with medication misuse are particularly high in cases of overdose, especially when the active substances are chiral, as enantioselectivity plays an important role in toxicity. Promethazine (PMZ) is a chiral antihistamine marketed as a racemate and it is misused in "Purple Drank", a recreational drug beverage, that combines codeine and/or PMZ, with soda or alcohol leading to serious health consequences and fatalities in consumers around the world, particularly among teenagers. Information regarding the enantioselectivity in the toxicity of (R,S)-PMZ and its main metabolites, namely promethazine sulfoxide (PMZSO) and desmonomethyl promethazine (DMPMZ), is unknown. This work reported, for the first time, the enantioseparation, in milligram scale, of (R,S)-PMZ, (R,S)-DMPMZ, (R,S)- PMZSO and the determination of their absolute configurations by electronic circular dichroism (ECD). The enantioseparation of all the six enantiomers was accomplished in a homemade semi-preparative column with amylose tris-3,5-dimethylphenylcarbamate (AD) coated with aminopropyl Nucleosil silica. The enantiomeric purity was evaluated using the analytical Lux® 3 µm i-Amylose-3 column, yielding enantiomeric purity values ranging between 94.4% and 99.7%. The elution order of all the enantiomers was accomplished combining the ECD results with an optical rotation detector. The elution order of the enantiomers was influenced only by the chiral selector, rather than the mobile phase. The cytotoxicity of the racemates and the isolated enantiomers towards differentiated SH-SY5Y cells was evaluated. (R,S)-DMPMZ exhibited a significantly higher cytotoxicity than (R,S)-PMZ, suggesting the metabolic bioactivation of (R,S)-PMZ. Conversely, no significant cytotoxicity was found for (R,S)-PMZSO, underscoring a metabolic detoxification pathway. Remarkably, enantioselectivity was observed for the cytotoxicity of PMZ; (R)-PMZ was significantly more cytotoxic than (S)-PMZ. The results underscore the importance to isolate the enantiomers in their enantiomerically form and their correct identification for toxicity enantioselectivity studies, which are vital to understand the drug's behaviour and safety, especially in case of overdoses.

Toxicity of butylone and its enantiomers to Daphnia magna and its degradation/toxicity potential using advanced oxidation technologies

Butylone (BTL) is a chiral synthetic cathinone available as a racemate and reported as contaminant in wastewater effluents. However, there are no studies on its impact on ecosystems and possible enantioselectivity in ecotoxicity. This work aimed to evaluate: (i) the possible ecotoxicity of BTL as racemate or its isolated (R)- and (S)- enantiomers using Daphnia magna; and (ii) the efficiency of advanced oxidation technologies (AOTs) in the removal of BTL and reduction of toxic effects caused by wastewaters. Enantiomers of BTL were obtained by liquid chromatography (LC) using a chiral semi-preparative column. Enantiomeric purity of each enantiomer was > 97 %. For toxicity assessment, a 9-day sub-chronic assay was performed with the racemate (at 0.10, 1.0 or 10 μg L-1) or each enantiomer (at 0.10 or 1.0 μg L-1). Changes in morphophysiological, behavioural, biochemical and reproductive endpoints were observed, which were dependent on the form of the substance and life stage of the organism (juvenile or adult). Removal rates of BTL in spiked wastewater (10 μg L-1) treated with different AOTs (ultraviolet, UV; ozonation, O3; and UV/O3) were similar and lower than 29 %. The 48 h D. magna acute toxicity assays demonstrated a reduction in the toxicity of the treated spiked effluents, but no differences were found amongst AOTs treatments. These results warn for the contamination and negative impact of BTL on ecosystems and highlight the need for efficient removal processes.

Enantioselectivity in ecotoxicity of pharmaceuticals, illicit drugs, and industrial persistent pollutants in aquatic and terrestrial environments: A review

At present, there is a serious concern about the alarming number of recalcitrant contaminants that can negatively affect biodiversity threatening the ecological status of marine, estuarine, freshwater, and terrestrial ecosystems (e.g., agricultural soils and forests). Contaminants of emerging concern (CEC) such as pharmaceuticals (PHAR), illicit drugs (ID), industrial persistent pollutants, such as polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) and chiral ionic solvents are globally spread and potentially toxic to non-target organisms. More than half of these contaminants are chiral and have been measured at different enantiomeric proportions in diverse ecosystems. Enantiomers can exhibit different toxicodynamics and toxicokinetics, and thus, can cause different toxic effects. Therefore, the enantiomeric distribution in occurrence cannot be neglected as the toxicity and other adverse biological effects are expected to be enantioselective. Hence, this review aims to reinforce the recognition of the stereochemistry in environmental risk assessment (ERA) of chiral CEC and gather up-to-date information about the current knowledge regarding the enantioselectivity in ecotoxicity of PHAR, ID, persistent pollutants (PCBs and PBDEs) and chiral ionic solvents present in freshwater and agricultural soil ecosystems. We performed an online literature search to obtain state-of-the-art research about enantioselective studies available for assessing the impact of these classes of CEC. Ecotoxicity assays have been carried out using organisms belonging to different trophic levels such as microorganisms, plants, invertebrates, and vertebrates, and considering ecologically relevant aquatic and terrestrial species or models organisms recommended by regulatory entities. A battery of ecotoxicity assays was also reported encompassing standard acute toxicity to sub-chronic and chronic assays and different endpoints as biomarkers of toxicity (e.g., biochemical, morphological alterations, reproduction, behavior, etc.). Nevertheless, we call attention to the lack of knowledge about the potential enantioselective toxicity of many PHAR, ID, and several classes of industrial compounds. Additionally, several questions regarding key species, selection of most appropriate toxicological assays and ERA of chiral CEC are addressed and critically discussed.

Evaluation of Antitumor Activity of Xanthones Conjugated with Amino Acids

Cancer is a complex disease characterized by several alterations, which confer, to the cells, the capacity to proliferate uncontrollably and to resist cellular death. Multiresistance to conventional chemotherapy drugs is often the cause of treatment failure; thus, the search for natural products or their derivatives with therapeutic action is essential. Chiral derivatives of xanthones (CDXs) have shown potential inhibitory activity against the growth of some human tumor cell lines. This work reports the screening of a library of CDXs, through viability assays, in different cancer cell lines: A375-C5, MCF-7, NCI-H460, and HCT-15. CDXs' effect was analyzed based on several parameters of cancer cells, and it was also verified if these compounds were substrates of glycoprotein-P (Pgp), one of the main mechanisms of resistance in cancer therapy. Pgp expression was evaluated in all cell lines, but no expression was observed, except for HCT-15. Also, when a humanized yeast expressing the human gene MDR1 was used, no conclusions could be drawn about CDXs as Pgp substrates. The selected CDXs did not induce significant differences in the metabolic parameters analyzed. These results show that some CDXs present promising antitumor activity, but other mechanisms should be triggered by these compounds.

Binding studies of synthetic cathinones to human serum albumin by high-performance affinity chromatography

The binding affinity to human serum albumin (HSA) of a series of fourteen synthetic cathinones, new psychoactive substances widely abused, was investigated by high-performance affinity chromatography (HPAC). Zonal elution experiments were conducted to measure the retention times of each synthetic cathinone on an HSA column, which enabled the calculation of the percentage of the drug bound. For some synthetic cathinones, enantioselectivity on HSA was found. To gather information on the HSA binding sites and better understand the chiral recognition mechanisms, enantioresolution of selected cathinones was carried out at a milligram scale through liquid chromatography (LC) with carbamate polysaccharide-based columns. This work was followed by zonal displacement chromatography using known competitors with specific binding sites on HSA, namely (S)-ibuprofen and warfarin. Competition was observed between the tested drugs and both competitors (except for pentedrone with warfarin), which is consistent with an allosteric competition involving a non-cooperative binding mechanism.

Synthesis and Anti-Inflammatory Evaluation of a Library of Chiral Derivatives of Xanthones Conjugated with Proteinogenic Amino Acids

In recent decades, the relationship between drug chirality and biological activity has been assuming enormous importance in medicinal chemistry. Particularly, chiral derivatives of xanthones (CDXs) have interesting biological activities, including enantioselective anti-inflammatory activity. Herein, the synthesis of a library of CDXs is described, by coupling a carboxyxanthone (1) with both enantiomers of proteinogenic amino esters as chiral building blocks (2-31), following the chiral pool strategy. The coupling reactions were performed at room temperature with good yields (from 44 to 99.9%) and very high enantiomeric purity, with most of them presenting an enantiomeric ratio close to 100%. To afford the respective amino acid derivatives (32-61), the ester group of the CDXs was hydrolyzed in mild alkaline conditions. Consequently, in this work, sixty new derivatives of CDXs were synthetized. The cytocompatibility and anti-inflammatory activity in the presence of M1 macrophages were studied for forty-four of the new synthesized CDXs. A significant decrease in the levels of a proinflammatory cytokine targeted in the treatment of several inflammatory diseases, namely interleukin 6 (IL-6), was achieved in the presence of many CDXs. The amino ester of L-tyrosine (X1AELT) was the most effective in reducing IL-6 production (52.2 ± 13.2%) by LPS-stimulated macrophages. Moreover, it was ≈1.2 times better than the D-enantiomer. Indeed, enantioselectivity was observed for the majority of the tested compounds. Thus, their evaluation as promising anti-inflammatory drugs should be considered.

Enantioselectivity in ecotoxicity of amphetamine using Daphnia magna as aquatic model organism: morphophysiological, behavioural, reproductive and biochemical parameters

Amphetamine (AMP) is a chiral psychoactive substance which exhibits enantioselectivity in its pharmacological properties. AMP has been detected in wastewaters and surface waters and can occur as enantiomeric mixtures, but little is known about its environmental risk and potential enantioselective toxicity to aquatic organisms. This study aimed to target enantioselectivity in AMP toxicity on the freshwater invertebrate Daphnia magna. Daphnids were sub-chronically exposed to the racemate (rac-AMP: 0.1, 1.0, and 10 µg/L) and pure enantiomers, (R)-AMP and (S)-AMP (0.1, and 1.0 µg/L), for 8 days. Morphophysiological, swimming behaviour, reproductive and biochemical variables were evaluated during critical life-stages (juveniles vs adults). Some responses were context-dependent and often enantioselective varying between racemate and enantiomers and across the life stage of the organisms. Overall, rac-AMP stimulated D. magna growth, decreased heart rate and area, affected behaviour, and stimulated reproduction. The effect of enantiomers was totally or partially concordant to rac-AMP, except for swimming behaviour and reproduction. Enantioselectivity was observed for body size and number of eggs per daphnia, and heart rate (steeper decrease caused by (R)-AMP at day 3). Changes in biochemical parameters were also observed: AMP caused a significant decrease in catalase activity as racemate or pure enantiomers, whereas a decrease in acetylcholinesterase activity was found only for rac-AMP. Evidence on oxidative stress was contradictory, although both enantiomers caused a significant decrease in reactive oxygen species (unlike rac-AMP). Overall, these results show that AMP can interfere in an enantioselective way with aquatic organisms at low concentrations (e.g., 0.1 µg/L), demonstrating the relevance of this kind of studies for an accurate environmental risk assessment regarding medium- to long-term exposure to this psychoactive drug.

Added-Value Compounds in Cork By-Products: Methods for Extraction, Identification, and Quantification of Compounds with Pharmaceutical and Cosmetic Interest

The growing threat of climatic crisis and fossil fuel extinction has caused a boom in sustainability trends. Consumer demand for so-called eco-friendly products has been steadily increasing, built upon the foundation of environmental protection and safeguarding for future generations. A natural product that has been used for centuries is cork, resulting from the outer bark of Quercus suber L. Currently, its major application is the production of cork stoppers for the wine industry, a process that, although considered sustainable, generates by-products in the form of cork powder, cork granulates, or waste such as black condensate, among others. These residues possess constituents of interest for the cosmetic and pharmaceutical industries, as they exhibit relevant bioactivities, such as anti-inflammatory, antimicrobial, and antioxidant. This interesting potential brings forth the need to develop methods for their extraction, isolation, identification, and quantification. The aim of this work is to describe the potential of cork by-products for the cosmetic and pharmaceutical industry and to assemble the available extraction, isolation, and analytical methods applied to cork by-products, as well the biological assays. To our knowledge, this compilation has never been done, and it opens new avenues for the development of new applications for cork by-products.

Integrated Approach for Synthetic Cathinone Drug Prioritization and Risk Assessment: In Silico Approach and Sub-Chronic Studies in Daphnia magna and Tetrahymena thermophila

Synthetic cathinones (SC) are drugs of abuse that have been reported in wastewaters and rivers raising concern about potential hazards to non-target organisms. In this work, 44 SC were selected for in silico studies, and a group of five emerging SC was prioritized for further in vivo ecotoxicity studies: buphedrone (BPD), 3,4-dimethylmethcathinone (3,4-DMMC), butylone (BTL), 3-methylmethcathinone (3-MMC), and 3,4-methylenedioxypyrovalerone (MDPV). In vivo short-term exposures were performed with the protozoan Tetrahymena thermophila (28 h growth inhibition assay) and the microcrustacean Daphnia magna by checking different indicators of toxicity across life stage (8 days sublethal assay at 10.00 µg L^-1). The in silico approaches predicted a higher toxic potential of MDPV and lower toxicity of BTL to the model organisms (green algae, protozoan, daphnia, and fish), regarding the selected SC for the in vivo experiments. The in vivo assays showed protozoan growth inhibition with MDPV > BPD > 3,4-DMMC, whereas no effects were observed for BTL and stimulation of growth was observed for 3-MMC. For daphnia, the responses were dependent on the substance and life stage. Briefly, all five SC interfered with the morphophysiological parameters of juveniles and/or adults. Changes in swimming behavior were observed for BPD and 3,4-DMMC, and reproductive parameters were affected by MDPV. Oxidative stress and changes in enzymatic activities were noted except for 3-MMC. Overall, the in silico data agreed with the in vivo protozoan experiments except for 3-MMC, whereas daphnia in vivo experiments showed that at sublethal concentrations, all selected SC interfered with different endpoints. This study shows the importance to assess SC ecotoxicity as it can distress aquatic species and interfere with food web ecology and ecosystem balance.

Toxicity of the 3,4-Methylenedioxymethamphetamine and Its Enantiomers to Daphnia magna after Isolation by Semipreparative Chromatography

MDMA (3,4-methylenedioxymethamphetamine) is a chiral psychoactive recreational drug sold in illicit markets as racemate. Studies on the impact of MDMA on aquatic organisms are scarce. While enantioselectivity in toxicity in animals and humans has been reported, none is reported on aquatic organisms. This study aimed to investigate the ecotoxicological effects of MDMA and its enantiomers in Daphnia magna. For that, enantiomers (enantiomeric purity > 97%) were separated by liquid chromatography using a homemade semipreparative chiral column. Daphnids were exposed to three concentrations of (R,S)-MDMA (0.1, 1.0 and 10.0 µg L^-1) and two concentrations of (R)- and (S)-enantiomers (0.1 and 1.0 µg L^-1) over the course of 8 days. Morphophysiological responses were dependent on the substance form and daphnia development stage, and they were overall not affected by the (R)-enantiomer. Changes in swimming behaviour were observed for both the racemate and its enantiomers, but enantioselective effects were not observed. Reproductive or biochemical changes were not observed for enantiomers whereas a significant decrease in acetylcholinesterase and catalase activity was noted at the highest concentration of (R,S)-MDMA (10 µg L^-1). Overall, this study showed that sub-chronic exposure to MDMA racemate and its enantiomers can interfere with morphophysiological and swimming behaviour of D. magna. In general, the (R)-enantiomer demonstrated less toxicity than the (S)-enantiomer.

Stereoselective Synthesis of Flavonoids: A Brief Overview

Stereoselective synthesis has been emerging as a resourceful tool because it enables the obtaining of compounds with biological interest and high enantiomeric purity. Flavonoids are natural products with several biological activities. Owing to their biological potential and aiming to achieve enantiomerically pure forms, several methodologies of stereoselective synthesis have been implemented. Those approaches encompass stereoselective chalcone epoxidation, Sharpless asymmetric dihydroxylation, Mitsunobu reaction, and the cycloaddition of 1,4-benzoquinone. Chiral auxiliaries, organo-, organometallic, and biocatalysis, as well as the chiral pool approach were also employed with the goal of obtaining chiral bioactive flavonoids with a high enantiomeric ratio. Additionally, the employment of the Diels-Alder reaction based on the stereodivergent reaction on a racemic mixture strategy or using catalyst complexes to synthesise pure enantiomers of flavonoids was reported. Furthermore, biomimetic pathways displayed another approach as illustrated by the asymmetric coupling of 2-hydroxychalcones driven by visible light. Recently, an asymmetric transfer hydrogen-dynamic kinetic resolution was also applied to synthesise (R,R)-cis-alcohols which, in turn, would be used as building blocks for the stereoselective synthesis of flavonoids.

On the Bioactivity of Echinacea purpurea Extracts to Modulate the Production of Inflammatory Mediators

Inflammatory diseases are the focus of several clinical studies, due to limitations and serious side effects of available therapies. Plant-based drugs (e.g., salicylic acid, morphine) have become landmarks in the pharmaceutical field. Therefore, we investigated the immunomodulatory effects of flowers, leaves, and roots from Echinacea purpurea. Ethanolic (EE) and dichloromethanolic extracts (DE) were obtained using the Accelerated Solvent Extractor and aqueous extracts (AE) were prepared under stirring. Their chemical fingerprint was evaluated by liquid chromatography-high resolution mass spectrometry (LC-HRMS). The pro- and anti-inflammatory effects, as well as the reduction in intracellular reactive oxygen and nitrogen species (ROS/RNS), of the different extracts were evaluated using non-stimulated and lipopolysaccharide-stimulated macrophages. Interestingly, AE were able to stimulate macrophages to produce pro-inflammatory cytokines (tumor necrosis factor -TNF-α, interleukin -IL-1β, and IL-6), and to generate ROS/RNS. Conversely, under an inflammatory scenario, all extracts reduced the amount of pro-inflammatory mediators. DE, alkylamides-enriched extracts, showed the strongest anti-inflammatory activity. Moreover, E. purpurea extracts demonstrated generally a more robust anti-inflammatory activity than clinically used anti-inflammatory drugs (dexamethasone, diclofenac, salicylic acid, and celecoxib). Therefore, E. purpurea extracts may be used to develop new effective therapeutic formulations for disorders in which the immune system is either overactive or impaired.

Quantification of a Sulfated Marine-Inspired Antifouling Compound in Several Aqueous Matrices: Biodegradation Studies and Leaching Assays from Polydimethylsiloxane Coatings

The development of marine-inspired compounds as non-toxic antifouling (AF) agents has been pursued in the last years. Sulfur is the third most common element in seawater. Sulfur is present in oxygenated seawater as sulfate anion (SO₄²⁻), which is the most stable combination of sulfur in seawater, and several promising AF secondary metabolites with sulfate groups have been described. However, sulfated compounds proved to be an analytical challenge to quantify by HPLC. Taking these facts into consideration, this work presents the development and validation of a method for the quantification of gallic acid persulfate (GAP) in seawater and ultrapure water matrix, based on hydrophilic interaction liquid chromatography (HILIC). This method was used to evaluate GAP stability following several abiotic and biotic degradation assays, and to quantify its release in seawater from room-temperature-vulcanizing polydimethylsiloxane commercial coating. GAP was very stable in several water matrices, even at different pH values and in the presence/absence of marine microorganisms and presented a leaching value lower than 0.5%. This work discloses HILIC as an analytical method to overcome the difficulties in quantifying sulfated compounds in water matrices and highlights the potential of GAP as a promising long-lasting coating.

Enantioselective Ecotoxicity of Venlafaxine in Aquatic Organisms: Daphnia and Zebrafish

Venlafaxine is a chiral antidepressant detected in aquatic compartments. It was recently included in the 3rd Watch List from the European Union. The present study aimed to investigate venlafaxine toxicity effects, targeting possible enantioselective effects, using two aquatic organisms, daphnia (Daphnia magna) and zebrafish (Danio rerio). Specimens were exposed to both racemate, (R,S)-venlafaxine (VEN), and to pure enantiomers. Acute assays with daphnia showed that up to 50 000 μg/L of the (R,S)-VEN induced no toxicity. Organisms were also exposed to sublethal concentrations (25-400 μg/L) of (R,S)-, (R)- and (S)-VEN, for 21 days. No significant effects on mortality, age at first reproduction, and size of the first clutch were observed. However, a decrease in fecundity was observed for both enantiomers at the highest concentration. Regarding zebrafish, the effects of venlafaxine on mortality, embryo development, behavior, biochemistry, and melanin pigmentation were investigated after 96 h of exposure to the range of 0.3-3000 μg/L. (R)-VEN significantly increased the percentage of malformations in comparison with (S)-VEN. Behavior was also enantiomer dependent, with a decrease in the total distance moved and an increase in avoidance behavior observed in organisms exposed to (R)-VEN. Despite the biochemical variations, no changes in redox homeostasis were observed. (R)-VEN also led to an increase in zebrafish pigmentation. The different susceptibility to venlafaxine and enantioselective effects were observed in zebrafish. Our results suggest that at environmental levels (R,S)-VEN and pure enantiomers are not expected to induce harmful effects in both organisms, but (R)-VEN increased malformations in zebrafish larvae, even at reported environmental levels. These results highlight the importance of including enantioselective studies for an accurate risk assessment of chiral pollutants. Environ Toxicol Chem 2022;41:1851-1864. © 2022 SETAC.

Analytical Methods for Determination of BPA Released from Dental Resin Composites and Related Materials: A Systematic Review

Knowing the impacts of bisphenol A (BPA) on human health, this systematic review aimed to gather the analytical methods for the quantification of BPA release of BPA in dental materials in in vitro and in vivo (biological fluids) studies. A brief critical discussion of the impacts of BPA on human health and the possible association with BPA in dental materials was also presented. The research was carried out by three independent researchers, (according to PRISMA guidelines) in PUBMED and SCOPUS databases, by searching for specific keywords and articles published between January 2011 and February 2022. Seventeen articles met the eligibility criteria and were included in this systematic review: 10 in vitro and 7 in vivo. In in vitro studies, the highest amounts of BPA released were from flowable to conventional resins, followed by resin-modified glass ionomer. In contrast, the smallest amount was released from "BPA-free" composites and CAD-CAM blocks. Regarding in vivo studies, a higher concentration of BPA were found in saliva than urine or blood. The best analytical method for trace quantifying BPA is LC-MS/MS (Liquid Chromatography with Tandem Mass Spectrometry) due to its selectivity, low quantification limits, and the unequivocal identification. However, further studies are required to develop faster and more sensitive methods, in order to obtain more reliable results.

Development and evaluation of Pirkle-type chiral stationary phase for flash chromatography

Liquid chromatography is the most applied methodology for enantioseparation in preparative and semi-preparative scale; however, flash chromatography is seldom the first choice. This work proposes a new sustainable method to achieve pure enantiomers in mg scale. Herein, the functionalization of silica for flash chromatography columns with a suitable chiral selector, for subsequent quantitative enantioseparation of chiral compounds, is described. Accordingly, the Whelk-O®1 chiral selector was bonded to flash silica and packed into a reused solid phase extraction cartridge. For the evaluation of the enantioselective performance of the flash column, the enantiomers of a chiral derivative of xanthone were quantitatively enantioseparated with an average recovery of 70% and an enantiomer ratio (e.r.) of 99% and 97% for each enantiomer. Evaluation with the anti-inflammatory drug naproxen was also performed, resulting in an average recovery of 95% and 89% and 95% e.r. for each enantiomer. The flash column showed high stability and load ability, versatility, and good reproducibility.

Erythrocyte-derived liposomes for the treatment of inflammatory diseases

Effective and safe therapies to counteract persistent inflammation are necessary. We developed erythrocyte-derived liposomes (EDLs) with intrinsic anti-inflammatory activity. The EDLs were prepared using lipids extracted from erythrocyte membranes, which are rich in omega-3 fatty acids with several health benefits. Diclofenac, a widely used anti-inflammatory drug, was incorporated into EDLs in relevant therapeutic concentrations. The EDLs were also functionalized with folic acid to allow their active targeting of M1 macrophages, which are key players in inflammatory processes. In the presence of lipopolysaccharide (LPS)-stimulated macrophages, empty EDLs and EDLs incorporating diclofenac were able to reduce the levels of important pro-inflammatory cytokines, namely interleukin-6 (IL-6; ≈85% and 77%, respectively) and tumor necrosis factor-alpha (TNF-α; ≈64% and 72%, respectively). Strikingly, cytocompatible concentrations of EDLs presented similar effects to dexamethasone, a potent anti-inflammatory drug, in reducing IL-6 and TNF-α concentrations, demonstrating the EDLs potential to be used as bioactive carriers in the treatment of inflammatory diseases.

Ketamine and Norketamine: Enantioresolution and Enantioselective Aquatic Ecotoxicity Studies

Ketamine is a chiral drug used for various clinical purposes but often misused. It is metabolized to norketamine, an active chiral metabolite. Both substances have been detected in environmental matrices, but studies about their enantioselective toxic effects are scarce. In the present study, the enantiomers of ketamine and norketamine were separated by a semipreparative enantioselective liquid chromatography method, and their toxicity was investigated in different aquatic organisms. The enantioseparation was achieved using a homemade semipreparative chiral column. Optimized conditions allowed the recovery of compounds with enantiomeric purity higher than 99%, except for (R)-ketamine (97%). The absolute configuration of the enantiomers was achieved by experimental electronic circular dichroism (ECD). The ecotoxicity assays were performed with the microcrustacean Daphnia magna and the protozoan Tetrahymena thermophila using Toxkit MicroBioTests. Different concentrations were tested (0.1-10 000 µg/L) to include environmental levels (~0.5-~100 µg/L), for racemates (R,S) and the isolated enantiomers (R or S) of ketamine and norketamine. No toxicity was observed in either organism at environmental levels. However, at greater concentrations, (R,S)-ketamine presented higher mortality for D. magna compared with its metabolite (R,S)-norketamine (85 and 20%, respectively), and the (S)-ketamine enantiomer showed higher toxicity than the (R)-ketamine enantiomer. In addition, (S)-ketamine also presented higher growth inhibition than (R)-ketamine for T. thermophila at the highest concentrations (5000 and 10 000 µg/L). Contrary to D. magna, growth inhibition was observed for both enantiomers of norketamine and in the same magnitude order of the (S)-ketamine enantiomer. The results showed that the 2 organisms had different susceptibilities to norketamine and that the toxicity of ketamine at high concentrations is enantioselective for both organisms. Environ Toxicol Chem 2022;41:569-579. © 2020 SETAC.

Assessment of effluents quality through ecotoxicological assays: evaluation of three wastewater treatment plants with different technologies

The water quality of the effluents is mainly focused on physicochemical and microbiological parameters. However, the ecotoxicological assessments are crucial to ensure an effective water quality of the effluents. This work aims to assess the ecotoxicity of effluents originated from WWTPs with different wastewater treatment technologies. For that, effluent samples from three WWTPs with different treatment processes were seasonally collected. Physicochemical parameters were determined, the toxicity towards daphnia, protozoan, and microalgae organisms was evaluated, and data correlated. Toxicity assays showed different susceptibility of the organisms to the effluents and that toxicity is dependent on the season and wastewater treatment technology. No toxicity was observed to daphnia in winter and spring, but ~100% of mortality was observed in effluent from WWTP A in summer. Growth inhibition was observed for both protozoan and microalgae for all effluents and in all seasons with highest values in spring in WWTP C (~80%) for the protozoan while the highest microalgae growth inhibition percentage was observed for WWTP B in both spring (~80%) and summer (~80%). These results show that effluents might have negative impacts into their receiving water systems and highlight that a global assessment of effluent quality should include ecotoxicological assays to complement physicochemical and microbiological data for an operative environmental management of wastewater treatment plants.

Chiral Flavonoids as Antitumor Agents

Flavonoids are a group of natural products with a great structural diversity, widely distributed in plant kingdom. They play an important role in plant growth, development and defense against aggressors. Flavonoids show a huge variety of biological activities such as antioxidant, anti-inflammatory, anti-mutagenic, antimicrobial and antitumor, being able to modulate a large diversity of cellular enzymatic activities. Among natural flavonoids, some classes comprise chiral molecules including flavanones, flavan-3-ols, isoflavanones, and rotenoids, which have one or more stereogenic centers. Interestingly, in some cases, individual compounds of enantiomeric pairs have shown different antitumor activity. In nature, these compounds are mainly biosynthesized as pure enantiomers. Nevertheless, they are often isolated as racemates, being necessary to carry out their chiral separation to perform enantioselectivity studies. Synthetic chiral flavonoids with promising antitumor activity have also been obtained using diverse synthetic approaches. In fact, several new chiral bioactive flavonoids have been synthesized by enantioselective synthesis. Particularly, flavopiridol was the first cyclin-dependent kinase (CDK) inhibitor which entered clinical trials. The chiral pool approaches using amino acid as chiral building blocks have also been reported to achieve small libraries of chrysin derivatives with more potent in vitro growth inhibitory effect than chrysin, reinforcing the importance of the introduction of chiral moieties to improve antitumor activity. In this work, a literature review of natural and synthetic chiral flavonoids with antitumor activity is reported for the first time.

Microfluidicmixing system for precise PLGA-PEG nanoparticles size control

In this study, a microfluidic device was employed to produce polymeric nanoparticles (NPs) with well-controlled sizes. The influence of several parameters in the synthesis process, namely, polymer concentration, flow rate and flow rate ratio between the aqueous and organic solutions was investigated. To evaluate the NPs size effect, three diameters were selected (30, 50 and 70nm). Their cytocompatibility was demonstrated on endothelial cells and macrophages. Additionally, their efficacy to act as drug carriers was assessed in an in vitro inflammatory scenario. NPs loaded and released diclofenac (DCF) in a size-dependent profile (smaller sizes presented lower DCF content and higher release rate). Moreover, 30nm NPs were the most effective in reducing prostaglandin E₂ concentration. Therefore, this study demonstrates that microfluidics can generate stable NPs with controlled sizes, high monodispersity and enhanced batch-to-batch reproducibility. Indeed, NPs size is a crucial parameter for drug encapsulation, release and overall biological efficacy.

Wastewater analysis of psychoactive drugs: Non-enantioselective vs enantioselective methods for estimation of consumption

The consumption of licit and illicit psychoactive drugs (PAD) is ubiquitous in all communities and a serious public health problem. Measuring drug consumption is difficult but essential for health-care professionals, risk assessment and policymakers. Different sources of information have been used for a comprehensive analysis of drug consumption. Among them, Wastewater based epidemiology (WBE) emerged as an essential and complementary methodology for estimating licit and illicit drugs consumption. This methodology can be used for quantification of unchanged drugs or their human-specific metabolites in wastewater for estimation of consumption or screening of new PAD. Although some limitations are still being pointed out (e.g., estimation of the population size, use of suitable biomarkers or pharmacokinetics studies), the non-invasive and potential for monitoring real-time data on geographical and temporal trends in drug use have been showing its capacity as a routine and complementary tool. Chromatographic methods, both non-enantioselective and enantioselective are the analytical tools used for quantification of PAD in wastewaters and further estimation of consumption. Therefore, this manuscript aims to summarize and critically discuss the works used for wastewater analysis of PAD based on WBE using non-enantioselective and enantioselective methods for estimation of consumption. Non-enantioselective methods are among the most reported including for chiral PAD. Nevertheless, a trend has been seen towards the development of enantioselective methods as most PAD are chiral and determination of the enantiomeric fraction can provide additional information (e.g., distinction between consumption or direct disposal, or manufacture processes) and fulfill some WBE gaps.

Enantioselectivity in Drug Pharmacokinetics and Toxicity: Pharmacological Relevance and Analytical Methods

Enzymes, receptors, and other binding molecules in biological processes can recognize enantiomers as different molecular entities, due to their different dissociation constants, leading to diverse responses in biological processes. Enantioselectivity can be observed in drugs pharmacodynamics and in pharmacokinetic (absorption, distribution, metabolism, and excretion), especially in metabolic profile and in toxicity mechanisms. The stereoisomers of a drug can undergo to different metabolic pathways due to different enzyme systems, resulting in different types and/or number of metabolites. The configuration of enantiomers can cause unexpected effects, related to changes as unidirectional or bidirectional inversion that can occur during pharmacokinetic processes. The choice of models for pharmacokinetic studies as well as the subsequent data interpretation must also be aware of genetic factors (such as polymorphic metabolic enzymes), sex, patient age, hepatic diseases, and drug interactions. Therefore, the pharmacokinetics and toxicity of a racemate or an enantiomerically pure drug are not equal and need to be studied. Enantioselective analytical methods are crucial to monitor pharmacokinetic events and for acquisition of accurate data to better understand the role of the stereochemistry in pharmacokinetics and toxicity. The complexity of merging the best enantioseparation conditions with the selected sample matrix and the intended goal of the analysis is a challenge task. The data gathered in this review intend to reinforce the importance of the enantioselectivity in pharmacokinetic processes and reunite innovative enantioselective analytical methods applied in pharmacokinetic studies. An assorted variety of methods are herein briefly discussed.

An integrative review on the toxicity of Bisphenol A (BPA) released from resin composites used in dentistry

The main aim of this study was to perform an integrative review on the release of bisphenol A (BPA) from resin-matrix composites and potential toxic effects. A bibliographic search was performed on the PubMed platform using the following keywords: "Bisphenol A" OR "BPA" AND "resin composite" OR "composite resin" AND "toxicity" OR "cytotoxicity" OR "release". Inclusion criteria involved in vitro and in vivo studies on the release and toxicity of BPA. Results highlighted the release of BPA from resin-matrix composites due to insufficient polymerization and/or degradation of the polymeric matrix. BPA is part of the organic matrix of resin-matrix composites and may be hydrolysed in human saliva, although studies report that low doses might not be detected by traditional chemical analysis. Studies exposing zebrafish embryos to different concentrations of Bis-GMA, showed 55% mortality at 10 μM Bis-GMA while 30% mortality was recorded at 1 μM Bis-GMA. In patients, a BPA concentration of around 2.09 × 10^-2 μg/ml was found in the saliva after placement of lingual orthodontic retainers with resin-matrix composites. Also, the BPA molecule can be swallowed and absorbed by the oral/gastrointestinal mucosa, which might result in systemic toxicity. The degradation of resin-matrix composites and release of BPA in oral environment are dependent on the organic matrix content and on the polymerization method. A increased release of BPA can lead to the absorption into oral and gastrointestinal mucosa with high risks of local and systemic toxicity.

New marine-derived indolymethyl pyrazinoquinazoline alkaloids with promising antimicrobial profiles

Due to the emergence of multidrug-resistant pathogenic microorganisms, the search for novel antimicrobials is urgent. Inspired by marine alkaloids, a series of indolomethyl pyrazino [1,2-b]quinazoline-3,6-diones was prepared using a one-pot microwave-assisted multicomponent polycondensation of amino acids. The compounds were evaluated for their antimicrobial activity against a panel of nine bacterial strains and five fungal strains. Compounds 26 and 27 were the most effective against Staphylococcus aureus ATCC 29213 reference strain with MIC values of 4 μg mL⁻¹, and a methicillin-resistant Staphylococcus aureus (MRSA) isolate with MIC values of 8 μg mL⁻¹. It was possible to infer that enantiomer (−)-26 was responsible for the antibacterial activity (MIC 4 μg mL⁻¹) while (+)-26 had no activity. Furthermore, compound (−)-26 was able to impair S. aureus biofilm production and no significant cytotoxicity towards differentiated and non-differentiated SH-SY5Y cells was observed. Compounds 26, 28, and 29 showed a weak antifungal activity against Trichophyton rubrum clinical isolate with MIC 128 μg mL⁻¹ and presented a synergistic effect with fluconazole.

Indolomethyl pyrazino [1,2-b]quinazoline-3,6-diones were prepared using a one-pot multicomponent polycondensation of amino acids and were evaluated for their antimicrobial activity against a panel of nine bacterial strains and five fungal strains.

Quantification of fluoroquinolones in wastewaters by liquid chromatography-tandem mass spectrometry

Antibiotics are the most consumed therapeutic classes worldwide and are released to the environment in their original form as well as potentially active metabolites and/or degradation products. Consequences of the occurrence of these compounds in the environment are primarily related to bacterial resistance development. This work presents a validated analytical method based on solid phase extraction (SPE) using HLB cartridges, followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) for quantification of seven different fluoroquinolone antibiotics, namely ciprofloxacin (CPF), enrofloxacin (ENR), lomefloxacin (LOM), norfloxacin (NOR), ofloxacin (OFL), prulifloxacin (PLF) and moxifloxacin (MOX) and its application to detect the target compounds in influents and effluents of wastewater treatment plants (WWTP). Linearity was established through calibration curves in solvent and matrix match using internal calibration method in the range of 50-1300 ng L^-1 and all the fluoroquinolones showed good linear fit (r² ≥ 0.991). Accuracy ranged between 80.3 and 92.9%, precision was comprised between 7.2 and 14.6%, and 10.7 and 18.1% for intra- and inter-batch determinations, respectively. Method detection and quantification limits ranged from 6.7 to 59.0 ng L^-1 and 22.3-196.6 ng L^-1, respectively. Influents and effluents of fifteen WWTPs of North of Portugal were analyzed. OFL was the fluoroquinolone found at the highest concentration, up to 4587.0 ng L^-1 and 987.9 ng L^-1, in influent and effluent, respectively. NOR and PLF were not detected.

New chiral stationary phases for liquid chromatography based on small molecules: Development, enantioresolution evaluation and chiral recognition mechanisms

Recently, we reported the development of new chiral stationary phases (CSPs) for liquid chromatography (LC) based on chiral derivatives of xanthones (CDXs). Based on the most promising CDX selectors, 12 new CSPs were successfully prepared starting from suitable functionalized small molecules including xanthone and benzophenone derivatives. The chiral selectors comprising one, two, three, or four chiral moieties were covalently bonded to a chromatographic support and further packed into LC stainless-steel columns (150 × 2.1 mm I.D.). The enantioselective performance of the new CSPs was evaluated by LC using different classes of chiral compounds. Specificity for enantioseparation of some CDXs was observed in the evaluation of the new CSPs. Besides, assessment of chiral recognition mechanisms was performed by computational studies using molecular docking approach, which are in accordance with the chromatographic parameters. X-Ray analysis was used to establish a chiral selector 3D structure.

Chiral Stationary Phases for Liquid Chromatography: Recent Developments

The planning and development of new chiral stationary phases (CSPs) for liquid chromatography (LC) are considered as continuous and evolutionary issues since the introduction of the first CSP in 1938. The main objectives of the development strategies were to attempt the improvement of the chromatographic enantioresolution performance of the CSPs as well as enlarge their versatility and range of applications. Additionally, the transition to ultra-high-performance LC were underscored. The most recent strategies have comprised the introduction of new chiral selectors, the use of new materials as chromatographic supports or the reduction of its particle size, and the application of different synthetic approaches for preparation of CSPs. This review gathered the most recent developments associated to the different types of CSPs providing an overview of the relevant advances that are arising on LC.

Synthetic Chiral Derivatives of Xanthones: Biological Activities and Enantioselectivity Studies

Many naturally occurring xanthones are chiral and present a wide range of biological and pharmacological activities. Some of them have been exhaustively studied and subsequently, obtained by synthesis. In order to obtain libraries of compounds for structure activity relationship (SAR) studies as well as to improve the biological activity, new bioactive analogues and derivatives inspired in natural prototypes were synthetized. Bioactive natural xanthones compromise a large structural multiplicity of compounds, including a diversity of chiral derivatives. Thus, recently an exponential interest in synthetic chiral derivatives of xanthones (CDXs) has been witnessed. The synthetic methodologies can afford structures that otherwise could not be reached within the natural products for biological activity and SAR studies. Another reason that justifies this trend is that both enantiomers can be obtained by using appropriate synthetic pathways, allowing the possibility to perform enantioselectivity studies. In this work, a literature review of synthetic CDXs is presented. The structures, the approaches used for their synthesis and the biological activities are described, emphasizing the enantioselectivity studies.

Chiral Derivatives of Xanthones with Antimicrobial Activity

According to the World Health Organization, the exacerbated use of antibiotics worldwide is increasing multi-resistant infections, especially in the last decade. Xanthones are a class of compounds receiving great interest in drug discovery and development that can be found as natural products or obtained by synthesis. Many derivatives of xanthones are chiral and associated with relevant biological activities, including antimicrobial. The aim of this review is to compile information about chiral derivatives of xanthones from natural sources and their synthesized examples with antimicrobial activity.

Carboxyxanthones: Bioactive Agents and Molecular Scaffold for Synthesis of Analogues and Derivatives

Xanthones represent a structurally diverse group of compounds with a broad range of biological and pharmacological activities, depending on the nature and position of various substituents in the dibenzo-γ-pyrone scaffold. Among the large number of natural and synthetic xanthone derivatives, carboxyxanthones are very interesting bioactive compounds as well as important chemical substrates for molecular modifications to obtain new derivatives. A remarkable example is 5,6-dimethylxanthone-4-acetic acid (DMXAA), a simple carboxyxanthone derivative, originally developed as an anti-tumor agent and the first of its class to enter phase III clinical trials. From DMXAA new bioactive analogues and derivatives were also described. In this review, a literature survey covering the report on carboxyxanthone derivatives is presented, emphasizing their biological activities as well as their application as suitable building blocks to obtain new bioactive derivatives. The data assembled in this review intends to highlight the therapeutic potential of carboxyxanthone derivatives and guide the design for new bioactive xanthone derivatives.

Influence of PDLA nanoparticles size on drug release and interaction with cells

Polymeric nanoparticles (NPs) are strong candidates for the development of systemic and targeted drug delivery applications. Their size is a determinant property since it defines the NP-cell interactions, drug loading capacity, and release kinetics. Herein, poly(d,l-lactic acid) (PDLA) NPs were produced by the nanoprecipitation method, in which the influence of type and concentration of surfactant as well as PDLA concentration were assessed. The adjustment of these parameters allowed the successful production of NPs with defined medium sizes, ranging from 80 to 460 nm. The surface charge of the different NPs populations was consistently negative. Prednisolone was effectively entrapped and released from NPs with statistically different medium sizes (i.e., 80 or 120 nm). Release profiles indicate that these systems were able to deliver appropriate amounts of drug with potential applicability in the treatment of inflammatory conditions. Both NPs populations were cytocompatible with human endothelial and fibroblastic cells, in the range of concentrations tested (0.187-0.784 mg/mL). However, confocal microscopy revealed that within the range of sizes tested in our experiments, NPs presenting a medium size of 120 nm were able to be internalized in endothelial cells. In summary, this study demonstrates the optimization of the processing conditions to obtain PDLA NPs with narrow size ranges, and with promising performance for the treatment of inflammatory diseases. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 482-493, 2019.

Distribution and environmental assessment of trace elements contamination of water, sediments and flora from Douro River estuary, Portugal

The present study evaluated the content and distribution of several trace elements (Li, Be, Al, V, Cr, Co, Ni, Cu, Zn, Se, Mo, Ag, Cd, Sb, Ba, Tl, Pb, and U) in the Douro River estuary. For that, three matrices were collected (water, sediments and native local flora) to assess the extent of contamination by these elements in this estuarine ecosystem. Results showed their occurrence in estuarine water and sediments, but significant differences were recorded on the concentration levels and pattern of distribution among both matrices and sampling points. Generally, the levels of trace elements were higher in the sediments than in the respective estuarine water. Nonetheless, no correlation among trace elements was determined between water and sediments, except for Cd. Al was the trace element found at highest concentration at both sediments and water followed by Zn. Pollution indices such as geo-accumulation (I_geo), enrichment factor (EF) and contamination factor (CF) were determined to understand the levels and sources of trace elements pollution. I_geo showed strong contamination by anthropogenic activities for Li, Al, V, Cr, Ni, Cu, Zn, Ba and Pb at all sampling points while EF and CF demonstrated severe enrichment and contamination by Se, Sb and Pb. Levels of trace elements were compared to acceptable values for aquatic organisms and Sediment Quality Guidelines. The concentration of some trace elements, namely Al, Pb and Cu, were higher than those considered acceptable, with potential negative impact on local living organisms. Nevertheless, permissible values for all trace elements are still not available, demonstrating that further studies are needed in order to have a complete assessment of environmental risk. Furthermore, the occurrence and possible accumulation of trace elements by local plant species and macroalgae were investigated as well as their potential use as bioindicators of local pollution and for phytoremediation purposes.

Enantioselective degradation of ofloxacin and levofloxacin by the bacterial strains Labrys portucalensis F11 and Rhodococcus sp. FP1

Fluoroquinolones are a class of antibiotics widely prescribed in both human and veterinary medicine of high environmental concern and characterized as environmental micropollutants due to their ecotoxicity and persistence and antibacterial resistance potential. Ofloxacin and levofloxacin are chiral fluoroquinolones commercialized as racemate and in enantiomerically pure form, respectively. Since the pharmacological properties and toxicity of the enantiomers may be very different, understanding the stereochemistry of these compounds should be a priority in environmental monitoring. This work presents the biodegradation of racemic ofloxacin and its (S)-enantiomer levofloxacin by the bacterial strains Labrys portucalensis F11 and Rhodococcus sp. FP1 at a laboratory-scale microcosm following the removal and the behavior of the enantiomers. Strain F11 could degrade both antibiotics almost completely when acetate was supplied regularly to the cultures. Enrichment of the (R)-enantiomer was observed in FP1 and F11 cultures supplied with ofloxacin. Racemization was observed in the biodegradation of the pure (S)-ofloxacin (levofloxacin) by strain F11, which was confirmed by liquid chromatography - exact mass spectrometry. Biodegradation of ofloxacin at 450 µg L^-1 by both bacterial strains expressed good linear fits (R² > 0.98) according to the Rayleigh equation. The enantiomeric enrichment factors were comprised between - 22.5% to - 9.1%, and - 18.7% to - 9.0% in the biodegradation of ofloxacin by strains F11 and FP1, respectively, with no significant differences for the two bacteria under the same conditions. This is the first time that enantioselective biodegradation of ofloxacin and levofloxacin by single bacteria is reported.

Assessment of Douro and Ave River (Portugal) lower basin water quality focusing on physicochemical and trace element spatiotemporal changes

Water quality of Douro and Ave lower basin was evaluated regarding physicochemical parameters (pH, conductivity, dissolved oxygen and temperature), nutrient compounds (nitrates, nitrites, ammonium and orthophosphates), chlorophyll a and occurrence of trace elements (Li, Be, Al, Ti, V, Cr, Co, Ni, Cu, Zn, Se, Mo, Ag, Cd, Sb, Ba, Tl, Pb, Th and U). To study spatiotemporal variations and possible anthropogenic sources, estuarine samples were collected at nine sampling sites in Douro and five in Ave distributed along the estuaries at four sampling campaigns (spring, summer, fall and winter). According to the water quality standards for aquatic life and recreation, Douro and Ave river water quality was found out of safe limits regarding several parameters. Nitrate levels were systematically high (> 50 mg L^-1 in a significant number of samples) and mean levels of trace elements were higher than the established values of Canadian Environmental Quality Guidelines for aquatic life protection for Al, Cu, Se, Ag, Cd and Pb in Douro and Ave, and also Zn in Ave. Significant spatial differences were found in Ave river estuary for trace elements with a clear trend for higher values from upstream to downstream found. Seasonal differences were also observed particularly in Douro river estuary with higher levels in spring for most elements.

Chiral Drug Analysis in Forensic Chemistry: An Overview

Many substances of forensic interest are chiral and available either as racemates or pure enantiomers. Application of chiral analysis in biological samples can be useful for the determination of legal or illicit drugs consumption or interpretation of unexpected toxicological effects. Chiral substances can also be found in environmental samples and revealed to be useful for determination of community drug usage (sewage epidemiology), identification of illicit drug manufacturing locations, illegal discharge of sewage and in environmental risk assessment. Thus, the purpose of this paper is to provide an overview of the application of chiral analysis in biological and environmental samples and their relevance in the forensic field. Most frequently analytical methods used to quantify the enantiomers are liquid and gas chromatography using both indirect, with enantiomerically pure derivatizing reagents, and direct methods recurring to chiral stationary phases.

Liquid chromatographic methods for the therapeutic drug monitoring of methotrexate as clinical decision support for personalized medicine: A brief review

Methotrexate (MTX) is an antifolate drug used for several diseases. Depending on the disease, MTX can be administered at low dose (LDMTX) in some autoimmune diseases, like rheumatoid arthritis, or at high dose (HDMTX) in some cancers, such as acute lymphoblastic leukemia. After absorption, MTX is metabolized in the liver to 7-hydroxymethotrexate and in the intestine to 2,4-diamino-N10-methylpteroic acid (DAMPA). Moreover, inside red blood cells, MTX is converted to active metabolites, MTX polyglutamates (MTXPGs), contributing to its pharmacodynamics. Owing to its narrow therapeutic range, and inter- and intra-patient variability, either noneffectiveness and/or toxicity may occur. Because of the existence of a relationship between drug therapeutic outcome and its systemic concentration, therapeutic drug monitoring (TDM) may ensure the effectiveness and safety of MTX use. In order to monitor the optimization of patient clinical response profile, several analytical methods have been described for TDM in biological samples. These include liquid chromatography (LC) coupled with ultraviolet detection, fluorescence detection or mass spectrometry, each one presenting advantages and drawbacks. This paper reviews the most commonly used techniques for sample preparation and critically discusses the current LC methods applied for the TDM of MTX in biological samples, at LDMTX and HDMTX.

Enantiomeric Resolution and Docking Studies of Chiral Xanthonic Derivatives on Chirobiotic Columns

A systematic study of enantioresolution of a library of xanthonic derivatives, prepared “in-house”, was successfully carried out with four commercially available macrocyclic glycopeptide-based columns, namely Chirobiotic^TM T, Chirobiotic^TM R, Chirobiotic^TM V and Chirobiotic^TM TAG. Evaluation was conducted in multimodal elution conditions: normal-phase, polar organic, polar ionic and reversed-phase. The effects of the mobile phase composition, the percentage of organic modifier, the pH of the mobile phase, the nature and concentration of different mobile phase additives on the chromatographic parameters are discussed. Chirobiotic^TM T and Chirobiotic^TM V, under normal-phase and reversed-phase modes, respectively, presented the best chromatographic parameters. Considering the importance of understanding the chiral recognition mechanisms associated with the chromatographic enantioresolution, and the scarce data available for macrocyclic glycopeptide-based columns, computational studies by molecular docking were also carried out.

New chiral stationary phases based on xanthone derivatives for liquid chromatography

Six chiral derivatives of xanthones (CDXs) were covalently bonded to silica, yielding the corresponding xanthonic chiral stationary phases (XCSPs). The new XCSPs were packed into stainless-steel columns with 150 x 4.6 mm i.d. Moreover, the greening of the chromatographic analysis by reducing the internal diameter (150 x 2.1 mm i.d.) of the liquid chromatography (LC) columns was also investigated. The enantioselective capability of these phases was evaluated by LC using different chemical classes of chiral compounds, including several types of drugs. A library of CDXs was evaluated in order to explore the principle of reciprocity as well as the chiral self-recognition phenomenon. The separation of enantiomeric mixtures of CDXs was investigated under multimodal elution conditions. The XCSPs provided high specificity for the enantiomeric mixtures of CDXs evaluated mainly under normal-phase elution conditions. Furthermore, two XCSPs were prepared with both enantiomers of the same xanthonic selector in order to confirm the inversion order elution.

Integrated liquid chromatography method in enantioselective studies: Biodegradation of ofloxacin by an activated sludge consortium

Ofloxacin is a chiral fluoroquinolone commercialized as racemate and as its enantiomerically pure form levofloxacin. This work presents an integrated liquid chromatography (LC) method with fluorescence detection (FD) and exact mass spectrometry (EMS) developed to assess the enantiomeric biodegradation of ofloxacin and levofloxacin in laboratory-scale microcosms. The optimized enantioseparation conditions were achieved using a macrocyclic antibiotic ristocetin A-bonded CSP (150×2.1mm i.d.; particle size 5μm) under reversed-phase elution mode. The method was validated using a mineral salts medium as matrix and presented selectivity and linearity over a concentration range from 5μgL(-1) (quantification limit) to 350μgL(-1) for each enantiomer. The method was successfully applied to evaluate biodegradation of ofloxacin enantiomers at 250μgL(-1) by an activated sludge inoculum. Ofloxacin (racemic mixture) and (S)-enantiomer (levofloxacin) were degraded up to 58 and 52%, respectively. An additional degradable carbon source, acetate, enhanced biodegradation up to 23%. (S)-enantiomer presented the highest extent of degradation (66.8%) when ofloxacin was supplied along with acetate. Results indicated slightly higher biodegradation extents for the (S)-enantiomer when supplementation was done with ofloxacin. Degradation occurred faster in the first 3days and proceeded slowly until the end of the assays. The chromatographic results from LC-FD suggested the formation of the (R)-enantiomer during levofloxacin biodegradation which was confirmed by LC-MS with a LTQ Orbitrap XL.

Bacterial degradation of moxifloxacin in the presence of acetate as a bulk substrate

Fluoroquinolones constitute a group of emerging pollutants and their occurrence in different environmental compartments is becoming object of increasing public concern due to their ecotoxicological effects and the potential to develop resistant bacteria. This study aimed to investigate the biodegradation of moxifloxacin (MOX), for which studies in the literature are very scarce. An activated sludge (AS) consortium and three bacterial strains able to degrade fluoroaromatic compounds - strains F11, FP1 and S2 - were tested. Biodegradation studies were conducted using acetate as a bulk carbon source. Strain F11 showed the highest biodegradation capacity, being able to completely consume and dehalogenate 7.5 μM of the target antibiotic when daily co-supplemented with acetate present as a readily degradable organic substrate in wastewaters. MOX could be used by strain F11 as a sole nitrogen source but the presence of an external nitrogen source in the culture medium was essential for complete biodegradation. Strain F11 was capable of completely consuming MOX in a range between 2 and 11 μM, although stoichiometric fluoride release was not obtained for the highest tested concentration. The antibacterial activity of residual MOX and of the metabolic products potentially resultant from the biodegradation process was investigated by agar diffusion tests, demonstrating that MOX biodegradation is associated with the elimination of the antibacterial properties of the target antibiotic and of the produced metabolites, which is an important result, as the activity of antibiotics and/or their metabolites in the environment, even at low levels, may lead to the development of resistant bacterial strains. Overall, the results obtained in this study suggest that strain F11 is a promising microorganism for the treatment of waters contaminated with MOX, where it could be used for bioaugmentation/bioremediation purposes. To the best of our knowledge, this is the first study reporting complete removal and dehalogenation of MOX by a single microorganism.