BODIPY-Based Analogue of the TREM2-Binding Molecular Adjuvant Sulfavant A, a Chemical Tool for Imaging and Tracking Biological Systems

Recently, we described synthetic sulfolipids named Sulfavants as a novel class of molecular adjuvants based on the sulfoquinovosyl-diacylglycerol skeleton. The members of this family, Sulfavant A (1), Sulfavant R (2), and Sulfavant S (3), showed important effects on triggering receptor expressed on myeloid cells 2 (TREM2)-induced differentiation and maturation of human dendritic cells (hDC), through a novel cell mechanism underlying the regulation of the immune response. As these molecules are involved in biological TREM2-mediated processes crucial for cell survival, here, we report the synthesis and application of a fluorescent analogue of Sulfavant A bearing the 4,4-difluoro-1,3,5,7-tetramethyl-4-bora-3a,4a-diaza-s-indacene moiety (Me4-BODIPY). The fluorescent derivative, named PB-SULF A (4), preserving the biological activity of Sulfavants, opens the way to chemical biology and cell biology experiments to better understand the interactions with cellular and in vivo organ targets and to improve our comprehension of complex molecular mechanisms underlying the not fully understood ligand-induced TREM2 activity.

Hands-on synthesis of furanamides and evaluation of their antimicrobial activity

Diverse natural and synthetic furan derivatives have shown biological activity. Here, we describe the preparation of benzyl and arylethyl β-furanamides with OH or OMe aryl substituents by an adapted sustainable method from a furoic acid using methyl chloroformate. Symmetric and asymmetric β,β'-furanamides have instead been prepared using azabenzotriazole based catalyst (HATU). The products have been evaluated for their antimicrobial properties on Gram positive and Gram negative bacteria. Just a minimal not-significant activity has been observed in some derivatives.

In Vitro Evaluation of Antiviral Activities of Funicone-like Compounds Vermistatin and Penisimplicissin against Canine Coronavirus Infection

Recent studies have demonstrated that 3-O-methylfunicone (OMF), a fungal secondary metabolite from Talaromyces pinophilus belonging to the class of funicone-like compounds, has antiviral activity against canine coronaviruses (CCoV), which causes enteritis in dogs. Herein, we selected two additional funicone-like compounds named vermistatin (VER) and penisimplicissin (PS) and investigated their inhibitory activity towards CCoV infection. Thus, both compounds have been tested for their cytotoxicity and for antiviral activity against CCoV in A72 cells, a fibrosarcoma cell line suitable for investigating CCoV. Our findings showed an increase in cell viability, with an improvement of morphological features in CCoV-infected cells at the non-toxic doses of 1 μM for VER and 0.5 μM for PS. In addition, we observed that these compounds caused a strong inhibition in the expression of the aryl hydrocarbon receptor (AhR), a ligand-activated transcription factor which is activated during CCoV infection. Our results also showed the alkalinization of lysosomes in the presence of VER or PS, which may be involved in the observed antiviral activities.

First report of 6-methylpyridione analogues from Dothiorella sarmentorum, a botryosphaeriaceous fungus associated with grapevine trunk diseases

Dothiorella species are fungal plant pathogens associated with Botryosphaeria dieback of grapevine. Symptoms caused by these fungi on grapevines suggest possible implication of phytotoxic metabolites in the infection mechanisms. However, few studies were conducted to investigate the secondary metabolism of these fungi. In this study, 6-methylpyridione analogues were isolated and identified for the first time in liquid cultures of Dothiorella sarmentorum isolated from symptomatic grapevine in Algeria.

Exploring the Binding of Natural Compounds to Cancer-Related G-Quadruplex Structures: From 9,10-Dihydrophenanthrenes to Their Dimeric and Glucoside Derivatives

In-depth studies on the interaction of natural compounds with cancer-related G-quadruplex structures have been undertaken only recently, despite their high potential as anticancer agents, especially due to their well-known and various bioactivities. In this frame, aiming at expanding the repertoire of natural compounds able to selectively recognize G-quadruplexes, and particularly focusing on phenanthrenoids, a mini-library including dimeric (1-3) and glucoside (4-5) analogues of 9,10-dihydrophenanthrenes, a related tetrahydropyrene glucoside (6) along with 9,10-dihydrophenanthrene 7 were investigated here by several biophysical techniques and molecular docking. Compounds 3 and 6 emerged as the most selective G-quadruplex ligands within the investigated series. These compounds proved to mainly target the grooves/flanking residues of the hybrid telomeric and parallel oncogenic G-quadruplex models exploiting hydrophobic, hydrogen bond and π-π interactions, without perturbing the main folds of the G-quadruplex structures. Notably, a binding preference was found for both ligands towards the hybrid telomeric G-quadruplex. Moreover, compounds 3 and 6 proved to be active on different human cancer cells in the low micromolar range. Overall, these compounds emerged as useful ligands able to target G-quadruplex structures, which are of interest as promising starting scaffolds for the design of analogues endowed with high and selective anticancer activity.

Mitidjospirone, a new spirodioxynaphthalene and GC-MS screening of secondary metabolites produced by strains of Lasiodiplodia mitidjana associated to Citrus sinensis dieback

Mitidjospirone, a new spiridioxynaphthalene, was isolated from the mycelial extract of a strain of Lasiodiplodia mitidjana, a recently described species belonging to the family Botryosphaeriaceae. Its structure was elucidated by extensive spectroscopic analysis and the absolute configuration was determined by electronic circular dichroism (ECD) experiment. Furthermore, several known compounds were identified during the screening of secondary metabolites produced by four strains of L. mitidjana.

Effectiveness of the Fungal Metabolite 3-O-Methylfunicone towards Canine Coronavirus in a Canine Fibrosarcoma Cell Line (A72)

Canine coronavirus (CCoV), an alphacoronavirus, may cause self-limiting enteric disease in dogs, especially in puppies. The noteworthy plasticity of coronaviruses (CoVs) occurs through mutation and recombination processes, which sometimes generate new dangerous variants. The ongoing SARS-CoV-2 pandemic and the isolation of a novel canine-feline recombinant alphacoronavirus from humans emphasizes the cross-species transmission ability of CoVs. In this context, exploring antiviral compounds is essential to find new tools for fighting against CoVs infections. Fungi produce secondary metabolites, which are often developed as antibiotics, fungicides, hormones, and plant growth regulators. Previous examinations of benzo-γ-pyrone 3-O-methylfunicone (OMF), obtained from Talaromyces pinophilus, showed that it reduces the infectivity of hepatitis C virus and bovine herpesvirus 1. Based on this evidence, this study evaluated the antiviral ability of OMF against CCoV infection in a canine fibrosarcoma (A72) cell line. During CCoV infection, a non-toxic dose of OMF markedly increased features of cell viability. Moreover, OMF induced a significant reduction in virus yield in the presence of an intense downregulation of the viral nucleocapsid protein (NP). These findings occurred in the presence of a marked reduction in the aryl hydrocarbon receptor (AhR) expression. Taken together, preliminary findings suggest that OMF inhibiting AhR shows promising activity against CCoV infection.

Interaction of the Fungal Metabolite Harzianic Acid with Rare-Earth Cations (Pr3+, Eu3+, Ho3+, Tm3+)

Rare-earth elements (REEs) are in all respect a class of new contaminants that may have toxic effects on organisms and microorganisms and information on their interactions with natural ligands should be of value to predict and control their diffusion in natural environments. In the current study, we investigate interactions of tripositive cations of praseodymium, europium, holmium, and thulium with harzianic acid (H₂L), a secondary metabolite produced by selected strains of fungi belonging to the Trichoderma genus. We applied the same techniques and workflow previously employed in an analogous study concerning lanthanum, neodymium, samarium, and gadolinium tripositive cations. Therefore, in the current study, HPLC-ESI-HRMS experiments, circular dichroism (CD), and UV-Vis spectrophotometric absorption data, as well as accurate pH measurements, were applied to characterize bonding interactions between harzianic acid and Pr³⁺, Eu³⁺, Ho³⁺, and Tm³⁺ cations. Problems connected to the low solubility of harzianic acid in water were overcome by employing a 0.1 M NaClO₄/(CH₃OH + H₂O 50/50 w/w) mixed solvent. For Pr³⁺, Ho³⁺, and Tm³⁺, only the mono complexes PrL⁺, HoL⁺, and TmL⁺ were detected and their formation constant determined. Eu³⁺ forms almost exclusively the bis complex EuL2− for which the corresponding formation constant is reported; under our experimental conditions, the mono complex EuL⁺ is irrelevant. Combining the results of the present and previous studies, a picture of interactions of harzianic acid with rare-earth cations extending over 8 of the 17 REEs can be composed. In order to complement chemical information with toxicological information, a battery of bioassays was applied to evaluate the effects of praseodymium, europium, holmium, and thulium tripositive cations on a suite of bioindicators including Aliivibrio fischeri (Gram-negative bacterium), Raphidocelis subcapitata (green alga), and Daphnia magna (microcrustacean), and median effective concentration (EC50) values of Pr³⁺, Eu³⁺, Ho³⁺, and Tm³⁺ for the tested species were assessed.

Secondary Metabolites, including a New 5,6-Dihydropyran-2-One, Produced by the Fungus Diplodia corticola. Aphicidal Activity of the Main Metabolite, Sphaeropsidin A

An undescribed 5,6-dihydropyran-2-one, namely diplopyrone C, was isolated and characterized from the cultures of an isolate of the fungus Diplodia corticola recovered from Quercus suber in Algeria. The structure and relative stereostructure of (5S,6S,7Z,9S,10S)-5-hydroxy-6-(2-(3-methyloxiran-2-yl)vinyl)-5,6-dihydro-2H-pyran-2-one were assigned essentially based on NMR and MS data. Furthermore, ten known compounds were isolated and identified in the same cultures. The most abundant product, the tetracyclic pimarane diterpene sphaeropsidin A, was tested for insecticidal effects against the model sucking aphid, Acyrthosiphon pisum. Results showed a toxic dose-dependent oral activity of sphaeropsidin A, with an LC₅₀ of 9.64 mM.

Interaction of the Fungal Metabolite Harzianic Acid with Rare-Earth Cations (La3+, Nd3+, Sm3+, Gd3+)

Rare-earth elements are emerging contaminants of soil and water bodies which destiny in the environment and effects on organisms is modulated by their interactions with natural ligands produced by bacteria, fungi and plants. Within this framework, coordination by harzianic acid (H₂L), a Trichoderma secondary metabolite, of a selection of tripositive rare-earth cations Ln³⁺ (Ln³⁺ = La³⁺, Nd³⁺, Sm^3+, and Gd³⁺) was investigated at 25 °C, and in a CH₃OH/0.1 M NaClO₄ (50/50 w/w) solvent, using mass spectrometry, circular dichroism, UV-Vis spectrophotometry, and pH measurements. Experimental data can be satisfactorily explained by assuming, for all investigated cations, the formation of a mono-complex (LnL⁺) and a bis-complex (LnL₂^-). Differences were found between the formation constants of complexes of different Ln³⁺ cations, which can be correlated with ionic radius. Since gadolinium is the element that raises the most concern among lanthanide elements, its effects on organisms at different levels of biological organization were explored, in the presence and absence of harzianic acid. Results of ecotoxicological tests suggest that harzianic acid can decrease gadolinium biotoxicity, presumably because of complex formation with Gd³⁺.

Direct evidence of the impact of aqueous self-assembly on biological behavior of amphiphilic molecules: The case study of molecular immunomodulators Sulfavants

Sulfavant A and Sulfavant R, sulfoquinovoside-glycerol lipids under study as vaccine adjuvants, structurally differ only for the configuration of glyceridic carbon, R/S and R respectively. The in vitro activity of these substances follows a bell-shaped dose-response curve, but Sulfavant A gave the best response around 20 µM, while Sulfavant R at 10 nM. Characterization of aqueous self-assembly of these molecules by a multi-technique approach clarified the divergent and controversial biological outcome. Supramolecular structures were present at concentrations much lower than critical aggregation concentration for both products. The kind and size of these aggregates varied as a function of the concentration differently for Sulfavant A and Sulfavant R. At nanomolar range, Sulfavant A formed cohesive vesicles, while Sulfavant R arranged in spherical micellar particles whose reduced stability was probably responsible for an increase of monomer concentration in accordance with immunomodulatory profile. Instead, at micromolar concentrations transition from micellar to vesicular state of Sulfavant R occurred and thermodynamic stability of the aggregates, assessed by surface tensiometry, correlated with the bioactivity of Sulfavant A at 20 µM and the complete loss of efficacy of Sulfavant R. The study of Sulfavants provides clear evidence of how self-aggregation, often neglected, and the equilibria between monomers and aqueous supramolecular forms of lipophilic molecules deeply determine the overall bio-response.

Natural compounds from Juncus plants interacting with telomeric and oncogene G-quadruplex structures as potential anticancer agents

Aiming at discovering novel, putative anticancer drugs featuring low-to-null side effects, natural compounds isolated from Juncaceae were studied here for their ability to target G-quadruplex structures originating from cancer-related telomeric and oncogene DNA sequences. Particularly, various dihydrophenanthrene, benzocoumarin and dihydrodibenzoxepin derivatives were firstly screened by the affinity chromatography-based G4-CPG assay, and the compound with the highest affinity and selectivity for G-quadruplexes (named J10) was selected for further studies. Fluorescence spectroscopy and circular dichroism experiments corroborated its capability to selectively recognize and stabilize G-quadruplexes over duplex DNA, also showing a preference for parallel G-quadruplexes. Molecular docking proved that the selective G-quadruplex interactions over duplex interactions could be due to the ability of J10 to bind to the grooves of the telomeric and oncogene G-quadruplex structures. Finally, biological assays demonstrated that J10 induces significant antiproliferative effects on human leukemia cells, with no relevant effects on healthy human fibroblasts. Interestingly, J10 exerts its antiproliferative action on tumor cells by activating the apoptotic pathway.

Ecotoxicity and photodegradation of Montelukast (a drug to treat asthma) in water

The present work focuses on the ecotoxicological effects of montelukast sodium (MTL) and its photoproducts, obtained under environmentally-like conditions. Despite of the potential presence in surface waters and the common use of MTL as asthma drug, limited data has been published for its photodegradation, while no information is available for its ecotoxicity. Light-induced degradation is an effective way for drugs to degrade in aquatic environments, and MTL is highly photosensitive, even by exposure to sunlight. In this study, solar-simulated irradiation of the drug in water was investigated. The drug was quickly converted into a series of photoproducts that were spectroscopically characterized. The possible photoreaction pathways were proposed. Ecotoxicity tests were performed on parent compound and mixture of photoproducts towards two bioindicators (Raphidocelis subcapitata and Daphnia magna). Results evidenced that effects of MTL on D. magna (EC50 = 16.4 mg/L) were greater than effects on R. subcapitata (EC50 = 195.7 mg/L). Microscopy observations revealed that MTL had mainly accumulated in the gut of daphnia. Toxicity data on photolysed solutions highlighted the presence of residual toxicity in all samples, evidencing that no complete mineralization occurred. Future research should focus on monitoring of MTL concentrations in the environment and study its effects in bioaccumulation tests.

A new cyanine from oxidative coupling of chlorogenic acid with tryptophan: Assessment of the potential as red dye for food coloring

A red pigment was prepared by reaction of chlorogenic acid (CGA) with tryptophan (TRP) in air at pH 9 (37% w/w yield) and evaluated as food dye. The main component of pigment was formulated as an unusual benzochromeno[2,3-b]indole linked to a TRP unit, featuring a cyanine type chromophore (λ_max 542, 546 nm, 1% extinction coefficient of the sodium salt = 244 ± 2). The chromophore showed a minimal pH dependence and proved stable for at least 3 h at 90 °C, both at pH 3.6 or 7.0, whereas red wine anthocyanins showed a substantial (30%) and betanin a complete abatement after 1 h at the acidic pHs. An intense coloring of different food matrices was obtained with the pigment at 0.01 % w/w. No toxicity was observed up to 0.2 mg/mL on hepatic and colonic cell lines. These data make this dye a promising alternative for red coloring of food.

Synergistic Effect of Abietic Acid with Oxacillin against Methicillin-Resistant Staphylococcus pseudintermedius

Resin acids are valued in traditional medicine for their antiseptic properties. Among these, abietic acid has been reported to be active against methicillin-resistant Staphylococcus aureus (MRSA) strains. In veterinary healthcare, the methicillin-resistant Staphylococcus pseudintermedius (MRSP) strain is an important reservoir of antibiotic resistance genes including mecA. The incidence of MRSP has been increasing, and treatment options in veterinary medicine are partial. Here, we investigated the antimicrobial and antibiofilm properties of abietic acid against three MRSP and two methicillin-susceptible Staphylococcus pseudintermedius (MSSP) strains, isolated from diseased pet animals and human wound samples. Abietic acid showed a significant minimal inhibitory concentration (MIC) value ranging from 32 to 64 μg/mL (MRSPs) and 8 μg/mL (MSSP). By checkerboard method we demonstrated that abietic acid increased oxacillin susceptibility of MRSP strains, thus showing a synergistic interaction with oxacillin. Abietic acid was also able to contrast the vitality of treated MSSP and MRSP1 biofilms at 20 μg/mL and 40 μg/mL, respectively. Finally, the compound moderately reduced mecA, mecR1 and mec1 gene expression. In conclusion, the results here reported demonstrate the antimicrobial activity of abietic acid against MRSP and support the use of this compound as a potential therapeutic agent to be used in combinatorial antibiotic therapy.

Physiological and Oxidative Stress Responses of Lettuce to Cleomside A: A Thiohydroximate, as a New Allelochemical from Cleome arabica L

The inclination toward natural products have led the onset for the discovery of new bioactive metabolites that could be targeted for specific therapeutic or agronomic applications. This study aimed to isolate bioactive compounds from Cleome arabica L., and subsequently determine the unexplored mechanism of action of the newly identified compounds on Lactuca sativa L. Chemical investigation of the ethyl acetate fraction of methanolic silique extract of C. arabica afforded seven secondary metabolites belonging to different classes such as flavonoids, triterpene, and a new thiohydroximate derivative, named cleomside A. Among phytotoxic assays, the growth of lettuce was totally inhibited by cleomside A compared to the other identified compounds. This effect was associated with the increased levels of electrolyte leakage, malondialdehyde, and hydrogen peroxide indicating disruption of membrane integrity and induction of oxidative stress. Activities of the antioxidant enzymes SOD, CAT, and APX were also elevated, thereby demonstrating the enhanced generation of reactive oxygen species upon identified allelochemical exposure. Thus, the changes caused by cleomside A described herein can contribute to better understanding the allelochemical actions of thiohydroximate and the potential use of these substances in the production of natural herbicides compared to the other identified flavonoids and triterpene.

Synthesis of novel lignan-like compounds and their antimicrobial activity

Herein we report the preparation of 3,4-dibenzylfurans and some oxidized derivatives with lignan backbone. The compounds were prepared using the Friedel-Crafts reaction with BF₃ etherate as catalyst, demethylation with iodocyclohexane, acetylation and oxidation reactions. The antimicrobial activity was evaluated through their capacity to inhibit the growth of Gram positive and Gram negative bacteria, and of the yeast Candida albicans. Among ten products assayed four furans displayed a good antimicrobial activity against Staphylococcus aureus, S. epidermidis and C. albicans; on the contrary, none of the compounds were active against Pseudomonas aeruginosa. One of them inhibited the growth of S. aureus, S. epidermidis (biofilm producer strain) and C. albicans at 16 μg/mL, showing a bactericidal activity already after one hour of treatment. In summary, the results suggest a possible use of these derivatives for general disinfection practices or antimicrobial agents in cosmesis skin-care.

Synthesis of 3-benzoyl-4-benzylfurans structural related to furolignans

Furolignan-type natural products, possessing important biological properties, have been synthesized from a commercially available furan. The elaborated synthetic strategy is based on an innovative Friedel-Crafts reaction starting from an alcohol or a carboxylic acid and triflic anhydride as promoter. Through this synthetic strategy, furolignans having two different aryl groups have been obtained. The products have been evaluated for their antimicrobial properties on Gram positive and Gram negative bacteria, in order to compare their biological activities with those of natural analogues.

Influence of new effective allelochemicals on the distribution of Cleome arabica L. community in nature

New allelochemicals were identified through bio-guided fractionation from the ethyl acetate of seeds extracts, which was the most autotoxic compared to the other plant parts. Phytochemical investigation of the seeds extracts of C. arabica by spectroscopy analyses has led to identify two new dammarane type triterpenes (4 and 9), with nine known analogues (1 - 3, 5 - 8, 10 and 11), a new cucurbitane triterpene (12), acylated dehydrodiconiferyl alcohol (13), and three highly oxygenated flavonols (14-16). The most autotoxic compounds on germination and seedling growth were elucidated as dammarane type triterpenes. However, less autotoxic effect was recorded by an inhibition under 50% for most of the identified flavonoids. These results suggest that those autotoxic substances may be used as a new bio-herbicide that may contribute to manage the distribution of C. arabica in agronomic field.[Formula: see text].

Identification of the Main Metabolites of a Marine-Derived Strain of Penicillium brevicompactum Using LC and GC MS Techniques

Marine-derived fungi are an important source of many valuable compounds with original structures and diverse physico-chemical properties. In this work, the metabolomic profile of a strain of Penicillium brevicompactum, recovered from a snakelocks sea anemone (Anemonia sulcata), was investigated through the parallel application of LC-ESI-HRMS, GC-MS, and NMR. Our strategy allowed the identification of mycophenolic acid, brevianamide A, and several compounds belonging to the thiosilvatins. Among the latter, five products are reported for the first time in this species. The main product of this series, cis-bis(methylthio)silvatin, was also tested for antiproliferative activity on both cancer and non-tumoral colon cell lines.

The Issue of Misidentification of Kojic Acid with Flufuran in Aspergillus flavus

In the course of investigations on the complex phenomenon of bee decline, Aspergillus flavus was isolated from the haemocoel of worker bees. Observations on the metabolomic profile of this strain showed kojic acid to be the dominant product in cultures on Czapek-Dox broth. However, an accurate review of papers documenting secondary metabolite production in A. flavus also showed that an isomer of kojic acid, identified as 5-(hydroxymethyl)-furan-3-carboxylic acid and named flufuran is reported from this species. The spectroscopic data of kojic acid were almost identical to those reported in the literature for flufuran. This motivated a comparative study of commercial kojic acid and 5-(hydroxymethyl)-furan-3-carboxylic acid, highlighting some differences, for example in the 13C-NMR and UV spectra for the two compounds, indicating that misidentification of the kojic acid as 5-(hydroxymethyl)-furan-3-carboxylic acid has occurred in the past.

Diasteroselective Colloidal Self-Assembly Affects the Immunological Response of the Molecular Adjuvant Sulfavant

Adjuvants are components of vaccine that enhance the specific immune response against co-inoculated antigens. Recently, we reported the characterization of a synthetic sulfolipid named Sulfavant A (1) as a promising candidate of a novel class of molecular adjuvants based on the sulfoquinovosyl-diacylglycerol skeleton. Here, we report an improved synthesis of the sulfolipid scaffold, as well as the preparation of two analogs named Sulfavant-S (2) and Sulfavant-R (3) with enhanced property to modulate master immune targets such as human dendritic cells (DCs). According to the present approach, synthesis of 1 is reduced from 14 to 11 steps with nearly triplication of the overall yield (11%). The new members 2 and 3 elicit DC maturation at a concentration of 10 nM, which is 1000 times more potent than the parent molecule 1. Analysis of dynamic light scattering indicates self-assembly of Sulfavants and formation of colloidal particles with a small hydrodynamic radius (50 nm) for the epimers 2 and 3 and a larger radius (150 nm) for 1. The colloidal aggregates are responsible for the bell-shaped dose-response curve of these products. We conclude that the particle size also affects the equilibrium with free monomers, thus determining the effective concentration of the sulfolipid molecule at the cellular targets and the different immunological efficacy of 1-3. Sulfavants (1-3) do not show in vitro cytotoxicity at concentrations 10⁵ higher than the dose that triggers maximal immune response, thus predicting a low level of toxicological risk in their formulation in vaccines.

Secondary metabolites produced by grapevine strains of Lasiodiplodia theobromae grown at two different temperatures

Lasiodiplodia theobromae is a fungal plant pathogen that has been associated with Botryosphaeria dieback of grapevine. Despite several studies on L. theobromae, until now the production of secondary metabolites by strains isolated from grapevines has not been reported. The ability of two strains of L. theobromae isolated from grapevine to produce lipophilic metabolites was studied. Although many typical compounds of low molecular weight were identified from the crude extracts of both strains (e.g., lasiolactols, substituted 2-dihydrofuranones, melleins, jasmonic acid, 3-indolcarboxylic acid, botryodiplodins), (2R/2S,3S,4S)-3-epi-botryodiplodin was isolated for the first time as a natural compound. Furthermore, a comparative study of metabolite production was conducted at 25 and 37 C to understand temperature effects on metabolite profiles. Some metabolites were produced only by one strain (e.g., (3S,4S)-4-acetyl-3-methyl-2-dihydrofuranone produced by LA-SOL3) and others only at a specific temperature (e.g., jasmonic acid at 25 C, botryodiplodins at 37 C). Phytotoxicity and cytotoxicity of pure compounds were evaluated to clarify the influence of lipophilic metabolites on the biological activities of culture filtrates of both strains. The most toxic compound for Vero and 3T3 cells was (2R/2S,3S,4S)-3-epi-botryodiplodin.

Ecotoxic effects of loratadine and its metabolic and light-induced derivatives

Loratadine and desloratadine are second-generation antihistaminic drugs. Because of human administration, they are continuously released via excreta into wastewater treatment plants and occur in surface waters as residues and transformation products (TPs). Loratadine and desloratadine residues have been found at very low concentrations (ng/L) in the aquatic environment but their toxic effects are still not well known. Both drugs are light-sensitive even under environmentally simulated conditions and some of the photoproducts have been isolated and characterized. The aim of the present study was to investigate the acute and chronic ecotoxicity of loratadine, desloratadine and their light-induced transformation products in organisms of the aquatic trophic chain. Bioassays were performed in the alga Pseudokirchneriella subcapitata, the rotifer Brachionus calyciflorus and in two crustaceans, Thamnocephalus platyurus and Ceriodaphnia dubia. Loratadine exerted its acute and chronic toxicity especially on Ceriodaphnia dubia (LC50: 600 µg/L, EC50: 28.14 µg/L) while desloratadine showed similar acute toxicity among the organisms tested and it was the most chronically effective compound in Ceriodaphnia dubia and Pseudokirchneriella subcapitata. Generally, transformation products were less active in both acute and chronic assays.

Antimicrobial and anti-biofilm properties of novel synthetic lignan-like compounds

Antibiotic resistance and biofilm tolerance are among the principal factors involved in the persistence of chronic infections. The need for new antimicrobials is an ever-increasing challenge in clinical environments and in the control of global health. Arylfurans form a set of structures that have been identified in many natural products, e.g. lignans. Lignans are a sub-group of non-flavonoid polyphenols that play an active role in plants' defense against bacteria and fungi infections. The aim of this study was to identify novel synthetic arylfurans and lignan-like arylbenzylfurans exhibiting antimicrobial properties. The molecules synthetized were tested against Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus and S. epidermidis. We found that among tested compounds, arylbenzylfuran 11 was active against S. aureus and S. epidermidis with an MIC of 4 μg ml-1. Compound 11 was also active on methicillin-resistant S. aureus and S. epidermidis. By confocal laser scanning microscopy, we showed that 32 μg ml-1 of compound 11 was able to induce a significant reduction in S. aureus and S. epidermidis biofilms viability. Finally, we demonstrated that compound 11 was not cytotoxic on HaCat cells up to 128 μg ml-1. This work shows the antimicrobial and anti-biofilm potential of a synthetic lignan-like furan.

Production of toxic metabolites by two strains of Lasiodiplodia theobromae, isolated from a coconut tree and a human patient

Lasiodiplodia theobromae is a phytopathogenic fungus that causes diseases not only in a broad number of plant hosts but also occasionally in humans. The capacity of L. theobromae to produce bioactive metabolites at 25 C (environmental mean temperature) and at 37 C (body mean temperature) was investigated. Two strains, CAA019 and CBS339.90, isolated respectively from a coconut tree and a human patient were characterized. The phytotoxicity and cytotoxicity (on mammalian cells) of the secretomes of both strains of L. theobromae were investigated. Also, phytotoxicity and cytotoxicity of pure compounds were evaluated. The phytotoxicity of the secretome of strain CAA019 was higher than the phytotoxicity of the secretome of strain CBS339.90 at 25 C. However, the phytotoxicity for both strains decreased when they were grown at 37 C. Only the secretome of strain CBS339.90 grown at 37 C induced up to 90% Vero and 3T3 cell mortality. This supports the presence of different metabolites in the secretome of strains CAA019 and CBS339.90. Metabolites typical of L. theobromae were isolated and identified from organic extracts of the secretome of both strains (e.g., 3-indolecarboxylic acid, jasmonic acid, lasiodiplodin, four substituted 2-dihydrofuranones, two melleins, and cyclo-(Trp-Ala)). Also, metabolites such as scytalone, not previously reported for this species, were isolated and identified. Metabolite production is affected by strain and temperature. In fact, some metabolites are strain specific (e.g., lasiodiplodin) and some metabolites are temperature specific (e.g., jasmonic acid). Although more strains should be characterized, it may be anticipated that temperature tuning of secondary-metabolite production emerges as a putative contributing factor in the modulation of L. theobromae pathogenicity towards plants, and also towards mammalian cells.

Rapid Solid-Liquid Dynamic Extraction (RSLDE): a New Rapid and Greener Method for Extracting Two Steviol Glycosides (Stevioside and Rebaudioside A) from Stevia Leaves

Stevioside and rebaudioside A are the main diterpene glycosides present in the leaves of the Stevia rebaudiana plant, which is used in the production of foods and low-calorie beverages. The difficulties associated with their extraction and purification are currently a problem for the food processing industries. The objective of this study was to develop an effective and economically viable method to obtain a high-quality product while trying to overcome the disadvantages derived from the conventional transformation processes. For this reason, extractions were carried out using a conventional maceration (CM) and a cyclically pressurized extraction known as rapid solid-liquid dynamic extraction (RSLDE) by the Naviglio extractor (NE). After only 20 min of extraction using the NE, a quantity of rebaudioside A and stevioside equal to 1197.8 and 413.6 mg/L was obtained, respectively, while for the CM, the optimum time was 90 min. From the results, it can be stated that the extraction process by NE and its subsequent purification developed in this study is a simple, economical, environmentally friendly method for producing steviol glycosides. Therefore, this method constitutes a valid alternative to conventional extraction by reducing the extraction time and the consumption of toxic solvents and favouring the use of the extracted metabolites as food additives and/or nutraceuticals. As an added value and of local interest, the experiment was carried out on stevia leaves from the Benevento area (Italy), where a high content of rebaudioside A was observed, which exhibits a sweet taste compared to stevioside, which has a significant bitter aftertaste.

A practical route to β(2,3)-amino acids with alkyl side chains

Enantiopure N(Boc)-β³-amino nitriles, valuable synthetic intermediates in the multistep homologation of α-amino acids, were alkylated using n-BuLi as base. Alkylations afforded easily separable, almost equimolecular mixtures of diastereomeric N(Boc)-protected syn and anti β^2,3-amino nitriles. Suitable manipulations of both cyano and amino groups eventually led to enantiopure N- and/or C-protected β^2,3-amino acids. For example, methanolysis using conc. HCl gas in MeOH, provides C-protected β^2,3 amino acids in excellent yields. This methodology is applied to the synthesis of a series N(Boc)-β^2,3-dialkyl amino nitriles derived from l-phenylalanine, d-phenylalanine, l-valine and one C-protected β^2,3 amino acid. We demonstrate an efficient procedure for the preparation of anti and syn β^2,3-amino acids with alkyl side chains, from α-amino acids in reasonable yields.

Photochemical fate and eco-genotoxicity assessment of the drug etodolac

The photochemical behavior of etodolac was investigated under various irradiation conditions. Kinetic data were obtained after irradiation of 10(-4) M aqueous solutions by UVB, UVA and direct exposure to sunlight. The Xenon lamp irradiation was used in order to determine the photodegradation quantum yield under sun-simulated condition (ϕsun). The value was determined to be=0.10±0.01. In order to obtain photoproducts and for mechanistic purposes, experiments were carried out on more concentrated solutions by exposure to sunlight and to UVA and UVB lamps. The drug underwent photooxidative processes following an initial oxygen addition to the double bond of the five membered ring and was mainly converted into a spiro compound and a macrolactam. Ecotoxicity tests were performed on etodolac, its photostable spiro derivative and its sunlight irradiation mixture on two different aquatic trophic levels, plants (algae) and invertebrates (rotifers and crustaceans). Mutagenesis and genotoxicity were detected on bacterial strains. The results showed that only etodolac had long term effects on rotifers although at concentrations far from environmental detection values. A mutagenic and genotoxic potential was found for its derivative.

Chlorpropham and phenisopham: phototransformation and ecotoxicity of carbamates in the aquatic environment

In this study, a comparison of two carbamic pesticides, chlorpropham and phenisopham, was carried out in terms of both photodegradability and ecotoxicity. The photochemical behaviour of the two pesticides was investigated under environmental-like conditions (aqueous media, UVB or solar irradiation). The photochemical kinetic parameters were calculated by irradiating 5 × 10(-5) M solutions (H₂O-CH₃CN, 9 : 1 v/v) using UVB lamps. For chlorpropham and phenisopham similar half-life times (39.0 and 55.0 min) were determined. Irradiation by sunlight leads to longer degradation half-life times (about 3 months), while it is possible to observe the formation of the same photoproducts. The well-known dechlorination reaction to a hydroxyphenylcarbamate was observed for chlorpropham. Phenisopham undergoes photo-Fries reaction to give rearranged products (hydroxybenzamides) and fragmentation products (hydroxyphenylcarbamate and N-ethylaniline). Acute and chronic toxicity tests of pesticides and their photoproducts were performed on organisms from two levels of the freshwater aquatic chain, the anostraca crustacean Thamnocephalus platyurus, the rotifer Brachionus calyciflorus and the alga Pseudokirchneriella subcapitata. The acute results showed that chlorpropham had median lethal concentrations for the crustacean T. platyurus and the rotifer B. calyciflorus of 10.16 and 35.19 mg L(-1), respectively, and phenisopham did not show any acute toxicity as the derivatives up to 10 mg L(-1). The only exception was N-ethylaniline which exhibited an acute LC₅₀ value of 0.46 mg L(-1). Phenisopham was the most toxic in the long term exposure while its five derivatives showed lower chronic potential for rotifers and algae. The same trend was observed for chlorpropham except for rotifers.

Sildenafil and tadalafil in simulated chlorination conditions: ecotoxicity of drugs and their derivatives

Chlorination experiments on two drugs (sildenafil and tadalafil) were performed mimicking the conditions of a typical wastewater treatment process. The main transformation products were isolated by chromatographic techniques (Thin Layer Chromatography (TLC), Column Chromatography (CC), High Performance Liquid Chromatography (HPLC)) and fully characterized employing Nuclear Magnetic Resonance (NMR) and Mass Spectrometry (MS) analyses. The environmental effects of the parent compounds and transformation products were evaluated using an overall toxicity approach that considered aquatic acute and chronic toxicity on Brachionus calyciflorus and Ceriodaphnia dubia as well as mutagenesis and genotoxicity on bacterial strains. The results revealed that both parent drugs did not show high acute and chronic toxicity for the organisms utilized in the bioassays while, chronic exposure to chlorine derivatives caused inhibition of growth population on rotifers and crustaceans. A mutagenic potential was found for all the compounds investigated.

Chemical fate and genotoxic risk associated with hypochlorite treatment of nicotine

Nicotine, the main alkaloid of tobacco, is a non- prescription drug to which all members of a tobacco-smoking society are exposed either through direct smoke inhalation or through second-hand passive 'smoking'. Nicotine is also commercially available in some pharmaceutical products and is used worldwide as a botanical insecticide in agriculture. Nicotine dynamics in indoor and outdoor environments as well as the human excretions and the manufacturing process are responsible for its entry in the environment through municipal and industrial wastewater discharges. The presence of nicotine in surface and ground waters points out that it survives a conventional treatment process and persists in potable-water supplies. Complete removal of nicotine is instead reported when additional chlorination steps are used. In this paper a simulation of STP chlorination of nicotine and a genotoxic evaluation of its main degradation products are reported. Under laboratory conditions removal of nicotine seems not to be due to mineralization but to transformation in oxidized and chlorinated products. The by-products have been isolated after fractionation by diverse chromatographic procedures and their structures determined using mass spectrometry and (1)H and (13)C NMR spectroscopy. Preliminary genotoxic SOS Chromotests with Escherichia coli PQ37 evidence no toxicity of the products.