The influence of exploration activities of a potential lithium mine to the environment in Western Serbia.

The proposed exploitation of the Jadar Valley lithium/borate deposit in Serbia, by the Rio Tinto Corporation, indicates that it would become large-scale processing of boron- and lithium-containing ore. It would be one of the world's very first lithium mines in populated and agricultural area. The company claims that the envisioned mining will be in accordance with environmental protection requirements.

Iron salt-promoted oxidation of steroidal phenols by -chloroperbenzoic acid: a route to possible antitumor agents.

A new oxidant, containing -chloroperoxybenzoic acid (MCPBA) and an iron salt, was developed and used for oxidation of steroidal phenols to a quinol/epoxyquinol mixture. Reaction was optimized for estrone, by varying initiators (Fe-salts), reaction temperature, time and mode of MCPBA application. A series of five more substrates (17β-estradiol and its hydrophobized derivatives) was subjected to the optimized oxidation, providing corresponding -quinols and 4β,5β-epoxyquinols in good to moderate yields.

Unraveling the anti-virulence potential and antifungal efficacy of 5-aminotetrazoles using the zebrafish model of disseminated candidiasis.

Candida albicans remains the main causal agent of candidiasis, the most common fungal infection with disturbingly high mortality rates worldwide. The limited diversity and efficacy of clinical antifungal drugs, exacerbated by emerging drug resistance, have resulted in the failure of current antifungal therapies. This imposes an urgent demand for the development of innovative strategies for effective eradication of candidal infections.

Aminoquinolines afford resistance to cerebral malaria in susceptible mice.

Objectives: Malaria treatment is impeded by increasing resistance to conventional antimalarial drugs. Here we explored the activity of ten novel benzothiophene, thiophene and benzene aminoquinolines.

Methods: In vitro testing was performed by the lactate dehydrogenase assay in chloroquine (CQ)-sensitive Plasmodium falciparum strain 3D7 and CQ-resistant (CQ) P.

4-Aminoquinoline-based compounds as antileishmanial agents that inhibit the energy metabolism of Leishmania.

Among neglected tropical diseases, leishmaniasis is one of the most relevant with an estimated 30,000 deaths annually. Existing therapies have serious drawbacks in safety, drug resistance, field-adapted application and cost; therefore, new safer and shorter treatments are needed for this disease. Here we report on the synthesis of novel 4-amino-7-chloroquinoline-based compounds with leishmanicidal activity, together with deeper insight into the mechanism of action of our previously published hit compound 1.

Second generation of diazachrysenes: Protection of Ebola virus infected mice and mechanism of action.

Ebola virus (EBOV) causes a deadly hemorrhagic fever in humans and non-human primates. There is currently no FDA-approved vaccine or medication to counter this disease. Here, we report on the design, synthesis and anti-viral activities of two classes of compounds which show high potency against EBOV in both in vitro cell culture assays and in vivo mouse models Ebola viral disease.

Benzothiazole carbamates and amides as antiproliferative species.

A series of new benzothiazole-based carbamates and amides were synthesized and their antiproliferative activity was determined. Derivatives with profound activity were identified and further investigated for their possible mechanism of action. It was found that these compounds induce specific apoptosis, G2/M cell cycle arrest and decrease ROS level in MCF-7 human breast cancer cell line.

Novel Aminoquinoline Derivatives Significantly Reduce Parasite Load in Infected Mice.

In this Letter, a detailed analysis of 30 4-aminoquinoline-based compounds with regard to their potential as antileishmanial drugs has been carried out. Ten compounds demonstrated IC < 1 μM against promastigote stages of and , and five compounds showed IC < 1 μM against intramacrophage amastigotes. Two compounds showed dose-dependent enhancement of NO and ROS production by bone marrow-derived macrophages and remarkable reduction of parasite load , with advantage of being short-term and orally active.

New Steroidal 4-Aminoquinolines Antagonize Botulinum Neurotoxin Serotype A in Mouse Embryonic Stem Cell Derived Motor Neurons in Postintoxication Model.

The synthesis and inhibitory potencies against botulinum neurotoxin serotype A light chain (BoNT/A LC) using in vitro HPLC based enzymatic assay for various steroidal, benzothiophene, thiophene, and adamantane 4-aminoquinoline derivatives are described. In addition, the compounds were evaluated for the activity against BoNT/A holotoxin in mouse embryonic stem cell derived motor neurons. Steroidal derivative 16 showed remarkable protection (up to 89% of uncleaved SNAP-25) even when administered 30 min postintoxication.

Human serum albumin binding of certain antimalarials.

Interactions between eight in-house synthesized aminoquinolines, along with well-known chloroquine, and human serum albumin (HSA) have been studied by fluorescence spectroscopy. The synthesized aminoquinolines, despite being structurally diverse, were found to be very potent antimalarials. Fluorescence measurements indicate that three compounds having additional thiophene or benzothiophene substructure bind more strongly to HSA than other studied compounds.

Antimalarials with Benzothiophene Moieties as Aminoquinoline Partners.

Malaria is a severe and life-threatening disease caused by parasites that are spread to humans through bites of infected mosquitoes. Here, we report on the efficacy of aminoquinolines coupled to benzothiophene and thiophene rings in inhibiting parasite growth. Synthesized compounds were evaluated for their antimalarial activity and toxicity, in vitro and in mice.

Synthesis and anti-Candida activity of novel benzothiepino[3,2-c]pyridine derivatives.

A novel series of thiepine derivatives were synthesized and evaluated as potential antimicrobials. All the synthesized compounds were evaluated for their antimicrobial activities in vitro against the fungi Candida albicans (ATCC 10231), C. parapsilosis (clinical isolate), Gram-negative bacterium Pseudomonas aeruginosa (ATCC 44752), and Gram-positive bacterium Staphylococcus aureus (ATCC 25923).

Synthesis and evaluation of thiophene-based guanylhydrazones (iminoguanidines) efficient against panel of voriconazole-resistant fungal isolates.

A series of new thiophene-based guanylhydrazones (iminoguanidines) were synthesized in high yields using a straightforward two-step procedure. The antifungal activity of compounds was evaluated against a wide range of medicaly important fungal strains including yeasts, molds, and dermatophytes in comparison to clinically used drug voriconazole. Cytotoxic properties of compounds were also determined using human lung fibroblast cell line and hemolysis assay.

Quantitative structure retention/activity relationships of biologically relevant 4-amino-7-chloroquinoline based compounds.

The chromatographic behaviour of series of 4-amino-7-chloroquinoline (4,7-ACQ) based compounds was studied by reversed-phase thin-layer chromatography (RPTLC) with binary mobile phases containing water and the organic modifiers, DMSO or acetone. The lipophilicity of the studied compounds was determined by extrapolation of retention parameters RM to pure water content in mobile phase. In order to obtain some basic insight into the chromatographic behaviour and structural features of investigated compounds, PCA was performed on both chromatographic data (RM values) and calculated 2D and 3D structural descriptors.

Reinvestigating Old Pharmacophores: Are 4-Aminoquinolines and Tetraoxanes Potential Two-Stage Antimalarials?

The syntheses and antiplasmodial activities of various substituted aminoquinolines coupled to an adamantane carrier are described. The compounds exhibited pronounced in vitro and in vivo activity against Plasmodium berghei in the Thompson test. Tethering a fluorine atom to the aminoquinoline C(3) position afforded fluoroaminoquinolines that act as intrahepatocytic parasite inhibitors, with compound 25 having an IC50 = 0.

Anti-Ebola Activity of Diazachrysene Small Molecules.

Herein we report on a diazachrysene class of small molecules that exhibit potent antiviral activity against the Ebola (EBOV) virus. The antiviral compounds are easily synthesized, and the most active compounds have excellent in vitro activity (0.34-0.

Investigation into novel thiophene- and furan-based 4-amino-7-chloroquinolines afforded antimalarials that cure mice.

We herein report the design and synthesis of a novel series of thiophene- and furan-based aminoquinoline derivatives which were found to be potent antimalarials and inhibitors of β-hematin polymerization. Tested compounds were 3-71 times more potent in vitro than CQ against chloroquine-resistant (CQR) W2 strain with benzonitrile 30 being as active as mefloquine (MFQ), and almost all synthesized aminoquinolines (22/27) were more potent than MFQ against multidrug-resistant (MDR) strain C235. In vivo experiments revealed that compound 28 showed clearance with recrudescence at 40 mg/kg/day, while 5/5 mice survived in Thompson test at 160 mg/kg/day.

Correlation study of retention data and antimalarial activity of 1,2,4,5-mixed tetraoxanes with their molecular structure descriptors and LSER parameters.

The chromatographic behavior of mixed 1,2,4,5-tetraoxanes, cholic and deoxycholic acid derivatives with distinct biological activity, was examined by high-performance thin-layer chromatography in order to correlate their structure and retention. Chromatographic systems were consisted of RP-18 or CN-silica as stationary phase, and binary mixtures of water with methanol, dioxane or acetone as mobile phase. Based on the respective retentions, the lipophilicity of the investigated compounds was determined.

Second generation steroidal 4-aminoquinolines are potent, dual-target inhibitors of the botulinum neurotoxin serotype A metalloprotease and P. falciparum malaria.

Significantly more potent second generation 4-amino-7-chloroquinoline (4,7-ACQ) based inhibitors of the botulinum neurotoxin serotype A (BoNT/A) light chain were synthesized. Introducing an amino group at the C(3) position of the cholate component markedly increased potency (IC50 values for such derivatives ranged from 0.81 to 2.

4-Amino-7-chloroquinolines: probing ligand efficiency provides botulinum neurotoxin serotype A light chain inhibitors with significant antiprotozoal activity.

Structurally simplified analogues of dual antimalarial and botulinum neurotoxin serotype A light chain (BoNT/A LC) inhibitor bis-aminoquinoline (1) were prepared. New compounds were designed to improve ligand efficiency while maintaining or exceeding the inhibitory potency of 1. Three of the new compounds are more active than 1 against both indications.

A limited structural modification results in a significantly more efficacious diazachrysene-based filovirus inhibitor.

Ebola (EBOV) and Marburg (MARV) filoviruses are highly infectious pathogens causing deadly hemorrhagic fever in humans and non-human primates. Promising vaccine candidates providing immunity against filoviruses have been reported. However, the sporadic nature and swift progression of filovirus disease underlines the need for the development of small molecule therapeutics providing immediate antiviral effects.

Correlation between structure, retention, property, and activity of biologically relevant 1,7-bis(aminoalkyl)diazachrysene derivatives.

The physicochemical properties, retention parameters (R(M)(0)), partition coefficients (logP(OW)), and pK(a) values for a series of thirteen 1,7-bis(aminoalkyl) diazachrysene (1,7-DAAC) derivatives were determined in order to reveal the characteristics responsible for their biological behavior. The investigated compounds inhibit three unrelated pathogens (the Botulinum neurotoxin serotype A light chain (BoNT/A LC), Plasmodium falciparum malaria, and Ebola filovirus) via three different mechanisms of action. To determine the most influential factors governing the retention and activities of the investigated diazachrysenes, R(M)(0), logP(OW), and biological activity values were correlated with 2D and 3D molecular descriptors, using a partial least squares regression.