Publications by authors named "Dubravko Jelic"

Edible berries such as the fruits of black chokeberry ( (Michx.) Elliott) and bilberry ( L.) are considered to be rich in phenolic compounds, which are nowadays attracting great interest due to their promising health benefits.

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The most common Aspergilli isolated from indoor air samples from occupied buildings and a grain mill were extracted and analyzed for their combined ( + , + ) cytotoxic, genotoxic and pro-inflammatory properties on human adenocarcinoma cells (A549) and monocytic leukemia cells induced in macrophages (THP-1 macrophages). Metabolite mixtures from the Aspergilli series increase the cytotoxic and genotoxic potency of extracts in A549 cells suggesting additive and/or synergistic effects, while antagonizing the cytotoxic potency of extracts in THP-1 macrophages and genotoxicity in A549 cells. All tested combinations significantly decreased IL-5 and IL-17, while IL-1β, TNF-α and IL-6 relative concentrations were increased.

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Certain macrolide antibiotics, azithromycin included, possess anti-inflammatory properties that are considered fundamental for their efficacy in the treatment of chronic inflammatory diseases, such as diffuse pan-bronchiolitis and cystic fibrosis. In this study, we disclose a novel azithromycin analog obtained via Barton-McCombie oxidation during which an unprecedented epimerization on the cladinose sugar occurs. Its structure was thoroughly investigated using NMR spectroscopy and compared to the natural epimer, revealing how the change in configuration of one single stereocenter (out of 16) profoundly diminished the antimicrobial activity through spatial manipulation of ribosome binding epitopes.

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Interleukin 17 (IL-17) cytokines promote inflammatory pathophysiology in many autoimmune diseases, including psoriasis, multiple sclerosis, rheumatoid arthritis, and inflammatory bowel disease. Such broad involvement of IL-17 in various autoimmune diseases makes it an ideal target for drug discovery. Psoriasis is a chronic inflammatory disease characterized by numerous defective components of the immune system.

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Novel imidazoline benzimidazole derivatives containing diversely substituted phenoxy moieties were synthesized with the aim of evaluating their antitrypanosomal activity, DNA/RNA binding affinity and in vitro ADME properties. The presence of the diethylaminoethyl subunit in 18a-18c led to enhanced antitrypanosomal potency, particularly for 18a and 18c, which contain unsubstituted and methoxy-substituted phenoxy moieties. They were found to be > 2-fold more potent against African trypanosomes than nifurtimox.

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Furanocoumarins, particularly furo[3,2-c]coumarins, are found in many natural products. However, coumarins annulated to a thiophene ring have received scarce attention to date in the literature. Therefore, we synthesized 4-oxo-4H-thieno[3,2-c]chromene derivatives and tested in vitro their anti-inflammatory activity.

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Extracellular Hsp70 (eHsp70) exerts its biological actions via Toll-like receptors 2 and 4, and is increased in sera of chronic obstructive pulmonary disease (COPD) patients. The aim of this study was to explore the pro-inflammatory effects and cytotoxicity of eHsp70 alone and in combination with bacterial components lipoteichoic acid (LTA) and lipopolysaccharide (LPS) on NCI-H292 airway epithelial cells. NCI-H292 cells were treated with recombinant human Hsp70 protein (rhHsp70), LPS, LTA and their combinations for 4, 12, 24 and 48 hours.

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The human histone demethylases of the KDM4 family have been related to diseases such as prostate and breast cancer. Majority of currently known inhibitors suffer from the low permeability and low selectivity between the enzyme isoforms. In this study, toxoflavin motif was used to design and synthesize new KDM4C inhibitors with improved biological activity and in vitro ADME properties.

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Autotaxin (ATX) is an extracellular enzyme that hydrolyses lysophosphatidylcholine (LPC) to lysophosphatidic acid (LPA), which has a role in the mediation of inflammation, fibrosis and cancer. ATX is a drug target that has been the focus of many research groups during the last ten years. To date, only one molecule, Ziritaxestat (GLPG1690) has entered the clinic; it is currently in Phase 3 clinical trials for idiopathic pulmonary fibrosis.

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Aspergilli section Flavi, originally isolated from air samples collected from inhabited apartments (AP), unoccupied basements (BS), and processing facilities of a grain mill (GM), were analyzed for their potential to produce aflatoxin B (AFB) on solid media. The isolates were further characterized with regard to their cytotoxic, genotoxic, and pro-inflammatory properties in vitro. Aspergilli were identified based on partial calmodulin (CaM) gene sequencing; the producing capacities of isolates were analyzed by HPLC/FLD and confirmed by genes in biosynthesis (aflR, norA, omtA).

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Extracellular Hsp70 (eHsp70) can act as damage-associated molecular pattern (DAMP) via Toll-like receptors TLR2 and TLR4, and stimulate immune and inflammatory responses leading to sterile inflammation and propagation of already existing inflammation. It was found elevated in the blood of patients with chronic obstructive pulmonary disease (COPD), who might suffer occasional bacterial colonizations and infections. We used a monocytic THP-1 cell line as a cellular model of systemic compartment of COPD to assess inflammatory effects of eHsp70 when present alone or together with bacterial products lypopolysaccharide (LPS) and lypoteichoic acid (LTA).

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Benzimidazo[1,2-a]quinolines and benzo[b]thieno[2,3-b]pyrido[1,2-a]benzimidazoles with amino chains on the different positions have been evaluated by 2D and 3D assays on the human breast cancer cells. Pentacyclic derivatives were synthesized by microwave assisted amination to study the influence of the thiophene substructure on antitumor activity in comparison to tetracyclic analogues. The results obtained from 2D assay reveals that the antitumor activity is strongly dependent on the nature and position of amino chains.

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A well-considered treatment of acute nerve agents poisoning involves the exogenous administration of butyrylcholinesterase (BChE, EC 3.1.1.

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Macrolides, as a class of natural or semisynthetic products, express their antibacterial activity primarily by reversible binding to the bacterial 50S ribosomal subunits and by blocking nascent proteins' progression through their exit tunnel in bacterial protein biosynthesis. Generally considered to be bacteriostatic, they may also be bactericidal at higher doses. The discovery of azithromycin from the class of macrolides, as one of the most important new drugs of the 20th century, is presented as an example of a rational medicinal chemistry approach to drug design, applying classical structure-activity relationship that will illustrate an impressive drug discovery success story.

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Due to a poor clinical predictive power of 2D cell cultures, standard tool for in vitro assays in drug discovery process, there is increasing interest in developing 3D in vitro cell cultures, biologically relevant assay feasible for the development of robust preclinical anti-cancer drug screening platforms. Herein, we tested amidino-substituted benzimidazoles and benzimidazo[1,2-a]quinolines as a small platform for comparison of antitumor activity in 2D and 3D cell culture systems and correlation with structure-activity relationship. 3D cell culture method was applied on a human cancer breast (SK-BR-3, MDA-MB-231, T-47D) and pancreatic cancer cells (MIA PaCa-2, PANC-1).

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In vitro high-throughput screening was carried out in order to detect new activities for old drugs and to select compounds for the drug development process comprising new indications. Tebrophen, a known antiviral drug, was found to inhibit activities on inflammation and cancer related targets. In primary screening this semisynthetic halogenated polyphenol was identified to inhibit the activities of kinases ZAP-70 and Lck (IC₅₀ 0.

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Macrolide antibiotics, like erythromycin, clarithromycin, and azithromycin, possess anti-inflammatory properties. These properties are considered fundamental to the efficacy of these three macrolides in the treatment of chronic inflammatory diseases like diffuse panbronchiolitis and cystic fibrosis. However, long-term treatment with macrolide antibiotics presents a considerable risk for promotion of bacterial resistance.

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A series of porphyrins, tetrapyrrole natural organic compounds, are evaluated here as endogenous anti-inflammatory agents. They directly inhibit the activity of Fyn, a non-receptor Src-family tyrosine kinase, triggering anti-inflammatory events associated with down-regulation of T-cell receptor signal transduction, leading to inhibition of tumor necrosis factor alpha (TNF-α) production. This is one of the major pro-inflammatory cytokines, associated with diseases such as diabetes, tumorigenesis, rheumatoid arthritis, and inflammatory bowel disease.

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Malaria remains one of the most widespread human infectious diseases, and its eradication will largely depend on antimalarial drug discovery. Here, we present a novel approach to the development of the azalide class of antimalarials by describing the design, synthesis, and characterization of novel 2'-O-substituted-9-deoxo-9a-methyl-9a-aza-9a-homoerythromycin A derivatives consisting of different quinoline moieties covalently liked to a 15-membered azalide scaffold at position 2'. By multistep straightforward synthesis, 19 new, stable, and soluble compounds were created and biologically profiled.

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Macrolides are stereospecific macrolactones of high molecular weights. Herein, 600 mostly semisynthetic macrolides are compared with 50,000 small non-macrolide synthetic molecules in terms of measured physicochemical properties in order to assess the drug-likeness and developability chances of macrolides. The pre-selected set of diverse macrolides is comprised mostly of derivatives of clarithromycin and azithromycin cores.

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Novel classes of antimalarial drugs are needed due to emerging drug resistance. Azithromycin, the first macrolide investigated for malaria treatment and prophylaxis, failed as a single agent and thus novel analogues were envisaged as the next generation with improved activity. We synthesized 42 new 9a-N substituted 15-membered azalides with amide and amine functionalities via simple and inexpensive chemical procedures using easily available building blocks.

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Azithromycin, a first member of the azalide family of macrolides, while having substantial antimalarial activity, failed as a single agent for malaria prophylaxis. In this paper we present the first analogue campaign to identify more potent compounds from this class. Ureas and thioureas of 15-membered azalides, N''-substituted 9a-(N'-carbamoyl-β-aminoethyl), 9a-(N'-thiocarbamoyl-β-aminoethyl), 9a-[N'-(β-cyanoethyl)-N'-(carbamoyl-β-aminoethyl)], 9a-[N'-(β-cyanoethyl)-N'-(thiocarbamoyl-β-aminoethyl)], 9a-{N'-[β-(ethoxycarbonyl)ethyl]-N'(carbamoyl-β-aminoethyl)}, and 9a-[N'-(β-amidoethyl)-N'-(carbamoyl-β-aminoethyl)] of 9-deoxo-9-dihydro-9a-aza-9a-homoerythromycin A, were synthesized and their biological properties evaluated.

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Tryptophol is an aromatic alcohol and secondary metabolite of the opportunistic fungus Candida albicans. Although its toxicity profile at cell level has been poorly investigated, recent data point to cytotoxic, cytostatic, and genotoxic effects in lymphocytes and the induction of apoptosis in leukaemic blood monocytes. In this pilot study we evaluated the genotoxicity of tryptophol in vitro on four permanent cell lines of animal and human origin: ovary cells, alveolar epithelium, liver cells, and blood monocytes using the alkaline comet assay.

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In this paper synthesis of macrolones 1-18 starting from azithromycin is reported. Two key steps in the construction of the linker between macrolide and quinolone moiety, are formation of central ether bond by alkylation of unactivated OH group, and formation of terminal C-C bond at 6-position of the quinolone unit. Due to the difficulty in formation of these two bonds the study of alternative synthetic methodologies and optimization of the conditions for the selected routes was required.

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