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A total of 14 of 1,5-disubstituted tetrazole derivatives were prepared by reacting appropriate thiourea and sodium azide in the presence of mercury (II) chloride and triethylamine. All compounds were evaluated in vitro for their antimicrobial activity. Derivatives 10 and 11 showed the highest inhibition against Gram-positive and Gram-negative strains (standard and hospital strains). The observed minimal inhibitory concentrations values were in the range of 1–208 μM (0.25–64 μg/ml). Inhibitory activity of 1,5-tetrazole derivatives 10 and 11 against gyrase and topoisomerase IV isolated from S. aureus was studied. Evaluation was supported by molecular docking studies for all synthesized derivatives and reference ciprofloxacin. Moreover, selected tetrazoles (2, 3, 5, 6, 8, 9, 10 and 11) were evaluated for their cytotoxicity. All tested compounds are non-cytotoxic against HaCaT and A549 cells (CC50 ≤ 60 μM).

Five of thiourea derivatives were prepared using as a starting compound 3-(trifluoromethyl)aniline, 4-chloro-3-nitroaniline, 1,3-thiazol- 2-amine, 2H-1,2,3-triazol-4-amine and commercial isothiocyanates. All compounds were evaluated in vitro for antimicrobial activity. Derivatives 2 and 3 showed the highest inhibition against Gram-positive cocci (standard and hospital strains). The observed MIC values were in the range of 0.5–8 μg/ml. The products effectively inhibited the formation of biofilms of methicillin-resistant and standard strains of Staphylococcus epidermidis. Inhibitory activity of thioureas 2 and 3 against Staphylococcus aureus topoisomerase IV was studied. The examined compounds were nongenotoxic.

4-Chloro-3-nitrophenylthioureas 1&ndash, 30 were synthesized and tested for their antimicrobial and cytotoxic activities. Compounds exhibited high to moderate antistaphylococcal activity against both standard and clinical strains (MIC values 2&ndash, 64 &mu, g/mL). Among them derivatives with electron-donating alkyl substituents at the phenyl ring were the most promising. Moreover, compounds 1&ndash, 6 and 8&ndash, 19 were cytotoxic against MT-4 cells and various other cell lines derived from human hematological tumors (CC50 &le, 10 &mu, M). The influence of derivatives 11, 13 and 25 on viability, mortality and the growth rate of immortalized human keratinocytes (HaCaT) was observed.

Monensin A (MON) is a polyether ionophore antibiotic, which shows a wide spectrum of biological activity. New MON derivatives such as double-modified ester-carbonates and double-modified amide-carbonates were obtained by a new and efficient one-pot synthesis with triphosgene as the activating reagent and the respective alcohol or amine. All new derivatives were tested for their antiproliferative activity against two drug-sensitive (MES-SA, LoVo) and two drug-resistant (MES-SA/DX5, LoVo/DX) cancer cell lines, and were also studied for their antimicrobial activity against different Staphylococcus aureus and Staphylococcus epidermidis bacterial strains. For the first time, the activity of MON and its derivatives against MES-SA and MES-SA/DX5 were evaluated.

A total of 31 of thiourea derivatives was prepared reacting 3-(trifluoromethyl)aniline and commercial aliphatic and aromatic isothiocyanates. The yields varied from 35% to 82%. All compounds were evaluated in vitro for antimicrobial activity. Derivatives 3 , 5 , 6 , 9 , 15 , 24 and 27 showed the highest inhibition against Gram-positive cocci (standard and hospital strains). The observed MIC values were in the range of 0.25–16 μg/ml. Inhibitory activity of thioureas 5 and 15 against topoisomerase IV isolated from Staphylococcus aureus was studied. Products 5 and 15 effectively inhibited the formation of biofilms of methicillin-resistant and standard strains of Staphylococcus epidermidis . Moreover, all obtained thioureas were evaluated for cytotoxicity and antiviral activity against a large panel of DNA and RNA viruses. Compounds 5, 6 , 8–12 , 15 resulted cytotoxic against MT-4 cells (CC 50 ≤ 10 μM).

A series of novel amino acid and dipeptide derivatives of neocryptolepine were synthesized and tested for their antimicrobial, antifungal and antiproliferative activity in vitro against cancer cell lines (KB, A549, MCF-7, LoVo) and normal mice fibroblast cells (BALB/3T3). Biological evaluation revealed that almost all of the new compounds displayed high antiproliferative activity against the tested cells and moderate to potent antibacterial activities. Interestingly, these compounds were active against Candida albicans biofilms at doses significantly lower than those required against free-floating planktonic fungal cells. The most promising compounds are derivatives with glycine and L-proline as a substituent both at 2 and at 9 position of 5H-indolo[2,3-b]quinoline. In general, these new compounds (2a, 3a, 6a and 7a) showed the highest dual action against cancer lines and infectious pathogenic microbes in vitro.

The aim of this study was comparison of antioxidant, anti-inflammatory, and antimicrobial activity, as well as chemical composition of extracts of Tropaeolum majus L. herb. Aqueous and hydroethanolic extracts derived from dried and freeze-dried nasturtium herb, prepared both at room temperature and at 90 °C, were studied. In the studies there were no significant differences between antioxidant activity of the extracts. All extracts showed scavenging activity against all the examined reactive species in a concentration-dependent manner. The strongest scavenging activity they showed against reactive nitrogen species, NO (SC50 4.54 ± 0.26–10.90 ± 1.39 μg/mL) and ONOO − (SC50 2.49 ± 1.50–6.37 ± 1.86 μg/mL). Among reactive oxygen species, they showed strong scavenging activity against H 2 O 2 (SC50 14.90 ± 3.91–38.63 ± 9.28 μg/mL). Scavenging activity against O 2 − was weaker, while against HClO the extracts showed very weak activity, practically at the level of statistical error. Against synthetic radical – DPPH scavenging activity of the tested extracts was negligible. The extracts demonstrated stronger antioxidant activity in ex vivo experiment on human neutrophils. The extracts showed no inhibitory activity on hyaluronidase, but at a concentration of 50 μg/mL they inhibited the activity of COX1 by approximately 60%. Lack of antimicrobial activity of the extracts seems to be associated with a low content of benzyl isothiocyanate. The aqueous extracts were characterized by the presence of esters of quinic acid with cinnamic acids (chlorogenic acids, p-coumaroylquinic acids) and the presence of flavonoids. Meanwhile the hydroethanolic extracts were mainly rich in the above mentioned acid esters.

Two new complexes of the ionophore antibiotic Lasalocid acid (LAS) with phenylamine (PhA) and butylamine (BuA) were synthesized and their molecular structures were studied using single crystal X-ray diffraction and spectroscopic methods. In the solid state both amines are protonated and all NH 3 + protons are hydrogen bonded to etheric, hydroxyl and carboxylic oxygen atoms of the LAS anion. In chloroform solutions the structure observed in the crystal of LAS–BuA complex is preserved and an equilibrium between the LAS–PhA complex and dissociated Lasalocid acid and phenylamine is observed. In vitro antimicrobial tests of the complexes showed a significant activity towards some strains of Gram-positive bacteria. For the first time Lasalocid acid and its complexes with amines were tested in vitro for cytotoxic activity against human cancer cell lines: A-549 (lung), MCF-7 (breast), HT-29 (colon) and mouse cancer cell line P-388 (leukemia). We found that LAS and its complexes are strong cytotoxic agents towards all tested cell lines. The cytostatic activity of the compounds studied is greater than that of cisplatin, indicating that Lasalocid and its complexes are promising candidates for new anticancer drugs.

For the first time a direct and practical approach to the synthesis of eight amide derivatives of polyether antibiotic-salinomycin is described. The structure of allyl amide (3a) has been determined using X-ray diffraction. Salinomycin and its amide derivatives have been screened for their in vitro antimicrobial activity against the typical gram-positive cocci, gram-negative rods and yeast-like organisms, as well as against a series of clinical isolates of methicillin-resistant Staphylococcus aureus and methicillin-sensitive S. aureus. Amides of salinomycin have been found to show a wide range of activities, from inactive at 256 μg/mL to active with MIC of 2 μg/mL, comparable with salinomycin. As a result, phenyl amide (3b) was found to be the most active salinomycin derivative against gram-positive bacteria, MRSA and MSSA.

Halogen derivatives of selected 3-benzofurancarboxylic acids were prepared using 6-acetyl-5-hydroxy-2-methyl-3-benzofuranocarboxylic acid as starting material. (1)H-NMR spectra were obtained for all of the synthesized structures, and for compound VI, an X-ray crystal structure was also obtained. All derivatives were tested for antimicrobial activity against a selection of Gram-positive cocci, Gram-negative rods and yeasts. Three compounds, III, IV, and VI, showed antimicrobial activity against Gram-positive bacteria (MIC 50 to 200 microg/mL). Compounds VI and III exhibited antifungal activity against the Candida strains C. albicans and C. parapsilosis (MIC-100 microg/mL).

Antibacterial and antifungal activity of 10-(diphenylmethylene)-4-azatricyclo[5.2.1.02,6]dec-8-ene-3,5-dione derivatives were examined by the disk diffusion method (growth inhibition zone diameter in agar medium). The minimal inhibitory concentrations (MICs) for the most active agents were determined. Title compounds were also evaluated in vitro against HIV-1 virus and their cytotoxicity was determined. Aminoalkanol derivatives exhibited activity against the majority of microorganisms studied.

Four 4-aryl-3-(2-methyl-furan-3-yl)-Δ2-1,2,4-triazole-5-thiones were synthesized by intramolecular cyclization of 4-aryl-1-[(2-methyl-furan-3-yl)carbonyl]thiosemicarbazides in alkaline medium. The antimicrobial activity of the synthesized triazoles was evaluated. Semiempirical calculations of geometries, energies, and QSAR parameters have been determined in the hope of gaining insight into different biological activities of closely related isomers. New RM1 parameterization has been shown to perform very well for this class of compounds.

A series of 13 new ether-linked derivatives of 2,2-dimethyl-2,3-dihydro-7-benzo[b]furanol have been designed and synthesized. Ten of them were evaluated for their potential antimicrobial activity against some Gram-positive and Gram-Negative bacteria and fungi of the Candida species.

Anhydrides, imides, N-ethylimides, N-hydroxyimides and N-aminoimides of 1,4,5,6-tetramethyl-bicyclo[5.2.1.0 2,6 ]hept-5-ene-2,3-dicarboxylic acid, 1,4,5,6,7-pentamethyl-bicyclo[5.2.1.0 2,6 ]hept-5-ene-2,3-dicarboxylic acid and 7-ethyl-1,4,5,6-tetramethyl-bicyclo[5.2.1.0 2,6 ]hept-5-ene-2,3-dicarboxylic acid were obtained. Antimicrobial activity of the newly obtained derivatives was tested against selected Gram-positive and Gram-negative bacteria and fungi of the Candida species. The structures of obtained compounds and their antimicrobial activity were compared. Structure of 1b, 2b and 1e were determined by an X-ray analysis.

A series of nineteen new thiourea and urea derivatives of 10-isopropyl-8-methyl-4-azatricyclo[5.2.2.0(2,6)]undec-8-ene-3,5-dione, 1-isopropyl-7-methyl-4-azatricyclo[5.2.2.0(2,6)]undec-8-ene-3,5-dione and 1,7,8,9,10-pentamethyl-4-azatricyclo[5.2.1.0(2,6)]dec-8-ene-3,5-dione have been prepared and studied by (1)H-NMR. The compound k1a (1-(1,7,8,9,10-pentamethyl-3,5-dioxo-4-aza-tricyclo[5.2.1.0(2,6)]dec-8-en-4-yl)-3-phenyl-urea) was tested for pharmacological activity on animal central nervous system (CNS). The activities of synthesized compounds were evaluated for their cytotoxicity and anti-HIV-1 activity in MT-4 cells. Antimicrobial activity of the newly obtained derivatives was tested against some Gram-positive and Gram-negative bacteria and fungi of the Candida species.

A series of new thiourea derivatives of 1,3-thiazole have been synthesized. All obtained compounds were tested in vitro against a number of microorganisms, including Gram-positive cocci, Gram-negative rods and Candida albicans. Compounds were also tested for their in vitro tuberculostatic activity against the Mycobacterium tuberculosis H37Rv strain, as well as two 'wild' strains isolated from tuberculosis patients. Compounds 3 and 9 showed significant inhibition against Gram-positive cocci (standard strains and hospital strain). The range of MIC values is 2-32 µg/mL. Products 3 and 9 effectively inhibited the biofilm formation of both methicillin-resistant and standard strains of S. epidermidis. The halogen atom, especially at the 3rd position of the phenyl group, is significantly important for this antimicrobial activity. Moreover, all obtained compounds resulted in cytotoxicity and antiviral activity on a large set of DNA and RNA viruses, including Human Immunodeficiency Virus type 1 (HIV-1) and other several important human pathogens. Compound 4 showed activity against HIV-1 and Coxsackievirus type B5. Seven compounds resulted in cytotoxicity against MT-4 cells (CC50

A set of 21 thiourea derivatives were prepared through reacting 3-amino-1H-1,2,4-triazole with the commercial aliphatic and aromatic isothiocyanates. The aliphatic isothiocyanate was used as reagent leading to substitution on NH atom of 3-aminotriazole ring, whereas the triazole amino group was substituted when isothiocyanate group was bonded to the Csp2 hybridized atom, e.g. an aryl or C=O fragment. All compounds were evaluated in vitro for the antimicrobial activity. The derivatives 1, 2, 4, 8, 9, 10 and 12 showed the highest inhibition against Gram-positive cocci (S. aureus and S. epidermidis). The observed MIC values were in the range of 4-32 μg/mL. Compounds were also tested for their in vitro antimicrobial activity against the hospital methicillin-resistant strains of S. aureus. The observed MIC values varied from 4 to 64 μg/mL. The products 4 and 10 effectively inhibited the formation of biofilms of the methicillin-resistant and standard strains of S. epidermidis. The compound 10 was found to be more promising with IC50 values of 2-6 μg/mL as compared to the control. Moreover, the cytotoxicity against the MT-4 cells of all studied thioureas was evaluated. The compound 18 was significantly cytotoxic (CC50 = 8 μM).

A series of 1,3,4-thiadiazoles and s-triazoles were subjected to Molinspiration, ALOGPS 2.1, and Osiris programs to predict their molecular properties that are important for drug candidates. Subsequently, all of them were docked into the active sites of enzymes namely glucosamine-6-phosphate synthase (GlcN-6-P), VIM-2 metallo-β- lactamase (VIM-2), chitinase A1 (ChiA1), and sterol 14 alpha-demethylase (CYP51) that were considered in antimicrobial studies of thiadiazole and s-triazole derivatives. Since all compounds fulfilled the criteria for good membrane permeability, oral bioavailability, low toxicity and the potential inhibitory activities towards VIM-2, ChiA1, and CYP51, most of them were synthesized and their antimicrobial activity has been tested.

In this study novel thiosemicarbazides bearing piperidine moiety were synthesized in order to investigate their possible antibacterial and antifungal activities. A structure-activity relationship (SAR) study including conformational analysis and some physicochemical descriptors was carried out to provide the guidance for further synthetic work. The significant molecular descriptors related to the compounds with antifungal activity were: electrostatic potential surface, the highest occupied molecular orbital energy, surface area, volume, and hydration energy.

Using Gossypol (GOS) extracted from cotton seeds, a series of its Schiff bases (1-18) and hydrazones (19-27) have been synthesized and evaluated for their antimicrobial activities against Gram-positive bacteria, Gram-negative bacteria and yeast-like organisms. Of the 27 aza-derivatives of gossypol, 11 have been found active against the microorganisms tested, similar to gossypol. Crystal structures of the new Schiff base (compound 7) and hydrazone (compound 25) of gossypol reveal the presence of two different tautomers within two types of the aza-derivatives studied. The newly synthesized aza-derivatives of gossypol are characterized by the FT-IR, NMR and MS methods.

The esters (2–10) of the ionophore antibiotic Monensin (1) were synthesized by four different methods, which are discussed in detail. These new esters were characterized by various spectroscopic techniques and subsequently tested in the face of their antimicrobial properties. Three derivatives (3, 8 and 10) showed activity against Gram-positive bacteria. Additionally derivative (10) exhibited a relatively low antifungal activity against Candida in contrast to Monensin A.

Staphylococcus epidermidis, a coagulase-negative Staphylococcus, is the most important pathogen responsible for chronic nosocomial infections. These bacteria produce extracellular slime and form biofilms on various biotic and abiotic surfaces. Bacterial biofilms are very resistant to standard antimicrobial therapy and difficult to eradicate, so it is important to search for new more effective anti-biofilm agents, for example in the group of natural substances. The aim of the study was to examine the activity of two ionophores-salinomycin and monensin against clinical S. epidermidis strains, using MIC/MBC method and biofilm formation inhibition assay. Bacterial strains were tested also for slime production using Congo Red Agar. Both tested ionophore antibiotics showed the highest activity against planktonic bacteria of clinical as well as standard S. epidermidis strains and effectively inhibited the formation of bacterial biofilm.