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Tropical parasitic diseases like leishmaniasis pose significant public health challenges, impacting millions of individuals globally. Current drug treatments for these diseases have notable drawbacks and side effects, underscoring the pressing need for new medications with improved selectivity and reduced toxicity. Through structural modifications of both natural and synthetic compounds using click chemistry, researchers have been able to produce derivatives showing promising activity against these parasites. In this study, 21 novel 1,2,3-triazole analogues of totarol were synthesized using O-propargylated totarol derivatives and substituted arylazide. These compounds were characterized through various analytical techniques, including 1 H NMR, 13 C NMR, and HRMS. An x-ray crystallographic study of compounds 4 and 6 was carried out to fully establish the structure of the newly prepared totarol derivatives. All synthesized compounds were then screened in vitro for their antileishmanial activities against Leishmania major promastigotes, amastigotes, and Toxoplasma gondii tachyzoites Out of the tested analogues, six compounds (7c, 8b-e, and 9 g) displayed antileishmanial activity against L. major amastigotes with IC 50 17.3, 14.2, 13.1 18.2 13.2 and 17.3 μg mL -1 respectively, while only 8e gave antileishmanial activity against both promastigotes and amastigotes with IC 50 11.7 and 13.2 μg mL -1 respectively. Additionally, the presence of a nitro group was correlated with enhanced antileishmanial activity. Moreover, a molecular docking study was conducted, focusing on 8e, the most active antileishmanial compound, to elucidate its putative binding pattern at the active site of the selected leishmanial trypanothione reductase target., (© 2025 John Wiley & Sons Ltd.)

The regiospecific reduction of 4,6-dinitrobenzimidazole derivatives leading to the corresponding 4-amino-6-nitrobenzimidazoles was studied. The identification of the formed product structures was accomplished by spectroscopic and X-ray diffraction data. The anticancer and antiparasitic activities of the synthesized compounds were examined, and promising activities against Toxoplasma gondii and Leishmania major parasites were discovered for certain 4,6-dinitrobenzimidazoles in addition to moderate anticancer activities of the 4-amino-6-nitrobenzimidazole derivatives against T. gondii cells. However, the tumor cell experiments revealed a promising sensitivity of p53-negative colon cancer cells to these compounds., (© 2023 The Authors. Chemistry & Biodiversity published by Wiley-VHCA AG, Zurich, Switzerland.)

A new 3,4-difluorobenzylidene analog of curcumin, CDF, was recently reported, which demonstrated significantly enhanced bioavailability and in vivo anticancer activity compared with curcumin. For highlighting the antiparasitic behavior of CDF, we tested this compound together with its new O-methylated analog MeCDF against Leishmania major and Toxoplasma gondii parasites. Both CDF and MeCDF were tested in vitro against L. major and T. gondii. In addition, the in vitro cytotoxicity against Vero cells and macrophages was determined and selectivity indices were calculated. The DPPH radical scavenging activity assay was carried out in order to determine the antioxidant activity of the test compounds. Both compounds showed high activities against both parasite forms with EC 50 values in the (sub-)micromolar range (0.35 to 0.8 μM for CDF, 0.31 to 1.2 μM for MeCDF). The higher activity of CDF against L. major amastigotes when compared with MeCDF can in parts be attributed to the antioxidant activity of CDF while MeCDF lacking any antioxidant activity was more active than CDF against T. gondii parasites. In conclusion, CDF and MeCDF are promising antiparasitic drug candidates due to their high activities against L. major and T. gondii parasites., (© 2021 The Authors. Chemistry & Biodiversity published by Wiley-VHCA AG, Zurich, Switzerland.)

A series of the title curcuminoids with structural variance in the heteroatom of the cycloalkanone and the p-substituents of the phenyl rings were tested for their activities against Leishmania major and Toxoplasma gondii parasites. The majority of them showed high activities against both parasite forms with EC 50 values in the sub-micromolar concentration range. Bis(p-pentafluorothio)-substituted 3,5-di[(E)-benzylidene]piperidin-4-one 1b was not just noticeable antiparasitic, but also exhibited a considerable selectivity for L. major promastigotes over normal Vero cells. While derivatives differing only in the p-phenyl substituents being CF 3 or SF 5 showed similar antiparasitic activities, the cyclic ketone hub was more decisive both for the anti-parasitic activities and the selectivities for the parasites vs. normal cells. QSAR calculations confirmed the observed structure-activity relations and suggested structural variations for a further improvement of the antiparasitic activity. Docking studies based on DFT calculations revealed L. major pteridine reductase 1 as a likely molecular target protein of the title compounds., (Copyright © 2021. Published by Elsevier Inc.)

A series of new lawsone Mannich bases derived from salicylaldehydes or nitrofurfural were prepared and tested for their activities against Leishmania major, Toxoplasma gondii, and Trypanosoma brucei brucei parasites. The hydrochloride salts 5a and 6a of the Mannich bases 2a and 3a, derived from unsubstituted salicylaldehyde and long-chained alkyl amines, were selectively and strongly active against T. gondii cells and appear to be new promising drug candidates against this parasite. Compound 6a showed an even higher activity against T. gondii than the known lawsone Mannich base 1b. Compound 4a, derived from salicylaldehyde and 2-methylaminopyridine, was also distinctly active against T. gondii cells. The derivatives 3a (salicyl derivative), 3b (3,5-dichloro-2-hydroxyphenyl derivative), and 3d (5-nitrofuranyl derivative) as well as the hydrochlorides 6a and 6b were also efficacious against T. b. brucei cells with compounds 3a and 3b being more selective for T. b. brucei over Vero cells when compared with the known control compound 1b. The derivatives 5a, 5c, 6a, and 6c proved to be up to five times more active than 1b against L. major promastigotes and up to four times more efficacious against L. major amastigotes., (© 2019 Deutsche Pharmazeutische Gesellschaft.)

Background: New drugs for the treatment of protozoal parasite infections such as toxoplasmosis and leishmaniasis are required. Cinnamaldehyde and its derivatives appear to be promising antiparasitic drug candidates. Methods: Acyl hydrazones of cinnamaldehyde, 4-dimethylaminocinnamaldehyde, and of the synthetic fragrances silvialTM and florhydralTM were prepared and tested for activity against Toxoplasma gondii (T. gondii) and Leishmania major (L. major) parasites. Results: Three cinnamaldehyde acyl hydrazones (3-hydroxy-2-naphthoyl 2a and the salicyloyls 2c and 2d) showed good activity against T. gondii, and two compounds derived from cinnamaldehyde and florhydralTM (3-hydroxy-2-naphthoyls 2a and 4a) exhibited moderate activity against L. major promastigotes. Conclusions: In particular, the identified antitoxoplasmal activities are promising and might lead to the development of new potent and cost-effective drug candidates for the therapy of toxoplasmosis. [ABSTRACT FROM AUTHOR]

This study outlines the synthesis of pyrazine sulfonamides (3 a–3 i) along with halo‐phenyl derivatives (4 a–4 j and 5 a–5 e). The antiproliferative effects were tested against MCF‐7 breast cancer, and colon carcinoma HT‐29, HCT‐116 WT, and HCT‐116 p53 knock‐out mutant cell lines. Compounds 3 b and 3 c were notably active against HCT‐116 WT cells, while 3 e and 3 h were moderately effective against MCF‐7 cells. Among the halo‐phenyl sulfonamides, 4e and 4j were active against MCF‐7 cells, and 5 b was active against HCT‐116 WT cells. The most promising compounds were evaluated against non‐tumorigenic cells, demonstrating cancer selectivity. Compounds 3 b, 3 c, 3 e, 3 h, and 5 b showed dose‐dependent inhibition of colony formation. Compound 3 f exhibited free radical scavenging activity comparable to ascorbic acid. Molecular docking revealed strong binding to thymidylate synthase (3 b, 5 b), Akt‐3 protein kinase (3 e, 3 h, 4 e, 4 j), and tyrosinase (3 f, 3 h). The compounds also exhibited antiparasitic activity against Toxoplasma gondii and Leishmania major, with modifications enhancing selectivity for T. gondii. Substitutions in compounds 4 b and 4 d increased activity against T. gondii while reducing toxicity. Notably, compound 4 f emerged as a T. gondii‐selective lead drug. These findings suggest sulfonamides may help treat complex diseases like cancer and infections. [ABSTRACT FROM AUTHOR]

A series of [RuCl2(p-cymene)(NHC)] complexes were obtained by reacting [RuCl2(p-cymene)]2 with in situ generated Ag-N-heterocyclic carbene (NHC) complexes. The structure of the obtained complexes was determined by the appropriate spectroscopy and elemental analysis. In addition, we evaluated the biological activities of these compounds as antienzymatic, antioxidant, antibacterial, anticancer, and antiparasitic agents. The results revealed that complexes 3b and 3d were the most potent inhibitors against AchE with IC50 values of 2.52 and 5.06 μM mL−1. Additionally, 3d proved very good antimicrobial activity against all examined microorganisms with IZ (inhibition zone) over 25 mm and MIC (minimum inhibitory concentration) < 4 µM. Additionally, the ligand 2a and its corresponding ruthenium (II) complex 3a had good cytotoxic activity against both cancer cells HCT-116 and HepG-2, with IC50 values of (7.76 and 11.76) and (4.12 and 9.21) μM mL−1, respectively. Evaluation of the antiparasitic activity of these complexes against Leishmania major promastigotes and Toxoplasma gondii showed that ruthenium complexes were more potent than the free ligand, with an IC50 values less than 1.5 μM mL−1. However, 3d was found the best one with SI (selectivity index) values greater than 5 so it seems to be the best candidate for antileishmanial drug discovery program, and much future research are recommended for mode of action and in vivo evaluation. In general, Ru-NHC complexes are the most effective against L. major promastigotes. [ABSTRACT FROM AUTHOR]

A series of fourteen pyrimido[1,2-a]benzimidazole compounds was prepared by straightforward heterocyclic chemistry and oxidation methods. The new pyrimidobenzimidazole derivative 2a with a 3-fluorophenyl substituent was identified as a new antiparasitic compound showing excellent activities against Leishmania major parasites. 2a was highly active against L. major promastigotes and amastigotes with EC50 values in the nanomolar concentration range. Compound 3b was less active than 2a against L. major, but more active against Toxoplasma gondii with considerable selectivity. Hence, two promising and selective antiparasitic drug candidates 2a and 3b for the treatment of two parasitic diseases were identified, which can be prepared by green chemistry methods using simple one-pot reactions and oxidation procedures, respectively. [ABSTRACT FROM AUTHOR]

Gold(I) complexes carrying imidazole‐2‐ylidene ligands and ferrocene substituents were prepared. Their activities against protozoal Leishmania major and Toxoplasma gondii parasites were analyzed. Certain gold(I) complexes with chlorido and 1,1′‐bis(triphenylphosphino)ferrocene ligands revealed promising antiparasitic effects. The new chlorido complexes 5b and 5c showed high activities against T. gondii tachyzoites and L. major promastigotes while the new ferrocene‐bridged bis‐gold(I) complexes 8a and 8b were particularly active against L. major amastigotes and considerably selective as to toxicity results from Vero cells and macrophages. [ABSTRACT FROM AUTHOR]

Leishmaniasis, a neglected tropical parasitic disease (NTPD), is caused by various Leishmania species. It transmits through the bites of the sandfly. The parasite is evolving resistance to commonly prescribed antileishmanial drugs; thus, there is an urgent need to discover novel antileishmanial drugs to combat drug-resistant leishmaniasis. Thymoquinone (2-isopropyl-5-methyl-1,4-benzoquinone; TQ), a primary pharmacologically active ingredient of Nigella sativa (black seed) essential oil, has been reported to possess significant antiparasitic activity. Therefore, the present study was designed to investigate the in vitro and in silico antileishmanial activity of TQ against various infectious stages of Leishmania major (L. major), i.e., promastigotes and amastigotes, and its cytotoxicity against mice macrophages. In silico molecular dockings of TQ were also performed with multiple selected target proteins of L. major, and the most preferred antileishmanial drug target protein was subjected to in silico molecular dynamics (MD) simulation. The in vitro antileishmanial activity of TQ revealed that the half-maximal effective concentration (EC50), half-maximal cytotoxic concentration (CC50), and selectivity index (SI) values for promastigotes are 2.62 ± 0.12 μM, 29.54 ± 0.07 μM, and 11.27, while for the amastigotes, they are 17.52 ± 0.15 μM, 29.54 ± 0.07 μM, and 1.69, respectively. The molecular docking studies revealed that squalene monooxygenase is the most preferred antileishmanial drug target protein for TQ, whereas triosephosphate isomerase is the least preferred. The MD simulation revealed that TQ remained stable in the binding pocket throughout the simulation. Additionally, the binding energy calculations using Molecular Mechanics Generalized-Born Surface Area (MMGBSA) indicated that TQ is a moderate binder. Thus, the current study shows that TQ is a promising antileishmanial drug candidate that could be used to treat existing drug-resistant leishmaniasis. [ABSTRACT FROM AUTHOR]

In this work, efficient synthesis of isoindolin‐1‐one‐3‐phosphonates under catalyst‐ and solvent‐free conditions was reported to afford the desired compounds in excellent yields with potent pharmacological properties. The synthesis method involves the preparation of isoindolin‐1‐one‐3‐phosphonates by a "one‐pot" three‐component reaction of 2‐formylbenzoic acid with primary amines and dimethyl phosphite under solvent‐ and catalyst‐free conditions. All new compounds were characterized by 1H NMR, 13C NMR, FT‐IR and elemental analysis techniques. The compounds were investigated for their bioactivities against a group of microorganisms, Leishmania major, Toxoplasma gondii parasites, and the DA‐MB‐231 and MCF‐7 cancer cell lines in vitro. Compound 4a was found to be the most active against L. M. luteus, L. monocytogenes and C. albicans microorganisms, with inhibition zones of 35, 22 and 38 mm, respectively. The compounds were also investigated for their antiparasitic activities, and compounds 4a and 4b were the most active against L. major amastigotes and promastigotes with EC50 < 1 μM. All tested compounds had potent anticancer activity against the MDA‐MB‐231 and MCF‐7 human cell lines with EC50 < 1.5 μM. Compounds 4a and 4b are good drug candidates for antimicrobial, antileishmanial and anticancer drug discovery, and further in vivo studies are highly recommended prior to any clinical trials. [ABSTRACT FROM AUTHOR]

New benzimidazolium salts were synthesized as N-heterocyclic carbene precursors. These NHC precursors were metallated with Cu2O and CuI in acetone and water under reflux to give novel copper(I) complexes. The structures of these benzimidazolium salts and copper(I) complexes were characterized on the basis of elemental analysis, 1H NMR, 13C NMR, IR and LC–MS spectroscopic techniques. The (NHC)Cu(I) complexes 3–4 were tested against MCF7 and MDA-MB-231 cancer cells, Escherichia coli, methicillin-resistant Staphylococcus aureus (MRSA) and Candida albicans microorganisms, Leishmania major promastigotes and amastigotes, Toxoplasma gondii parasites and against Vero cell line in vitro. The synthesized copper NHC carbene complex 4b (1,3-bis(2,3,4,5,6-pentamdthylbenzyl)-2,3-dihydro-1H-benzo[d]imidazol-2-yl)copper(I) chloride) was the most active against MCF7 cancer cells (half growth Inhibition Concentrations (IC50) = 0.3 µg mL−1), as well as the most potent antimicrobial against E. coli (inhibition zone (IZ) = 23.3 mm), MRSA (IZ = 25.5 mm) and C. albicans (IZ = 28.5 mm) besides its antileishmanial activities against L. major promastigotes and amastigotes (IC50 < 0.04 µg mL−1). Compound 4c (1,3-bis(4-(tert-butyl)benzyl)-2,3-dihydro-1H-benzo[d]imida-zol-2-yl)copper(II) bromide) is the most potent anticancer against MDA-MB-231 cancer cells IC50 = 0.4 µg mL−1). Compound 4e (5,6-dimethyl-1,3-bis(2,4,6-trimethylbenzyl)-2,3-dihydro-1H-benzo[d]imidazol-2-yl)copper(I) chloride) is the best suitable antitoxoplasmal drug candidate due to its SI of 16.5. These candidates need further study to identify mode of action and drug standardization. [ABSTRACT FROM AUTHOR]

Miscellaneous imines and acyl hydrazones were prepared from 5-nitrofuraldehyde and 5-nitrothiophene-2-carboxaldehyde. Their activities against Toxoplasma gondii and Leishmania major parasites were evaluated. Promising antiparasitic effects and selectivities were observed for certain acyl hydrazones and imines. Cobalt(II) and copper(II) complexes conserved the high anti-Toxoplasma activities of 3-hydroxy-2-naphthoic carboxyl hydrazone (2a). In addition, sound activities against L. major promastigotes were observed for various analogs of 2a (2b and 2i) and pyrid-2-ylpyrazole-based imines (3g and 3h). Relatively low toxicities to kidney cells and macrophages indicate promising selectivity profiles for these compounds. [ABSTRACT FROM AUTHOR]

N-heterocyclic carbene (NHC) precursors (2a–i), their pyridine-enhanced precatalyst preparation stabilization and initiation (PEPPSI)-themed palladium N-heterocyclic carbene complexes (3a–i) and palladium N-heterocyclic triphenylphosphines complexes (4a–i) were synthesized and characterized by elemental analysis and 1H NMR, 13C NMR, IR, and LC–MS spectroscopic techniques. The (NHC)Pd(II) complexes 3–4 were tested against MCF7 and MDA-MB-231 cancer cells, Escherichia coli, methicillin-resistant Staphylococcus aureus (MRSA), Candida albicans microorganisms, Leishmania major promastigotes and amastigotes, Toxoplasma gondii parasites, and Vero cells in vitro. The biological assays indicated that all compounds are highly active against cancer cells, with an IC50 < 1.5 µg mL−1. Eight compounds proved antibacterial and antileishmanial activities, while only three compounds had strong antifungal activities against C. albicans. In our conclusion, compounds 3 (b, f, g, and h) and 4b are the most suitable drug candidates for anticancer, antimicrobial, and antiparasitical. [ABSTRACT FROM AUTHOR]

[Display omitted] • New (η6-arene)dichloridoruthenium(II) complexes of antifungal azoles were prepared and tested for anti-parasitic activity. • T. gondii and L. major parasite growth was inhibited at low micromolar concentrations. • Acceptable selectivity for T. gondii over Vero kidney and macrophage cells was observed for one new complex. • Positive Tg CDPK1 docking and ADME-T results were obtained. A series of six (η6-arene)Ru(II) complexes with antifungal imidazole drug ligands such as clotrimazole, bifonazole and climbazole was prepared and analyzed. They were tested for their activities against Leishmania major and Toxoplasma gondii parasites, and were compared with the activities of the metal-free azole ligands. Activities superior to those of the azole ligands were observed for the Ru complexes, which indicate the beneficial role of the (η6-arene)ruthenium(II) moiety in terms of antiparasitic properties. The modifications of the arene ligand also played a role in the biological activity. Docking of selected ruthenium complexes into T. gondii kinase CDPK1 and ADME-T calculations revealed promising binding affinities and drug-like properties. [ABSTRACT FROM AUTHOR]

[Display omitted] • 1 H -Indeno[2′,1′:5,6]dihydropyrido[2,3- d ]pyrimidine and 1 H -indeno[2′,1′:5,6]pyrido[2,3- d ]pyrimidine derivatives were prepared. • High activity against Toxoplasma gondii parasites and Leishmania major amastigotes was observed. • A catechol derivative inhibits HIV-1 RT-associated RNase H. • Docking and ADME-T calculations confirmed drug-like properties of active compounds. A series of 1 H -indeno[2′,1′:5,6]dihydropyrido[2,3- d ]pyrimidine and 1 H -indeno[2′,1′:5,6]pyrido[2,3- d ]pyrimidine derivatives was prepared and screened for antiparasitic and viral RNase H inhibitory activity. Several compounds showed considerable activity against Toxoplasma gondii parasites and Leishmania major amastigotes, which warrants further investigation. Based on the structural similarities of certain derivatives with common viral RNase H inhibitors, a HIV-1 RNase H assay was used to study the RNase H inhibition by selected test compounds. Docking of active derivatives into the active site of the HIV-1 RNase H enzyme was carried out. The new compound 2a , inactive in the antiparasitic tests, showed distinct HIV-1 RNase H inhibition. Thus, ring substitution determines antiparasitic or HIV-1 RNase H inhibitory activity of this promising compound class. [ABSTRACT FROM AUTHOR]