Benzimidazoles Containing Piperazine Skeleton at C-2 Position as Promising Tubulin Modulators with Anthelmintic and Antineoplastic Activity.

Benzimidazole anthelmintic drugs hold promise for repurposing as cancer treatments due to their interference with tubulin polymerization and depolymerization, manifesting anticancer properties. We explored the potential of benzimidazole compounds with a piperazine fragment at C-2 as tubulin-targeting agents. In particular, we assessed their anthelmintic activity against isolated Trichinella spiralis muscle larvae and their effects on glioblastoma (U-87 MG) and breast cancer (MDA-MB-231) cell lines. Compound 7c demonstrated exceptional anthelmintic efficacy, achieving a 92.7% reduction in parasite activity at 100 µg/mL after 48 hours. In vitro cytotoxicity analysis of MDA-MB 231 and U87 MG cell lines showed that derivatives 7b, 7d, and 7c displayed lower IC50 values compared to albendazole (ABZ), the control. These piperazine benzimidazoles effectively reduced cell migration in both cell lines, with compound 7c exhibiting the most significant reduction, making it a promising candidate for further study. The binding mode of the most promising compound 7c, was determined using the induced fit docking-molecular dynamics (IFD-MD) approach. Regular docking and IFD were also employed for comparison. The IFD-MD analysis revealed that 7c binds to tubulin in a unique binding cavity near that of ABZ, but the benzimidazole ring was fitted much deeper into the binding pocket. Finally, the absolute free energy of perturbation technique was applied to evaluate the 7c binding affinity, further confirming the observed binding mode.

Fused Triazinobenzimidazoles Bearing Heterocyclic Moiety: Synthesis, Structure Investigations, and In Silico and In Vitro Biological Activity.

[1,3,5]Triazino[1,2-a]benzimidazole-2-amines bearing heterocyclic moiety in 4-position were synthesized. The compounds were characterized by elemental analysis, IR, 1H-NMR, 13C-NMR, and HRMS spectroscopy. The molecular geometry and electron structure of these molecules were theoretically studied using density functional theory (DFT) methods. The molecular structure of the synthesized fused triazinobenzimidazole was confirmed to correspond to the 3,4-dihydrotriazinobenzimidazole structure through the analysis of spectroscopic NMR data and DFT calculations. The antinematodic activity was evaluated in vitro on isolated encapsulated muscle larvae (ML) of Trichinella spiralis. The results showed that the tested triazinobenzimidazoles exhibit significantly higher efficiency than the conventional drug used to treat trichinosis, albendazole, at a concentration of 50 µg/mL. The compound 3c substituted with a thiophen-2-yl moiety exhibited the highest anthelmintic activity, with a larvicidal effect of 58.41% at a concentration of 50 µg/mL after 24 h of incubation. Following closely behind, the pyrrole analog 3f demonstrated 49.90% effectiveness at the same concentration. The preliminary structure-anti-T. spiralis activity relationship (SAR) of the analogues in the series was discussed. The cytotoxicity of the benzimidazole derivatives against two normal fibroblast cells (3T3 and CCL-1) and two cancer human cell lines (MCF-7 breast cancer cells and chronic myeloid leukemia cells AR-230) was evaluated using the MTT-dye reduction assay. The screening results indicated that the compounds showed no cytotoxicity against the tested cell lines. An in silico study of the physicochemical and pharmacokinetic characteristics of the novel synthesized fused triazinobenzimidazoles showed that they were characterized by a significant degree of drug-likeness and optimal properties for anthelmintic agents.

1H-benzimidazole-2-yl hydrazones as tubulin-targeting agents: Synthesis, structural characterization, anthelmintic activity and antiproliferative activity against MCF-7 breast carcinoma cells and molecular docking studies.

In the present study, fifteen benzimidazolyl-2-hydrazones 7a-7o of fluoro-, hydroxy- and methoxy-substituted benzaldehydes and 1,3-benzodioxole-5-carbaldehyde were synthesized and their structure was identified by IR, NMR, and elemental analysis. The compounds 7j 2-(3-hydroxybenzylidene)-1-(5(6)-methyl-1H-benzimidazol-2-yl)hydrazone and 7i 2-(3-hydroxybenzylidene)-1-(1H-benzimidazol-2-yl)hydrazone have exerted the strongest anthelmintic activity (100% after 24 h incubation period at 37 °C) against isolated muscle larvae of Trichinella spiralis in an in vitro experiment. The in vitro cytotoxicity assay towards MCF-7 breast cancer cells and mouse embryo fibroblasts 3T3 showed that the studied benzimidazolyl-2-hydrazones exhibit low to moderate cytotoxic effects. The ability of the studied benzimidazolyl-2-hydrazones to modulate microtubule polymerization was confirmed and suggested that their anthelmintic action is mediated through inhibition of the tubulin polymerization likewise the other known benzimidazole anthelmitics. It was also shown that the four most promising benzimidazolyl-2-hydrazones do not affect significantly the AChE activity even at high tested concentration, thus indicating that they do not have the potential for neurotoxic effects. The binding mode of compounds 7j and 7n in the colchicine-binding site of tubulin were clarified by molecular docking simulations. Taken together, these results demonstrate that for the synthesized benzimidazole derivatives the anthelmintic activity against T. spiralis and the inhibition of tubulin polymerization are closely related.

New 1H-benzimidazole-2-yl hydrazones with combined antiparasitic and antioxidant activity.

Parasitic infections, caused mainly by the species Trichinella spiralis (T. spiralis), are widespread around the world and lead to morbidity and mortality in the population. Meanwhile, some studies have showed that these parasites induce oxidative stress in the infected host. With the aim of developing a class of compounds combining anthelmintic with antioxidant properties, a series of new benzimidazolyl-2-hydrazones 5a-l, bearing hydroxyl- and methoxy-groups, were synthesized. The anthelmintic activity on encapsulated T. spiralis was studied in vitro thus indicating that all hydrazones were more active than the clinically used anthelmintic drugs albendazole and ivermectin. 5b and 5d killed the total parasitic larvae (100% effectiveness) after 24 hours incubation period at 37 °C in both concentrations (50 and 100 µg ml-1). The antioxidant activity of the target compounds was elucidated in vitro against stable free radicals DPPH and ABTS as well as iron induced oxidative damage in model systems containing biologically relevant molecules lecithin and deoxyribose. The two 2,3- and 3,4-dihydroxy hydrazones 5b and 5d were the most effective radical scavengers in all studied systems. DFT calculations were applied to calculate the reaction enthalpies in polar and nonpolar medium and estimate the preferred mechanism of antioxidant activity. The relative radical scavenging ability of compounds 5a-l showed a good correlation to the experimentally observed trends. It was found that the studied compounds are capable to react with various free radicals - ˙OCH3, ˙OOH and ˙OOCH3, through several possible reaction pathways - HAT in nonpolar medium, SPLET in polar medium and RAF in both media.

Cutaneous Leishmaniasis - Dermoscopic Findings And Cryotherapy.

We present a 60-year-old male patient who, three months after a holiday in Southern Greece, found a small 'pimple' on his back, which gradually got as big as a small walnut, the central part becoming ulcerated and scabby. Dermatological examination found an erythematous-to-livid nodular lesion on the right shoulder; it was 16 mm in diameter with central ulceration, covered with brownish crust which discharged pus-like secretion upon pressure. Microscope examination of Romanowsky-Giemsa stained lesion material detected amastigote forms of Leishmania tropica. The culture investigation and serological tests for leishmaniasis were negative. Dermoscopy of the lesion found the following features: erythema, hyperkeratosis, central ulceration covered with brownish crust, "yellow tears-like" structures and "white starburst-like" patterns, and various vascular structures (including dotted vessels, comma-shaped vessels, hairpin- and glomerular-like vessels). The patient was diagnosed with cutaneous leishmaniasis and underwent four cryotherapy sessions every other week with excellent therapeutic results - complete resolution of infiltrate with subsequent gentle hypopigmented scarring. In conclusion, dermoscopy is an easily accessible non-invasive method which can be useful for the diagnosis of cutaneous leishmaniasis. Cryotherapy is the treatment of choice for single skin lesions.

Efficacy and safety of PAIR for cystic echinococcosis: experience on a large series of patients from Bulgaria.

We report our experience with puncture, aspiration, injection, and reaspiration (PAIR) for the treatment of cystic echinococcosis in Bulgaria. PAIR was performed in 230 patients with 348 echinococcal cysts. At 12-month follow-up, 77.6% of the cysts, all cystic echinococcosis (CE) 1 and CE3a cysts according to the World Health Organization Informal Working Group classification, showed various degrees of obliteration. In 11.5% of cysts, all of which were > 10 cm-type CE1, a significant amount of fluid persisted, and they were punctured again. Of those, 16 (4.6%) contained protoscolices and were treated by a second PAIR. The remaining 24 (6.9%) cysts were treated by simple aspiration or drainage. No significant reduction in size and no changes in the structure were observed in 10.9% of cysts, all of which were classified as CE2 or CE3b. Complications developed in 25.2% of patients, including severe anaphylactic reaction in two (0.9%) patients. Our experience confirms that PAIR is a successful first-choice treatment when a stage-specific approach is taken.

Synthesis, antitrichinnellosis and antiprotozoal activity of some novel thieno[2,3-d]pyrimidin-4(3H)-ones containing benzimidazole ring.

Some novel thieno[2,3-d]pyrimidin-4(3H)-ones containing benzimidazol-2-yl-thioethyl- and benzimidazol-2-yl-methanethioethyl moiety in second position of the pyrimidine ring were synthesized in order to determine their antitrichinellosis and antiprotozoal effects. The structures of the compounds were confirmed by IR, (1)H NMR and elemental analysis. The antiparasitic screening showed that the benzimidazole derivatives of thieno[2,3-d]pyrimidin-4(3H)-ones exhibited higher activity against Trichinella spiralis in vitro in comparison albendazole. The most active compound, 2-[2-(5-nitro-1H-benzimidazol-1-yl)ethyl]-5,6,7,8-tetrahydro[1]benzothieno[2,3-d]pyrimidin-4(3H)-one 22 revealed 95% activity at a dosage of 5 mg/kg mw after 24 h, while compounds 8 and 10 applied at the same dose showed efficacy of 90% after 48 h. The compound 2-{2-[(5(6)-nitro-1H-benzimidazol-2-yl)thio]ethyl}-5,6,7,8-tetrahydro[1]-benzothieno[2,3-d]pyrimidin-4(3H)-one 11 exhibited 90% efficacy after 24 h. The pharmaco-therapeutic study in vivo on invaded with Lamblia muris white mice showed 100% effectiveness of the compounds 8, 10, 11, 13-15 and 22, 23 after five-days-treatment course.

Antihelminthic activity of some newly synthesized 5(6)-(un)substituted-1H-benzimidazol-2-ylthioacetylpiperazine derivatives.

Piperazine derivatives of 5(6)-substituted-(1H-benzimidazol-2-ylthio)acetic acids were synthesized by using two methods and studied for antihelminthic activity. The antiparasitic screening showed that compounds 18-24 exhibited higher activity against Trichinella spiralis in vitro in comparison to methyl 5-(propylthio)-1H-benzimidazol-2-yl-carbamate (albendazole). Most active were compounds 2-({2-[4-(4-chlorophenyl)piperazin-1-yl]-2-oxoethyl}thio)-1H-benzimidazole 21 and 2-{[2-oxo-2-(4-benzhydrylpiperazin-1-yl)ethyl]thio}-5(6)-methyl-1(H)-benzimidazole 19 as well as 2-({2-[4-(4-chlorophenyl)piperazin-1-yl]-2-oxoethyl}thio)-5(6)-methyl-1(H)-benzimidazole 23 with efficacy of 96.0%, 98.4% and 100%, respectively. The tested derivatives 15-19 and 20-23 were less active against Syphacia obvelata in vivo than albendazole and exhibited the same efficacy as piperazine, but in twice lower concentration.Compounds 2-({2-[4-(4-chlorophenyl)piperazin-1-yl]-2-oxoethyl}thio)-1H-benzimidazole 21, 1,4-bis[(5(6)-methyl-1(H)-benzimidazol-2-ylthio)acetyl]piperazine 17 and 2-({2-[4-(4-chlorophenyl)piperazin-1-yl]-2-oxoethyl}thio)-5(6)-methyl-1(H)-benzimidazole 23 had higher efficacies of 73%, 76%, and 77%, respectively.

Synthesis and antitrichinellosis activity of some 2-substituted-[1,3]thiazolo[3,2-a]benzimidazol-3(2H)-ones.

Some new thiazolo[3,2-a]benzimidazolone derivatives were synthesized using two methods. The structures of the synthesized compounds were proved by means of IR, (1)H NMR and mass spectral data. Ab initio computations were performed in order to determine the electronic structure and geometry of the investigated molecules and to compare it to the geometry of albendazole. Biologically, experiments in vitro and in vivo were accomplished in order to identify the efficacy of the obtained thiazolobenzimidazolones against Trichinella spiralis. The effectiveness of compounds 4a-c in the intestinal phase of trichinellosis was 100% and in the muscle phase were 88% and 80% at a concentration of 100mg/kg mw for the compounds 4a and 4c. The results of the hepatotoxicity test showed that the compounds 4a and 4b possess hepatotoxicity comparable to that of albendazole.