Synthesis and evaluation of novel 2,4-disubstituted arylthiazoles against T. brucei

Antimicrobial Peptides (AMPs): Potential Therapeutic Strategy against Trypanosomiases?

Trypanosomiases are a group of tropical diseases that have devastating health and socio-economic effects worldwide. In humans, these diseases are caused by the pathogenic kinetoplastids Trypanosoma brucei, causing African trypanosomiasis or sleeping sickness, and Trypanosoma cruzi, causing American trypanosomiasis or Chagas disease. Currently, these diseases lack effective treatment. This is attributed to the high toxicity and limited trypanocidal activity of registered drugs, as well as resistance development and difficulties in their administration. All this has prompted the search for new compounds that can serve as the basis for the development of treatment of these diseases. Antimicrobial peptides (AMPs) are small peptides synthesized by both prokaryotes and (unicellular and multicellular) eukaryotes, where they fulfill functions related to competition strategy with other organisms and immune defense. These AMPs can bind and induce perturbation in cell membranes, leading to permeation of molecules, alteration of morphology, disruption of cellular homeostasis, and activation of cell death. These peptides have activity against various pathogenic microorganisms, including parasitic protists. Therefore, they are being considered for new therapeutic strategies to treat some parasitic diseases. In this review, we analyze AMPs as therapeutic alternatives for the treatment of trypanosomiases, emphasizing their possible application as possible candidates for the development of future natural anti-trypanosome drugs.

Hybrid-Compounds Against Trypanosomiases

Neglected tropical diseases (NTDs) are a global public health problem associated with approximately 20 conditions. Among these, Chagas disease (CD), caused by Trypanosoma cruzi, and human African trypanosomiasis (HAT), caused by T. brucei gambiense or T. brucei rhodesiense, affect mainly the populations of the countries from the American continent and sub- Saharan Africa. Pharmacological therapies used for such illnesses are not yet fully effective. In this context, the search for new therapeutic alternatives against these diseases becomes necessary. A drug design tool, recently recognized for its effectiveness in obtaining ligands capable of modulating multiple targets for complex diseases, concerns molecular hybridization. Therefore, this review aims to demonstrate the importance of applying molecular hybridization in facing the challenges of developing prototypes as candidates for the treatment of parasitic diseases. Therefore, studies involving different chemical classes that investigated and used hybrid compounds in recent years were compiled in this work, such as thiazolidinones, naphthoquinones, quinolines, and others. Finally, this review covers several applications of the exploration of molecular hybridization as a potent strategy in the development of molecules potentially active against trypanosomiases, in order to provide information that can help in designing new drugs with trypanocidal activity.

Probing Adamantane Arylhydroxamic Acids against Trypanosoma brucei and Trypanosoma cruzi

In this work, we present the synthesis and the anti-trypanosomal activity of the 2-(4-(adamant-1-yl)phenyl)-N-hydroxyarylamides, 1a,b and the 2-(4-(adamant-1-yl)phenoxy)-N-hydroxyacetamide, 1c. The 4-(adamant-1-yl)phenyl- and 4-(adamant-1-yl)phenoxy- moieties, which are endowed with promising drug-like properties, are functionalized at the side chain termini as hydroxamic acids. The phenoxy acetohydroxamic derivative, 1c, shows the most interesting profile in terms of activity and toxicity against trypanosomes and merits further investigation.

A novel high-content phenotypic screen to identify inhibitors of mitochondrial DNA maintenance in trypanosomes

Kinetoplastid parasites cause diverse neglected diseases in humans and livestock, with an urgent need for new treatments. The survival of kinetoplastids depends on their uniquely structured mitochondrial genome (kDNA), the eponymous kinetoplast. Here, we report the development of a high-content screen for pharmacologically induced kDNA loss, based on specific staining of parasites and automated image analysis. As proof of concept, we screened a diverse set of ∼14,000 small molecules and exemplify a validated hit as a novel kDNA-targeting compound.

Synthesis and evaluation of trypanocidal activity of derivatives of naturally occurring 2,5-diphenyloxazoles

African trypanosomiasis is a zoonotic protozoan disease affecting the nervous system. Various natural products reportedly exhibit trypanocidal activity. Naturally occurring 2,5-diphenyloxazoles present in Oxytropis lanata, and their derivatives, were synthesized. The trypanocidal activities of the synthesized compounds were evaluated against Trypanosoma brucei brucei, T. b. gambiense, T. b. rhodesiense, T. congolense, and T. evansi. Natural product 1 exhibited trypanocidal activity against all the species/subspecies of trypanosomes, exhibiting half-maximal inhibitory concentrations (IC₅₀) of 1.1-13.5 μM. Modification of the oxazole core improved the trypanocidal activity. The 1,3,4-oxadiazole (7) and 2,4-diphenyloxazole (9) analogs exhibited potency superior to that of 1. However, these compounds exhibited cytotoxicity in Madin-Darby bovine kidney cells. The O-methylated analog of 1 (12) was non-cytotoxic and exhibited selective trypanocidal activity against T. congolense (IC₅₀ = 0.78 µM). Structure-activity relationship studies of the 2,5-diphenyloxazole analogs revealed aspects of the molecular structure critical for maintaining selective trypanocidal activity against T. congolense.

Thiazole Ring-A Biologically Active Scaffold

BACKGROUND

Thiazole is a good pharmacophore nucleus due to its various pharmaceutical applications. Its derivatives have a wide range of biological activities such as antioxidant, analgesic, and antimicrobial including antibacterial, antifungal, antimalarial, anticancer, antiallergic, antihypertensive, anti-inflammatory, and antipsychotic. Indeed, the thiazole scaffold is contained in more than 18 FDA-approved drugs as well as in numerous experimental drugs.

OBJECTIVE

To summarize recent literature on the biological activities of thiazole ring-containing compounds Methods: A literature survey regarding the topics from the year 2015 up to now was carried out. Older publications were not included, since they were previously analyzed in available peer reviews.

RESULTS

Nearly 124 research articles were found, critically analyzed, and arranged regarding the synthesis and biological activities of thiazoles derivatives in the last 5 years.

Antitrichomonal activity and docking analysis of thiazole derivatives as TvMP50 protease inhibitors

Trichomoniasis, caused by the protozoan Trichomonas vaginalis, is the most prevalent non-viral sexually transmitted infection that affects over 170 million people worldwide. The only type of drug recommended for the therapeutic control of trichomoniasis is the 5-nitroimidazoles, although there have been reports of some undesirable side effects and clinical resistance. Hence, the need for the search for new tricomonicidal agents is necessary. In a previous work, we demonstrated that two 2-amino-4-aryl thiazole derivatives (ATZ-1 and ATZ-2) possess a portent antigiardial effect. In the current paper, we investigated the in vitro antitrichomonal activity of these thiazole compounds. Both ATZ-1 and ATZ-2 reduced the viability and growth of parasites in a dose-dependent manner, with an IC₅₀ value of 0.15 μg/mL and 0.18 μg/mL, respectively. Furthermore, both thiazole compounds were able to decrease the proteolytic activity in T. vaginalis trophozoites compared with untreated parasites. Interestingly, a full proteolytic inhibition profile was observed in the 50-kDa region which was associated with the decreased expression of the gene that codes for the trichomonad protease TvMP50. The docking simulations predicted strong interactions of the thiazole compounds in the TvMP50 protease's active site, suggesting a possible role as protease inhibitors. Our results demonstrate the potential of 2-amino-4-aryl thiazole derivatives as trichomonicidal compounds and could be, mechanistically, involved in the inhibition of key trichomonad proteases.

Green Synthesis of Thiazole Derivatives using Multi-component Reaction of Aldehydes, Isothiocyanate and Alkyl Bromides: Investigation of Antioxidant and Antimicrobial Activity

Aims & Objective: In this work, the multicomponent reaction of aldehydes, benzoylisothiocyanate and alkyl bromides in the presence of ammonium acetate, sodium cyanide and a catalytic amount of KF/Clinoptilolite nanoparticles (KF/CP NPs) in the water at 100oC was investigated.

MATERIALS AND METHODS

In these reactions, thiazole derivatives were produced in good to excellent yields and short time. Also, the antioxidant activity was studied for some newly synthesized compounds using the DPPH radical trapping and reducing of ferric ion experiments and comparing results with the synthetic antioxidants (TBHQ and BHT).

RESULTS

As a result, the compounds 4b showed excellent DPPH radical trapping and reducing the strength of ferric ion. These compounds have biological potential because of the thiazole core. For this reason, the antimicrobial activity of some synthesized compounds was studied by employing the disk diffusion test on Gram-positive bacteria and Gram-negative bacteria.

CONCLUSION

The results of the disk diffusion test showed that these compounds prevented bacterial growth.