Novel Hybrid Formulations Based on Thiourea Derivatives and Core@Shell Fe₃O₄@C18 Nanostructures for the Development of Antifungal Strategies

Nanoformulations for dismantling fungal biofilms: The latest arsenals of antifungal therapy

Globally, fungal infections have evolved as a strenuous challenge for clinicians, particularly in patients with compromised immunity in intensive care units. Fungal co-infection in Covid-19 patients has made the situation more formidable for healthcare practitioners. Surface adhered fungal population known as biofilm often develop at the diseased site to elicit antifungal tolerance and recalcitrant traits. Thus, an innovative strategy is required to impede/eradicate developed biofilm and avoid the formation of new colonies. The development of nanocomposite-based antibiofilm solutions is the most appropriate way to withstand and dismantle biofilm structures. Nanocomposites can be utilized as a drug delivery medium and for fabrication of anti-biofilm surfaces capable to resist fungal colonization. In this context, the present review comprehensively described different forms of nanocomposites and mode of their action against fungal biofilms. Amongst various nanocomposites, efficacy of metal/organic nanoparticles and nanofibers are particularly emphasized to highlight their role in the pursuit of antibiofilm strategies. Further, the inevitable concern of nanotoxicology has also been introduced and discussed with the exigent need of addressing it while developing nano-based therapies. Further, a list of FDA-approved nano-based antifungal formulations for therapeutic usage available to date has been described. Collectively, the review highlights the potential, scope, and future of nanocomposite-based antibiofilm therapeutics to address the fungal biofilm management issue.

N-Naphthoyl Thiourea Derivatives: An Efficient Ultrasonic-Assisted Synthesis, Reaction, and In Vitro Anticancer Evaluations

This work demonstrates the optimization of an efficient, mild, and environmentally friendly synthetic approach to access a diverse library of N-naphthoyl thioureas. These derivatives could be exploited as precursor scaffolds for designing valuable heterocycles with anticipated biological activities. Additionally, the utilization of a copper complex derived from the newly synthesized N-naphthoyl thiourea ligand in the photodegradation of methyl orange (MO) dye was explored. The antiproliferative effect of the synthesized derivatives was examined against MCF-7, HCT116, and A549 cancer cell lines. Most of the assembled derivatives revealed a significant cytotoxic effect, in some cases, greater than doxorubicin. Of these, the copper complex demonstrated significant antitumor activities (IC50 < 1.3 μM) and lesser cytotoxic impact (IC50 > 76 μM), indicating its possibility as a pioneering candidate for future carcinogenic pharmaceutics. Relations between the structure and activity also have been addressed.

Hybrid Nanosystems for Biomedical Applications

Inorganic/organic hybrid nanosystems have been increasingly developed for their versatility and efficacy at overcoming obstacles not readily surmounted by nonhybridized counterparts. Currently, hybrid nanosystems are implemented for gene therapy, drug delivery, and phototherapy in addition to tissue regeneration, vaccines, antibacterials, biomolecule detection, imaging probes, and theranostics. Though diverse, these nanosystems can be classified according to foundational inorganic/organic components, accessory moieties, and architecture of hybridization. Within this Review, we begin by providing a historical context for the development of biomedical hybrid nanosystems before describing the properties, synthesis, and characterization of their component building blocks. Afterward, we introduce the architectures of hybridization and highlight recent biomedical nanosystem developments by area of application, emphasizing hybrids of distinctive utility and innovation. Finally, we draw attention to ongoing clinical trials before recapping our discussion of hybrid nanosystems and providing a perspective on the future of the field.

Synthesis, crystal structure and Hirshfeld Surface analysis of benzamide derivatives of thiourea as potent inhibitors of α-glucosidase in-vitro

Benzamide based structural analogues 1-15 were synthesized, and evaluated for α-glucosidase inhibition activity in vitro for the first time. Compounds 1-9 were found to be known, while compounds 10-15 were found to be new. However, to the best of our knowledge we are reporting α-glucosidase inhibitory activity of these bezamide derivatives of thiourea for the first time. Compounds 1, 3, 6-8, 10-14 were found to be potent inhibitors of α-glucosidase within IC₅₀ range of 20.44-333.41 µM, in comparison to the standard inhibitor, acarbose (IC₅₀ = 875.75 ± 2.08 µM). Mode of the enzyme inhibition was determined on the basis of kinetic studies which demonstrated that compounds 8, and 10 were non-competitive and competitive inhibitors of α-glucosidase enzyme, respectively. These compounds were also evaluated for their DPPH radical scavenging activity, and cytotoxicity against 3T3 mouse fibroblast cell lines. All synthesized compounds showed a significant to moderate DPPH radical scavenging activity and appeared to be non-cytotoxic except compound 9 which showed cytotoxicity against 3T3 normal mouse fibroblast cell lines. A single crystal X-ray and Hirshfeld Surface analysis of a representative compound is also presented.

Anti-biofilm Fe3O4@C18-[1,3,4]thiadiazolo[3,2-a]pyrimidin-4-ium-2-thiolate Derivative Core-shell Nanocoatings

The derivatives 5,7-dimethyl[1,3,4]thiadiazolo[3,2-a]pyrimidin-4-ium-2-thiolate (1) and 7-methyl-5-phenyl[1,3,4]thiadiazolo[3,2-a]pyrimidin-4-ium-2-thiolate (2) were fully characterized by single-crystal X-ray diffraction. Their supramolecular structure is built through both π–π stacking and C=S–π interactions for both compounds. The embedment of the tested compounds into Fe₃O₄@C₁₈ core-shell nanocoatings increased the protection degree against Candida albicans biofilms on the catheter surface, suggesting that these bioactive nanocoatings could be further developed as non-cytotoxic strategies for fighting biofilm-associated fungal infections.

Design, Synthesis and In Vitro Characterization of Novel Antimicrobial Agents Based on 6-Chloro-9H-carbazol Derivatives and 1,3,4-Oxadiazole Scaffolds

In this paper, we aimed to exploit and combine in the same molecule the carbazole and the 1,3,4-oxadiazole pharmacophores, to obtain novel carprofen derivatives, by using two synthesis pathways. For the first route, the following steps have been followed: (i) (RS)-2-(6-chloro-9H-carbazol-2-yl)propanonic acid (carprofen) treatment with methanol, yielding methyl (RS)-2-(6-chloro-9H-carbazol-2-yl)propanoate; (ii) the resulted methylic ester was converted to (RS)-2-(6-chloro-9H-carbazol-2-yl)propane hydrazide (carprofen hydrazide) by treatment with hydrazine hydrate; (iii) reaction of the hydrazide derivative with acyl chlorides led to N-[(2RS)-2-(6-chloro-9H-carbazol-2-yl)propanoil]-N′-R-substituted-benzoylhydrazine formation, which; (iv) in reaction with phosphorus oxychloride gave the (RS)-1-(6-chloro-9H-carbazol-2-yl)-1-(1,3,4-oxadiazol-2-yl)ethane derivatives. In the second synthesis pathway, new 1,3,4-oxadiazole ring compounds were obtained starting from carprofen which was reacted with isoniazid, in the presence of phosphorus oxychloride to form (RS)-1-(6-chloro-9H-carbazol-2-yl)-1-[5-(4-pyridyl)-1,3,4-oxadiazol-2-yl]ethane. The synthesized compounds were characterized by IR, ¹H-NMR and ¹³C-NMR, screened for their drug-like properties and evaluated for in vitro cytotoxicity and antimicrobial activity. The obtained compounds exhibited a good antimicrobial activity, some of the compounds being particularly active on E. coli, while others on C. albicans. The most significant result is represented by their exceptional anti-biofilm activity, particularly against the P. aeruginosa biofilm. The cytotoxicity assay revealed that at concentrations lower than 100 μg/mL, the tested compounds do not induce cytotoxicity and do not alter the mammalian cell cycle. The new synthesized compounds show good drug-like properties. The ADME-Tox profiles indicate a good oral absorption and average permeability through the blood brain barrier. However, further research is needed to reduce the predicted mutagenic potential and the hepatotoxicity.

Synthesis, physical characterization, and antifungal and antibacterial activities of oleic acid capped nanomagnetite and cobalt-doped nanomagnetite

Nanoparticles, 10–14 nm, consisting of either Fe3O4 or Co0.2Fe2.8O4 stabilized with oleic acid, were prepared using solution combustion. Their structural and magnetic properties were examined using X-ray diffractometry, scanning electron microscopy, vibrating sample magnetometry, and Fourier-transform infrared spectroscopy. The properties of both sets of materials are similar, except that the cobalt-doped particles are considerably less magnetic. The in vitro inhibitory activities of the nanoparticles were assessed against pathogenic bacteria Shigella dysenteriae, Klebsiella pneumoniae, Acinetobacter baumannii, Streptococcus pyogenes, and pathogenic fungi and molds Candida albicans, Fusarium oxysporum, and Aspergillus fumigatus. The magnetite nanoparticles were moderately effective against all tested pathogens, but the activity of the cobalt-doped nanoparticles was significantly lower, possibly due to an interruption of the Fenton reaction at the bacterial membrane. This work suggests that potentially doping magnetite with stronger metal oxidants may instead enhance their antimicrobial effects.