Design, synthesis, biological screening and molecular docking studies of novel multifunctional 1,4-di (aryl/heteroaryl) substituted piperazine derivatives as potential antitubercular and antimicrobial agents

Phytochemicals Analysis, In Vitro Antibacterial Activities of Extracts, and Molecular Docking Studies of the Isolated Compounds from Melhania zavattarii Cufod Leaves

Melhania zavattarii Cufod is an endemic plant species to Ethiopia and is used to treat ailments related to kidney infection. The phytochemical composition and biological activity of M. zavattarii have been not reported yet. Therefore, the present work aimed to investigate phytochemical constituents and evaluate the antibacterial activity of different solvents' leaf extracts and analyze the molecular binding capacity of isolated compounds from the chloroform leaf extract of M. zavattarii. Accordingly, preliminary phytochemical screening was tested by using standard procedures and the result indicated that phytosterols and terpenoids as major and others like alkaloids, saponins, flavonoids, tannins, phlobatannin, and coumarins were detected as minor in extracts. Antibacterial activity of the extracts was evaluated using the disk diffusion agar method, and the activities revealed that chloroform extract showed the highest inhibition zones, 12.08 ± 0.38, 14.00 ± 0.50, and 15.58 ± 0.63 mm against Escherichia coli at 50, 75, and 125 mg/mL concentrations, respectively, compared to that of n-hexane and methanol extracts at respective concentrations. Methanol extract showed the highest zone of inhibition 16.42 + 0.52 against Staphylococcus aureus at 125 mg/mL concentration compared to that of n-hexane and chloroform extracts. Two compounds, namely, β-amyrin palmitate (1) and lutein (2) were isolated and identified for the first time from the chloroform leaf extract of M. zavattarii, and structural elucidations of these compounds were accomplished by using spectroscopic methods (IR, UV, and NMR). For the molecular docking study, 1G2A, which is a protein of E. coli and chloramphenicol standard target, was selected. Binding energies of -9.09, -7.05, and -6.87 kcal/mol were calculated for β-amyrin palmitate, lutein, and chloramphenicol, respectively. The drug-likeness property result indicated that both β-amyrin palmitate and lutein violated two rules of Lipinski's rule of five with molecular weight (g/mol) > 500 and LogP > 4.15. In the near future, further phytochemical investigation and biological activity evaluation should be conducted on this plant.

Verification of preparations of (1H-indol-3-yl)methyl electrophiles and development of their microflow rapid generation and substitution

Although highly reactive (1H-indol-3-yl)methyl electrophiles such as (1H-indol-3-yl)methyl halides are potential precursors for the synthesis of various indole derivatives, some researchers have reported difficulties in their preparation due to concomitant undesired dimerization/oligomerization. Nevertheless, there have been some reports on the preparation of (1H-indol-3-yl)methyl halides. To resolve this contradiction, all the previously reported preparations of (1H-indol-3-yl)methyl halides were examined. However, we could not reproduce any of these preparations, and we revised several structures of indole derivatives. Here we show the rapid (0.02 s) and mild (25 °C) generation of an (1H-indol-3-yl)methyl electrophile that enables the rapid (0.1 s) and mild (25 °C) nucleophilic substitution in a microflow reactor. Eighteen unprotected indole analogues can be successfully synthesized using the developed microflow nucleophilic substitution with various nucleophiles.

Ball-Milling-Enabled Zn(OTf)2-Catalyzed Friedel-Crafts Hydroxyalkylation of Imidazo[1,2-a]pyridines and Indoles

A facile and efficient synthetic method for the construction of C3-hydroxyalkylated imidazo[1,2-a]pyridines and indoles by a Zn(OTf)₂-catalyzed Friedel-Crafts hydroxyalkylation of imidazo[1,2-a]pyridines and indoles with carbonyl compounds under mechanochemical conditions is reported. Good product selectivity, shorter reaction time, ambient reaction temperature, tolerance of a wide range of functional groups, broad substrate scope, moderate to good yield of products, and scalability are the salient features of the developed methodology.

Recent updates in click and computational chemistry for drug discovery and development

Drug discovery is a costly and time-consuming process with a very high failure rate. Recently, click chemistry and computer-aided drug design (CADD) represent popular areas for new drug development. Herein, we summarized the recent updates in click and computational chemistry for drug discovery and development including clicking to effectively synthesize druggable candidates, synthesis and modification of natural products, targeted delivery systems, and computer-aided drug discovery for target identification, seeking out and optimizing lead compounds, ADMET prediction as well as compounds synthesis, hopefully, inspires new ideas for novel drug development in the future.

The Effect of the New Imidazole Derivatives Complexation with Betacyclodextrin, on the Antifungal Activity in Oropharyngeal Infections

Ketoconazole (KZ) is a broad-spectrum drug used to treat fungal infections. Local use of ketoconazole has been associated with some side effects in healthy adults, especially local reactions, such as stinging, severe irritation, and itching. Moreover, the bioavailability of KZ after oral administration is low in tablets due to its low water solubility. In addition, oral administration of ketoconazole produces systemic exposure, associated with significant side effects, such as cholestatic and hepatocellular lesions. In an attempt to reduce hepatotoxicity, ketoconazole may be administered at the primary site of infection with cutaneous candidiasis, specifically on the skin tissue. However, the use of ketoconazole in topical dosage forms is limited by its high lipophilicity and extremely poor aqueous solubility (1 ng/mL), thus leading to the rare availability of topical dosage forms on the market. Therefore, a new approach to the effective delivery of ketoconazole to the site of infection is targeted, including obtaining new derivatives (keeping the imidazolic nucleus), with a similar spectrum of action, and finally, their inclusion in betacyclodextrin complexes in order to optimize bioavailability and physico-chemical stability.

An Insight into All Tested Small Molecules against Fusarium oxysporum f. sp. Albedinis: A Comparative Review

Bayoud disease affects date palms in North Africa and the Middle East, and many researchers have used various methods to fight it. One of those methods is the chemical use of synthetic compounds, which raises questions centred around the compounds and common features used to prepare targeted molecules. In this review, 100 compounds of tested small molecules, collected from 2002 to 2022 in Web of Sciences, were divided into ten different classes against the main cause of Bayoud disease pathogen Fusarium oxysporum f. sp. albedinis (F.o.a.) with structure-activity relationship (SAR) interpretations for pharmacophore site predictions as (δ^-···δ^-), where 12 compounds are the most efficient (one compound from each group). The compounds, i.e., (Z)-1-(1.5-Dimethyl-1H-pyrazole-3-yl)-3-hydroxy but-2-en-1-one 7, (Z)-3-(phenyl)-1-(1,5-dimethyl-1H-pyrazole-3-yl)-3-hydroxyprop-2-en-1-one 23, (Z)-1-(1,5-Dimethyl-1H-pyrazole-3-yl)-3-hydroxy-3-(pyridine-2-yl)prop-2-en-1-one 29, and 2,3-bis-[(2-hydroxy-2-phenyl)ethenyl]-6-nitro-quinoxaline 61, have antifungal pharmacophore sites (δ^-···δ^-) in common in N1---O4, whereas other compounds have only one δ^- pharmacophore site pushed by the donor effect of the substituents on the phenyl rings. This specificity interferes in the biological activity against F.o.a. Further understanding of mechanistic drug-target interactions on this subject is currently underway.

Design, synthesis and biological evaluation of benzo-[d]-imidazo-[2,1-b]-thiazole and imidazo-[2,1-b]-thiazole carboxamide triazole derivatives as antimycobacterial agents

In the search for new anti-mycobacterial agents, we revealed the importance of imidazo-[2,1-b]-thiazole and benzo-[d]-imidazo-[2,1-b]-thiazole carboxamide derivatives. We designed, in silico ADMET predicted and synthesized four series of novel imidazo-[2,1-b]-thiazole and benzo-[d]-imidazo-[2,1-b]-thiazole carboxamide analogues in combination with piperazine and various 1,2,3 triazoles. All the synthesized derivatives were characterized by ¹H NMR, ¹³C NMR, HPLC and MS spectral analysis and evaluated for in vitro antitubercular activity. The most active benzo-[d]-imidazo-[2,1-b]-thiazole derivative IT10, carrying a 4-nitro phenyl moiety, displayed IC₉₀ of 7.05 μM and IC₅₀ of 2.32 μM against Mycobacterium tuberculosis (Mtb) H37Ra, while no acute cellular toxicity was observed (>128 μM) towards the MRC-5 lung fibroblast cell line. Another benzo-[d]-imidazo-[2,1-b]-thiazole compound, IT06, which possesses a 2,4-dichloro phenyl moiety, also showed significant activity with IC₅₀ 2.03 μM and IC₉₀ 15.22 μM against the tested strain of Mtb. Furthermore, the selected hits showed no activity towards a panel of non-tuberculous mycobacteria (NTM), thus suggesting a selective inhibition of Mtb by the tested imidazo-[2,1-b]-thiazole derivatives over the selected panel of NTM. Molecular docking and dynamics studies were also carried out for the most active compounds IT06 and IT10 in order to understand the putative binding pattern, as well as stability of the protein–ligand complex, against the selected target Pantothenate synthetase of Mtb.

In the search for new anti-mycobacterial agents, we revealed the importance of imidazo-[2,1-b]-thiazole and benzo-[d]-imidazo-[2,1-b]-thiazole carboxamide derivatives.