The 10 most-cited articles in Archiv der Pharmazie, 2016

A series of ureas derived from phenethylamines were synthesized and evaluated for human carbonic anhydrase (hCA) I and II, acetylcholinesterase (AChE), and butyrylcholinesterase (BChE) enzyme inhibitory activities and antioxidant properties. The ureas were synthesized from the reactions of substituted phenethylamines with N,N‐dimethylcarbamoyl chloride; then, the synthesized compounds were converted to their corresponding phenolic derivatives via O‐demethylation. hCA I and II were effectively inhibited by the newly synthesized compounds, with Ki values in the range of 0.307–0.432 nM for hCA I and 0.149–0.278 nM for hCA II. On the other hand, the Ki parameters of these compounds for AChE and BChE were determined in the range of 0.129–0.434 and 0.095–0.207 nM, respectively. Phenolic ureas also showed good antioxidant activities.

Benzimidazole derivatives are crucial structural scaffolds found in diverse libraries of biologically active compounds which are therapeutically useful agents in drug discovery and medicinal research. They are structural isosteres of naturally occurring nucleotides, which allows them to interact with the biopolymers of living systems. Hence, there is a need to couple the latest information with the earlier documentations to understand the current status of the benzimidazole nucleus in medicinal chemistry research. This present work unveils the benzimidazole core as a multifunctional nucleus that serves as a resourceful tool of information for synthetic modifications of old existing candidates in order to tackle drug resistance bottlenecks in therapeutic medicine. This manuscript deals with the recent advances in the synthesis of benzimidazole derivatives, the widespread biological activities as well as pharmacokinetic reports. These present them as a toolbox for fighting infectious diseases and also make them excellent candidates for future drug design.

Quinoxaline derivatives, also called benzopyrazines, are an important class of heterocyclic compounds. Quinoxalines have drawn great attention due to their wide spectrum of biological activities. They are considered as an important basis for anticancer drugs due to their potential activity as protein kinase inhibitors. In this review, we focus on the chemistry of the quinoxaline derivatives, the strategies for their synthesis, their potential activities against various tyrosine kinases, and on the structure-activity relationship studies reported to date.

A series of 11 indole-based chalcones (IC1-11) with various electron donating and withdrawing groups at the para position of the phenyl ring B were synthesized. All the compounds were tested for their human monoamine oxidase (hMAO)-A and hMAO-B inhibitory potencies. Most of the synthesized candidates proved to be potent and selective inhibitors of MAO-B rather than MAO-A, with a reversible and competitive mode. Among them, compound IC9 was found to be a potent inhibitor of hMAO-B with Ki = 0.01 ± 0.005 μM and a selectivity index of 120. It was found to be better than the standard drug, selegiline (hMAO-B with Ki = 0.20 ± 0.020 μM) with a selectivity index of 30.55. PAMPA assays were carried out for all the compounds in order to evaluate the capacity of the compounds to cross the blood-brain barrier. Moreover, the most potent MAO-B inhibitor, IC9, was nontoxic at 5 and 25 μM, with 95.20 and 69.17% viable cells, respectively. The lead compound IC9 has an antioxidant property of 1.18 Trolox equivalents by ABTS assay. Molecular modeling studies were performed against hMAO-B to observe…

Inhibition of the metalloenzyme urease has important pharmacologic applications in the field of antiulcer and antigastric cancer agents. Urease is involved in many serious infections caused by Helicobacter pylori in the gastric tract as well as by Proteus and related species in the urinary tract. Although numerous studies have described several novel urease inhibitors (UIs) used for the treatment of gastric and urinary infections, all these compounds have exhibited severe side effects, toxicity, and instability. Therefore, to overcome such problems, it is necessary to search for new sources of UIs, such as natural products, that provide reduced side effects, low toxicity, greater stability, and bioavailability. As limited studies have been conducted on plant-derived UIs, this paper aims to highlight and summarize the most promising compounds isolated and identified from plants, such as terpenoids, phenolic compounds, alkaloids, and other substances with inhibitory activities against plant and bacterial ureases; these are in vitro and in vivo studies with an emphasis on…

Design and synthesis of a new type of bischalcones as an alternative to natural and synthetic bischalcones are reported for the first time. Key steps involved the solvent-free Claisen-Schmidt condensation of chalcones, and the successful first application of the diazotization-diazocoupling reaction in the synthesis of CNNC-linked bischalcones by simple structural modification of p-aminoacetophenone. The structures of all compounds were confirmed by means of FT-IR, (1) H and (13) C NMR, ESI/MS, and elemental analysis. In addition, the newly synthesized compounds were screened for carbonic anhydrase inhibition activities. Almost all bischalcones exhibited moderate-to-good inhibitory activities.

Understanding the mechanisms responsible for the various biological activities of chalcones, particularly the direct cellular targets, presents an unmet challenge. Here, we prepared a series of fluorescent chalcone derivatives as chemical probes for their mechanistic investigation. Upon systematic physicochemical characterization, we explored their potential to elucidate the mode of action of chalcones' cytotoxicity. The fluorescence of the chalcones was found to be highly sensitive to structural and environmental factors. Structurally, a 4-dialkylamino group on the B ring, suitable electronic properties of the A ring substituents, and the planar conformation of the chalcone's core structure were essential for optimal fluorescence. Environmental factors influencing fluorescence included solvent polarity, pH, and the interactions of the chalcones with proteins and detergents. It was found that 18 chalcones showed a fluorescent brightness greater than 6000 M(-1) cm(-1) in DMSO. However, water dramatically quenched the fluorescence, although it could be partially recovered in the…

Being overexpressed in several types of cancer, the epidermal growth factor receptor (EGFR) is considered one of the key therapeutic targets in oncology. Although many first-generation EGFR inhibitors had been FDA approved for the treatment of certain types of cancer, patients soon developed resistance to these reversible ATP competitive inhibitors via mutations in the kinase domain of EGFR. A new trend was adopted to design covalent irreversible inhibitors, that is, second- and third-generation inhibitors. Second-generation inhibitors can inhibit the mutant forms but, unfortunately, they had dose limiting side effects due to wild-type EGFR inhibition. Third-generation inhibitors emerged shortly, which were capable of inhibiting the mutant forms exclusively while sparing the wild type. Many other strategies have also been developed to reduce the risk of covalent interactions with off-targets, thus improving the pharmacokinetic and/or pharmacodynamic profile of the antiproliferative agents. In this review, we focused mainly on second- and third-generation EGFR inhibitors, their…

Carbonic anhydrase (CA, EC 4.2.1.1) is a member of the metalloenzyme family. It catalyzes the rapid conversion of carbon dioxide (CO2) and water to bicarbonate (HCO3−) and protons (H+) and also plays an important role in biochemical and physiological processes. In this study, a number of novel 2‐(4‐(aryl)thiazole‐2‐yl)‐3a,4,7,7a‐tetrahydro‐1H‐4,7‐methanoisoindole‐1,3(2H)‐dione derivatives were synthesized and evaluated for their inhibitory characteristics against the human CA isoenzymes I and II (hCA I and hCA II). The structures of the new molecules 8a–i were confirmed by means of IR, 1H NMR, 13C NMR, and elemental analysis. These compounds exhibited excellent inhibitory effects, in the low nanomolar range, with Ki values in the range of 27.07–37.80 nM against hCA I and in the range of 11.80–25.81 nM against hCA II. Our findings suggest that the new isoindolylthiazole derivatives have superior inhibitory effect over acetazolamide (AZA), which is used as clinical CA inhibitor with Ki values of 34.50 and 28.93 nM against the hCA I and hCA II isoenzymes, respectively.

A series of new coumarin-triazolothiadiazine hybrid compounds (5a-j) was designed and synthesized by using the molecular hybridization concept. The cyclocondensation reaction involves the coumarinyl 4-amino-1,2,4-triazole and a range of bromo-acetophenones, delivering the desired products in good yields. The structures of the synthesized compounds were established on the basis of spectro-analytical data. The prepared compounds were evaluated against alkaline phosphatase (ALP) where compound 5j incorporating bis-coumarinyl motifs at the 3- and 6-positions of the heteroaromatic core turned out to be a potent inhibitor with an IC50 value of 1.15 ± 1.0 µM. The synthesized compounds were also tested against Leishmania major and 5h was the lead member with an IC50 value of 0.89 ± 0.08 μM. Anticancer activity was also determined using kidney fibroblast (BHK-21) and lung carcinoma (H-157) cancer cell lines. Compound 5i showed highest cytotoxic potential against H-157 cells with an IC50 value of 1.01 ± 0.12 μM, which is an improved inhibition compared to the standards (vincristine and…