The Eighth Central European Conference "Chemistry towards Biology": Snapshot

The Design and Synthesis of a New Series of 1,2,3-Triazole-Cored Structures Tethering Aryl Urea and Their Highly Selective Cytotoxicity toward HepG2

Target cancer drug therapy is an alternative treatment for advanced hepatocellular carcinoma (HCC) patients. However, the treatment using approved targeted drugs has encountered a number of limitations, including the poor pharmacological properties of drugs, therapy efficiency, adverse effects, and drug resistance. As a consequence, the discovery and development of anti-HCC drug structures are therefore still in high demand. Herein, we designed and synthesized a new series of 1,2,3-triazole-cored structures incorporating aryl urea as anti-HepG2 agents. Forty-nine analogs were prepared via nucleophilic addition and copper-catalyzed azide-alkyne cycloaddition (CuAAC) with excellent yields. Significantly, almost all triazole-cored analogs exhibited less cytotoxicity toward normal cells, human embryonal lung fibroblast cell MRC-5, compared to Sorafenib and Doxorubicin. Among them, 2m’ and 2e exhibited the highest selectivity indexes (SI = 14.7 and 12.2), which were ca. 4.4- and 3.7-fold superior to that of Sorafenib (SI = 3.30) and ca. 3.8- and 3.2-fold superior to that of Doxorubicin (SI = 3.83), respectively. Additionally, excellent inhibitory activity against hepatocellular carcinoma HepG2, comparable to Sorafenib, was still maintained. A cell-cycle analysis and apoptosis induction study suggested that 2m’ and 2e likely share a similar mechanism of action to Sorafenib. Furthermore, compounds 2m’ and 2e exhibit appropriate drug-likeness, analyzed by SwissADME. With their excellent anti-HepG2 activity, improved selectivity indexes, and appropriate druggability, the triazole-cored analogs 2m’ and 2e are suggested to be promising candidates for development as targeted cancer agents and drugs used in combination therapy for the treatment of HCC.

Styrylquinoline – A Versatile Scaffold in Medicinal Chemistry

Background: :

Styrylquinolines are characteristic fully aromatic compounds with flat, rather lipophilic structures. The first reports on their synthesis and biological activity were published roughly a century ago. However, their low selectivity, unfavorable toxicity and problems with their mechanism of action significantly hampered their development. As a result, they have been abandoned for most of the time since they were discovered.

Objective: :

Their renaissance was observed by the antiretroviral activity of several styrylquinoline derivatives that have been reported to be HIV integrase inhibitors. Subsequently, other activities such as their antifungal and anticancer abilities have also been revisited.

Methods:

In the present review, the spectrum of the activity of styrylquinolines and their use in drug design is presented and analyzed.

Results:

New properties and applications that were reported recently have re-established styrylquinolines within medicinal and material chemistry. The considerable increase in the number of published papers regarding their activity spectrum will ensure further discoveries in the field.

Conclusions:

Styrylquinolines have earned a much stronger position in medicinal chemistry due to the discovery of their new activities, profound mechanisms of action and as drug candidates in clinical trials.

Synthesis of Bis(1,2,3-Triazole) Functionalized Quinoline-2,4-Diones

Derivatives of 3-(1H-1,2,3-triazol-1-yl)quinoline-2,4(1H,3H)-dione unsubstituted on quinolone nitrogen atom, which are available by the previously described four step synthesis starting from aniline, were exploited as intermediates in obtaining the title compounds. The procedure involves the introduction of propargyl group onto the quinolone nitrogen atom of mentioned intermediates by the reaction of them with propargyl bromide in N,N-dimethylformamide (DMF) in presence of a potassium carbonate and the subsequent formation of a second triazole ring by copper catalyzed cyclisation reaction with azido compounds. The products were characterized by ¹H, ¹³C and ¹⁵N NMR spectroscopy. The corresponding resonances were assigned on the basis of the standard 1D and gradient selected 2D NMR experiments (¹H–¹H gs-COSY, ¹H–¹³C gs-HSQC, ¹H–¹³C gs-HMBC) with ¹H–¹⁵N gs-HMBC as a practical tool to determine ¹⁵N NMR chemical shifts at the natural abundance level of ¹⁵N isotope.

The capability of minor quaternary benzophenanthridine alkaloids to inhibit TNF-α secretion and cyclooxygenase activity

Quaternary benzophenanthridine alkaloids are known to have a wide range of biological effects, including antimicrobial, antifungal, anti-inflammatory, and antitumour activities. However, only sanguinarine and chelerythrine have been studied intensively. The aim of this study was to evaluate the anti-inflammatory potential of the five minor quaternary benzophenanthridine alkaloids sanguilutine, sanguirubine, chelirubine, chelilutine, and macarpine in vitro and to compare them with more thoroughly studied sanguinarine and chelerythrine. Before making cell-based assays, the cytotoxicity of the alkaloids was evaluated. The anti-inflammatory potential of the chosen alkaloids was evaluated as for their ability to modulate the lipopolysaccharide-induced secretion of tumour necrosis factor α (TNF-α) in the macrophage-like cell line THP-1. The cyclooxygenase (COX)-1 and COX-2 inhibitory activities were also measured. The results indicate that the presence of a methylenedioxy ring attached at carbon (C)7-C8 is important for reducing the secretion of TNF-α. Interestingly, this effect did not show a simple dependence on concentration. The selected alkaloids showed little or no anti-COX activity. The results obtained from the present experiments may provide additional information useful in understanding the structure-to-activity relationship of the quaternary benzophenanthridine alkaloids. The anti-inflammatory potential and the cytotoxic effect are driven by the presence of a methylenedioxy ring attached at C7-C8 and C2-C3, respectively.

Beware of ligand efficiency (LE): understanding LE data in modeling structure-activity and structure-economy relationships

Background

On the one hand, ligand efficiency (LE) and the binding efficiency index (BEI), which are binding properties (B) averaged versus the heavy atom count (HAC: LE) or molecular weight (MW: BEI), have recently been declared a novel universal tool for drug design. On the other hand, questions have been raised about the mathematical validity of the LE approach.

Results

In fact, neither the critics nor the advocates are precise enough to provide a generally understandable and accepted chemistry of the LE metrics. In particular, this refers to the puzzle of the LE trends for small and large molecules. In this paper, we explain the chemistry and mathematics of the LE type of data. Because LE is a weight metrics related to binding per gram, its hyperbolic decrease with an increasing number of heavy atoms can be easily understood by its 1/MW dependency. Accordingly, we analyzed how this influences the LE trends for ligand-target binding, economic big data or molecular descriptor data. In particular, we compared the trends for the thermodynamic ∆G data of a series of ligands that interact with 14 different target classes, which were extracted from the BindingDB database with the market prices of a commercial compound library of ca. 2.5 mln synthetic building blocks.

Conclusions

An interpretation of LE and BEI that clearly explains the observed trends for these parameters are presented here for the first time. Accordingly, we show that the main misunderstanding of the chemical meaning of the BEI and LE parameters is their interpretation as molecular descriptors that are connected with a single molecule, while binding is a statistical effect in which a population of ligands limits the formation of ligand-receptor complexes. Therefore, LE (BEI) should not be interpreted as a molecular (physicochemical) descriptor that is connected with a single molecule but as a property (binding per gram). Accordingly, the puzzle of the surprising behavior of LE is explained by the 1/MW dependency. This effect clearly explains the hyperbolic LE trend not as a real increase in binding potency but as a physical limitation due to the different population of ligands with different MWs in a 1 g sample available for the formation of ligand-receptor complexes.Graphical abstract