Chalcones Bearing Nitrogen-Containing Heterocyclics as Multi-Targeted Inhibitors: Design, Synthesis, Biological Evaluation and Molecular Docking Studies

In this work, a series of chalcones (1a-d, 2a-d, 3a-d, 4a-d and 5a-d) was designed and synthesized by Claisen-Schmidt condensation. Also, their chemical structures were elucidated using UV-Vis, FT IR, ¹ H NMR, ¹³ C NMR, MS spectral data and Elemental analyses. Subsequently, anticholinesterase, tyrosinase, urease inhibitory activities and antioxidant activities of all chalcones were evaluated. The inhibitory potential of all chalcones in terms of IC₅₀ value was observed ranging from 7.18 ± 0.43 to 29.62 ± 0.30 μM against BChE by comparing with Galantamine (IC₅₀ 46.06 ± 0.10 μM) as a reference drug. Also compounds 2c, 3c, 4c, 4b and 4d exhibited high anticholinesterase activity against both AChE and BChE enzymes. The tyrosinase inhibitory activity results revealed that three compounds (IC₅₀ 1.75 ± 0.83 μM for 2b, IC₅₀ 2.24 ± 0.11 μM for 3b and IC₅₀ 1.90 ± 0.64 μM for 4b) displayed good inhibitory activity against tyrosinase compared to kojic acid (IC₅₀ 0.64 ± 0.12 μM). In addition, other different three chalcones (IC₅₀ 22.34 ± 0.25 μM for 2c, IC₅₀ 20.98 ± 0.08 μM for 3c and IC₅₀ 18.26 ± 0.13 μM for 4c) showed excellent inhibitory activity against the urease by comparing with thiourea (IC₅₀ 23.08 ± 0.19 μM). Compounds 3c and 4c showed the best potency in all antioxidant activity tests. In the light of these findings, the structure-activity relationship for compounds was also described. Furthermore, molecular modeling studies including molecular docking, ADMET and pharmacophore analyses of compounds gave important information about the interactions and drug likeness properties. As a result, all chalcones exhibited suitable ADMET findings predicting good oral bioavailability. This article is protected by copyright. All rights reserved.

Synthesis, Biological Evaluation and Ligand Based Pharmacophore Modeling of New Aromatic Thiosemicarbazones as Potential Anticancer Agents

Two series of new aromatic thiosemicarbazone derivatives were synthesized by condensation of N-(4-cyanophenyl)hydrazine carbothioamide (I) and N-(4-methylsulfanylphenyl)hydrazine carbothioamide (II) with appropriate aromatic aldehydes in order to investigate their antiviral and cytostatic potency. The chemical structures of all compounds were fully characterized by elemental analysis and spectroscopic techniques. The results of the bioassays indicated that compounds Id, Ie, If and IIf proved inhibitory against influenza virus A (EC₅₀ = 13 – 27 μg/mL for strain H1N1 and 9.3 – 18 μg/mL for strain H3N2). Compounds Ig and IIg were the most cytostatic compounds with inhibition of HeLa cell proliferation at an IC₅₀ = 0.3 μg/mL for Ig and 1.9 μg/mL for IIg. Especially, compound Ig showed the highest cytostatic activity with IC₅₀ of 0.30, 0.70 and 2.50 μg/mL against HeLa, CEM and L1210 cell lines, respectively. This inhibition range was within the same order of magnitude as that for cisplatin. Furthermore, molecular modeling was carried out to examine the cytostatic activity and determine the best pharmacophore model as a guide for the design and development of potential prodrugs in future studies.

New piperidine-hydrazone derivatives: Synthesis, biological evaluations and molecular docking studies as AChE and BChE inhibitors

Hydrazones and the piperidine ring containing compounds were considered as beneficial substrates in drug design. Therefore, this study was aimed at the synthesis of new benzoyl hydrazones derived from ethyl 4-oxopiperidine-1-carboxylate and 2,6-diphenylpiperidin-4-one. The synthesized compounds (1-19) were screened for their antioxidant, anticholinesterase and anticancer activities. The antioxidant capacity of the compounds was evaluated by using four complementary tests. The results showed that compound 7 and 17 have the higher lipid peroxidation inhibitory activity than the other compounds. In DPPH˙ scavenging assay, compounds 5, 6, 10, 14, 17 demonstrated better activity than that of standard BHT, while in ABTS⁺˙ scavenging assay compound 6 and 17 exhibited better activity among the other compounds. The CUPRAC assay disclosed that compound 2 displayed better activity than α-tocopherol. The anticholinesterase activity was performed against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes. Compound 11 (IC₅₀: 35.30 ± 1.11 μM) inhibited BChE better than galantamine (IC₅₀: 46.03 ± 0.14 μM). We conclude that the compound 11 can be considered as a candidate for BChE inhibitor. Moreover docking method was applied to elucidate the AChE and BChE inhibitory mechanism of the compound 11. Molecular docking analysis revealed that compound 11 bound to BChE enzyme more efficiently when compared to the AChE due to its orientations and different types of interactions. In addition, the non-cytotoxic properties of the compounds brought them into prominence, although they did not show significant anticancer properties.