Design and multi-step synthesis of chalcone-polyamine conjugates as potent antiproliferative agents

The aim of this study is to synthesize chalcone-polyamine conjugates in order to enhance bioavailability and selectivity of chalcone core towards cancer cells, using polyamine-based vectors. 3-hydroxy-3′,4,4′,5′-tetramethoxychalcone (1) and 3′,4,4′,5′-tetramethoxychalcone (2) were selected as parent chalcones since they were found to be efficient anti-proliferative agents on various cancer cells. A series of ten chalcone-polyamine conjugates was obtained by reacting carboxychalcones with different polyamine tails. Chalcones 1 and 2 showed a strong cytotoxic activity against two prostatic cancer (PC-3 and DU-145) and two colorectal cancer (HT-29 and HCT-116) cell lines. Then, chalcone-spermine conjugates 7d and 8d were shown to be the most active of the series and could be considered as promising compounds for colon and prostatic cancer adjuvant therapy.     

Discovery of novel methanone derivatives acting as antimycobacterial agents

A series of pyrazoline derivatives were synthesized and in vitro activity against Mycobacterium tuberculosis H37Rv was carried out. Among the synthesized compounds, compounds (4d) and (4f) 4-aminophenyl-3-(3,4-dimethoxyphenyl)-6,7-dimethoxy-2,3,3a,4-tetrahydroindeno[1,2-c]pyrazol-2-ylmethanone and 4-aminophenyl-6,7-dimethoxy-3-phenyl-2,3,3a,4-tetrahydroindeno[1,2-c]pyrazol-2-ylmethanone were found to be the most active agent against M. tuberculosis H37Rv with a minimum inhibitory concentration of 10?μg/mL.     

Discovery and evaluation of novel nitrodihydroimidazooxazoles as promising anti-tuberculosis agents

New analogues of antitubercular drug Delamanid were prepared, seeking drug candidates with enhanced aqueous solubility and high efficacy. The strategy involved replacement of phenoxy linker proximal to the 2-nitroimidazooxazole of Delamanid by piperidine fused 5 or 6-membered ring heterocycles (ring A). The new compounds were all more hydrophilic than Delamanid, and several class of analogues showed remarkable activities against M. bovis. And among these series, the tetrahydro-naphthyridine-linked nitroimidazoles displayed excellent antimycobacterial activity against both replicating (MABA) and nonreplicating (LORA) M. tb H37Rv and low cytotoxicity. Compared to Delamanid, these new compounds (6, 7, 45) demonstrated dramatically improved physicochemical properties and are suitable for further in vitro and in vivo evaluation.     

The synthesis and evaluation of quinolinequinones as anti-mycobacterial agents

A library of thirty-two quinolinequinones (QQs) with various amine substituents at the 6- and 7-positions were synthesised efficiently and in good yields for evaluation as potential anti-tuberculosis agents. Mycobacterium tuberculosis growth inhibition assays demonstrated that QQs bearing moderate length alkyl chains (i.e. heptylphenylamino- and octylamino-QQs), and aryl groups (i.e. phenylethylamino- and benzylamino-QQs) exhibited encouraging inhibitory activity, while QQ analogue 7-chloro-6-propargylamino-quinoline-5,8-dione (16b) had excellent inhibitory activity (MIC = 8 μM). The cLogP values and redox activities of the QQs were determined, and neither readout correlated with the anti-mycobacterial activities of the compounds. Notwithstanding, mode of action studies of 16b revealed that treatment of M. tuberculosis with this compound led to activation of NADH-dependent oxygen consumption suggesting a redox cycling mechanism. To this end, the promising anti-mycobacterial activity of several QQs and their ability to perturb oxygen management leading to an uncontrolled respiratory burst, as identified in this work and by others, demonstrates the merit of further optimising the anti-mycobacterial activity of this readily synthesised class of compound.     

Discovery of 2-pyridineformamide thiosemicarbazones as potent antiausterity agents

Series of 2-pyridineformamide thiosemicarbazones were synthesized. Their preferential cytotoxicity in nutrient deprived medium (NDM) was evaluated using PANC-1 human pancreatic cancer cells by employing an antiausterity strategy. 2-Pyridineformamide thiosemicarbazones induced apoptosis and exhibited preferential cytotoxic activity toward PANC-1 cells in NDM, with potencies in the submicromolar range. These compounds are potential candidates for the development of therapeutics against pancreatic cancer.     

Discovery of nitroaryl urea derivatives with antiproliferative properties

A series of urea derivatives bearing nitroaryl moiety has been synthesized and assayed for their potential antiproliferative activities. Some of the tested compounds displayed activity in RK33 laryngeal cancer cells and TE671 rhabdomyosarcoma cells while being generally less toxic to healthy HSF human fibroblasts cells. One compound was demonstrated to be a moderate CDK2 inhibitor with IC₅₀?=?14.3?µM. Its structure was solved by an X-ray crystallography and molecular modelling was performed to determine structure-activity relationship. Obtained compounds constitute novel structures and generally demonstrated greater cytotoxicity in comparison to cisplatin. This study offers new structural motifs with potential for further development.     

Discovery of novel 4(1H)-quinolone derivatives as potential antiproliferative and apoptosis inducing agents

A series of novel 4(1H)-quinolone derivatives was synthesized and evaluated for antiproliferative activity in vitro. The results showed that these compounds exhibited more potent antiproliferative effect against a panel of human tumor cell lines than the lead compound 7-chloro-4(1H)-quinolone 1. Compound 7e was found to be the most potent antiproliferative agent and to exhibit selective cytotoxic activity against HepG2 cell lines with IC₅₀ value lower than 1.0 μM. Annexin V/FITC-PI assay showed that compound 7e induced apoptosis in HepG2 cells with a dose-dependent manner. Western blotting analysis indicated that compound 7e induced cell cycle arrest in G2/M phase by p53-depedent pathway.     

Synthesis and biological evaluation of 3-functionalized 2-phenyl- and 2-alkylbenzo[b]furans as antiproliferative agents against human melanoma cell line

The key function of microtubules and mitotic spindle in cell division make them attractive targets in anticancer therapy. In the present study, functionalized in 3 position 2-phenyl- and 2-alkylbenzo[b]furans were synthesized and evaluated as antitumor agents. Among the synthesized derivatives 13a, 13b and 14 exhibited the most potent antiproliferative activity against human melanoma A375 cell line with IC₅₀ values of 2.85 µM, 0.86 µM, 0.09 µM, respectively. The most promising compound defined was 14 with three methoxy groups in the 3-aroyl substituent and 7-methoxy group in 2-phenylbenzo[b]furan skeleton. Tubulin polymerization assay, confocal microscopy imaging and flow cytometry analysis revealed that 2-phenyl-3-aroylbenzo[b]furans (13a, 13b and 14) inhibited tubulin polymerization leading to disruption of mitotic spindle formation, cell cycle arrest in G2/M phase and apoptosis.     

Quinolines derivatives as novel sunscreening agents

Currently, the research and development of sunscreens play an important role on the synthesis of actives that are stable in various kinds of formulations—in addition to their efficiency and broad spectrum of protection against ultraviolet radiation. Our objective here was to synthesize new sunscreening chemical agents using quinoline as a base molecule. Twelve quinoline derivatives were synthesized, four of them novel molecules, and their photoprotective activity was determined in vitro using diffuse transmittance spectrophotometry. We determined their SPF, UVAPF, UVA/UVB ratio, critical wavelength and Boots Star Rating. The quinolines derivatives presented a varied profile of photoprotection, their SPF ranging from 2 to 11 and their UVAPF from 2 to 7. In terms of the critical wavelength, all molecules were considered of broad-spectrum by different classifications. Regarding the Boots Star Rating, one compound received no rating, seven of them received a three stars rating, three received a four stars rating and three were given a five stars rating. The molecules showed in the present work have a wide range of possibilities for creating new sunscreen products, once they have good SPF or UVAPF for single molecules, and they also possess other different qualities that can act synergistically.     

Design and synthesis of tryptophan containing peptides as potential analgesic and anti‐inflammatory agents

A new series of smaller peptides with tryptophan at C‐terminal and varying N‐protected amino acids/peptides were designed, synthesized and characterized by analytical and spectroscopic techniques. Analgesic and anti‐inflammatory properties of these peptides were carried out in vivo using tail‐flick method and carrageenan‐induced paw edema method, respectively, at different doses and different time intervals. Most of the peptides synthesized displayed enhanced activity, and particularly tetra and hexapeptides 29–31 were found to be even more potent than the reference standards used. Moreover, some peptides have exhibited promising activity even after 24 h of administration, whereas the reference standards were active only up to 3 h. Further, the compounds did not present any ulcerogenic liability. Copyright © 2012 European Peptide Society and John Wiley & Sons, Ltd.     

Discovery of N-(benzyloxy)-1,3-diphenyl-1H-pyrazole-4-carboxamide derivatives as potential antiproliferative agents by inhibiting MEK

Mitogen activated protein kinase (MAPK) signal transduction pathway has been proved to play an important role in tumorigenesis and cancer development. MEK inhibitor has been demonstrated significant clinical benefit for blocking MAPK pathway activation and possibly could block reactivation of the MAPK pathway at the time of BRAF inhibitor resistance. Twenty N-(benzyloxy)-1,3-diphenyl-1H-pyrazole-4-carboxamide derivatives have been designed and synthesized as MEK inhibitors, and their biological activities were evaluated. Among these compounds, compound 7b showed the most potent inhibitory activity with IC₅₀ of 91 nM for MEK1 and GI₅₀ value of 0.26 μM for A549 cells. The SAR analysis and docking simulation were performed to provide crucial pharmacophore clues that could be used in further structure optimization.     

Discovery and development of a novel class of phenoxyacetyl amides as highly potent TRPM8 agonists for use as cooling agents

The paper presents the activity trends for a novel series of phenoxyacetyl amides as human TRPM8 receptor agonists. This series encompasses in vitro activity values ranging from the micromolar to the picomolar levels. Sensory evaluation of these molecules highlights their relevance as cooling agents for oral applications. The positive outcome of the complete evaluation of N-(1H-pyrazol-3-yl)-N-(thiophen-2-ylmethyl)-2-(p-tolyloxy)acetamide resulted in its approval for Generally Recognized As Safe (GRAS) status by the Flavor & Extract Manufacturer Association (FEMA) as FEMA 4809.     

Design,green synthesis and pharmacological evaluation of novel 5,6-diaryl-1,2,4-triazines bearing 3-morpholinoethylamine moiety as potential antithrombotic agents*

The aim of this research work was to investigate a series of novel 5,6-diaryl-1,2,4-triazines (3a–3q) containing 3-morpholinoethylamine side chain, and to address their antiplatelet activity by in vitro, ex vivo and in vivo methods. All compounds were synthesized by environment benign route and their structures were unambiguously confirmed by spectral data. Compounds (3l) and (3m) were confirmed by their single crystal X-ray structures. Out of all the synthesized compounds, 10 were found to be more potent in vitro than aspirin; six of them were found to be prominent in ex vivo assays and one compound (3d) was found to have the most promising antithrombotic profile in vivo. Moreover, compound (3d) demonstrated less ulcerogenicity in rats as compared to aspirin. The selectivity of the most promising compound (3d) for COX-1 and COX-2 enzymes was determined with the help of molecular docking studies and the results were correlated with the biological activity.     

Sterically induced conformational restriction: Discovery and preclinical evaluation of novel pyrrolo[3,2-d]pyrimidines as microtubule targeting agents

The discovery, synthesis and biological evaluations of a series of nine N5-substituted-pyrrolo[3,2-d]pyrimidin-4-amines are reported. Novel compounds with microtubule depolymerizing activity were identified. Some of these compounds also circumvent clinically relevant drug resistance mechanisms (expression of P-glycoprotein and βIII tubulin). Compounds 4, 5, and 8–13 were one to two-digit nanomolar (IC₅₀) inhibitors of cancer cells in culture. Contrary to recent reports (Banerjee et al. J. Med. Chem.2018, 61, 1704–1718), the conformation of the most active compounds determined by ¹H NMR and molecular modeling are similar to that reported previously and in keeping with recently reported X-ray crystal structures. Compound 11, freely water soluble as the HCl salt, afforded statistically significant inhibition of tumor growth in three xenograft models [MDA-MB-435, MDA-MB-231 and NCI/ADR-RES] compared with controls. Compound 11 did not display indications of animal toxicity and is currently slated for further preclinical development.     

Synthesis and biological evaluation of quinoline derivatives as potential anti-prostate cancer agents and Pim-1 kinase inhibitors

In this work, a series of quinoline derivatives were designed and synthesized as antitumor agents. Most quinolines showed potent anti-proliferative activity against human prostatic cancer PC-3 cell line. Among which, 9d, 9f and 9g were the most effective compounds with GI₅₀ values of 2.60, 2.81 and 1.29 μM, respectively. Structure–activity relationship analysis indicated that the secondary amine linked quinoline and pyridine ring played an important role in the anti-proliferative effects. Mechanistic studies revealed that 9g was a potential Pim-1 kinase inhibitor with abilities of cell cycle arrest and apoptosis induction. Considering of the increased activity of Pim-1 in prostate cancer, such compounds have potential to be developed as anti-prostate cancer agents.     

Design,synthesis and biological evaluation of nonsecosteroidal vitamin D3 receptor ligands as anti-tumor agents

1α,25-dihydroxyvitamin D₃ (1,25-(OH)₂D₃, also known as calcitriol), the active form of vitamin D₃, is being increasingly recognized for cancer therapy. Our previous work showed that phenyl-pyrrolyl pentane analogs, which mimicked anti-proliferative activities against several cancer cell lines of the natural secosteroidal ligand 1,25-(OH)₂D₃. Here, in order to optimize the structural features and discover more potent derivative, a series of nonsecosteroidal vitamin D₃ receptor (VDR) ligands bearing acetylene bond linker was designed, synthesized and evaluated. Most of them showed moderate to good binding affinities and agonistic activities. Especially, compound 19f displayed the most anti-proliferative activities against MCF-7 and PC-3 cells with the IC₅₀ values of 1.80 and 5.35 μM, respectively, which was comparable to positive control 1,25-(OH)₂D₃. Moreover, compound 19f exhibited reduced toxicity against human normal liver cell line (L02) compared with the parental compound 7. Besides, the preliminary structure–activity relationships (SARs) were also analyzed.     

Identification of novel HDAC inhibitors through cell based screening and their evaluation as potential anticancer agents

A series of benzimidazole based HDAC inhibitors have been rationally designed, synthesized and screened. The SAR of this new chemotype is described. The lead compound, 11e, showed strong activity in several cellular assays and demonstrated in vivo efficacy in mouse xenograft pancreatic cancer models.