Novel chiral Schiff base Palladium(II), Nickel(II), Copper(II) and Iron(II) complexes: Synthesis, characterization, anticancer activity and molecular docking studies

In this study, two chiral Schiff base ligands (L1 and L2) were synthesized from the condensation reaction of (S)-2-amino-3-phenyl-1-propanol with 2-hydroxybenzaldehyde and 2-hydroxy-1-naphthaldehyde as metal precursors for the preparation of transition metal complexes with Pd(II), Fe(II), Ni(II) and Cu(II). The compounds were characterized by using X-ray (for L1-Pd(II)), NMR, FT-IR, UV-Vis, magnetic susceptibility, molar conductivity, and elemental analysis. The in vitro cytotoxic effects of ligands (L1 and L2) and their metal complexes on colon cancer cells (DLD-1), breast cancer cells (MDA-MB-231) and healthy lung human cell lines were investigated by using the 3-(4,5-dimethylthiazol-2-yl)-2,5‑diphenyl tetrazolium bromide (MTT) assay. Among the synthesized compounds, L1-Pd(II) was particularly found to be the most potent anticancer drug candidate in this series with IC50 values of 4.07, and 9.97 µM in DLD-1 and MDA-MB-231 cell lines, respectively. In addition, molecular docking results indicate that Glu122, Asn103, Ala104, Lys126, Phe114, Leu123, and Lys126 amino acids are the binding site of the colon cancer antigen protein, in which the most active complex, L1-Pd(II) can inhibit the current target.

Nile Red fluorescence spectrum decomposition enables rapid screening of large protein aggregates in complex biopharmaceutical formulations like influenza vaccines

The extensive presence of large (high molecular weight) protein aggregates in biopharmaceutical formulations is a concern for formulation stability and possibly safety. Tests to screen large aggregate content in such bioformulations are therefore needed for rapid and reliable quality control in industrial settings. Herein, non-commercial seasonal influenza split-virus vaccine samples, produced using various strains and extracted from selected industrial processing steps, were used as model complex bioformulations. Orthogonal characterization through transmission electron microscopy, UV-Vis absorption spectroscopy, fluorescence emission spectroscopy, high-performance liquid chromatography and single-radial immunodiffusion revealed that large, amorphous protein aggregates are formed after virus splitting and their presence is linked mainly, albeit not only, to surfactant (Triton X-100) content in a sample. Importantly, the presence of large virus aggregates in purified whole virus samples and large protein aggregates in vaccine samples was found to correlate with broadening/shouldering in Nile Red fluorescence spectra. Accordingly, decomposition of Nile Red spectra into components allowed the development of a novel, rapid, reliable and user-friendly test with high-throughput potential for screening large aggregate content in influenza split-virus vaccines. The test can be adapted for screening other complex biopharmaceutical formulations, provided relevant controls are done for informed decomposition of fluorescence spectra into their components.

Chemical profiling and biological activity evaluation of propolis from Çayeli-Rize, Eastern Black Sea Region, Anatolia

The constituents of the aqueous, ethanol, hexane, and methanol extracts of Anatolian propolis collected from the Eastern Black Sea Region (Çayeli-Rize) were investigated by GC-MS, HPLC and AAS. Interestingly, lactulose has been identified. Ten phenolic compounds, namely caffeic acid, ferulic acid, rutin, taxifolin, quercetin, kaempferol, apigenin, silicristin, silibinin and gallic acid were determined. The contents of phenolic acids and flavonoids varied between 17.04-642.59 and 1.18-2749.20 ppm, respectively. Minerals found in propolis were Na, K, Ca, Mg and Zn. The methanol extract had the highest antiproliferative activity against the A549 cell line with an IC50 value of 0.1821 µL/mL. The extracts showed higher antibacterial activity against Gram-negative bacteria compared to Gram-positive bacteria.

Investigation of the sensitivity of human A549 cells to paclitaxel and sesquiterpene lactone alantolactone via apoptosis induction

Alantolactone (ALA), a sesquiterpene lactone compound obtained from Inula helenium root, is known to have anticancer activity in many types of cancer. Paclitaxel (PAX) is an effective first-line chemotherapeutic drug and is widely used in the treatment of lung cancer. The in vitro anticancer efficacy of combined treatment of ALA with PAX was investigated in the A549 human lung cancer cell line. The results show that ALA potentiated the effect of PAX-induced growth restriction and apoptosis in A549 cells. The combined administration more effectively decreased the Bcl-2 expression and increased Bax gene expression in cells compared to ALA or PAX alone. Also, co-treatment of ALA and PAX caused apoptotic nuclear formations. Additionally, coadministration increased the caspase-3 and caspase-9 levels more than PAX or ALA alone. The increase in NF-κB gene expression levels suggests that an NF-κB-independent apoptotic trigger mechanism operates in cells. Together, the present in vitro findings suggest that ALA may contribute as a potential therapeutic strategy in the treatment of lung cancer.

Synthesis of Novel Cu(II), Co(II), Fe(II), and Ni(II) Hydrazone Metal Complexes as Potent Anticancer Agents: Spectroscopic, DFT, Molecular Docking, and MD Simulation Studies

Metal complexes [FeL], [NiL]·H2O, [CuL], and [CoL]·H2O were formed by the ligand (L, 4-fluoro-N'-(2-hydroxybenzylidene)benzohydrazide) reacting with Fe(OAc)2, Ni(OAc)2·4H2O, Cu(OAc)2·H2O, and Co(OAc)2·4H2O. The produced compounds were characterized using a variety of methods, such as NMR, UV-vis, FT-IR, magnetic susceptibility, elemental analysis, and molar conductivity. The spectrum of the data indicates that the geometry of the complex molecular structures is octahedral with six coordination sites. The ligand and its different metal complexes were tested in a human lung cancer cell line and a normal embryonic kidney cell line. A cytotoxic assay revealed that L-Cu is the most potent chelate against cancer cell lines. A computational study was performed to rationalize this finding. The binding potential of relatively active compounds to a suitable target was analyzed. For this purpose, a target that is known to be inhibited by small compounds with a scaffold similar to that of the synthesized compounds, lysine-specific demethylase 1 (LSD1), was first determined. Molecular docking studies demonstrated that L-Cu has a high binding potential to LSD1 at a level comparable to that of a standard ligand. Molecular dynamics (MD) simulations revealed that L-Cu and L form stable complexes with the enzyme. Furthermore, the MD simulation study showed that L-Cu remained inside the binding pocket of the enzyme during the 200 ns simulation period. Density functional theory (DFT) studies demonstrated that the chemical stability of L was higher than that of its chelate form, L-Cu.

Investigation of the cytotoxic activity, DFT calculation, and docking studies newly synthesized 1,3-disubstituted benzimidazolium chlorides on human liver cancer, lung cancer, and normal embryonic kidney cell lines

Three 1,3-disubstituted benzimidazolium salts (3a-c) were efficiently synthesized in moderate to high yields (52-83 %) and analyzed through NMR spectra. The anti-cancer efficiency of these compounds was tested on human liver cancer (HepG2), lung cancer (A549), and normal embryonic kidney (HEK-293T) cell lines. The results demonstrated that compound 3b emerges as a promising candidate for further investigation due to its high cytotoxicity, comparable to cisplatin. The optimized geometry, electronic properties, chemical parameters and frontier molecular orbitals of 3a-c were determined by DFT calculation using density functional theory (DFT) with the B3LYP/6-31++G(d,p) level in the ground state. In addition to the experimental studies, compounds 3a-c were docked against target protein PDB ID: 6V9C representing the HepG2 cell line.

A Newly Synthesized Benzimidazolium Salt: 1-(2-Cyanobenzyl)-3-(4-Vinylbenzyl)-1H-Benzo[D]imidazol-3-ium Chloride as a Potential Anticancer Agent for Colon Cancer Treatment, In Vitro Study

Colon cancer is one of the most common cancer-related deaths. Drug resistance is one of the biggest challenges in cancer treatment. Numerous pharmacological and biochemical investigations have documented the benzimidazole ring's anticancer, anti-inflammatory, and antioxidant properties. Within the scope of our project, the effect of newly synthesized benzimidazolium salt (BS) on cell proliferation was tested with MTT assay, and its effect on apoptosis and cell cycle was tested with annexin V and PI in the two different colon cancer cell lines (HT-29 and DLD-1). Our study examined the expressions of some genes related to apoptosis and, additionally, caspase activities with the multicaspase kit. BS showed an antiproliferative effect at lower doses in HT-29 colon cancer cells. When HT-29 cells were exposed to a 20 µM dosage, they showed increased caspase activity and apoptosis compared to DLD-1 cells. HT-29 accumulated in the G2/M phase of the cell cycle, whereas DLD-1 cells accumulated more in the S phase. In HT-29 cells, colony formation was inhibited; however, in DLD-1 cells, this effect was insufficient. Based on the apoptosis-death pathway, BS is expected to have anti-cancer effects. As a result of this work, this chemical was thoroughly examined in two different colon cancer cell lines, and additional, more comprehensive initiatives are being planned in light of the information obtained from this study.

Molecular Hybrid Design, Synthesis, In Vitro Cytotoxicity, In Silico ADME and Molecular Docking Studies of New Benzoate Ester-Linked Arylsulfonyl Hydrazones

In this paper, we present the synthesis and characterization of two known sulfonyl hydrazides (1 and 2) and their new sulfonyl hydrazone derivatives (9-20), as well as in vitro and in silico investigations of their cytotoxic properties against human lung (A549) and human breast (MCF-7) cancer cell lines. The target compounds (9-20) obtained in high yields were synthesized for the first time by a multi-step reaction, and their structures were confirmed by elemental analysis and various spectral techniques, including FT-IR, 1H-, and 13C-NMR. The antiproliferative profiles of these compounds (1, 2, and 9-20) in this study were determined at concentrations of 200, 100, 50, and 25 µM against selected cancer cell lines for 72 h using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) method. Except for compounds 1 and 2, other compounds (9-20) demonstrated cytotoxic activity at concentrations lower than 200 µM. The newly synthesized compounds (9-20) demonstrated antiproliferative activities at a micromolar level, with IC50 values in the range of 29.59-176.70 μM for the A549 cell line and 27.70-170.30 μM for the MCF-7 cell line. Among these compounds, compound 15 (IC50 = 29.59 μM against A549 cell line and IC50 = 27.70 μM against MCF-7 cell line) showed the highest cytotoxic activity against these two cancer cell lines compared to the reference drug cisplatin (IC50 = 22.42 μM against A549 cell line and IC50 = 18.01 μM against MCF-7 cell line). From docking simulations, to establish a plausible binding mode of compounds, we noticed that compound 15 demonstrated the highest affinity (-6.8508 kcal/mol) for estrogen receptor-beta (ERbeta) compared to others, suggesting promising ERbeta binding potential. Most compounds followed Lipinski's rule of five, with acceptable logP values. Additionally, all had mixed gastrointestinal absorption and limited blood-brain barrier permeability. Overall, our study proposed new sulfonyl hydrazones as a potential class of anticancer agents.

Density functional modeling, and molecular docking with SARS-CoV-2 spike protein (Wuhan) and omicron S protein (variant) studies of new heterocyclic compounds including a pyrazoline nucleus

Nowadays, different vaccines and antiviral drugs have been developed and their effectiveness has been proven against SARS-CoV-2. Pyrazoline derivatives are biologically active molecules and exhibit broad-spectrum biological activity properties. In this scope, four new molecules (4a-d) including a pyrazoline core were synthesized in order to predict their antiviral properties theoretically. Compounds 4a-d were purified by the crystallization method. The structures of 4a-d were completely characterized by NMR, IR, and elemental analysis. The molecular structures of the compounds in the ground state have been optimized using density functional theory with the B3LYP/6-31++G(d,p) level. The quantum chemical parameters were predicted by density functional theory calculations. Moreover, the molecular docking studies of 4a-d with SARS-CoV-2 Spike protein (Wuhan) and omicron S protein (variant) were presented to investigate and predict potential interactions. The binding sites, binding types and energies, bond distances of the non-covalent interactions and calculated inhibition constants (calc. Ki) as a consequence of molecular docking for 4a-d were presented in this study. Furthermore, the stability of the protein-4a complex obtained from the docking was investigated through molecular dynamics simulation.Communicated by Ramaswamy H. Sarma.

Design, spectroscopic characterization, in silico and in vitro cytotoxic activity assessment of newly synthesized thymol Schiff base derivatives

Cancer is a global public health problem affecting millions of people every year. New anticancer drug candidates are needed to overcome the resistance to drugs used in the treatment of various types of cancer. In this study, two new series of benzenesulfonate-based thymol derivatives (14-19 and 20-25) were synthesized for the first time as promising chemotherapeutic agents and characterized using FT-IR, 1D NMR (1H- and 13C-NMR, APT, DEPT 135), 2D NMR (HETCOR and HMBC), and elemental analysis (CHNS). Antiproliferative activity of the molecules was determined against cancer cell lines, namely, the human lung adenocarcinoma cell line (A549) and the colorectal adenocarcinoma cell line (DLD-1), using MTT method for both 48 and 72 h. Compounds (14-25) showed cytotoxic activities against A549 with IC50 values ranging from 9.98 to 81.83 μM, respectively, compared to cisplatin (6.65 μM). These compounds exhibited antiproliferative activities against DLD-1 cancer cells at concentrations ranging from 4.29 to 53.62 μM, respectively, compared to cisplatin (9.91 μM). Especially, compound 16 displayed significant cytotoxicity on A549 and DLD-1 cancer cells with IC50 values of 9.98 and 10.75 μM, respectively. Finally, molecular docking studies were performed with Bcl-2, VEGFR-2, EGFR, and HER2 targets using the Schrödinger 2021-2 Maestro Glide program. The binding energy values and binding interactions of compounds 16 and 22 were determined to be the result of their interactions with these targets. Schrödinger 2021-2 Qikprop wizard drug similarity ratios and ADME prediction of all compounds 14-25 were also calculated.

Synthesis, characterization, antiproliferative activity, docking, and molecular dynamics simulation of new 1,3-dihydro-2H-benzimidazol-2-one derivatives

Cancer is a global public health problem that affects millions each year. Novel anticancer drug candidates are in need to treat various cancers and to overcome the resistance that exists against drugs in use. Benzimidazole derivatives have been reported as anticancer agents. These lead us to synthesize similar benzimidazole derivatives and investigate their anticancer activity. In this study, six new 1,3-dihydro-2H-benzimidazol-2-one-based molecules (2a-f) were synthesized. The structures of these molecules were verified by spectroscopic methods. The antiproliferative activities of molecules 2a-f were screened against a panel of human cancer cell lines, including the liver, colon, lung, and breast. The molecules were also tested towards normal human lung cell line to determine their selectivity. The results demonstrated that compound 2d had the highest cytotoxic effect compared to compounds 2a-c, 2e, and 2f against DLD-1 and MDA-MB-231 cell lines. The binding potential of the relatively active compound, 2d, with three targets was investigated through molecular docking. The stability of target-compound complexes procured from the docking was explored through molecular dynamics (MD) simulation. The docking and MD simulation studies revealed that compound 2d had the highest potential to bind to GALR3 among the targets. Furthermore, the computational pharmacokinetic study demonstrated that the synthesized compounds had drug-like properties.Communicated by Ramaswamy H. Sarma.

Design, Synthesis, and In Silico and In Vitro Cytotoxic Activities of Novel Isoniazid-Hydrazone Analogues Linked to Fluorinated Sulfonate Esters

Cancer is a life-threatening disease, and significant efforts are still being made to treat it. In this study, we synthesized and characterized novel hybrid molecules (10-18) containing hydrazone and sulfonate moieties and tested their cell growth inhibitory effect on human colon cancer cells (DLD-1), human prostate cancer cells (PC3), and human embryonic kidney cells (HEK-293T) using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) method for 72 h. In cell culture studies, all tested hybrid molecules except for 12 and 13 showed significant cytotoxic activities at a micromolar level with IC50 values in the range of 10.28-214.0 μM for the PC3 cell line and 13.49-144.30 μM for the DLD-1 cell line. Compounds 4 (10.28 μM) and 5 (11.22 μM) demonstrated the highest cytotoxicity against the PC3 cell line. Against the DLD-1 cell line, compounds 1 (22.53 μM), 4 (13.49 μM), 5 (19.33 μM), 6 (17.82 μM), 8 (24.71 μM), 9 (17.56 μM), and 10 (17.90 μM) in the series showed anticancer activity at lower micromolar levels compared to cisplatin (26.70 μM). Moreover, the study was handled computationally, and molecular docking studies were performed for compounds 1, 4, and 5 for PC3-FAK and PC3-Scr and compounds 4, 6, and 9 for the DLD-1-TNKS target. In this study, compound 4 was found to be the most effective and promising molecule for both targets.

A benzimidazolium salt induces apoptosis and arrests cells at sub-G1 phase in epithelial ovarian cancer cells

BACKGROUND

Ovarian cancer, also known as a silent killer, is the deadliest gynecological cancer in women worldwide. Epithelial ovarian cancers constitute the majority of ovarian cancers, and diagnosis can be made in advanced stages, which greatly reduces the likelihood of treatment and lowers the survival rate. For the treatment of epithelial ovarian cancers, the search for synthetic agents as well as agents of natural origin continues. The effects of 1-(2-cyanobenzyl)-3-(4-vinylbenzyl)-1H-benzo[d]imidazole-3-ium chloride (BD), a benzimidazole derivative, were investigated on epithelial ovarian cancer cells.

METHODS AND RESULTS

In our study, the effects of BD on proliferation, colony formation, cell death by apoptosis and the cell cycle in A2780 and A2780 Adriamycin (ADR) ovarian cancer cell lines were investigated. Proliferation was examined with cell viability analysis, colony formation and apoptosis with Annexin V staining and cell cycle analyses with PI staining, respectively. As a result of the analyses, BD inhibited cell proliferation and colony formation, induced apoptosis and cell death at 48 h in A2780 and A2780 ADR cells at 10.10 and 10.36 µM concentrations, respectively. In addition, A2780 and A2780ADR cells were arrested in the Sub-G1 phase of the cell cycle.

CONCLUSIONS

BD suppresses cancer cell progression by showing antiproliferative effects on ovarian cancer cells. Further analyses are required to determine the mechanism of action of this agent and to demonstrate its potential as a suitable candidate for the treatment of epithelial ovarian cancer.

Biological evaluations and computational studies of newly synthesized thymol-based Schiff bases as anticancer, antimicrobial and antioxidant agents

Three new thymol-based molecules were synthesized and evaluated as anticancer, antimicrobial and antioxidant agents. Liver, colon, lung and prostate cancer cell lines were utilized in cytotoxicity tests. The results demonstrated that synthesized molecules had a cytotoxic effect against the screened cell lines. One of the molecules (4a) was found to have a higher efficacy towards the colon cancer cell line (DLD-1) with an IC50 value of 12.39 µM and the other (4c) towards the prostate cancer cell line (PC3) with an IC50 value of 7.67 µM than the positive control drug cisplatin. To assess the antimicrobial activity of molecules (4a-c), Gram-positive bacteria, Gram-negative bacteria and yeast were subjected to agar disc diffusion and broth microdilution assays. The investigation of antioxidant potential was conducted using the DPPH radical scavenging activity assay. While all compounds displayed strong cytotoxic and antioxidant properties, they exhibited only moderate antimicrobial activity. Molecular docking studies were performed on epidermal growth factor receptor (EGFR), vascular endothelial growth factor receptor 2 (VEGFR-2), focal adhesion kinase (FAK), B-Raf and phosphoinositide 3-kinase (PI3K). The binding energies and interactions obtained from the docking results of compounds (4a-c) supported the experimental results. Drug similarity rates and pharmacokinetic properties were analyzed with the absorption, distribution, metabolism and excretion (ADME) method. Geometric parameters such as chemical potential (µ), electrophilicity index (ω) and chemical softness (σ) of compounds (4a-c) were calculated using the 6-31*G basis set B3LYP method.

Novel Thioether-Bridged 2,6-Disubstituted and 2,5,6-Trisubstituted Imidazothiadiazole Analogues: Synthesis, Antiproliferative Activity, ADME, and Molecular Docking Studies

In this study, starting from 2-amino-1,3,4-thiadiazole derivatives (3-5), a new series of 2,6-disubstituted (compounds 7-15) and 2,5,6-trisubstituted (compounds 16-33) imidazo[2,1-b][1,3,4]-thiadiazole derivatives were synthesized using cyclization and Mannich reaction mechanisms, respectively. All synthesized compounds were characterized by ¹ H-NMR, ¹³ C-NMR, FT-IR, elemental analysis, and mass spectroscopy techniques. Also, X-ray diffraction analysis were used for compounds 4, 7, 11, 17, and 19. The cytotoxic effects of the new compounds on the viability of colon cancer cells (DLD-1), lung cancer cells (A549), and liver cancer cells (HepG2) were investigated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method in vitro. Compound 15 was found to be the most potent anticancer drug candidate in this series with an IC₅₀ value of 3.63 μM against HepG2 for 48 h. Moreover, the absorption, distribution, metabolism, and excretion (ADME) parameters of the synthesized compounds were calculated and thus, their potential to be safe drugs was evaluated. Finally, to support the biological activity experiments, molecular docking studies of these compounds were carried out on three different target cancer protein structures (PDB IDs: 5ETY, 1M17, and 3GCW), and the amino acids that play key roles in the binding of the compounds to these proteins were determined.

Molecular modeling and cytotoxic activity studies of oxirane-2-carboxylate derivatives

In this study, five 3-aryloxirane-2-carboxylate derivatives were prepared, and the antiproliferative activities of molecules were screened in lung and colon cancer cell lines. The results showed that molecules had antiproliferative activity on cancerous cells with IC50 values under 100 µM. Furthermore, all of the molecules were found to have a much higher cytotoxic effect than cisplatin in colon cancer cells. The interactions of the relatively active compounds to the crucial enzyme in cancer cell proliferation, cyclin-dependent kinase 1 (CDK1), were investigated using molecular docking. The stability of the resulting CDK1-compound complexes procured from the docking was also assessed through molecular dynamics (MD) simulations. Then, the binding affinity of compounds 2-3a and 2-3c to the target enzyme was computed by MMPBSA. The molecular docking study demonstrated that the two most active compounds could bind to the enzyme. The binding potential of 2-3a is anticipated to be higher as it had one more conventional hydrogen bond and a slightly lower binding energy than compound 2-3c. The MD simulation study exhibited that the two compounds formed a stable complex with the enzyme. On the other hand, the MMPBSA energy computation implicated a slightly higher binding affinity for compound 2-3c toward the enzyme. Furthermore, electrical and frontier molecular orbital analysis of all of the tested compounds was conducted by density functional theory (DFT) studies. Compound 2-3a is anticipated to be the most chemically stable as it gave the highest energy gap value in the DFT analysis.