Synthesis, biological evaluation, and molecular docking studies of cinnamic acyl 1,3,4-thiadiazole amide derivatives as novel antitubulin agents

Design and synthesis of novel 1,3,4-thiadiazole thioglycosides as promising antimicrobial potent structures

Thiosemicarbazide was used as a key starting material for the building of a diversity of novel heterocyclic moieties. The heterocyclization reaction of thiosemicarbazide derivatives with carbon disulfide in basic conditions afforded novel heterocyclic 1,3,4-thiadiazolethiolate derivatives. 1,3,4-thiadiazole-2-thiol was successfully reacted with protected α-D-gluco- and galacto-pyranosyl bromides in dimethylformamide at room temperature to give the matching 1,3,4-thiadiazole S-glycosides in good yields. The latter compounds were reacted with ammonia-methanol at room temperature for 10 min, and the deprotected derivatives were obtained in good yields. The newly synthesized compounds were characterized by basic analyses and spectral information (IR,1H NMR, and 13C NMR, X-ray). All newly produced compounds were evaluated and screened for their antibacterial activities. Compound 6f proved to be the most active antimicrobial among the investigated heterocycles.

Novel quinazolines bearing 1,3,4-thiadiazole-aryl urea derivative as anticancer agents: design, synthesis, molecular docking, DFT and bioactivity evaluations

A novel series of 1-(5-((6-nitroquinazoline-4-yl)thio)-1,3,4-thiadiazol-2-yl)-3-phenylurea derivatives 8 were designed and synthesized to evaluate their cytotoxic potencies. The structures of these obtained compounds were thoroughly characterized by IR, 1H, and 13C NMR, MASS spectroscopy and elemental analysis methods. Additionally, their in vitro anticancer activities were investigated using the MTT assay against A549 (human lung cancer), MDA-MB231 (human triple-negative breast cancer), and MCF7 (human hormone-dependent breast cancer). Etoposide was used as a reference marketed drug for comparison. Among the compounds tested, compounds 8b and 8c demonstrated acceptable antiproliferative activity, particularly against MCF7 cells. Considering the potential VEGFR-2 inhibitor potency of these compounds, a molecular docking study was performed for the most potent compound, 8c, to determine its probable interactions. Furthermore, computational investigations, including molecular dynamics, frontier molecular orbital analysis, Fukui reactivity descriptor, electrostatic potential surface, and in silico ADME evaluation for all compounds were performed to illustrate the structure-activity relationship (SAR).

A discovery of potent kaempferol derivatives as multi-target medicines against diabetes as well as bacterial infections: an in silico approach

Flavonoids demonstrate beneficial effects on human health because flavonoids contain important biological properties. Kaempferol is a flavonol, type of flavonoid found in eatable plants and in plants usually employed in ancient drugs (Moringa oleifera, Tilia spp., fern genus spp. and gingko etc.). Some medicinal studies have shown that the use of foods full of kaempferol decreases the risk of many (cancer, vascular) diseases. All the data of 50 kaempferol derivatives were collected from PubChem database. Through Schrödinger software, 3D-QSAR study was performed for 50 compounds by using method of field base. Conformer of kaempferol derivatives was docked against anti-diabetic, anti-microbial co-crystal structures and protein. To monitor the best anti-diabetic and antibacterial agent, particular kaempferol derivatives were downloaded from PubChem database. Virtual screening by molecular docking provided four lead compounds with four different proteins. These hit compounds were found to be potent inhibitor for diabetic enzymes alpha-amylase and DPP IV and had the potential to suppress DNA gyrase and dihydrofolate reductase synthesis. Molecular dynamic simulation of docked complexes evaluates the value of root mean square fluctuation by iMOD server. Kaempferol 3-O-alpha-L-(2, 3-di-Z-p-coumaroyl) rhamnoside (42) compound used as anti-diabetic and kaempferol 3-O-gentiobioside (3) as antibacterial with good results can be used for drug discovery.Communicated by Ramaswamy H. Sarma.

Crystal structure of 5-(β-d-gluco-pyran-osyl-thio)-N-(4-methyl-phen-yl)-1,3,4-thia-diazol-2-amine

In the structure of the title compound, C15H19N3O5S2, the bond lengths at the linking sulfur atom are significantly different [1.7473 (17) and 1.811 (2) Å], and the angle at the exocyclic nitro-gen atom is wide at 128.45 (18)°. The inter-planar angle between the tolyl and thia-diazole rings is 9.2 (1)°. The complex hydrogen-bonding pattern, involving five donors and five acceptors, can be broken down into a one-dimensional ribbon parallel to the b axis, involving hydrogen bonds of the sugar residues only, and a two-dimensional layer structure parallel to the ab plane, based on the N-H⋯O and O-H⋯N hydrogen bonds.

New 5-Aryl-1,3,4-Thiadiazole-Based Anticancer Agents: Design, Synthesis, In Vitro Biological Evaluation and In Vivo Radioactive Tracing Studies

A new series of 5-(4-chlorophenyl)-1,3,4-thiadiazole-based compounds featuring pyridinium (3), substituted piperazines (4a-g), benzyl piperidine (4i), and aryl aminothiazoles (5a-e) heterocycles were synthesized. Evaluation of the cytotoxicity potential of the new compounds against MCF-7 and HepG2 cancer cell lines indicated that compounds 4e and 4i displayed the highest activity toward the tested cancer cells. A selectivity study demonstrated the high selective cytotoxicity of 4e and 4i towards cancerous cells over normal mammalian Vero cells. Cell cycle analysis revealed that treatment with either compound 4e or 4i induced cell cycle arrest at the S and G2/M phases in HepG2 and MCF-7 cells, respectively. Moreover, the significant increase in the Bax/Bcl-2 ratio and caspase 9 levels in HepG2 and MCF-7 cells treated with either 4e or 4i indicated that their cytotoxic effect is attributed to the ability to induce apoptotic cell death. Finally, an in vivo radioactive tracing study of compound 4i proved its targeting ability to sarcoma cells in a tumor-bearing mice model.

Synthesis and Antimicrobial Activity Screening of Piperazines Bearing N,N'-Bis(1,3,4-thiadiazole) Moiety as Probable Enoyl-ACP Reductase Inhibitors

A new N,N'-disubstituted piperazine conjugated with 1,3,4-thiadiazole and 1,2,4-triazole was prepared and the chemical structures were identified by IR, NMR and elemental analysis. All the prepared compounds were tested for their antimicrobial activity. The antimicrobial results indicated that the tested compounds showed significant antibacterial activity against gram-negative strains, especially E. coli, relative to gram-positive bacteria. Docking analysis was performed to support the biological results; binding modes with the active site of enoyl reductase amino acids from E. coli showed very good scores, ranging from -6.1090 to -9.6184 kcal/mol. Correlation analysis was performed for the inhibition zone (nm) and the docking score.

New 1,3,4-Thiadiazole Derivatives with Anticancer Activity

We designed and synthesized the 1,3,4-thiadiazole derivatives differing in the structure of the substituents in C2 and C5 positions. The cytotoxic activity of the obtained compounds was then determined in biological studies using MCF-7 and MDA-MB-231 breast cancer cells and normal cell line (fibroblasts). The results showed that in both breast cancer cell lines, the strongest anti-proliferative activity was exerted by 2-(2-trifluorometylophenylamino)-5-(3-methoxyphenyl)-1,3,4-thiadiazole. The IC₅₀ values of this compound against MCF-7 and MDA-MB-231 breast cancer cells were 49.6 µM and 53.4 µM, respectively. Importantly, all new compounds had weaker cytotoxic activity on normal cell line than on breast cancer cell lines. In silico studies demonstrated a possible multitarget mode of action for the synthesized compounds. The most likely mechanism of action for the new compounds is connected with the activities of Caspase 3 and Caspase 8 and activation of BAX proteins.

Design, Synthesis, Molecular Docking, and Biological Evaluation of Pyrazole Hybrid Chalcone Conjugates as Potential Anticancer Agents and Tubulin Polymerization Inhibitors

Some (E)-3-(3-(4-(benzyloxy)phenyl)-1-phenyl-1H-pyrazol-4-yl)-1-phenylprop-2-en-1-one conjugates 5a–r were designed; synthesized; characterized by ¹H, ¹³C NMR, and ESI-MS; and evaluated for tubulin polymerization inhibitory activity and in vitro cytotoxicity against breast (MCF-7), cervical (SiHa), and prostate (PC-3) cancer cell lines, as well as a normal cell line (HEK-293T). The compounds were also tested to determine their binding modes at the colchicine-binding site of tubulin protein (PDB ID-3E22), for in silico ADME prediction, for bioactivity study, and for PASS prediction studies. Among all the synthesized conjugates, compound 5o exhibited excellent cytotoxicity with an IC₅₀ value of 2.13 ± 0.80 µM (MCF-7), 4.34 ± 0.98 µM (SiHa), and 4.46 ± 0.53 µM (PC-3) against cancer cell lines. The compound did not exhibit significant toxicity to the HEK cells. Results of the in silico prediction revealed that the majority of the conjugates possessed drug-like properties.

In Vitro Cytotoxicity and Apoptosis Inducing Evaluation of Novel Halogenated Isatin Derivatives

BACKGROUND

Isatin (1H-indole-2,3-dione) and its derivatives have been shown their responsibility in a wide range of biological activities. Among the range of beneficial properties, anticancer compounds were the most extensively highlighted and explored.

OBJECTIVE

Herein, we report the targeting effect of halogenated isatin derivatives on cancer cell mitochondria and their antiproliferative mechanism.

METHOD

A series of novel 5-halo-Isatin derivatives consisting 5-Amino-1,3,4-thiadiazole-2-thiol scaffold were synthesized and easily conducted in good yields through a condensation reaction between keto groups of Isatin and primary amine under alcoholic conditions, followed by S-benzylation. The compounds were fully characterized using spectroscopic methods such as 1H-NMR, FTIR, mass spectroscopy and then tested in vitro towards three cancer cell lines HT-29 (colon cancer), MCF-7 (breast cancer) and SKNMC (neuroblastoma). Apoptosis induction was investigated through assessment of caspase 3 and mitochondrial membrane potential.

RESULTS

The most potent compounds of 5b, 5r (IC50 = 18,13 µM) and 5n (IC50 = 20,17 µM) were found to show strong anticancer activity, especially for MCF7 cells. Further anticancer mechanism studies indicated that 5b and 5r induced apoptosis through the intrinsic mitochondrial pathway.

CONCLUSION

This research demonstrated that 5b and 5r have an anticancer property via the modulation of oxidative stress-mediated mitochondrial apoptosis and immune response, which deserves further studies on their clinical applications.

Synthesis and Preliminary Anticancer Activity Assessment of N-Glycosides of 2-Amino-1,3,4-thiadiazoles

The addition of 2-amino-1,3,4-thiadiazole derivatives with parallel iodination of differently protected glycals has been achieved using a double molar excess of molecular iodine under mild conditions. The corresponding thiadiazole derivatives of N-glycosides were obtained in good yields and anomeric selectivity. The usage of iodine as a catalyst makes this method easy, inexpensive, and successfully useable in reactions with sugars. Thiadiazole derivatives were tested in a panel of three tumor cell lines, MCF-7, HCT116, and HeLa. These compounds initiated biological response in investigated tumor models in a different rate. The MCF-7 is resistant to the tested compounds, and the cytometry assay indicated low increase in cell numbers in the sub- G1 phase. The most sensitive are HCT-116 and HeLa cells. The thiadiazole derivatives have a pro-apoptotic effect on HCT-116 cells. In the case of the HeLa cells, an increase in the number of cells in the sub-G1- phase and the induction of apoptosis was observed.

Synthesis, characterization and biological evaluation of thiadiazole amide derivatives as nucleoside triphosphate diphosphohydrolases (NTPDases) inhibitors

Importance of extracellular nucleotides is widely understood. These nucleotides act as ligand for P2X and P2Y receptors and modulate a variety of biological functions. However, their extracellular concentration is maintained by a chain of enzymes termed as ecto-nucleotidases. Amongst them, nucleoside triphosphate diphosphohydrolases (NTPDases) is an important enzyme family responsible for the dephosphorylation of these nucleotides. Overexpression of NTPDases leads to many pathological conditions such as cancer and thrombosis. So far, only a few NTPDase inhibitors have been reported. Considering this scarcity of (NTPDase) inhibitors, a number of thiadiazole amide derivatives were synthesized and screened against human (h)-NTPDases. Several compounds showed promising inhibitory activity; compound 5a (IC₅₀ (µM); 0.05 ± 0.008) and 5g (IC₅₀ (µM); 0.04 ± 0.006) appeared to be the most distinguished molecules corresponding to h-NTPDase1 and -2. However, h-NTPDase3 was the least susceptible isozyme and only three compounds (5d, 5e, 5j) strongly inhibited h-NTPDase3. Interestingly, compound 5e was recognized as the most active compound that showed dual inhibition against h-NTPDase3 as well as against h-NTPDase8. For better comprehension of binding mode of these inhibitors, most potent inhibitors were docked with their respective isozyme.

3D-QSAR-Based Pharmacophore Modeling, Virtual Screening, and Molecular Docking Studies for Identification of Tubulin Inhibitors with Potential Anticancer Activity

In this study, we aimed to develop a pharmacophore-based three-dimensional quantitative structure activity relationship (3D-QSAR) for a set including sixty-two cytotoxic quinolines (1-62) as anticancer agents with tubulin inhibitory activity. A total of 279 pharmacophore hypotheses were generated based on the survival score to build QSAR models. A six-point pharmacophore model (AAARRR.1061) was identified as the best model which consisted of three hydrogen bond acceptors (A) and three aromatic ring (R) features. The model showed a high correlation coefficient (R 2 = 0.865), cross-validation coefficient (Q 2 = 0.718), and F value (72.3). The best pharmacophore model was then validated by the Y-Randomization test and ROC-AUC analysis. The generated 3D contour maps were used to reveal the structure activity relationship of the compounds. The IBScreen database was screened against AAARRR.1061, and after calculating ADMET properties, 10 compounds were selected for further docking study. Molecular docking analysis showed that compound STOCK2S-23597 with the highest docking score (-10.948 kcal/mol) had hydrophobic interactions and can form four hydrogen bonds with active site residues.

1,2,5-Thiadiazole Scaffold: A review on recent progress in biological activities

BACKGROUND

Thiadiazoles can be considered as the privileged scaffold having diverse pharmacological potentials such as antihypertensive, anti-HIV, antimicrobials, antileishmanial agents, etc. In particular, 1,2,5-thiadiazoles and their fused analogues are subjects of fast-growing interest due to their higher significance in the fields of biomedicine and material sciences.

OBJECTIVE

This study aims to collect detailed medicinal information about aspects of 1,2,5-thiadiazole.

METHODS

A systemic search has been carried out using PubMed, Google Scholar, CNKI, etc., for relevant studies having the keyword, '1,2,5-thiadiazole'.

RESULTS AND CONCLUSION

In this mini-review, we have covered known procedures of the synthesis and explored in detail all known advancements of this scaffold concerning to its biological activities.

Cytotoxic Properties of 1,3,4-Thiadiazole Derivatives-A Review

During recent years, small molecules containing five-member heterocyclic moieties have become the subject of considerable growing interest for designing new antitumor agents. One of them is 1,3,4-thiadiazole. This study is an attempt to collect the 1,3,4-thiadiazole and its derivatives, which can be considered as potential anticancer agents, reported in the literature in the last ten years.

Cytotoxicity Evaluation of Dimethoxy and Trimethoxy Indanonic Spiroisoxazolines Against Cancerous Liver Cells

Background:

3'-(3,4-dimethoxyphenyl)-4'-(4-(methylsulfonyl)phenyl)-4'H-spiro [indene-2,5'-isoxazol]-1(3H)-one and 4'-(4-(methylsulfonyl)phenyl)-3'-(3,4,5-trimethoxyphenyl)- 4'H-spiro[indene-2,5'-isoxazol]-1(3H)-one compounds containing indanonic spiroisoxazoline core are widely known for their antiproliferative activities and investigation of tubulin binding modes.

Objective:

To evaluate the cytotoxicity effect of Dimethoxy and Trimethoxy Indanonic Spiroisoxazolines against HepG2 cancerous liver cell line and to perform a comparison with other known anti-liver cancer drugs.

Methods:

The evaluation of cytotoxicity of dimethoxy and trimethoxy indanonic spiroisoxazoline compounds, Oxaliplatin, Doxorubicin, 5-fluorouracil and Cisplatin against HepG2 (hepatocellular liver carcinoma) cell line has been performed using MTT assay and analyzed by GraphPad PRISM software (version 8.0.2).

Results:

Potent cytotoxicity effects against HepG2 cell line, comparable to Cisplatin (IC50= 0.047±0.0045 µM), Oxaliplatin (IC50= 0.0051µM), Doxorubicin (IC50= 0.0014µM) and 5- fluorouracil (IC50= 0.0089 µM), were shown by both dimethoxy (IC50= 0.059±0.012 µM) and trimethoxy (IC50= 0.086±0.019 µM) indanonic spiroisoxazoline compounds.

Conclusion:

In vitro biological evaluations revealed that dimethoxy and trimethoxy indanonic spiroisoxazoline compounds are good candidates for the development of new anti-liver cancer agents.

In vitro cytogenetic activity of 3-amino-4-[4-(dimethylamino)phenyl]-4,5-dihydro-1,2,5-thiadiazole 1,1-dioxide

In a previous study, 3-amino-4-[4-(dimethylamino)phenyl]-4,5-dihydro-1,2,5-thiadiazole 1,1-dioxide (DPTD), which is five-membered cyclosulfamide, was synthesized and structurally characterized. The aim of this study was to investigate the cytotoxic and genotoxic effects of DPTD on cultured human lymphocytes in the presence and absence of a metabolic activation system (S9 mix). The cytotoxicity and genotoxicity of DPTD in human peripheral blood lymphocytes were examined in vitro by using chromosomal aberration (CA) and micronucleus (MN) tests. Mitomycin-C (MMC) for cultures without S9 mix and cyclophosphamide monohydrate (CP) for cultures with S9 mix were used as positive controls. The cultures were treated with DPTD (45, 90, and 180 µg/mL) in the absence and presence of S9 mix. The cells were also co-treated with DPTD together with MMC or CP. DPTD showed cytotoxic activity due to decreases in mitotic index (MI) and nuclear division index (NDI) in the absence and presence of S9 mix. DPTD also increased the CAs, aberrant cells with CAs and MN values in cultures with and without S9 mix. When DPTD and MMC or CP were used together, lower MI and NDI values and higher CA and MN values were found than those DPTD treated alone. Both DPTD and its metabolites have cytotoxic, cytostatic and genotoxic potential on human peripheral blood lymphocyte cultures under the experimental conditions. Furthermore, co-treatment of DPTD and MMC or CP can cause more cytotoxicity and genotoxicity. Our results indicated that the use of DPTD with other chemotherapeutic drugs may display more effective results.

Phenylpropanoids and its derivatives: biological activities and its role in food, pharmaceutical and cosmetic industries

Phenylpropanoids and their derivatives are plant secondary metabolites widely present in fruits, vegetables, cereal grains, beverages, spices and herbs. They are known to have multifaceted effects which include antimicrobial, antioxidant, anti-inflammatory, antidiabetic, anticancer activities and as well as exhibits renoprotective, neuroprotective, cardioprotective and hepatoprotective effects. Owing to their antioxidant, antimicrobial and photoprotective properties, these compounds have wide application in the food (preservation, packaging films and edible coating), pharmaceutical, cosmetic and other industries such as textile (colorant), biofuel (antioxidant additive) and sensors (sensing biologically relevant molecules). Phenylpropanoids are present in commercially available dietary supplements and skin care products. In this review, we have presented the current knowledge on the biosynthesis, occurrence, biological activities of phenylpropanoids and their derivatives, along with the mechanism of action and their potential applications in various industries.

Recent Development on Importance of Heterocyclic Amides as Potential Bioactive Molecules: A Review

Background:

Heterocyclic compounds are an integral part of the chemical and life sciences and constitute a considerable quantum of the modern research that is being currently pursued throughout the world.

Methods:

This review was prepared by collecting the available literature reports on various databases and an extract was prepared for each report after thorough study and compiling the recent literature reports on heterocyclic amides from 2007 to 2018.

Results:

This review summarizes the bio-potential of heterocyclic amides as antimicrobial, anticancer, anti-tubercular and antimalarial agents which would be very promising in the field of medicinal chemistry.

Conclusion:

A wide variety of heterocyclic amides have already been reported and some are currently being used as active medicaments for the treatment of disease. Still, the research groups are focusing on the development of newer heterocyclic amide derivatives with better efficacy, potency and lesser side effects. This area has got the tremendous potential to come up with new chemical entities of medicinal importance.

New antimicrobial compounds produced by endophytic Penicillium janthinellum isolated from Panax notoginseng as potential inhibitors of FtsZ

A total of 180 fungal isolates, belonging to 20 genera and 47 species, were obtained from the roots, stems and leaves of Panax notoginseng. One isolate, the endophytic fungus Penicillium janthinellum SYPF 7899, displayed the strongest antibacterial activity and was studied for its production of secondary metabolites. In total, three new compounds, including rotational isomers 1a, 1b and 2 were isolated from the solid cultures of P. janthinellum, as well as eight known compounds (3-10). These structures were determined on the basis of 1D, 2D NMR and electronic circular dichroism (ECD) spectroscopic analyses as well as theoretical calculations. Compound 1 exhibited significant inhibitory activities against Bacillus subtilis and Staphylococcus aureus with MIC values of 15 and 18 μg/ml, respectively. The other compounds showed moderate or weak activities. In addition, morphological observation showed the rod-shaped cells of B. subtilis growing into long filaments, which reached 1.5- to 2-fold of the length of the original cells after treatment with compound 1. The coccoid cells of S. aureus exhibited a similar response and swelled to a 2-fold volume after treatment with compound 1. In silico molecular docking was explored to study the binding interactions between the compounds and the active sites of filamentous temperature-sensitive protein Z (FtsZ) from B. subtilis and S. aureus. Compound 1a, 1b and 2 showed high binding energies, strong H-bond interactions and hydrophobic interactions with FtsZ. Based on the antimicrobial activities, cellular phenotype observation and docking studies, compound 1 is considered to be a promising antimicrobial inhibitor of FtsZ.

Insights into the mechanism of antiproliferative effects of primaquine-cinnamic acid conjugates on MCF-7 cells

In our previous paper, we showed that three primaquine-cinnamic acid conjugates composed of primaquine (PQ) residue and cinnamic acid derivatives (CADs) bound directly by an amide linkage (1) or through an acylsemicarbazide spacer (2 and 3) had significant growth inhibitory effects on some cancer cell lines. Compound 1 induced significant growth inhibition in the colorectal adenocarcinoma (SW620), human breast adenocarcinoma (MCF-7) and cervical carcinoma (HeLa) cell lines, while compounds 2 and 3 selectively inhibited the growth of MCF-7 cells. To better understand the underlying mechanisms of action of these PQ-CADs, morphological studies of the effects of test compounds on MCF-7 cells were undertaken using haematoxylin and eosin stain. Further analysis to determine the effects of test compounds on caspase activity and on the levels of apoptosis proteins were undertaken using the enzyme-linked immunosorbent assay (ELISA). Haematoxylin and eosin staining revealed that compounds 1 and 3 induced morphological changes in MCF-7 cells characteristic of apoptosis, while 2-treated cells were in interphase. Cell cycle analysis showed that cells treated with 1 and 3 were in sub-G1, while cells treated with 2 were mainly in interphase (G1 phase). Further, the study showed that the treatment of MCF-7 cells with 1 and 3 resulted in poly ADP ribose polymerase (PARP) cleavage as well as caspase-9 activation, indicating that they induced apoptotic cell death. We further investigated their effects on two important processes during metastasis, namely, migration and invasion. Compounds 1 and 3 inhibited the migration and invasion of MCF-7 cells, while compound 2 had a marginal effect.

5-(Thiophen-2-yl)-1,3,4-thiadiazole derivatives: synthesis, molecular docking and in vitro cytotoxicity evaluation as potential anticancer agents

Background

Nowadays, cancer is an important public health problem in all countries. Limitations of current chemotherapy for neoplastic diseases such as severe adverse reactions and tumor resistance to the chemotherapeutic drugs have been led to a temptation for focusing on the discovery and development of new compounds with potential anticancer activity. The importance of thiophene and thiadiazole rings as scaffolds present in a wide range of therapeutic agents has been well reported and has driven the synthesis of a large number of novel antitumor agents.

Methods

A series of new 1,3,4-thiadiazoles were synthesized by heterocyclization of N-(4-nitrophenyl)thiophene-2-carbohydrazonoyl chloride with a variety of hydrazine-carbodithioate derivatives. The mechanisms of these reactions were discussed and the structure of the new products was elucidated via spectral data and elemental analysis. All the new synthesized compounds were investigated for in vitro activities against human hepatocellular carcinoma (HepG-2) and human lung cancer (A-549) cell lines compared with cisplatin standard anticancer drug. Moreover, molecular docking using MOE 2014.09 software was also carried out for the high potent compound 20b with the binding site of dihydrofolate reductase (DHFR, PDB ID (3NU0)).

Results

The results showed that compound 20b has promising activities against HepG-2 and A-549 cell lines (IC50 value of 4.37±0.7 and 8.03±0.5 μM, respectively) and the results of molecular docking supported the biological activity with total binding energy equals −1.6 E (Kcal/mol).

Conclusion

Overall, we synthesized a new series of 1,3,4-thiadiazoles as potential antitumor agents against HepG-2 and A-549 cell lines.

Synthesis of pyrazole acrylic acid based oxadiazole and amide derivatives as antimalarial and anticancer agents

Depravity of malaria in terms of morbidity and mortality in human beings makes it a major health issue in tropical and subtropical areas of the globe. Drug counterfeiting and non-adherence to the treatment regimen have significantly contributed to development and spread of multidrug resistance that has highlighted the need for development of novel and more efficient antimalarial drugs. Complexity associated with cancer disease and prevalence of diversified cell populations vindicates highly specific treatment options for treatment of cancer. Resistance to these anticancer agents has posed a great hindrance in successful treatment of cancer. Pondering this ongoing situation, it was speculated to develop novel compounds targeting malaria and cancer. Moving on the same aisle, we synthesized pyrazole acrylic acid based oxadiazole and amide derivatives using multi-step reaction pathways (6a-x; 6a'-h'). Schizont maturation inhibition assay was employed to determine antimalarial potential. Compound 6v emerged as the most potent antimalarial agent targeting falcipain-2 enzyme. Anticancer activity was done using sulforhodamine B assay. Compounds 6b' and 6g' demonstrated promising results against all the tested cell lines. Further, Microscopic view clearly indicated formation of apoptotic bodies, chromatin condensation, shrinkage of cells and bleb formation. Validation of the results was achieved using molecular docking studies. From the obtained results, it was observed that cyclization (oxadiazole) favored antimalarial activity while non-cyclized compounds (amides) emerged as better anticancer agents.

Synthesis and Evaluation of 5-Benzyl-1,3,4-Thiadiazole Derivatives as Acetylcholinesterase Inhibitors

Three novel 5-benzyl-1,3,4-thiadiazole derivatives were synthesised starting from phenylacetic acid derivatives. These compounds were characterised by NMR, HRMS and single-crystal X-ray diffraction analysis. 2-Pyrrolidyl-5-[2-(4-bromophenyl)methyl]-1,3,4-thiadiazole showed moderate acetylcholinesterase-inhibition activity with a 50% inhibitory concentration value of 33.16 μM. 2-Pyrrolidyl-5-[2-(4-bromophenyl)methyl]-1,3,4-thiadiazole and acetylcholinesterase docking was demonstrated using the Molecular Operating Environment program.

N-Heterocyclic (4-Phenylpiperazin-1-yl)methanones Derived from Phenoxazine and Phenothiazine as Highly Potent Inhibitors of Tubulin Polymerization

We report here a series of 27 10-(4-phenylpiperazin-1-yl)methanones derived from tricyclic heterocycles which were screened for effects on tumor cell growth, inhibition of tubulin polymerization, and induction of cell cycle arrest. Several analogues, among them the 10-(4-(3-methoxyphenyl)piperazine-1-carbonyl)-10H-phenoxazine-3-carbonitrile (16o), showed excellent antiproliferative properties, with low nanomolar GI₅₀ values (16o, mean GI₅₀ of 3.3 nM) against a large number (93) of cancer cell lines. Fifteen compounds potently inhibited tubulin polymerization. Analysis of cell cycle by flow cytometry revealed that inhibition of tumor cell growth was related to an induction of G2/M phase cell cycle blockade. Western blotting and molecular docking studies suggested that these compounds bind efficiently to β-tubulin at the colchicine binding site. Our studies demonstrate the suitability of the phenoxazine and phenothiazine core and also of the phenylpiperazine moiety for the development of novel and potent tubulin polymerization inhibitors.

Thiadiazole inhibitors: a patent review

INTRODUCTION

Four isomeric structures of thiadiazole motifs have outstanding pharmacological inhibitory applications are reported in this review. Thiadiazole nucleus is present in several biologically active natural products and commercial drugs. Most of thiadiazoles reported herein are emphasized to have broad spectrum of medicinal activities. Areas covered: This review represents the recent inhibitory activities of thiadiazole isomeric scaffolds and their broad-spectrum biological applications published as full texts during 2010-2016 as well as the patents published during 2005-2016. The inhibition areas covered included anti-inflammatory, antimicrobial, antitumor, antioxidant, antitubercular, antiviral, antileishmanial, anticonvulsant, herbicidal and algicidal activities in addition to enzymes, human platelet aggregation and neuroprotective inhibitors. Expert opinion: This survey revealed very interesting data about the applications of thiadiazoles, where some synthetic or natural thiadiazole derivatives were components of drugs available in the market. Many thiadiazole derivatives can be considered as lead compounds for drug synthesis. The most inhibitory active 1,3,4-thiadiazole compounds are those incorporating secondary alkyl(aryl)amido- and/or benzylthio(mercapto) groups at positions 2 and 5. Several thiadiazole derivatives demonstrated higher antibacterial, antitumor and antiviral activities than the standard drugs. Some thiadiazole derivatives exhibited high selective enzymes inhibitory activities based on the electronic properties of the substituents at positions 2 or 5.

Recent advances of cytotoxic chalconoids targeting tubulin polymerization: Synthesis and biological activity

Since microtubules have an important role in mitosis and other vital cellular functions, tubulin-targeting chemotherapy has been received growing attention in anticancer drug design and development. It was found that a number of naturally occurring compounds including distinct chalcones exert their effect by inhibition of tubulin polymerization. After the identification of tubulin polymerization as potential target for chalcone-type compounds, extensive researches have been made to design and synthesis of new anti-tubulin chalconoids. Although diverse chalcones have found to be potent anticancer agents but in the present review, we focused on the recently reported tubulin polymerization inhibitors from chalcone origin and related synthetic compounds, and their detailed synthetic methods and biological activities.

Synthesis of o-Carboxyarylacrylic Acids by Room Temperature Oxidative Cleavage of Hydroxynaphthalenes and Higher Aromatics with Oxone

A simple procedure for the synthesis of a variety of o-carboxyarylacrylic acids has been developed with Oxone (2KHSO5·KHSO4·K2SO4); the oxidation reaction involves the stirring of methoxy/hydroxy-substituted naphthalenes, phenanthrenes, anthracenes, etc. with Oxone in an acetonitrile-water mixture (1:1, v/v) at rt. Mechanistically, the reaction proceeds via initial oxidation of naphthalene to o-quinone, which undergoes cleavage to the corresponding o-carboxyarylacrylic acid. The higher aromatics are found to yield carboxymethyl lactones derived from the initially formed o-carboxyarylacrylic acids.

Synthesis, characterization, and pharmacological evaluation of novel azolo- and azinothiazinones containing 2,4-dihydroxyphenyl substituent as anticancer agents

ABSTRACT

We reported the synthesis and characterization of a series of azolo- and azino[1,3]thiazinones containing the 2,4-dihydroxyphenyl substituent. The compounds were prepared by a new one-step reaction of aryl-modified sulfinylbis[(2,4-dihydroxyphenyl)methanethione]s and the corresponding aminoazolo(azino)carboxamides. Their chemical structures were confirmed by IR, NMR: 1H, 13C, HSQC, and EI-MS spectral data. The compounds inhibited proliferation and viability of lung cancer A549, colon cancer HT-29, and glioma C6 cells in a structure- and concentration-dependent manner. The activity of some analogues was below 10 μmol dm-3 (IC50). Glioma C6 cells were the most sensitive to tested compounds. Generally, the derivatives were not toxic for the skin fibroblast HSF culture. Moreover, some of them exerted a protective effect on the treated normal cells. Evaluation of compound properties in silico showed that they possess significant drug-like characteristics and most of them display a low toxicity.

GRAPHICAL ABSTRACT