Synthesis of novel (R)-carvone-tagged thiazolidinone as anticancer leads: characterization, in vitro antiproliferative evaluation and in silico studies

This work describes the successful synthesis of a series of three novel thiazolidinone-carvone-O-alkyl hybrids through a two-step approach involving heterocyclization and O-alkylation reactions. Comprehensive structural characterization of the obtained products was achieved using NMR and HRMS spectroscopic techniques. This study assessed in vitro antiproliferative activity of synthesized thiazolidinone-carvone-O-alkyl hybrids (5a-c) against various human cancer cell lines, viz. HT-1080 (fibrosarcoma), A-549 (lung cancer), MCF-7 (breast cancer) and MDA-MB-231 (breast cancer). MTT assay revealed promising results for compounds 5b and 5c, demonstrating good antiproliferative activity against A-549 and MCF-7 cell lines comparable to the positive control, Doxorubicin. Compound 5a, harbouring an O-acetoxy group, displayed limited anticancer activity against MCF-7 and MDA-MB-231 cells, with IC50 values of 69.33 ± 0.42 µM and >100 µM, respectively. Docking results confirmed that the compounds 5a-c binds at the active site of p21 with docking scores -2.0, -4.8, and -7.0 kcal/mol, respectively. Compound 5a-c also showed good binding potential against Bcl2 protein with docking score of -4.9, -6.0, -5.5 kcal/mol, respectively. Furthermore, binding energy analysis and dynamics simulation studies of compounds towards p21 and Bcl2 yielded promising results. In PAK4 assay, compound 5c showed comparable potency (IC50 6.76 µM) with the standard control UC2288 (IC50 6.40 µM), while in BCL-2 TR-FRET assay, 5c exhibited good inhibition (IC50 1.78 µM) as compared to Venetoclax (IC50 0.016 µM). In conclusion, compounds 5a-c could be used as a structural framework for the discovery of novel therapeutics to combat different types of cancer.Communicated by Ramaswamy H. Sarma.

Design, synthesis, molecular docking, and in vitro studies of 2-mercaptoquinazolin-4(3H)-ones as potential anti-breast cancer agents

Triple-negative breast cancer (TNBC) comprises 10 % to 20 % of breast cancer, however, it is more dangerous than other types of breast cancer, because it lacks druggable targets, such as the estrogen receptors (ER) and the progesterone receptor (PR), and has under expressed receptor tyrosine kinase, ErbB2. Present targeted therapies are not very effective and other choices include invasive procedures like surgery or less invasive ones like radiotherapy and chemotherapy. This study investigated the potential anticancer activity of some novel quinazolinone derivatives that were designed on the structural framework of two approved anticancer drugs, Ispinesib (KSP inhibitor) and Idelalisib (PI3Kδ inhibitor), to find out solutions for TNBC. All the designed derivatives (3a-l) were subjected to extra precision molecular docking and were synthesized and spectrally characterized. In vitro enzyme inhibition assay of compounds (3a, 3b, 3e, 3 g and 3 h) revealed their nanomolar inhibitory potential against the anticancer targets, KSP and PI3Kδ. Using MTT assay, the cytotoxic potential of compounds 3a, 3b and 3e were found highest against MDA-MB-231 cells with an IC50 of 14.51 µM, 16.27 µM, and 9.97 µM, respectively. Remarkably, these compounds were recorded safe against the oral epithelial normal cells with an IC50 values of 293.60 µM, 261.43 µM, and 222 µM, respectively. The anticancer potential of these compounds against MDA-MB-231 cells was revealed to be associated with their apoptotic activity. This was established by examination with the inverted microscope that revealed the appearance of various apoptotic features like cell shrinkage, apoptotic bodies, and membrane blebbing. Using flow cytometry, the Annexin V/PI-stained cancer cells showed an increase in early and late apoptotic cells. In addition, DNA fragmentation was revealed to occur after treatment with the tested compounds by gel electrophoresis. The relative gene expression of pro-apoptotic and anti-apoptotic genes revealed an overexpression of the P53 and BAX genes and a downregulation of the BCL-2 gene by real-time PCR. So, this work proved that compounds 3a, 3b, and 3e could be developed as anticancer candidates, via their P53-dependent apoptotic activity.

Novel 2-Sulfanylquinazolin-4(3H)-one Derivatives as Multi-Kinase Inhibitors and Apoptosis Inducers: A Synthesis, Biological Evaluation, and Molecular Docking Study

The discovery of multi-targeted kinase inhibitors emerged as a potential strategy in the therapy of multi-genic diseases, such as cancer, that cannot be effectively treated by modulating a single biological function or pathway. The current work presents an extension of our effort to design and synthesize a series of new quinazolin-4-one derivatives based on their established anti-cancer activities as inhibitors of multiple protein kinases. The cytotoxicity of the new derivatives was evaluated against a normal human cell line (WI-38) and four cancer lines, including HepG2, MCF-7, MDA-231, and HeLa. The most active compound, 5d, showed broad-spectrum anti-cancer activities against all tested cell lines (IC₅₀ = 1.94-7.1 µM) in comparison to doxorubicin (IC₅₀ = 3.18-5.57 µM). Interestingly, compound 5d exhibited lower toxicity in the normal WI-38 cells (IC₅₀ = 40.85 µM) than doxorubicin (IC₅₀ = 6.72 µM), indicating a good safety profile. Additionally, the potential of compound 5d as a multi-targeted kinase inhibitor was examined against different protein kinases, including VEGFR2, EGFR, HER2, and CDK2. In comparison to the corresponding positive controls, compound 5d exhibited comparable activities in nanomolar ranges against HER2, EGFR, and VEGFR2. However, compound 5d was the least active against CDK2 (2.097 ± 0.126 µM) when compared to the positive control roscovitine (0.32 ± 0.019 µM). The apoptotic activity investigation in HepG2 cells demonstrated that compound 5d arrested the cell cycle at the S phase and induced early and late apoptosis. Furthermore, the results demonstrated that the apoptosis pathway was provoked due to an upregulation in the expression of the proapoptotic genes caspase-3, caspase-9, and Bax and the downregulation of the Bcl-2 anti-apoptotic gene. For the in silico docking studies, compound 5d showed relative binding interactions, including hydrogen, hydrophobic, and halogen bindings, with protein kinases that are similar to the reference inhibitors.

Synthesis, characterization, biological evaluation and molecular docking of a new quinazolinone-based derivative as a potent dual inhibitor for VEGFR-2 and EGFR tyrosine kinases

An efficient process for the preparation of a new ethyl 2-((3-(4-fluorophenyl)-6-methyl-4-oxo-3,4-dihydroquinazolin-2-yl)thio) acetate (5) was described. The prepared derivative was synthesized using the S-arylation method. Several analytical techniques, such as NMR, Raman and infrared spectroscopy, were used to characterize this compound. The compound was screened for cytotoxic activity against three human cancer cell lines: human cervical cancer (HeLa), human lung adenocarcinoma (A549) and triple negative breast cancer (MDA-MB-231) cells using an MTT assay. It exhibited potent cytotoxic activity against the tested cell lines with IC₅₀ values in the low micromolar range when compared to a standard drug, docetaxel. It also displayed potent inhibitory activity towards VEGFR-2 and EGFR tyrosine kinases, reflecting its potential to act as an effective anti-cancer agent.Communicated by Ramaswamy H. Sarma.

Electrophilic Aromatic Synthesis of Radioiodinated Aripiprazole: Experimental and DFT Investigations

BACKGROUND

Aripiprazole is a quinolinone derivative. It shows a high affinity for neurotransmitters dopamine and serotonin receptors, which can overcome the blood-brain barrier (BBB) to reach the central nervous system (CNS) to exert therapeutic effects. Its radioiodination may lead to high radiochemical yield and improved its affinity. Aripiprazole radioiodination is an aromatic electrophilic substitution.

OBJECTIVE

Herein, we investigate the favorable atom site of the aromatic electrophilic substitution of aripiprazole by calculating the Fukui indices of heavy atoms and ESP charges of the parent molecule.

METHODS

The calculations have been carried out at the B3LYP/LanL2DZ level of theory. The iodinated aripiprazole structure is confirmed by comparing the experimental and the predicted 1H NMR chemical shifts of the parent molecule and its iodinated forms.

RESULTS

Finally, the electronic properties of aripiprazole and its iodinated form were calculated at the same level of theory. Nucleophilic Fukui indices and ESP charges calculations confirm that C8 is the most favorable site of the electrophilic substitution. The calculated electronic properties (e.g, gap energy, electron affinity, and electronegativity) of aripiprazole and its iodinated form reveal the higher reactivity of iodinated aripiprazole compared with aripiprazole.

CONCLUSION

This may explain the higher affinity of iodinated aripiprazole and the increase of its radiochemical yield.

Synthesis, Antiproliferative, and Antioxidant Activities of Substituted N-[(1,3,4-Oxadiazol-2-yl) Methyl] Benzamines

Background:

Oxadiazole emerged as an important class of heterocyclic compound with diverse biological activities like anticancer, antitubercular, anticonvulsant, anti-tubulin, antimicrobial, anti-inflammatory, antioxidant etc.

Objective:

The objective of this study is to synthesis series of twelve substituted N-[(1,3,4-oxadiazol-2- yl)methyl]benzamines (6a-l) and their evaluation as antiproliferative and antioxidant agents.

Methods:

The substituted N-[(1,3,4-oxadiazol-2-yl)methyl]benzamines (6a-l) analogues were synthesized as per the reported procedure. The antiproliferative activity was tested against nine different panels cancer cell lines (leukemia, colon, renal, non-small cell lung, breast, CNS, melanoma, prostate, and ovarian cancer) at 10 µM drug concentrations as per the NCI US Protocol.

Results:

2-(5-((3-Chloro-4-fluorophenylamino)methyl)-1,3,4-oxadiazol-2-yl)phenol (6e) revealed the significant antiproliferative activity among the series of title compounds (6a-l). The compound, 6e showed maximum sensitivity towards CCRF-CEM, MCF-7, MOLT-4, T-47D, and SR cell lines with percent growth inhibitions (%GIs) of 79.92, 56.67, 39.62, 34.71 and 33.35, respectively. Furthermore, the compounds, 6e and 6c showed promising antioxidant activity with an IC50 value of 15.09 and 19.02 µM, respectively in DPPH free radicals (FR) scavenging activity.R

Conclusion:

The present study may support a significant value in cancer drug discovery programme.

Ultrasound-assisted extraction of some branded tea: Optimization based on polyphenol content, antioxidant potential and thermodynamic study

Tea is one of the top beverages used around the world every day, which contains a high amount of polyphenols and antioxidants. The main aim of this research is to quantify some marketed black tea (Rabea, Lipton, Alkbous, Green gold and Haritham) for phenolic contents and antioxidant potential evaluation by ultrasound solvent extraction and was compared with conventional extraction. Ultrasonic extraction was optimized by considering frequencies (26 kHz, 40 kHz), temperature (30, 40 and 50 °C), and power (30, 40 and 50%) at a fixed time of 30 min. In both the ultrasonic frequencies, 40 °C temperature and 40% power combination exhibited highest cumulative yield (mg/100 g DW), total phenolic content (mg gallic acid/g DW), flavonoids (mg/g DW) and DPPH radical scavenging activity (%) in all branded tea. Within each brand of tea, at any temperature-power combination at particular frequency results were not significantly different. But, at a similar condition of temperature power results were found significantly different between two frequencies. Furthermore, ultrasonic extraction process was analyzed thermodynamically by selecting some basic parameters. Thermodynamics results showed the extraction process was feasible, spontaneous and irreversible. Also, 26 kHz ultrasonic probe is more appropriate for the extraction purpose and thermodynamically more acceptable as compared to 40 kHz ultrasonic bath. Moreover, Haritham was selected as the best tea brand due to its high polyphenol contents and antioxidant potential.

Synthesis, Molecular Docking and β-Glucuronidase Inhibitory Potential of Indole Base Oxadiazole Derivatives

β-glucuronidase is a lysosomal glycosidase enzyme which catalyzes the extracellular matrix of cancer and normal cells and the glycosaminoglycans of the cell membrane, which is important for cancer cell proliferation, invasion, and metastasis. Liver cancer, colon carcinoma, and neoplasm bladder are triggered by the increase of the level of β-glucuronidase activity. The most valuable structures are indole and oxadiazole which has gain immense attention because of its pharmacological behavior and display many biological properties. Twenty-two (1⁻22) analogs of indole based oxadiazole were synthesized and screened for their inhibitory potential against β-glucuronidase. Majority of the compounds showed potent inhibitory potential with IC₅₀ values ranging between 0.9 ± 0.01 to 46.4 ± 0.9 µM, under positive control of standard drug d-saccharic acid 1,4 lactone (IC₅₀ = 48.1 ± 1.2 µM). Structural activity relationship (SAR) has been established for all synthesized compounds. To shed light on molecular interactions between the synthesized compounds and β-glucuronidase, 1, 4, and 6 compounds were docked into the active binding site of β-glucuronidase. The obtained results showed that this binding is thermodynamically favorable and β-glucuronidase inhibition of the selected compounds increases with the number of hydrogen bonding established in selected compound-β-glucuronidase complexes.

Computational screening of medicinal plant phytochemicals to discover potent pan-serotype inhibitors against dengue virus

Emergence of Dengue as one of the deadliest viral diseases prompts the need for development of effective therapeutic agents. Dengue virus (DV) exists in four different serotypes and infection caused by one serotype predisposes its host to another DV serotype heterotypic re-infection. We undertook virtual ligand screening (VLS) to filter compounds against DV that may inhibit inclusively all of its serotypes. Conserved non-structural DV protein targets such as NS1, NS3/NS2B and NS5, which play crucial role in viral replication, infection cycle and host interaction, were selected for screening of vital antiviral drug leads. A dataset of plant based natural antiviral derivatives was developed. Molecular docking was performed to estimate the spatial affinity of target compounds for the active sites of DV’s NS1, NS3/NS2B and NS5 proteins. The drug likeliness of the screened compounds was followed by ADMET analysis whereas the binding behaviors were further elucidated through molecular dynamics (MD) simulation experiments. VLS screened three potential compounds including Canthin-6-one 9-O-beta-glucopyranoside, Kushenol W and Kushenol K which exhibited optimal binding with all the three conserved DV proteins. This study brings forth novel scaffolds against DV serotypes to serve as lead molecules for further optimization and drug development against all DV serotypes with equal effect against multiple disease causing DV proteins. We therefore anticipate that the insights given in the current study could be regarded valuable towards exploration and development of a broad-spectrum natural anti-dengue therapy.

Synthesis, Cytotoxic Evaluation, and Molecular Docking Studies of N-(7- hydroxy-4-methyl-2-oxoquinolin-1(2H)-yl)acetamide/benzamide Analogues

Background:

Cancer caused nearly 8.8 million deaths in 2015. Limited efficacy, selectivity, drug resistance and toxicity are major complications associated with chemotherapy, potentiating the discovery of anticancer agents.

Methods:

A new series of N-(7-hydroxy-4-methyl-2-oxoquinolin-1(2H)-yl)acetamide/benzamide analogues (5a-j) was prepared from the precursor, 7-hydroxy-4-methyl-2H-chromen-2-one (3), as anticancer agent. The structural assignment of quinolone analogues (5a-j) was based on spectroscopic data analyses. The cytotoxicity was tested on breast cancer cell lines (MCF7 and MDA-MB- 231) by sulforhodamine B (SRB) assay and three dose-related parameters GI50, TGI, and LC50 were calculated.

Results:

2-(2-chlorophenoxy)-N-(7-hydroxy-4-methyl-2-oxoquinolin-1(2H)-yl)acetamide (5a) showed the most potent cytotoxicity against the MCF7 and MDA-MB-231 cancer cell lines with GI50 of 18.7 and 48.1 µM respectively. The glide scores of the compounds, 5a-d were found to be related to the cytotoxicity profile and the emodel scores for ligands, 5a-j were found to be related to significant cytotoxicity.

Conclusion:

Compound 5a exhibited the most potent cytotoxicity and this report may provide some predictions to design more potent novel quinolines as cytotoxic agents.

Quantum Chemical Calculations and Statistical Analysis: Structural Cytotoxicity Relationships of some Synthesized 2-thiophen-naphtho(benzo)oxazinone Derivatives

Twenty-two 2-thiophen-naphtho(benzo)oxazinone derivatives are prepared using 3-amino-2-naphthoic and 5-nitroanthranilic acids as building blocks. The target compounds (1-22) were evaluated quantitatively for their cytotoxic effects in vitro against three cancer cell lines, including the lung A549, the hepatocyte HepG2, and the breast MCF-7 carcinoma cells. Compounds 1, 12, 14, and 21 were found to exhibit remarkable cytotoxicity against the tested cancer cell lines. Compound 21 has shown the highest activity against A549 and MCF-7 (IC₅₀: 9.8 & 3.6 µg mL^-1) whereas 1 (IC₅₀: 5.9 µg mL^-1) and 5 (3.6 µg mL^-1) were the most active against HepG2. To elucidate the structure-cytotoxicity relationships of the synthesized compounds, a number of their chemical descriptors are determined including electronic, steric and hydrophobicity descriptors. The electronic properties were calculated through density functional theory (DFT) calculations at the B3LYP/6-31 + G(d,p). The impact of the chosen descriptors is evaluated statistically through simple and multiple linear regression analyses (SLR and MLR). SLR analyses reveal that the impact of each descriptor on the cell lines are relatively weak except for MCF-7, where hardness and softness show moderate correlations with correlation coefficients higher than 60%. The correlations were improved by considering MLR analyses (R² ≥ 90%), which showed that the cytotoxicity of synthesized compounds is correlated with their combined descriptors hardness, softness, electrophiliciy and hydrophobicity (LogP).

Crystal structure of ethyl 4-amino-5-(5-methyl-1-(4-tolyl)-1H-1,2,3-triazole-4-carbonyl)-2-(phenylamino)thiophene-3-carboxylate, C24H23N5O3S

C24H23N5O3S, triclinic, P1̅ (no. 2), a = 9.1704(9) Å, b = 10.1253(11) Å, c = 12.2182(14) Å, α = 83.686(10)°, β = 89.542(9)°, γ = 76.982(9)°, V = 1098.5(2) Å3, Z = 2, R gt(F) = 0.0551, wR ref(F 2) = 0.1510, T = 296(2) K.

Rationale Design, Synthesis, Cytotoxicity Evaluation, and Molecular Docking Studies of 1,3,4-oxadiazole Analogues

Background:

1,3,4-Oxadiazole heterocycles possess a broad spectrum of biological activities. They were reported as potent cytotoxic agents and tubulin inhibitors; hence it is of great interest to explore new oxadiazoles as cytotoxic agents targeting tubulin polymerization.

Objective:

Two new series of oxadiazoles (5a-h and 12a-h) were synthesized, structurally related to the heterocyclic linked aryl core of IMC-038525, NSC 776715, and NSC 776716, with further modification by incorporating methylene linker.

Method:

The 2,5-disubstituted-1,3,4-oxadiazoles (5a-h and 12a-h) were synthesized by refluxing an equimolar mixture of the intermediates [(4) and (8a-d)] and aromatic aldehydes in water-ethanol system using sodium bisulphite catalyst. The cytotoxicity evaluation was carried out according to the National Cancer Institute (NCI US) Protocol, while the tubulin polymerization assay kits from Cytoskeleton ™(bk011p) was used to perform an in vitro tubulin polymerization assay.

Results:

2-(5-{[(4-Chlorophenyl)amino]methyl}-1,3,4-oxadiazol-2-yl)phenol (5f) and 2-[(2,4-dichlorophenoxy) methyl]-5-(3,4-dimethoxyphenyl)-1,3,4-oxadiazole (12c) showed maximum cytotoxicity with the mean percent growth inhibitions (GIs) of 71.56 and 72.68 respectively at 10 µM drug concentrations. Both the compounds (5f and 12c) showed superior cytotoxicity than clinically prevalent anticancer drugs, Imatinib and Gefitinib in one dose assay. The compound 12c showed promising results in five dose assay, with GI50 values varies between 1.61 and >100 µM. Furthermore, the compounds, 5f and 12c also inhibited the polymerization of tubulin with, an IC50 of 2.8 and 2.2 µM, respectively.

Conclusion:

The oxadiazoles reported herein are tubulin inhibitors and cytotoxic agents. These findings will be helpful in future drug design of more potent tubulin inhibitor cytotoxic agents.