Synthesis and biological evaluation of novel isoxazolines linked via piperazine to 2- benzoisothiazoles as potent apoptotic agents

Cytotoxic and apoptotic effects of some (R)-carvone-isoxazoline derivatives on human fibrosarcoma and carcinoma cells: experimental evaluation for cytotoxicity, molecular docking and molecular dynamics studies

This study aimed to analyze the cytotoxic and apoptotic effects of isoxazoline derivatives with monoterpene scaffold 9a-e in HT-1080 fibrosarcoma, MCF-7, and MDA-MB-231 breast carcinoma, and A-549 lung carcinoma. The cytotoxic effects data revealed that compounds 9a-e generally induced significant cell growth inhibition in all cell lines, with IC₅₀ ranging from 10 to 30 µM. However, for compounds 9c and 9e, the IC₅₀ reached a value of 100 µM in HT-1080 cells. Compounds 9a, 9b, and 9d could induce apoptosis in HT-1080 cells as demonstrated by Annexin-V labeling and Caspase-3/7 activity. The apoptotic effect was accompanied by cell cycle arrest in the S phase. Molecular docking and molecular dynamics confirmed the empirical assay results and confirmed the stability of the complex with the inhibition of the anti-apoptotic protein, leading to cancer cell death. Overall, these data suggest that the proposed isoxazoline derivatives may be potential candidates for further investigation to evaluate their efficacy and optimal use in cancer treatment.Communicated by Ramaswamy H. Sarma.

Novel isoxazoline-linked 1,3,4-thiadiazole hybrids as anticancer agents: Design, synthesis, biological evaluation, molecular docking, and molecular dynamics simulation

In the current study, natural (R)-carvone was utilized as a starting material for the efficient synthesis of two series of isoxazoline derivatives bearing the 1,3,4-thiadiazole moiety. The new compounds were obtained in good yields and were characterized by ¹ H and ¹³ C NMR and HRMS analysis. The newly synthesized monoterpenic isoxazoline 1,3,4-thiadiazole and their thiosemicarbazone intermediate derivatives were evaluated for their anticancer activity in four cancer cell lines (HT-1080, A-549, MCF-7, and MDA-MB-231). Most of the synthesized compounds exhibited moderate to high anticancer effects. Compound 13c showed the highest anticancer activity with IC₅₀ values ranging from 19.33 ± 1.81 to 34.81 ± 3.03 µM. Further investigation revealed that compounds 12e and 13c could inhibit the cell growth of HT-1080 and MCF-7 cells by inducing apoptosis through caspase-3/7 activation. The apoptotic effect was accompanied by an S phase and G2/M cell cycle arrest for 13c and 12e, respectively. Compounds 12e and 13c were assessed in silico using molecular docking and molecular dynamics. We found that compound 13c is moderately active against the caspase-3 protein, which triggers apoptosis via intrinsic and extrinsic routes, making compound 13c a promising candidate to activate the proapoptotic protein (caspase-3).

Characterization and Cytotoxicity of Pseudomonas Mediated Rhamnolipids Against Breast Cancer MDA-MB-231 Cell Line

A biosurfactant producing bacterium was identified as Pseudomonas aeruginosa DNM50 based on molecular characterization (NCBI accession no. MK351591). Structural characterization using MALDI-TOF revealed the presence of 12 different congeners of rhamnolipid such as Rha-C8-C8:1, Rha-C10-C8:1, Rha-C10-C10, Rha-C10-C12:1, Rha-C16:1, Rha-C16, Rha-C17:1, Rha-Rha-C10:1-C10:1, Rha-Rha-C10-C12, Rha-Rha-C10-C8, Rha-Rha-C10-C8:1, and Rha-Rha-C8-C8. The radical scavenging activity of rhamnolipid (DNM50RL) was determined by 2, 3-diphenyl-1-picrylhydrazyl (DPPH) assay which showed an IC₅₀ value of 101.8 μg/ ml. The cytotoxic activity was investigated against MDA-MB-231 breast cancer cell line by MTT (4,5-dimethylthiazol-2-yl-2,5-diphenyl tetrazolium bromide) assay which showed a very low IC50 of 0.05 μg/ ml at 72 h of treatment. Further, its activity was confirmed by resazurin and trypan blue assay with IC₅₀ values of 0.01 μg/ml and 0.64 μg/ ml at 72 h of treatment, respectively. Thus, the DNM50RL would play a vital role in the treatment of breast cancer targeting inhibition of p38MAPK.

Polyhalonitrobutadienes as Versatile Building Blocks for the Biotargeted Synthesis of Substituted N-Heterocyclic Compounds

Substituted nitrogen heterocycles are structural key units in many important pharmaceuticals. A new synthetic approach towards heterocyclic compounds displaying antibacterial activity against Staphylococcus aureus or cytotoxic activity has been developed. The selective synthesis of a series of 64 new N-heterocycles from the three nitrobutadienes 2-nitroperchloro-1,3-butadiene, 4-bromotetrachloro-2-nitro-1,3-butadiene and (Z)-1,1,4-trichloro-2,4-dinitrobuta-1,3-diene proved feasible. Their reactions with N-, O- and S-nucleophiles provide rapid access to push-pull substituted benzoxazolines, benzimidazolines, imidazolidines, thiazolidinones, pyrazoles, pyrimidines, pyridopyrimidines, benzoquinolines, isothiazoles, dihydroisoxazoles, and thiophenes with unique substitution patterns. Antibacterial activities of 64 synthesized compounds were examined. Additionally, seven compounds (thiazolidinone, nitropyrimidine, indole, pyridopyrimidine, and thiophene derivatives) exhibited a significant cytotoxicity with IC₅₀-values from 1.05 to 20.1 µM. In conclusion, it was demonstrated that polyhalonitrobutadienes have an interesting potential as structural backbones for a variety of highly functionalized, pharmaceutically active heterocycles.

Current Strategies in Development of New Chromone Derivatives with Diversified Pharmacological Activities: A Review

Chromone derivatives possess a spectrum of biological activities. Chromone has been recognized as a privileged structure for new drug invention and development. Substitution pattern of chromone scaffold determines different type of biological activities. The type, number and position of substituents connected to the chromone core play a vital role in determining pharmacological activities. In the present review, we have discussed new chromone derivatives as anticancer, anti-diabetic, antimicrobial, anti-inflammatory, antioxidant and as anti-Alzheimer agents. This review deals with the chromone derivatives prepared by combining chromone molecule with various natural and synthetic pharmacophores and pharmacological activities presented by them. The main aim is to highlight the diversified pharmacological activities exhibited by chromone hybrid molecules during the last eight to ten years.

Development of Promising Thiopyrimidine-Based Anti-cancer and Antimicrobial Agents: Synthesis and QSAR Analysis

Objective & Methodology:

New hybrids of thiopyrimidine-five/six heterocyclic rings were synthesized and in vitro evaluated for their antiproliferative activity against three human cancer cell lines, namely HCT116 (human colorectal carcinoma), PC-3 (human prostate adenocarcinoma) and HepG2 (human liver carcinoma) cell lines. The most potency was elicited by the target candidates against the viability of HCT116 cell lines. It was higher than that obtained by the positive control 5-Fluorouracil (IC50 range; 0.11-0.49 μM, IC50, 5-FU; 1.10 μM).

Results:

Cell cycle analysis and apoptosis activation revealed that compound 20 induced G2/M phase arrest and apoptosis in HCT116 cells. In addition, compound 20 activates the caspases-9 and -3, a process which might mediate the apoptosis of HCT116 cells.

Conclusion:

Furthermore, there is a good agreement between the observed pIC50 and the predicted pIC50 values, in addition, the low RMSD and standard error values indicate the accuracy of the model. Antimicrobial evaluation revealed that some of these compounds exhibited significant activities against the tested pathogenic bacteria and fungi, wherein compounds 7a, 14, 15a, 21a, produced the most potent and broad spectrum antibacterial and antifungal potency that was equivalent to that revealed by Vibramycin and Ketoconazole (MIC; 125 μg/mL). Moreover, compounds 15a, 21c, investigated dual potent antimicrobial and anticancer activity.

Synthesis and Biological Evaluation of New Piperazine Substituted 3, 5-Diarylisoxazolines

Aim and Objective:

Isoxazolines are an important class of nitrogen and oxygen-containing heterocycles, which have gained much importance as the potential biological agents. In order to study structureactivity relationships of isoxazolines, this work has been conducted.

Materials and Methods:

A series of new piperazine substituted 3, 5-diarylisoxazoline derivatives (6-31) were designed and synthesized, and in vitro anti-inflammatory activity in lipopolysaccharide (LPS)-stimulated RAW-264.7 macrophages and anticancer effect against a panel of human tumor cell lines (Hela, A549 and SGC7901) by MTT assay were evaluated.

Results:

The substituents of the NH group of piperazine ring had an obvious influence on biological activities. Especially, compounds 5, 7, 8, 10, 11, 13 and 27-showed good inhibitory effect on the generation of NO compared to dexamethasone. Furthermore, derivatives 5, 6, 7, 8, 9, 13 and 26 were found to be potential selectively anticancer activity on human tumor cell lines, which displayed better cytotoxic activity to positive control 5- FU.

Conclusion:

Piperazine substituted 3, 5-diarylisoxazoline derivatives could be considered as new antiinflammatory and anticancer agents.

Synthesis and Screening of Pro-apoptotic and Angio-inhibitory Activity of Novel Benzisoxazole Derivatives both In Vitro and In Vivo

BACKGROUND

Triple Negative Breast Cancer (TNBC) tends to be more aggressive than other types of breast cancer. Resistance to chemotherapy is a major obstacle hence there is a significant need for new antineoplastic drugs with multi-target potency. Numerous Benzoisoxazole moieties have been found to possess a broad spectrum of pharmacological activities. In the present study, we have synthesized 9 novel derivatives of Benzisoxazole 7(a-i) and screened them for their biological potential.

METHODS

Chemical synthesis, Mass spectrometry (HRMS), cell proliferation and cytotoxicity assay, wound healing assay, flow cytometry and nuclear staining. Angio-inhibitory activity assessed by corneal micropocket assay and in vivo peritoneal angiogenesis assay.

RESULTS

The Benzisoxazole derivatives 7(a-i) were synthesized and screened for their biological potency by both in vitro and in vivo experimental models. Among the series, compound 3-(1-((3-(3(Benzyloxy)-4-methoxyphenyl)- 4,5-dihydroisoxazole-5-yl)methyl)piperidine-4-yl)6-fluorobenzo[d] isoxazole (7e) was found to be most promising, with an average IC50 value of 50.36 ± 1.7 µM in MTT assay and showed 81.3% cell death. The compound 7e also showed 60-70% inhibition on a recombinant Metastasis-Associated protein (MTA1) induced proliferation and cell migration in MDAMB-231 cells, which is known to play a major role in angiogenesis. The anti-tumour studies inferred the regression of tumour activity. This was due to inhibition of neovascularization and evoking apoptosis process as assessed by corneal vascularization, peritoneal angiogenesis and apoptotic hallmarks in 7e treated cells.

CONCLUSION

These findings not only show the biological efficacy of compound 7e but it is also an effective beginning to explore the mechanism of metastasis and cancer therapy strategy targeting MTA1. The observed biological activity makes compound 7e an attractive drug candidate.

Synthesis of piperazine-based thiazolidinones as VEGFR2 tyrosine kinase inhibitors inducing apoptosis

Aim: VEGFR2 tyrosine kinase is a main target in suppressing cancer growth and metastasis. Materials & methods: Piperazine-based thiazolidinones were synthesized and screened for their anticancer and VEGFR2 tyrosine kinase inhibitory activity. Results: Compounds 11, 13 and 16 displayed potent anticancer activity against HepG-2 with IC50 values 0.03–0.06 μM. They were safe on normal human fibroblasts with selectivity indices 8.09, 11.40 and 4.37, respectively. Also, these compounds showed VEGFR2 tyrosine kinase inhibitory activities more than the reference staurosporine with IC50 values <0.3 μM. Lineweaver–Burk plot revealed that these compounds behaved as uncompetitive VEGFR2 tyrosine kinase inhibitors. They also induced caspase-dependent apoptosis in HepG-2. In addition, these compounds revealed good binding within VEGFR2 tyrosine kinase enzyme in comparison with sorafenib reference. Conclusion: Compounds 11, 13 and 16 comprise a new promising scaffold of selective VEGFR2 tyrosine kinase inhibitors with caspase-dependent apoptotic activities.

Alkyne Cycloadditions Mediated by Tetrabutylammonium Fluoride: A Unified and Diversifiable Route to Isoxazolines and Pyrazolines

A versatile approach to isoxazolines and pyrazolines by the cyclization of alkyne substrates using tetrabutylammonium fluoride (TBAF) is described. The reported diheteroatom cycles were produced under mild reaction conditions and with broad product scope. Evidence is also provided for a vinyl anion intermediate produced under unusually mild conditions, which was trapped in situ as part of a tandem cyclization/aldehyde addition sequence. Finally, a deprotection/functionalization method is described, leading to a substituted pyrazoline in good diastereoselectivity.