Automated Radiosynthesis and Molecular Docking Studies of Coumarin- Triazole Hybrid with fluorine-18: A feasibility study.

BACKGROUND: Fluorine-18 is one of the promising radiotracers that can report target specific information related to its physiology to understand the disease status through the PET modality. In the current study, the radiochemical synthesis, purification, and molecular docking studies of fluorine-18 (18F) radiolabeled coumarin-triazole hybrid have been performed. OBJECTIVE: To develop target specific fluorine-18 radiotracer for the diagnosis in oncology. METHODS: GE Tracer-lab FX2N module with few modifications in the line connections was used for the radiosynthesis and purification of target molecule [18F]SG-2, 4-((2,6-dimethylmorpholino) methyl)-7-((1-(4-(fluoro-18F) benzyl)-1H-1,2,3-triazol-4-yl) oxy)-2H-chromen-2-one, through the nucleophilic radiofluorination mechanism. The radiochemical purity was measured by HPLC, and TLC analytical methods. The kryptofix levels were also evaluated by using the TLC method. The residual solvents like DMF, ethanol were measured using GC. The Schrödinger drug discovery suite 2018 was used to study the protein and ligand interactions. RESULTS: The quality control parameters revealed the purity, chemical identity, and limits of residual solvents. The radiochemical purity was 95.5 ± 2.3%, and dimethylformamide solvent limit was 89 ± 3 ppm. The molecular docking results had suggested that the cold target molecule has made strong electronic interactions and showed the possible pharmacokinetic (ADME) properties with galectin-1 protein. Overall, these results showed that [[18F]SG-2 radiolabeling with 18F radionuclide was feasible, and support of molecular docking studies suggest possible interactions with Galectin- 1. CONCLUSION: we reported a feasibility study for labeling coumarin-triazole hybrid with fluorine-18 through aromatic nucleophilic fluorination reaction (SNAr).

Synthesis and Biological Evaluation of Novel Heterocyclic Imines Linked Coumarin- Thiazole Hybrids as Anticancer Agents.

BACKGROUND: Human Galectin-1, a protein of lectin family showing affinity towards ß-galactosides has emerged as a critical regulator of tumor progression and metastasis, by modulating diverse biological events including homotypic cell aggregation, migration, apoptosis, angiogenesis and immune escape. Therefore, galectin-1 inhibitors might represent novel therapeutic agents for cancer. METHODS: A new series of heterocyclic imines linked coumarin-thiazole hybrids (6a-6r) was synthesized and evaluated for its cytotoxic potential against a panel of six human cancer cell lines namely, lung (A549), prostate (DU-145), breast (MCF-7 & MDA-MB-231), colon (HCT-15 & HT-29) using MTT assay. Characteristic apoptotic assays like DAPI staining, cell cycle, annexin V and Mitochondrial membrane potential studies were performed for the most active compound. Furthermore, Gal-1 inhibition was confirmed by ELISA and fluorescence spectroscopy. RESULTS: Among all, compound 6g {3-(2-(2-(pyridin-2-ylmethylene) hydrazineyl) thiazol-4-yl)-2H-chromen-2- one} exhibited promising growth inhibition against HCT-15 colorectal cancer cells with an IC50 value of 1.28 ± 0.14 µM. The characteristic apoptotic morphological features like chromatin condensation, membrane blebbing and apoptotic body formation were clearly observed with compound 6g on HCT-15 cells using DAPI staining studies. Further, annexin V-FITC/PI assay confirmed effective early apoptosis induction by treatment with compound 6g. Loss of mitochondrial membrane potential and enhanced ROS generation were confirmed with JC-1 and DCFDA staining method, respectively by treatment with compound 6g, suggesting a possible mechanism for inducing apoptosis. Moreover, flow cytometric analysis revealed that compound 6g blocked G0/G1 phase of the cell cycle in a dose-dependent manner. Compound 6g effectively reduced the levels of Gal-1 protein in a dose-dependent manner. The binding constant (Ka) of 6g with Gal-1 was calculated from the intercept value which was observed as 1.9 x 107 M-1 by Fluorescence spectroscopy. Molecular docking studies showed strong interactions of compound 6g with Gal-1 protein. CONCLUSION: Our studies demonstrate the anticancer potential and Gal-1 inhibition of heterocyclic imines linked coumarin-thiazole hybrids.