Investigation of the Relationship between Electronic Structures and Bioactivities of Polypyridyl Ru(II) Complexes.

Ruthenium (Ru)-based organometallic drugs have gained attention as chemotherapeutic and bioimaging agents due to their fewer side effects and excellent physical optical properties. Tuning the electronic structures of Ru complexes has been proven to increase the cytotoxicity of cancer cells and the luminescent efficiency of the analytical probes. However, the relationship between electronic structures and bioactivities is still unclear due to the potential enhancement of both electron donor and acceptor properties. Thus, we investigated the relationship between the electronic structures of Ru(II) complexes and cytotoxicity by optimizing the electron-withdrawing (complex 1), electron-neutral (complex 2), and electron-donating (complex 3) ligands through DFT calculations, bioactivities tests, and docking studies. Our results indicated that it was not sufficient to consider only either the effect of electron-withdrawing or electron-donating effects on biological activities instead of the total electronic effects. Furthermore, these complexes with electron-donating substituents (complex 3) featured unique "off-on" luminescent emission phenomena caused by the various "HOMO-LUMO" distributions when they interacted with DNA, while complex with electron-withdrawing substituent showed an "always-on" signature. These findings offer valuable insight into the development of bifunctional chemotherapeutic agents along with bioimaging ability.

Quinazolin-4(3H)-one based potential multiple tyrosine kinase inhibitors with excellent cytotoxicity.

A series of quinazolin-4(3H)-one derivatives were synthesised and evaluated for their cytotoxicity against human Caucasian breast adenocarcinoma (MCF-7) and human ovarian carcinoma (A2780) cell lines. Cytotoxicity of the most tested compounds was 2- to 30-fold more than the positive control lapatinib (IC50 of 2j = 3.79 ± 0.96; 3j = 0.20 ± 0.02; and lapatinib = 5.9 ± 0.74) against MCF7 cell lines except two compounds (IC50 of 2 b = 15.72 ± 0.07 and 2e = 14.88 ± 0.99). On the other hand, cytotoxicity was 4 - 87 folds (IC50 of 3a = 3.00 ± 1.20; 3 g = 0.14 ± 0.03) more the positive control lapatinib (IC50 = 12.11 ± 1.03) against A2780 cell lines except compound 2e (IC50 = 16.43 ± 1.80). Among the synthesised quinazolin-4(3H)-one derivatives, potent cytotoxic 2f-j and 3f-j were investigated for molecular mechanism of action. Inhibitory activities of the compounds were tested against multiple tyrosine protein kinases (CDK2, HER2, EGFR and VEGFR2) enzymes. As expected, all the quinazolin-4(3H)-one derivatives were showed comparable inhibitory activity against those kinases tested, especially, compound 2i and 3i showed potent inhibitory activity against CDK2, HER2, EGFR tyrosine kinases. Therefore, molecular docking analysis for quinazolin-4(3H)-one derivatives 2i and 3i were performed, and it was revealed that compounds 2i and 3i act as ATP non-competitive type-II inhibitor against CDK2 kinase enzymes and ATP competitive type-I inhibitor against EGFR kinase enzymes. However, in case of HER2, compounds 2i act as ATP non-competitive type-II inhibitor and 3i act as ATP competitive type-I inhibitor. Docking results of known inhibitors were compared with synthesised compounds and found synthesised 2i and 3i are superior than the known inhibitors in case of interactions. In addition, in silico drug likeness properties of quinazolin-4(3H)-one derivatives showed better predicted ADME values than lapatinib.

Synthesis of Pyridine-Dicarboxamide-Cyclohexanone Derivatives: Anticancer and α-Glucosidase Inhibitory Activities and In Silico Study.

An efficient and practical method for the synthesis of 2,6-diaryl-4-oxo-N,N'-di(pyridin-2-yl)cyclohexane-1,1-dicarboxamide is described in this present study, which occurs through a double Michael addition reaction between diamide and various dibenzalacetones. The reaction was carried out in dichloromethane (DCM) in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). The anticancer activities of the synthesized compounds were evaluated in several cancer cell lines, including MCF-7, MDA-MB-231, SAS, PC-3, HCT-116, HuH-7 and HepG2 cells. From these experiments, we determined that MDA-MB-231 was the most sensitive cancer cell line to the compounds 3c, 3e, 3d, 3j and 3l, which exhibited variable anticancer activities (3l [IC50 = 5 ± 0.25 µM] > 3e [IC50 = 5 ± 0.5 µM] > 3c [IC50 = 7 ± 1.12 µM] > 3d [IC50 = 18 ± 0.87 µM] > 3j [IC50 = 45 ± 3 µM]). Of these, 3l (substituted p-trifluoromethylphenyl and chloropyridine) showed good potency (IC50 = 6 ± 0.78 µM) against HCT-116 colorectal cancer cells and exhibited high toxicity against HuH-7 liver cancer cells (IC50 = 4.5 ± 0.3 µM). These values were three times higher than the values reported for cisplatin (IC50 of 8 ± 0.76 and 14.7 ± 0.5 µM against HCT-116 and HuH-7 cells, respectively). The highest α-glucosidase inhibitory activity was detected for the 3d, 3i and 3j compounds. The details of the binding mode of the active compounds were clarified by molecular docking studies.

Linear diarylheptanoids as potential anticancer therapeutics: synthesis, biological evaluation, and structure-activity relationship studies.

In efforts to develop effective anticancer therapeutics with greater selectivity toward cancerous cell and reduced side-effects, such as emetic effects due to detrimental action of the drug toward the intestinal flora, a series of linear diarylheptanoids (LDHs) were designed and synthesized in 7 steps with good-to-moderate yields. All synthesized compounds were evaluated for their antibacterial, antiproliferative, and topoisomerase-I and -IIα inhibitory activity. Overall, all compounds showed little to no activity against the bacterial strains tested. Most of the synthesized compounds showed good antiproliferative activity against human breast cancer cell lines (T47D); specifically, the IC50 values of compounds 6a, 6d, 7j, and 7e were 0.09, 0.64, 0.67, and 0.99 µM, respectively. Among the tested compounds, 7b inhibited topo-I by 9.3% (camptothecin 68.8%), 7e and 7h inhibited topo-IIα by 38.4 and 47.4% (etoposide 76.9%), respectively, at the concentration of 100 µM. These results suggest that a set of promising anticancer agents can be obtained by reducing inhibitory actions on different microbes to provide enhanced selectivity against cancerous cells.

Studies on the reactions of 3,2'-polymethylene-2-phenylbenzo[b]-1,10-phenanthrolines with Ru(tpy)Cl3 and properties of the products.

A series of 3,2-polymethylene-2-phenylbenzo[b]-1,10-phenanthrolines was reacted with Ru(tpy)Cl3 to afford two ruthenium (Ru) complexes, a pentaaza-coordinated (N5Cl) complex [Ru(tpy)(L)Cl]+ and a hexa-coordinated (N5C) complex [Ru(tpy)(L)]+. The ratio of these two complexes was found to be highly dependent on the length of the polymethylene bridge between terminal phenyl and central pyridine rings. The reaction between the dimethylene-bridged ligand and Ru(tpy)Cl3 afforded a hexa-coordinated (N5C) complex as an only isolatable product in 83% yield, while the others afforded pentaaza-coordinated products and hexa-coordinated products in ratios of 1:1.6-3.5 with 80-90% overall yields. The UV spectra of pentaaza-coordinated complexes (N5Cl) and hexa-coordinated (N5C) cycloruthenated complexes were similar to show absorbances at 253-255, 276-286, 312-324, 360-373, and 490-532 nm. All of these complexes showed greenish blue light emissions in the range 450-460 nm upon excitation in the range 368-382 nm, while excitation at 500-532 nm resulted in green light emissions at 570 nm for pentaaza-coordinated complexes and 577-579 nm for hexaaza-coordinated species. Irradiation of the plasmid (100 µM) in the presence of 8c (λirr > 395 nm, 10 min) in air resulted in single-strand cleavage leading to the production of nicked plasmid (Form II), probably via intercalation.

2,2-dimethyl-2H-pyran-derived alkaloids I. Practical synthesis of acronycine and benzo[b]acronycine and their biological properties.

The 2,2-dimethyl-2H-pyran-derived alkaloids acronycine and its demethylated congeners were prepared in three steps from anthranilic acid and phloroglucinol. The phenylboronic acid-mediated interamolecular cyclization reaction of 1,3-dihydroxyacridone and 3-methylbut-2-enal was employed as a key step, which was also applied to the synthesis of related cytotoxic benzo[b]acronycine. Inhibitory activities of the compounds prepared on topoisomerase I and II as well as their cytotoxicities were evaluated. Cytotoxicity of 2 is closely related to the strong inhibitory activity against topo II at 20 microM level.