Irena Sović

Novel phenyl and pyridyl substituted derivatives of isoindolines: Synthesis, antitumor activity and DNA binding features

Novel phenyl-substituted (3a-3d, 4a, 5, 8a, 8b and 9a) and pyridyl-substituted (3e-3i, 4b, 8c-8e, 9b and 9c) isoindolines were prepared in the reaction of o-phthalaldehyde and corresponding substituted aromatic and heteroaromatic amines by modification of reaction conditions from low to high temperature and from neutral to acidic environment. The antiproliferative activity of chosen substituted isoindolines was assessed on a panel of tumour cell lines and normal human fibroblasts. The majority of tested compounds was active at the highest tested concentrations phenyl-substituted isoindolines 3a and 3b and pyridyl-substituted isoindoline 3g showed a selective effect at micromolar concentrations on HepG2 cell line in comparison with other tested tumour cell lines and normal human fibroblasts. The strongest yet non-selective effect was observed for the pyridyl-substituted isoindoline 8c. These isoindoline derivatives showed diverse mechanism of action on tumour cell death induction as compounds 3a and 8c probably induced mitotic catastrophe while compound 3b induced apoptosis. Indeed, DNA binding properties evidenced that compounds 8a, 8c and 8d bind to DNA as highly potent DNA intercalators. By contrast, compounds 3b, 3e, 3i, 4a and 5 did not target the DNA. At last, the phenyl-substituted compound 8b proved to be a strong DNA binding compound with sequence selective binding and without DNA intercalation profile.

Benzothiazolyl- and benzimidazolyl-substituted 1-iminoisoindolines: synthesis, mechanistic studies, and crystal structure determination

New benzothiazolyl- and benzimidazolyl-substituted 1-iminoisoindolines are prepared in the reaction of o-phthalaldehyde and substituted 2-aminobenzothiazoles and 2-aminobenzimidazoles. The optimization of these reactions is discussed, and the reaction mechanisms are proposed based on the experimental findings. Isoindolines with other heterocyclic substituents are prepared as a confirmation of the proposed mechanisms. Molecular and crystal structures of several prepared compounds are determined by a single crystal X-ray diffraction. These structures are found to be in line with projections based on the chemical and spectroscopic properties, and thus offer an additional confirmation of the proposed reaction mechanisms.Graphical abstract

Synthesis, antitumor activity and DNA binding features of benzothiazolyl and benzimidazolyl substituted isoindolines

In this paper novel isoindolines substituted with cyano and amidino benzimidazoles and benzothiazoles were synthesized as new potential anti-cancer agents. The new structures were evaluated for antiproliferative activity, cell cycle changes, cell death, as well as DNA binding and topoisomerase inhibition properties on selected compounds. Results showed that all tested compounds exerted antitumor activity, especially amidinobenzothiazole and amidinobenzimidazole substituted isoindolin-1-ones and benzimidazole substituted 1-iminoisoindoline that showed antiproliferative effect in the submicromolar range. Moreover, the DNA-binding properties of selected compounds were evaluated by biophysical and biochemical approaches including thermal denaturation studies, circular dichroism spectra analyses and topoisomerase I/II inhibition assays and results identified some of them as strong DNA ligands, harboring or not additional topoisomerase II inhibition and able to locate in the nucleus as determined by fluorescence microscopy. In conclusion, we evidenced novel cyano- and amidino-substituted isoindolines coupled with benzimidazoles and benzothiazoles as topoisomerase inhibitors and/or DNA binding compounds with potent antitumor activities.

Synthesis, antioxidative and antiproliferative activity of methoxy amidino substituted benzamides and benzimidazoles

Within this manuscript the synthesis and potential antioxidative and antiproliferative activity of novel methoxy amidino substituted bezamides 6–17 and benzimidazoles 23–28 and 32–35 is presented. Their antioxidative potency has been evaluated by in vitro spectrophotometric assays and preliminary structure–activity relationships among the synthesized compounds are discussed. The compound 28 bearing three methoxy groups on a phenyl ring and imidazolinyl amidine group on benzimidazole nuclei directly attached to the phenyl ring exhibited the most prominent reducing activity as well as free-radical scavenging activity. Furthermore all novel compounds were tested against three human cell lines: HCT 116 (colon carcinoma), H 460 (lung carcinoma) and MCF-7 (breast carcinoma). The most prominent antiproliferative effect in the single-digit micromolar range was observed for compound 33 on MCF-7 (IC50 = 9 µM) cell line, comparable to the standard etoposide.

Exploring antiproliferative activity of heteroaromatic amides and their fused derivatives using 3D-QSAR, synthesis, and biological tests

In this manuscript the synthesis, antiproliferative activity, and 3D-QSAR study of novel heteroaromatic benzamides and their cyclic products, quinolones and naphthyridones were described. The in vitro antiproliferative screening on three tumor cell lines showed in general moderate antiproliferative effect, except 2-benzimidazolyl and 2-benzothiazolyl substituted heteroaromatic amides, which showed prominent antiproliferative effect with GI50 concentration at micromolar range. Cyclic quinolones and naphthyridones demonstrated similar activity as their acyclic precursors. Using measured anticancer activities, 3D-QSAR models were obtained. Their prediction abilities were tested by internal and external prediction. Molecular properties with the highest positive or negative influence on compound’s anticancer activities have been identified. It was found that possibility of compound to accept H-bond (WN1), sum of hydrophobic surface areas, possibility of weak hydrophobic interactions (D1), and complete molecular surface of compound (S) should be increased, while possibility of weak hydrophilic interactions (W1) should be decreased in order to enhance anticancer activity of investigated compounds.Graphical abstract

Amino-Substituted Benzamide Derivatives as Promising Antioxidant Agents: A Combined Experimental and Computational Study

We prepared a range of N-arylbenzamides with a variable number of methoxy and hydroxy groups, bearing either amino or amino-protonated moieties, and used DPPH and FRAP assays to evaluate their antioxidant capacity. Most of the systems exhibit improved antioxidative properties relative to the reference BHT molecule in both assays. Combining results from both sets of experiments, the most promising antioxidative potential was displayed by the trihydroxy derivative 26, which we propose as a lead compound for a further optimization of the benzamide scaffold. Computational analysis helped in interpreting the observed trends and demonstrated that protonated systems are better antioxidants than their neutral counterparts, while underlying the positive influence of the electron-donating methoxy group on the antioxidant properties, thus confirming the experiments. It also revealed that the introduction of the hydroxy groups shifts the reactivity from both amide and amine groups toward this moiety and additionally enhances antioxidative features. This is particularly evident in 26H•+, which owes its pronounced reactivity to the stabilizing [O•···H-O] hydrogen bonding between the created phenoxyl radical and the two neighboring hydroxy groups. We demonstrated that its antioxidative activities are more favorable than those for analogous trihydroxy derivatives without the N-phenyl group or without the amide moiety, which strongly justifies the employed strategy in utilizing bisphenylamides in designing potent antioxidants.