ABSTRACT
Bioorganometallic complexes have attracted considerable interest and have shown promise for potential application in the treatment and diagnosis of cancer, as well as bioimaging agents, some acting as theranostic agents. The series of novel ferrocene, benzimidazo[1,2-a]quinoline and fluorescein derivatives with bidentate pyridyl-1,2,3-triazole and 2,2'-dipyridylamine and their tricarbonylrhenium(I) complexes was prepared and fully characterised by NMR, single-crystal X-ray diffraction, UV-Vis and fluorescence spectroscopy in biorelevant conditions. The fluorescein and benzimidazo[1,2-a]quinoline ligands and their complexes with Re(I) showed interactions with ds-DNA/RNA and HSA, characterised by thermal denaturation measurements, fluorimetric and circular dichroism titrations. The binding constants revealed that addition of Re(I) increases the affinity of fluorescein but decreases the affinity of benzimidazo[1,2-a]quinoline. The complexation of Re(I) had the opposite effect on fluorescein and benzimidazo[1,2-a]quinoline ligands' fluorimetric sensitivity upon biomacromolecule binding, Re(I) fluorescein complex emission being strongly quenched by DNA/RNA or HSA, while emission of Re(I) benzimidazo[1,2-a]quinolone complex was enhanced, particularly for HSA, making it a promising fluorescent probe. Some mono- and heterobimetallic complexes showed considerable antiproliferative activity on colon cancer cells (CT26 and HT29), with ferrocene dipyridylamine complexes exhibiting the best inhibitory activity, comparable to cisplatin. The correlation of the cytotoxicity data with the linker type between the ferrocene and the 1,2,3-triazole ring suggests that direct binding of the metallocene to the 1,2,3-triazole is favourable for antitumor activity. The Re(I) benzimidazo[1,2-a]quinolone complex showed moderate antiproliferative activity, in contrast to the Re(I) fluorescein complex, which exhibited weak activity on CT26 cells and no activity on HT29 cells. The accumulation of the Re(I) benzimidazo[1,2-a]quinolone complex in the lysosomes of CT26 cells indicates the site of its bioactivity, thus making this complex a potential theranostic agent.
Subject(s)
Antineoplastic Agents , Coordination Complexes , Quinolones , Humans , Metallocenes , Ligands , Chelating Agents , DNA/chemistry , Quinolones/chemistry , Pyridines/pharmacology , Pyridines/chemistry , Triazoles/pharmacology , Triazoles/chemistry , RNA , Fluoresceins , Coordination Complexes/chemistry , Antineoplastic Agents/chemistryABSTRACT
The three series of 5-mono- and 2,5-bis-1,2,3-triazolyl-substituted benzimidazo[1,2-a]quinolines as potential antitumor agents were synthesized. Their growth-inhibitory activity is influenced by the introduction of fluorine at C-2 and the mono-triazolyl nuclei at C-5 of the tetracyclic skeleton, particularly if the 1,2,3-triazole moiety contains a short aliphatic side-chain. Thus, the chloropropyl side-chain in all three series had the highest impact on the inhibitory effect. 1,2,3-Triazolyl-2-fluorobenzimidazo[1,2-a]quinoline conjugates 8a and 8b with 3-chloropropyl and 2-hydroxyethyl substituents, respectively, exhibited the most pronounced cytostatic effect on colon cancer (HCT116) cells in the submicromolar range. The compound 8a emerged as the most promising candidate because of its higher potency and some selectivity in the non-tumor aneuploid immortal keratinocyte (HaCaT) cells. Fluorescence and CD spectroscopy, as well as the thermal denaturation assays, revealed moderate to high DNA/RNA binding affinities of the selected compounds and identified intercalation as a dominant binding mode to both polynucleotides. However, results of intracellular distribution assay in human lung carcinoma (H460) cells suggest that both 8a and 8b do not target nuclear DNA and that their non-specific cytotoxic effect may be attributed to the damage of intercellular membranes.
Subject(s)
Antineoplastic Agents/pharmacology , Benzimidazoles/pharmacology , DNA/chemistry , Quinolones/pharmacology , RNA/chemistry , Animals , Antineoplastic Agents/chemical synthesis , Antineoplastic Agents/chemistry , Benzimidazoles/chemical synthesis , Benzimidazoles/chemistry , Binding Sites/drug effects , Cattle , Cell Line, Tumor , Cell Proliferation/drug effects , Dose-Response Relationship, Drug , Drug Screening Assays, Antitumor , Humans , Molecular Structure , Quinolones/chemical synthesis , Quinolones/chemistry , Structure-Activity RelationshipABSTRACT
L-Ascorbic acid (ASA), vitamin C, is a ubiquitous carbohydrate-like compound that has an essential role in a number of cellular processes, such as collagen synthesis, cellular oxidation, and various hydroxylation reactions. ASA is a biomolecule of critical importance for protection of cellular components against oxidative damage caused by toxic free radicals and other reactive oxygen species (ROS) that are involved in the development of various types of chronic diseases. Vitamin C has a switchover role from being an antioxidant in physiological conditions to a prooxidant under pathologic conditions. Moreover, some l-ascorbic acid derivatives exhibit strong and selective antitumor and antiviral activity. This review emphasizes the advances on diverse and potent biological profiles of l-ascorbic acid and its derivatives, and their perspective in the development of new bioactive chemical entities in the future. The work is primarily addressed at antioxidant, anticancer, and antiviral potencies of l-ascorbic acid and compounds containing its butenolide structural motif.
