Cytotoxicity of some potential DNA intercalators (carbazole, acridine and anthracene derivatives) evaluated through neutrophil chemiluminescence

Palindromic carbazole derivatives: unveiling their antiproliferative effect via topoisomerase II catalytic inhibition and apoptosis induction

Human DNA topoisomerases are essential for crucial cellular processes, including DNA replication, transcription, chromatin condensation, and maintenance of its structure. One of the significant strategies employed in cancer treatment involves the inhibition of a specific type of topoisomerase, known as topoisomerase II (Topo II). Carbazole derivatives, recognised for their varied biological activities, have recently become a significant focus in oncological research. This study assesses the efficacy of three symmetrically substituted carbazole derivatives: 2,7-Di(2-furyl)-9H-carbazole (27a), 3,6-Di(2-furyl)-9H-carbazole (36a), and 3,6-Di(2-thienyl)-9H-carbazole (36b) - as anticancer agents. Among investigated carbazole derivatives, compound 3,6-di(2-furyl)-9H-carbazole bearing two furan moieties emerged as a novel catalytic inhibitor of Topo II. Notably, 3,6-di(2-furyl)-9H-carbazole effectively selectively inhibited the relaxation and decatenation activities of Topo IIα, with minimal effects on the IIβ isoform. These findings underscore the potential of compound 3,6-Di(2-furyl)-9H-carbazole as a promising lead candidate warranting further investigation in the realm of anticancer drug development.

Prospects for More Efficient Multi-Photon Absorption Photosensitizers Exhibiting Both Reactive Oxygen Species Generation and Luminescence

The use of two-photon absorption (TPA) for such applications as microscopy, imaging, and photodynamic therapy (PDT) offers several advantages over the usual one-photon excitation. This creates a need for photosensitizers that exhibit both strong two-photon absorption and the highly efficient generation of reactive oxygen species (ROS), as well as, ideally, bright luminescence. This review focuses on different strategies utilized to improve the TPA properties of various multi-photon absorbing species that have the required photophysical properties. Along with well-known families of photosensitizers, including porphyrins, we also describe other promising organic and organometallic structures and more complex systems involving organic and inorganic nanoparticles. We concentrate on the published studies that provide two-photon absorption cross-section values and the singlet oxygen (or other ROS) and luminescence quantum yields, which are crucial for potential use within PDT and diagnostics. We hope that this review will aid in the design and modification of novel TPA photosensitizers, which can help in exploiting the features of nonlinear absorption processes.

Synthesis and DNA binding profile of N-mono- and N,N'-disubstituted indolo[3,2-b]carbazoles

A series of N-monosubstituted and N,N'-disubstituted derivatives of the indolo[3,2-b]carbazole chromophore have been prepared, and their binding affinity for duplex DNA has been evaluated by ultraviolet and fluorescence spectroscopies. It has been found that indolo[3,2-b]carbazoles bearing basic N-alkyl substituents are intercalators that bind DNA with affinities in the micromolar and submicromolar range and a preference for associating with sequences of mixed composition and purine-pyrimidine steps.

Novel carbazole-based two-photon photosensitizer for efficient DNA photocleavage in anaerobic condition using near-infrared light

Novel carbazole derivatives are first reported as two-photon photosensitizers for DNA photodamage under near-infrared light exposure.

Functionalization of anthracene: A selective route to brominated 1,4-anthraquinones

Efficient and stereoselective syntheses are described for the preparation of 2,3,9,10-tetrabromo-1,4-dimethoxy-1,2,3,4-tetrahydroanthracenes 7, 8 and the corresponding 1,4-diol 17 by silver ion-assisted solvolysis of hexabromotetrahydroanthracene 6. Base-promoted aromatization of 7 and 8 afforded synthetically valuable tribromo-1-methoxyanthracenes 10 and 11. The reaction of 17 with sodium methoxide generated tribromodihydroanthracene-1,4-diol 27, whose oxidation with PCC gave 2,9,10-tribromoanthracene-1,4-dione (28). Therefore a selective and efficient method was developed for the preparation of compound 28 starting from 9,10-dibromoanthracene (1), in a simple four-step process. Compounds 10 and 11, and diol 27 constitute key precursors for the preparation of functionalized substituted anthracene derivatives that are difficult to prepare by other routes. The studies also reveal the broad range of reactivity and selectivity of the stereoisomeric anthracene derivatives.

Ability of carbazole salts, inhibitors of Alzheimer beta-amyloid fibril formation, to cross cellular membranes

Alzheimer's disease is characterized by the presence of beta-amyloid fibril formation. The inhibition of this peptide accumulation may be a prevention method for Alzheimer's disease. Several classes of molecules have been reported to inhibit beta-amyloid fibril formation and among them carbazoles. However, very few studies have been performed to determine the destination of such molecules in vivo and especially if they can pass the blood brain barrier. The aim of this paper is to study whether carbazoles could pass the blood brain barrier, i.e. if they can circumvent ATP Binding Cassette (ABC) transporters such as P-glycoprotein (P-gp) and Multidrug Resistance-associated protein (MRP1) which efficiently limit drug brain uptake. For this purpose we have synthesized a fluorescent derivative of carbazole benzothiazolium iodide 1,2 disubstituted ethylene (referred as carbazole thiazole: CT), which can be easily detected and followed in the pre-trial study phases in cells or in tissue. We use cellular models overexpressing P-gp and MRP1. Our results show that: i) CT is able to cross membranes and to penetrate rapidly inside the cells, ii) CT is a P-gp substrate and consequently its accumulation in P-gp overexpressing cells is very low, iii) CT is a poor MRP1 substrate. In addition once inside the cells, CT rapidly binds to DNA and is then slowly reduced by intracellular reducing agents. In conclusion, the efficiency of carbazole derivatives in inhibiting the beta-amyloid formation in vivo could be highly compromised because, as P-gp substrates, they will probably not cross the blood brain barrier.

Synthesis of New Anthracene Derivatives

An efficient synthesis is described for hexabromoanthracenes 3 and 4 by direct bromination of 9,10-dibromoanthrecene 2. Whereas base-induced elimination of hexabromide 3 with t-BuOK gave 2,3,9,10-tetrabromoanthracene 5, the reaction of hexabromide 4 with DBU afforded 1,3,9,10-tetrabromoanthracene 6 as the sole product. Tetrabromide 5 was also obtained by aromatization of 1,4-dinitroxy-2,3,9,10-tetrabromo-1,2,3,4-tetrahydroanthracene 17. Efficient and convenient synthetic routes are described for the preparation of dinotroxy 17, dimethoxy 23, and dihydroxides 18 and 19 with silver-induced substitution of hexabromides 3 and 4. The hydroxy compounds 19 and 18 were converted to diepoxide 20 and monoepoxide 21, respectively, with sodium methoxide. Base-promoted aromatization of dimethoxide 23 afforded dibromomonomethoxides 26 and 27. Bromoanthracenes and isomeric arene oxides constitute valuable precursors for the preparation of functionalized substituted anthracene derivatives that are difficult to prepare by other routes.