Carbazole-based fluorescent probes for G-quadruplex DNA targeting with superior selectivity and low cytotoxicity

G-quadruplex DNA plays a very important role in clinical diagnosis and fluorescence analysis has attracted extensive attention. A class of carbazole-based fluorescent probes for the detection of G-quadruplex DNA was established in this work. In this system, the installation of an oligo(ethylene glycol) chain on the scaffold will improve the water-solubility and biocompatibility. The presence of styrene-like different side groups could tune the selectivity toward G-quadruplex DNA binding. Results revealed that the substitution pattern and position gave a great influence on the ability for the discrimination of the G-quadruplex from other DNA structures. Especially, probe E1 bound to G-quadruplex DNA with superior selectivity, which exhibiting almost no fluorescence response in the presence of non-G-quadruplex DNA structures. Comprehensive analyses revealed that E1 could bind both ends of the G-quadruplex, resulting in a significant increase of fluorescence emission intensity. Cellular uptake assay suggested that E1 could pass through membrane and enter living cells with low cytotoxicity.     

Synthesis,antimicrobial activity and cytotoxicity of some new carbazole derivatives

In this work, some N-(9-Ethyl-9H-carbazole-3-yl)-2-(phenoxy)acetamide derivatives were synthesised and evaluated for their antimicrobial activity and cytotoxicity. The structural elucidation of the compounds was performed by IR, ¹H-NMR, ¹³C-NMR and FAB⁺-MS spectral data and elemental analyses. The title compounds were obtained by reacting 2-chloro-N-(9-ethyl-9H-carbazole-3-yl)acetamide with some substituted phenols. The synthesised compounds were investigated for their antibacterial and antifungal activities against Micrococcus luteus, Bacillus subtilis, Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, Listeria monocytogenes and Candida albicans. The compounds N-(9-Ethyl-9H-carbazole-3-yl)-2-(4-ethylphenoxy)acetamide (2c) and N-(9-Ethyl-9H-carbazole-3-yl)-2-(quinolin-8-yloxy)acetamide (2n) showed notable antimicrobial activity. The compounds were also studied for their cytotoxic effects using MTT assay, and it was seen that 2n had the lowest cytotoxic activity against NIH/3T3 cells.     

Degradation of carbazole and its derivatives by a Pseudomonas sp.

Carbazole, carbazoles with monomethyl or dimethyls substituted on different positions (C₁-carbazoles or C₂-carbazoles), and benzocarbazoles, as toxic and mutagenic components of petroleum and creosote contamination, were biodegradable by an isolated bacterial strain Pseudomonas sp. XLDN4-9. C₁-carbazoles were degraded in preference to carbazole and C₂-carbazoles. The biodegradation of C₁-carbazoles or C₂-carbazoles was influenced by the positions of methyl substitutions. Among C₁-carbazole isomers, 1-methyl carbazole was the most susceptible. C₂-carbazole isomers with substitutions on the same benzo-nucleus were more susceptible at a concentration of less than 3.4 μg g⁻¹ petroleum, especially when harboring one substitution on position 1. In particular, 1,5-dimethyl carbazole was the most recalcitrant dimethyl isomer.     

Novel carbazole sulfonamide derivatives of antitumor agent: Synthesis,antiproliferative activity and aqueous solubility

The current optimization of IG-105 (3) on the carbazole-ring provided a series of new carbazole sulfonamides derivatives 13a–13m. All of the compounds have been evaluated against HepG2 cells (hepatoma cancer) for antiproliferative activity. Compounds that showed activity better or comparable to that of 3 versus HepG2 were evaluated against MCF-7 (breast cancer), MIA PaCa-2 (pancreatic cancer), and Bel-7402 (hepatoma/liver cancer) for antiproliferative activity. Of the seven compounds selected for further study five (13b, 13g, 13j, 13k and 13l) were found to give IC₅₀ values against the four cell lines comparable to those for 3. Two compounds (13f and 13i) were more active than 3 and their activity against HepG2 and MCF-7 (IC₅₀:0.01–0.07 μM) approached that of the positive controls podophyllotoxin (podo) and CA-4. Most of compounds showed aqueous solubility (0.11–19.60 μg/mL at pH 7.4 and 2.0) better than 3. These promising results warrant further development of new compounds 13f and 13i as potential potent antitumor drug candidates.     

Synthesis and cytotoxicity evaluation of A-ring derivatives of cycloartanone

Sixteen derivatives, eight of which are new compounds, were prepared from cycloartenone (1) and cycloartanone (2), and the cytotoxic activity of 14 of these compounds, together with 1 and 2, was evaluated against a panel of four cell lines. Compound 1 was obtained from the epiphyte plant Tillandsia tenuifolia collected at Salta, Argentina. Due to chemoselectivity and regioselectivity problems observed in the reactions of compound 1, this substance was hydrogenated to compound 2. The attempted transformations were focused on ring A of the cited triterpenes with the aim to verify previous structure-activity relationships obtained from related compounds. The cytotoxicity results of the derivatives showed that only the diosphenol 13 displayed significant activity against all the tested cell lines. These results show that an oxidized side chain, for example an ether bridge between the side chain and ring D, is necessary for the cytotoxic activity of cycloartane derivatives.     

Synthesis, photoluminescence and electrochemiluminescence of ruthenium(II) polypyridyl complexes based on bipyridine derivatives with carbazole moieties

Six complexes (1-6) with the type of [Ru(bpy)₂L]X₂ (1-3: L = L1-L3, X = Cl⁻; 4-6: L = L1-L3, X = PF₆⁻) were synthesized based on 2,2′-bipyridine and three 2,2′-bipyridine derivatives L1, L2 and L3 (L1 = 5,5′-dibromo-2,2′-bipyridine, L2 = 5-bromo-5′-carbazolyl-2,2′-bipyridine, L3 = 5,5′-dicarbazolyl-2,2′-bipyridine). The complexes 1-6 were characterized by ¹H NMR, MS(ESI) and IR spectra, along with the X-ray crystal structure analysis for 1, 5 and 6. Their photophysical properties and electrochemiluminescence (ECL) properties were investigated in detail. In the UV-Vis absorption spectra, all complexes 1-6 show strong intraligand (π → π^∗) transitions and metal-ligand charge transfer (MLCT, dπ (Ru) → π^∗) bands. Upon the excitation wavelengths at ∼508 nm, all complexes 1-6 exhibit typical MLCT emission of ruthenium(II) polypyridyl complexes. The introduction of carbazole moieties improves the MLCT absorption and emission intensity. The ruthenium(II) complexes 1-6 exhibit good electrochemiluminescence (ECL) properties in [Ru(bpy)₂L]²⁺/tri-n-propylamine (TPrA) acetonitrile solution and the complexes with PF₆⁻ showed higher ECL emission intensity than that of the complexes with Cl⁻ based on the same ligands.     

New quaternary ammonium camphor derivatives and their antiviral activity,genotoxic effects and cytotoxicity

The synthesis and biological evaluation of a novel series of dimeric camphor derivatives are described. The resulting compounds were studied for their antiviral activity, cyto- and genotoxicity. Compounds 3a and 3d in which the quaternary nitrogen atoms are separated by the C5H10 and С9H18 aliphatic chain, exhibited the highest efficiency as an agent inhibiting the reproduction of the influenza virus A(H1N1)pdm09. The cytotoxicity data of compounds 3 and 4 revealed their moderate activity against malignant cell lines; compound 3f had the highest activity for the CEM-13 cells. These results show close agreement with the data of independent studies on toxicity of these compounds, in particular that the toxicity of compounds strongly depends on spacer length.     

Design,synthesis and cytotoxicity of cell death mechanism of rotundic acid derivatives

In the present investigation, 16 new rotundic acid (RA) derivatives modified at the C-3, C-23 and C-28 positions were synthesized. The cytotoxicities of the derivatives were evaluated against HeLa, A375, HepG2, SPC-A1 and NCI-H446 human tumor cell lines by MTT assay. Among these derivatives, compounds 4–7 exhibited stronger cell growth inhibitory than RA and compound 4 was found to be the best inhibition activity on five human tumor cell lines with IC₅₀ <10 μM. The apoptosis mechanism of compound 4 in HeLa cells was investigated by western blot analysis. The results indicated that compound 4 could induce apoptosis through increasing protein expression of cleaved caspase-3 and Bax, and decreasing protein expression of Bcl-2. In summary, the present work suggests that compound 4 might serve as an effective chemotherapeutic candidate.     

New derivatives of lupane triterpenoids disturb breast cancer mitochondria and induce cell death

Novel cationic dimethylaminopyridine derivatives of pentacyclic triterpenes were previously described to promote mitochondrial depolarization and cell death in breast and melanoma cell lines. The objective of this work was to further investigate in detail the mechanism of mitochondrial perturbations, correlating those effects with breast cancer cell responses to those same agents. Initially, a panel of tumor and non-tumor cell lines was grown in high-glucose or glucose-free glutamine-containing media, the later forcing cells to synthesize ATP by oxidative phosphorylation only. Cell proliferation, cell cycle, cell death and mitochondrial membrane polarization were evaluated. Inhibition of cell proliferation was observed, accompanied by an arrest in the G1-cell cycle phase, and importantly, by loss of mitochondrial membrane potential. On a later time-point, caspase-9 and 3 activation were observed, resulting in cell death. For the majority of test compounds, we determined that cell toxicity was augmented in the galactose media. To investigate direct evidences on mitochondria isolated rat liver mitochondria were used. The results showed that the compounds were strong inducers of the permeability transition pore. Confirming our previous results, this work shows that the novel DMAP derivatives strongly interact with mitochondria, resulting in pro-apoptotic signaling and cell death.     

Cytotoxicity of synthesized 1,4-naphthoquinone analogues on selected human cancer cell lines

In an effort to establish new candidates with enhanced anticancer activity of 5-hydroxy-7-methyl-1,4-naphthoquinone scaffold (7-methyljuglone) previously isolated from the root extract of Euclea natalensis, a series of 7-methyljuglone derivatives have been synthesized and assessed for cytotoxicity on selected human cancer lines. These compounds were screened in vitro for anticancer activity on MCF-7, HeLa, SNO and DU145 human cancer cell lines by MTT assay. Most of them exhibited significant toxicity on cancer cell lines with lower IC₅₀ values. The most potent derivative (19) exhibited the toxicity on HeLa and DU145 cell lines with IC₅₀ value of 5.3 and 6.8 μM followed by compound (5) with IC₅₀ value of 10.1 and 9.3 μM, respectively. Structure–activity relationship reveals that the fluoro substituents at position C-8 while hydroxyl substituents at C-2 and C-5 positions played an important role in toxicity.     

Design,synthesis and biological evaluation of 1,4-dihydroxyanthraquinone derivatives as anticancer agents

The novel hydroxyanthraquinone derivatives containing nitrogen-mustard and thiophene group were designed to covalently bind to topoisomerase II, and their structures were confirmed by nuclear magnetic resonance and high resolution mass spectrometer technologies in this article. The in vitro cytotoxicity against different cancer cell lines and one normal liver cell line (L02) was evaluated by MTT assay. Compound A1 was the most potent anti-proliferative agent against the human liver cancer HepG-2 cells (IC₅₀?=?12.5?μM), and there is no obvious growth inhibitory effect on normal liver tissue L02 cells. The good cytotoxicity and selectivity of compound A1 suggest that it could be a promising lead for further optimization. The mechanisms of action about compound A1 and A4 were further investigated through analysis of cell apoptosis. Confocal microscopy tracks the location of compound A1 in the cell, which could enter the cytoplasm and nucleus, and induce severe deformation of the nucleus. The docking study demonstrated that A1 could interact with the catalytic active site in topoisomerase II.     

Synthesis and biological evaluation of pyridinium-functionalized carbazole derivatives as promising antibacterial agents

Various pyridinium-functionalized carbazole derivatives were constructed by coupling the key fragments of carbazole skeleton and pyridinium nucleus in a single molecular architecture. Antibacterial bioassays revealed that some of the title compounds displayed impressive bioactivities against plant pathogens such as Xanthomonas oryzae pv. oryzae, Ralstonia solanacearum, and Xanthomonas axonopodis pv. citri with minimal EC₅₀ values of up to 0.4, 0.3, and 0.3 mg/L, respectively. These bioactivities were achieved by systematically tuning and optimizing bridging linker, alkyl length of the tailor, and substituents on the carbazole scaffold. Compared with the bioactivity of the lead compound (AP-10), antibacterial efficacy dramatically increased by approximately 13-, 104- and 21-fold. This finding suggested that these compounds can serve as new lead compounds in research on antibacterial chemotherapy.     

Design,synthesis and evaluation of carbazole derivatives as potential antimicrobial agents

Five series of novel carbazole derivatives containing an aminoguanidine, dihydrotriazine, thiosemicarbazide, semicarbazide or isonicotinic moiety were designed, synthesised and evaluated for their antimicrobial activities. Most of the compounds exhibited potent inhibitory activities towards different bacterial strains (including one multidrug-resistant clinical isolate) and one fungal strain with minimum inhibitory concentrations (MICs) between 0.5 and 16 µg/ml. Compounds 8f and 9d showed the most potent inhibitory activities (MICs of 0.5–2 µg/ml). Furthermore, compounds 8b, 8d, 8f, 8k, 9b and 9e with antimicrobial activities were not cytotoxic to human gastric cancer cell lines (SGC-7901 and AGS) or a normal human liver cell line (L-02). Structure–activity relationship analyses and docking studies implicated the dihydrotriazine group in increasing the antimicrobial potency and reducing the toxicity of the carbazole compounds. In vitro enzyme activity assays suggested that compound 8f binding to dihydrofolate reductase might account for the antimicrobial effect.     

Synthesis, growth inhibition, and cell cycle evaluations of novel flavonoid derivatives

As a continuation of our search for potential new anticancer agents, a series of ten flavonoid derivatives has been synthesized by cyclization of substituted chalcones. Target compounds were evaluated for their biological activity. Among them, compounds 1–4 and 9 displayed a significant growth inhibitory action against a panel of tumor cell lines including Jurkat, PC-3, and Colon 205. On treatment with an equitoxic (IC₅₀) concentration, compounds 1–5 and 7–9 blocked cells in the G2/M phase of the Jurkat cell cycle, whereas compound 6 blocked the same in the G0/G1 phase.     

DNA-binding affinity,cytotoxicity, apoptosis,cell cycle inhibition and molecular docking studies of a new stilbene derivative

Stilbene derivatives have been found to possess promising anticancer activities against human cancer cell lines in vitro. In the present study, we have investigated cytotoxic, apoptosis induction and DNA binding activity of new stilbene derivative, (E)-1-(4-Chlorophenyl)-4,5-diphenyl-2-[4-(4-methoxystryl)phenyl]-1H-imidazol (STIM) on K562 chronic myeloid leukemia cell line. Via MTT assay STIM demonstrated cytotoxic activity against K562 cell line with IC₅₀ value of 150?µM. Apoptosis, as the mechanism of cell death, was evaluated by morphological study and flow cytometric analysis. In vitro DNA binding property of STIM has been studied by vital spectroscopic techniques, which indicated that STIM interact with ctDNA through groove binding mode and binding constant (K_b) was estimated to be 6.9?×?10⁴?M^?1. Docking studies revealed that hydrophobic is the most important interaction in STIM-DNA complex, and that the ligand (STIM) interacts with DNA via groove binding mode and the bindiyspng energy was calculated as ?13.37?kcal/mol. Taken together, the present study suggests that STIM exhibits anticancer effect on K562 cell line through the induction of apoptosis as well as cell cycle arrest at Sub-G1 phase and also can bind to double helix DNA in vitro.     

Synthesis and cytotoxicity of 17a-aza-D-homo-androster-17-one derivatives

A series of 17a-aza-d-homo-andrester-17-one derivatives, bearing hydroxyl, hydroximino, carbonyl and thiosemicarbazido groups at the position-3 or position-6 of steroidal nucleus, were prepared and evaluated in vitro against two human cell lines (Hela (human cervical carcinoma) and SMMC 7404 (human liver carcinoma)). The results showed that these compounds could exhibit a high cytotoxicity to Hela tumor cell line, especially for compounds 8 and 12, the IC₅₀ values are 15.1 and 14.0 nmol/mL, respectively. Our findings could provide new evidence showing the relationship between the chemical structure and biological activity and may be useful for the discovery of new anti-cancer drugs.     

Synthesis,characterization, in vitro cytotoxicity and antimicrobial investigation and evaluation of physicochemical properties of novel 4-(2-methylacetamide)benzenesulfonamide derivatives

In this study, several sulfonamide derivatives, 4-(2-methylacetylamino)benzenesulfonamides were synthesized. Chemical structures of the derivatives were characterized by ¹H NMR, ¹³C NMR, LC–MS–MS, UV–Vis, FTIR, photoluminescence and elemental analysis. Sulfanilamide was reacted with 2-bromopropionyl bromide, in the presence of pyridine, to form bromo-substituted sulfonamide key intermediates, which were subsequently treated with secondary amines to obtain novel sulfonamide derivatives. All the synthesized compounds were evaluated for in vitro antimicrobial activities and cytotoxicity. Increases in ring size, and rings bearing a nitrogen heteroatom led to improvements in antimicrobial activities. As the presence of CA IX and CA XII enzymes have been implicated in some cancerous tumors, the studies presented herein focuses on targeting these enzymes. It was found that the synthesized derivatives had in vitro anti-cancer properties, where compounds (3–6) were found to be active against all cancerous cells, and no cytotoxic effects on normal cells were observed.     

微囊藻毒素LR诱导细胞毒性机制研究的细胞模型建立

以18种细胞系为材料,研究微囊藻毒素LR(20μg/mL和50μg/mL)所诱导的细胞毒性。形态观察表明,在经过30h以上的微囊藻毒素处理后,PC-3,J82,786-0,5637,VERO-E6等5种细胞出现了明显的细胞形态改变,毒素浓度越高,形态改变越厉害。微囊藻毒素LR的细胞毒性用LDH泄漏来表示。结果显示,5种毒素处理细胞的LDH泄漏呈剂量依赖性增加,其中5637和PC-3的LDH泄漏在同样的处理后较为厉害;同对照比较,SOD活力在20μg/mL MCLR处理下呈增加趋势,但在50μg/mL浓度下则下降;GSH含量在两种浓度处理下呈总体下降趋势。鉴于对微囊藻毒素敏感性差异分析,作者选择以5637细胞为基础,建立微囊藻毒素的毒理机制研究模型。       

Three new jacaranone derivatives from the aerial parts of Senecio chrysanoides DC. with their cytotoxic activity

Three new jacaranone derivatives, namely, (1R)-ethyl 1-hydroxy-4-oxo-2-cyclohexenylacetate (1), (1R, 6S)-ethyl 6-ethoxy-1-hydroxy-4-oxo-2-cyclohexenylacetate (2) and (1R, 6R)-ethyl 6-ethoxy-1-hydroxy-4-oxo-2-cyclohexenylacetate (3), along with a known jacaranone derivative, ethyl 1-hydroxy-4-oxocyclohexylacetate (4) were isolated from the aerial parts of Senecio chrysanoides DC.. Their structures were elucidated by spectroscopic methods, optical rotation calculations and CD analyses. All the isolated compounds were evaluated for their cytotoxicity against three human cancer cell lines in vitro. Compound 2 exhibited moderate inhibitory effects against these cancer cell lines.     

Design,synthesis and biological evaluation of new carbazole derivatives as anti-cancer and anti-migratory agents

Based on the efficacy of EHop-016 as an inhibitor of migration and Rac1 activation, a new series of carbazole derivatives has been synthesized. Cytotoxic and anti-migratory effects of these compounds were evaluated in MCF-7 and MDA-MB-231 breast cancer cell lines. Preliminary investigations of their anticancer activity demonstrated that several compounds have moderate antiproliferative effects on cancer cell lines with GI₅₀ values in the range of 13–50?µM. Furthermore, compounds 3b and 11b inhibit migration activity of metastatic cell line MDA-MB-231 by 32% and 34%, respectively. Compound 11b was shown to inhibit activation of the Rho GTPase Rac1 by 55% at 250?nM in both MDA-MB-231 and MDA-MB-435 cell lines. Compared with the IC₅₀ of Rac1 inhibition by lead compound EHop-016 of 1.1?µM, compound 11b demonstrates 4X improved in vitro efficacy.