Synthesis, characterization and potent DNA-cleaving activity of copper(II)-complexed berberine carboxylate

Targeting an Artificial Metal Nuclease to DNA by a Simple Chemical Modification and Its Drastic Effect on Catalysis

A novel metal complex was synthesized containing a purine derived ligand in order to increase its binding to DNA. We observed a huge increase in nuclease activity and, quite interestingly, an improvement on DNA sequence selectivity. A potential site of specific cleavage in the presence of a reductant in the reaction medium is suggested. We were able to synthesize a novel metal nuclease with improved activity on DNA, and with sequence specificity when exposed to a coreactant, this opens up new possibilities to create site specific and redox status modulated artificial nucleases.

A novel berberine-based colorimetric and fluorimetric probe for hydrazine detection

Hydrazine in water and soil has caused serious diseases for human health. In this work, a simple fluorescent probe (BP) for hydrazine detection was synthesized from berberine. The probe has excellent fluorescence properties and naked-eye detection.

Lanthanum-Based Metal-Organic Frameworks for Specific Detection of Sudan Virus RNA Conservative Sequences down to Single-Base Mismatch

Reactions of La(NO₃)₃·6H₂O with the polar, tritopic quaternized carboxylate ligands N-carboxymethyl-3,5-dicarboxylpyridinium bromide (H₃CmdcpBr) and N-(4-carboxybenzyl)-3,5-dicarboxylpyridinium bromide (H₃CbdcpBr) afford two water-stable metal-organic frameworks (MOFs) of {[La₄(Cmdcp)₆(H₂O)₉]}_n (1, 3D) and {[La₂(Cbdcp)₃(H₂O)₁₀]}_n (2, 2D). MOFs 1 and 2 absorb the carboxyfluorescein (FAM)-tagged probe DNA (P-DNA) and quench the fluorescence of FAM via a photoinduced electron transfer (PET) process. The nonemissive P-DNA@MOF hybrids thus formed in turn function as sensing platforms to distinguish conservative linear, single-stranded RNA sequences of Sudan virus with high selectivity and low detection limits of 112 and 67 pM, respectively (at a signal-to-noise ratio of 3). These hybrids also exhibit high specificity and discriminate down to single-base mismatch RNA sequences.

A zwitterionic 1D/2D polymer co-crystal and its polymorphic sub-components: a highly selective sensing platform for HIV ds-DNA sequences

Polymorphic compounds {[Cu(dcbb)₂(H₂O)₂]·10H₂O}_n (2, 1D chain), [Cu(dcbb)₂]_n (3, 2D layer) and their co-crystal {[Cu(dcbb)₂(H₂O)][Cu(dcbb)₂]₂}_n (4) have been prepared from the reaction of [Na(dcbb)(H₂O)]_n (1) with Cu(NO₃)₂·3H₂O at different temperatures.

Highly selective, sensitive and fluorescent sensing of dimeric G-quadruplexes by a dimeric berberine

This paper describes the highly selective, sensitive and topology-specific fluorescent sensing of dimeric G-quadruplexes by a polyether-tethered dimeric berberine.

Five water-soluble zwitterionic copper(ii)-carboxylate polymers: role of dipyridyl coligands in enhancing the DNA-binding, cleaving and anticancer activities

Five water-soluble zwitterionic copper-carboxylate polymers were prepared and their DNA-binding, cleaving and anticancer activities were studied.

Lanthanide-Based Polymers with Charged Ligand Backbones: Triple-Stranded Chain Structures and their DNA Cleavage Studies

Four rare-earth metal complexes, [Ln(Ccbp)3(H2O)3]n (Ln = La (1), Ce (2), Pr (3) and Nd (4)) are synthesised from the ligand H2CcbpBr (H2CcbpBr = 4-carboxy-1-(4-carboxybenzyl)pyridinium bromide) and the respective lanthanide metal ions. Complexes 1–4 are isostructural in that every three Ccbp– ligands juxtapose two Ln3+ ions in a monodentate coordination mode to form triple-stranded one-dimensional chain structures. Each central Ln3+ atom further associates with three H2O molecules, furnishing a monocapped square-antiprism geometry. Agarose gel electrophoresis studies indicate that 1–4 are capable of cleaving DNA in the presence of H2O2, most probably via an oxidative cleavage mechanism. Complexes 1 and 2 exhibited catalytic efficiencies (kmax/KM) of 37.69 and 34.11 h–1 mM–1, and are approx. 15- and 20-fold more effective than those of complexes 3 (kmax/KM = 1.75 h–1 mM–1) and 4 (kmax/KM = 2.21 h–1 mM–1).

Berberine alters epigenetic modifications, disrupts microtubule network, and modulates HPV-18 E6-E7 oncoproteins by targeting p53 in cervical cancer cell HeLa: a mechanistic study including molecular docking

Increased evidence of chemo-resistance, toxicity and carcinogenicity necessitates search for alternative approaches for determining next generation cancer therapeutics and targets. We therefore tested the efficacy of plant alkaloid berberine on human papilloma virus (HPV) -18 positive cervical cancer cell HeLa systematically-involving certain cellular, viral and epigenetic factors. We observed disruptions of microtubule network and changes in membrane topology due to berberine influx through confocal and atomic force microscopies (AFM). We examined nuclear uptake, internucleosomal DNA damages, mitochondrial membrane potential (MMP) alterations and cell migration assays to validate possible mode of cell death events. Analytical data on interactions of berberine with pBR322 through fourier transform infrared (FTIR) and gel migration assay strengthen berberine׳s biologically significant DNA binding abilities. We measured cellular uptake, DNA ploidy and DNA strand-breaks through fluorescence activated cell sorting (FACS). To elucidate epigenetic modifications, in support of DNA binding associated processes, if any, we conducted methylation-specific restriction enzyme (RE) assay, methylation specific-PCR (MSP) and expression studies of histone proteins. We also analyzed differential interactions and localization of cellular tumor suppressor p53 and viral oncoproteins HPV-18 E6-E7 through siRNA approach. We further made in-silico approaches to determine possible binding sites of berberine on histone proteins. Overall results indicated cellular uptake of berberine through cell membrane depolarization causing disruption of microtubule networks and its biological DNA binding abilities that probably contributed to epigenetic modifications. Results of modulation in p53 and viral oncoproteins HPV-18 E6-E7 by berberine further proved its potential as a promising chemotherapeutic agent in cervical cancer.

Synthesis, hydrolytic DNA-cleaving activities and cytotoxicities of EDTA analogue-tethered pyrrole-polyamide dimer-based Ce(IV) complexes

Two EDTA analogue-tethered C2-symmetrical dimeric monopyrrole-polyamide 5 and dipyrrole-polyamide 6, and their corresponding Ce(IV) complexes Ce-5 and Ce-6 were synthesized and fully characterized. Agarose gel electrophoresis studies on pBR322 DNA cleavage indicate that complexes Ce-5 and Ce-6 exhibited potent DNA-cleaving activities under physiological conditions. The maximal first-order rate constants (kmax's) were (0.42 ± 0.02) h(-1) for Ce-5 and (0.52 ± 0.02) h(-1) for Ce-6, respectively, suggesting that both complexes catalyzed the cleavage of supercoiled DNA by up to approximately 10(8)-fold. Complex Ce-6 exhibited ca 10-fold higher overall catalytic activity (kmax/KM) than Ce-5, which may be ascribed to its higher DNA-binding affinity. Inhibition experiments and a model study convincingly suggest that both complexes Ce-5 and Ce-6 functioned as hydrolytic DNA-cleavers. In addition, both complexes were found to display moderate inhibitory activity toward A549 and HepG-2 cells.