New amino and acetamido monomethine cyanine dyes for the detection of DNA in agarose gels

Synthesis, modelling, and solvatochromic properties of a phenothiazine derivative

A new A-π-D-π-A phenothiazine derivative, 2,2'-((10-octyl-10H-phenothiazine-3,7-diyl)bis (ethene-2,1-diyl))bis(1-ethyl-3,3-dimethyl-3H-indol-1-ium)iodide (PTZ-BEI) was prepared and fully characterized using infra-red (IR), ¹ H nuclear magnetic resonance (NMR), ¹³ C NMR, ultraviolet-visible light and mass spectra. Electronic spectra of PTZ-BEI solutions in solvents with different polarities displayed absorption bands (λ_max ) related to intramolecular charge transfer. In addition, the emission spectra of PTZ-BEI solutions were strongly solvent dependent for both wavelength and intensity. Stokes' shift ( Δ ν ¯ ) increased with increasing solvent polarity up to 4105 cm^-1 in the most polar solvent, dimethylformamide. The linear solvation-energy relationship was utilized to investigate solvent dependency of the Stokes' shifts. Relative quantum yield (φ) of PTZ-BEI was calculated. Finally, density functional theory was employed at the B3LYP level for geometrical optimization and simulation of electron spectra for the PTZ derivative in gaseous and solvated states to explore the solvent effect.

A New Organic Dye-Based Staining for The Detection of Plant DNA in Agarose Gels

Ethidium bromide (EtBr) is used to stain DNA in agarose gel electrophoresis, but this dye is mutagenic and carcinogenic. We investigated N-719, which is a visible, reliable and organic Ruthenium-based dye, and five fluorescent alternatives for staining plant DNA. For prestaining and poststaining, N-719, GelRed, and SYBR Safe stained both DNA and PCR product bands as clearly as EtBr. SYBR Green I, methylene blue, and crystal violet were effective for poststaining only. The organic dye N-719 stained DNA bands as sensitively and as clearly as EtBr. Consequently, organic dyes can be used as alternatives to EtBr in plant biotechnology studies.

Antimalarial activity of 4-amidinoquinoline and 10-amidinobenzonaphthyridine derivatives

Chloroquine (CQ) has been used as first line malaria therapeutic drug for decades. Emergence of CQ drug-resistant Plasmodium falciparum malaria throughout endemic areas of the world has limited its clinical value. Mefloquine (MQ) has been used as an effective malaria prophylactic drug due to its being long-acting and having a high potency against blood stage P. falciparum (Pf). However, serious CNS toxicity of MQ has compromised its clinical value as a prophylaxis drug. Therefore, new and inexpensive antimalarial drugs with no cross-resistance to CQ or CNS toxicity are urgently needed to combat this deadly human disease. In this study, a series of new 4-amidinoquinoline (4-AMQ) and 10-amidinobenzonaphthyridine (10-AMB) derivatives were designed, prepared, and assessed to search for new therapeutic agents to replace CQ and MQ. The new derivatives displayed high activity in vitro and in vivo, with no cross-resistance to CQ, and none were toxic in mice up to 160 mpk × 3. The best compound shows IC50 < 1 ng/mL against D6, W2 and C235 Pf clones, low inhibitory activity in hERG K(+) channel blockage testing, negativity in the Ames test, and 5/5 cure @ <15 mpk × 3 in mice infected with Plasmodium berghei. In addition to these desirable pharmacological profiles, compound 13b, one of the most active compounds, is metabolically stable in both human and mouse liver microsomal preparations and has a plasma t(1/2) of 50 h in mice, which made it a good MQ replacement candidate.

Study on synthesis and spectrum of novel styryl cyanine dyes with a carbazole bridged chain

Based on the frequently-used cyanine dye probe thiazole orange (TO), a novel kind of cyanine dye was designed and synthesized. Carbazole was inserted into the methylidyne structure of TO as a bridge to afford a kind of novel styryl cyanine dye with carbazole bridged chain. The dyes were characterized by HNMR and MS. The spectra of the novel dyes were also studied and the results showed that the fluorescent wavelength of novel carbzole dye shifted red for 100 nm, stock shift increased by 70 nm and the fluorescent intensity enhanced by 70 times compared to that of TO. When the novel dye was labeled by BSA, its fluorescent wavelength changed little and the intensity enhanced. It is indicated that it can be used as an excellent fluorescent probe in biological labeling.

Synthesis of a new beta-naphthothiazole monomethine cyanine dye for the detection of DNA in aqueous solution

Novel monomethine cyanine dye (MC) derived from beta-naphthothiazole and benzothiazole has been prepared and characterized by (1)H and (13)C NMR, FTIR, ESIMS, elemental analyses, absorption and fluorescence spectroscopy. The dye was conveniently synthesized by the condensation of two sulfate heterocyclic quaternary salts. The interaction between calf thymus DNA (ct-DNA) in tris(hydroxymethyl)aminomethane-HCl (Tris-HCl) aqueous buffer solution and MC has been studied with spectral fluorescence method. The binding constant value has been determined by fluorescence titration of MC with ct-DNA concentrations. The result obtained is consistent with an intercalative binding interaction between MC and ct-DNA. Compared with ethidium bromide (EB), MC showed a huge fluorescence enhancement upon mixing with ct-DNA.