Vascular response of ruthenium tetraamines in aortic ring from normotensive rats.

Background: Ruthenium (Ru) tetraamines are being increasingly used as nitric oxide (NO) carriers. In this context, pharmacological studies have become highly relevant to better understand the mechanism of action involved.

Objective: To evaluate the vascular response of the tetraamines trans-[Ru(II)(NH3)4(Py)(NO)](3+), trans-[Ru(II)(Cl)(NO) (cyclan)](PF6)2, and trans-[Ru(II)(NH3)4(4-acPy)(NO)](3+).

Light-triggered and cysteine-mediated nitric oxide release from a biodegradable starch-based film.

A new nitric oxide-releasing material produced with cassava starch is described. The ruthenium nitrosyl complex trans-[Ru(NH)(isn)NO](BF) (RuNOisn; isn = isonicotinamide) is able to release NO upon either photolysis or chemical reduction. Impregnating this complex under mild conditions into cassava starch (CS) films produced a NO-delivery platform (CS-RuNOisn).

A fluorescence-based method for cyanate analysis in ethanol/water media: correlation between cyanate presence and ethyl carbamate formation in sugar cane spirit.

Unlabelled: Based on the fluorescence properties of 2,4-(1H,3H)-quinazolinedione, a product of the reaction between cyanate and 2-aminobenzoic acid, a simple, sensitive, selective, and reproducible method for the cyanate analysis in aqueous ethanolic media is proposed. In this method, λ(exc) and λ(em) are 310 and 410 nm, respectively, and the limits of detection and quantification are 2.2 × 10(-7) and 6.

Biological activity of ruthenium nitrosyl complexes.

Nitric oxide plays an important role in various biological processes, such as neurotransmission, blood pressure control, immunological responses, and antioxidant action. The control of its local concentration, which is crucial for obtaining the desired effect, can be achieved with exogenous NO-carriers. Coordination compounds, in particular ruthenium(III) and (II) amines, are good NO-captors and -deliverers.

Nitrosyl induces phosphorous-acid dissociation in ruthenium(II).

The trans-[Ru(NO)(NH(3))(4)(P(OH)(3))]Cl(3) complex was synthesized by reacting [Ru(H(2)O)(NH(3))(5)](2+) with H(3)PO(3) and characterized by spectroscopic ((31)P-NMR, δ = 68 ppm) and spectrophotometric techniques (λ = 525 nm, ε = 20 L mol(-1) cm(-1); λ = 319 nm, ε = 773 L mol(-1) cm(-1); λ = 241 nm, ε = 1385 L mol(-1) cm(-1); ν(NO(+)) = 1879 cm(-1)). A pK(a) of 0.74 was determined from infrared measurements as a function of pH for the reaction: trans-[Ru(NO)(NH(3))(4)(P(OH)(3))](3+) + H(2)O ⇌ trans-[Ru(NO)(NH(3))(4)(P(O(-))(OH)(2))](2+) + H(3)O(+).

Formation of dextran deposits in Brazilian sugar cane spirits.

The formation of dextran deposits in sugared Brazilian cachaça was studied as a function of the time considering the effects of temperature, molecular weight (M(w)), visible light, pH, and the presence of Ca, Mg, Cu, and Fe ions in the concentrations at which they are usually present in this beverage. At 25 °C and pH 4.4, the experimental half-lives (t(1/2)) for precipitation are 73 and 124 days for dextrans with M(w) 5.

Antileishmanial activity of ruthenium(II)tetraammine nitrosyl complexes.

The complexes trans-[Ru(NO)(NH(3))(4)L](X)(3) (X = BF(4)(-), PF(6)(-) or Cl(-) and L = N-heterocyclic ligands, P(OEt)(3), SO(3)(-2)), and [Ru(NO)Hedta)] were shown to exhibit IC(50pro) in the range of 36 (L = imN) to 5000 microM (L = imC). The inhibitory effects of trans-[Ru(NO)(NH(3))(4)imN](BF(4))(3) and of the Angeli's salt on the growth of the intramacrophage amastigote form studied were found to be similar while the trans-[Ru(NH(3))(4)imN(H(2)O)](2+) complex was found not to exhibit any substantial antiamastigote effect. The trans-[Ru(NO)(NH(3))(4)imN](BF(4))(3) compound, administered (500 nmol kg(-1) day(-1)) in BALB/c mice infected with Leishmania major, was found to exhibit a 98% inhibition on the parasite growth.

Novel ruthenium complexes as potential drugs for Chagas's disease: enzyme inhibition and in vitro/in vivo trypanocidal activity.

Background And Purpose: The discovery of the pharmacological functions of nitric oxide has led to the development of NO donor compounds as therapeutic agents. A new generation of ruthenium NO donors, cis-[Ru(NO)(bpy)(2)L]X(n), has been developed, and our aim was to show that these complexes are able to lyse Trypanosoma cruzi in vitro and in vivo.

Experimental Approach: NO donors were incubated with T.

Coumarins and phenolic fingerprints of oak and Brazilian woods extracted by sugarcane spirit.

A total of 25 sugarcane spirit extracts of six different Brazilian woods and oak, commonly used by cooperage industries for aging cachaça, were analyzed for the presence of 14 phenolic compounds (ellagic acid, gallic acid, vanillin, syringaldehyde, synapaldehyde, coniferaldehyde, vanillic acid, syringic acid, quercetin, trans-resveratrol, catechin, epicatechin, eugenol, and myricetin) and two coumarins (scopoletin and coumarin) by HPLC-DAD-fluorescence and HPLC-ESI-MS(n). Furthermore, an HPLC-DAD chromatographic fingerprint was build-up using chemometric analysis based on the chromatographic elution profiles of the extracts monitored at 280 nm. Major components identified and quantified in Brazilian wood extracts were coumarin, ellagic acid, and catechin, whereas oak extracts shown a major contribution of catechin, vanillic acid, and syringaldehyde.

Complexation of the anti-Trypanosoma cruzi drug benznidazole improves solubility and efficacy.

The ruthenium complex, trans-[Ru(Bz)(NH 3) 4SO 2](CF 3SO 3) 2 1, Bz = benznidazole ( N-benzyl-2-(2-nitro-1 H-imidazol-1-yl)acetamide), is more hydrosoluble and more active (IC 50try/1 h = 79 +/- 3 microM) than free benznidazole 2 (IC 50try/1 h > 1 mM). 1 also exhibits low acute toxicity in vitro (IC 50macrophages > 1 mM) and in vivo (400 micromol/kg < LD 50 < 600 micromol/kg) and the formation of hydroxylamine is more favorable in 1 than in 2 by 9.6 kcal/mol.

Chemical profile of rums as a function of their origin. The use of chemometric techniques for their identification.

To identify chemical descriptors to distinguish Cuban from non-Cuban rums, analyses of 44 samples of rum from 15 different countries are described. To provide the chemical descriptors, analyses of the the mineral fraction, phenolic compounds, caramel, alcohols, acetic acid, ethyl acetate, ketones, and aldehydes were carried out. The analytical data were treated through the following chemometric methods: principal component analysis (PCA), partial least square-discriminate analysis (PLS-DA), and linear discriminate analysis (LDA).

Influence of type of distillation apparatus on chemical profiles of brazilian cachaças.

Brazilian cachaças (115 samples; 73 samples derived from distillation in copper pot stills, 42 samples derived from distillation in stainless steel columns), collected directly at the producers, were analyzed for the contents of 34 constituents by chromatography, inductively coupled plasma optical emission spectrometry, and atomic absorption spectrometry. The analytical data were subjected to principal component analysis (PCA) and linear discriminant analysis (LDA). The PCA treatment led to discrimination of the two groups of cachaças, explaining 65.

Electrochemical and spectrophotometric methods for evaluation of NO dissociation rate constants from nitrosyl metal complexes activated through reduction.

Electrochemical and spectrophotometric methods are described for measuring the rate of nitric oxide (NO) dissociation (k(NO)) from coordination compounds. Electrochemical methods based on double-potential step chronoamperometry and rotating ring-disc electrode voltammetry techniques proved to be suitable for measuring NO dissociation from 0.03 to 4.

The [Ru(Hedta)NO](0.1-) system: structure, chemical reactivity and biological assays.

The [Ru(II)(Hedta)NO(+)] complex is a diamagnetic species crystallizing in a distorted octahedral geometry, with the Ru-N(O) length 1.756(4) A and the RuNO angle 172.3(4) degrees .

Reactivity of radicals generated on irradiation of trans-[Ru(NH3)4(NO2)P(OEt)3](PF6).

The electronic absorption spectrum of trans-[Ru(NH(3))(4)(NO(2))(P(OEt)(3)](+) in aqueous solution is characterized by a strong absorption band at 334 nm (lambda(max) = 1800 mol(-1) L cm(-1)). On the basis of quantum mechanics calculations, this band has been assigned to a MLCT transition from the metal to the nitro ligand. Molecular orbital calculations also predict an LF transition at 406 nm, which is obscured by the intense MLCT transition.

A new inorganic vasodilator, trans-[Ru(NO)(NH(3))(4)(POEt)(3)](PF(6))(3): hypotensive effect of endothelium-dependent and -independent vasodilators in different hypertensive animals models.

The hypotensive effect of RuNO was investigated in acute and chronic hypertensive rats, as well as in normotensive rats. Acute hypertension rats were used with 30% increase on basal BP (phenylephrine, angiotensin II (Ang II), N(G)-nitro-L-arginine methyl ester (L-NAME), and adult spontaneously hypertensive rats (SHR) (basal BP 168 +/- 3 mm Hg) were used as models for chronic hypertension. Rats were implanted with catheters (iv/ia) for BP measurements and for in bolus administration of RuNO, sodium nitroprusside (SNP), and acetylcholine (Ach) (10, 20, 40 nmol/kg, iv).

Release of NO by a nitrosyl complex upon activation by the mitochondrial reducing power.

The reaction of trans-[Ru(NH(3))(4)P(OEt)(3)NO](3+) and mitochondria was investigated through differential pulse polarography and fluorimetry. The nitrosyl complex undergoes one-electron reduction centered on the NO ligand site. The reaction between the mitochondrial reductor and trans-[Ru(NH(3))(4)P(OEt)(3)NO](3+) exhibits a second order specific rate constant calculated as k=2 x 10(1) M(-1) s(-1).

Hypotensive properties and acute toxicity of trans-[Ru(NH(3))(4)P(OEt)(3)(NO)](PF(6))(3), a new nitric oxide donor.

The hypotensive effect and the acute toxicity of trans-[Ru(NH(3))(4)P(OEt)(3)(NO)](PF(6))(3) (RuNO) were investigated in conscious animals. The approximate lethal dose of RuNO is 257.5 micromol/kg in mice i.