Chemical characterization of the antioxidant, antihyperglycemic and antihypertensive capacities of red rice (Oryza sativa L. ) whole flour / Caracteristicas físico-químicas, capacidad antioxidante, anti-hiperlucémica y antihipertensiva de la harina de arroz rojo (Oryza sativa L. )

Oryza sativa L. rice has large amounts of proteins and minerals, besides presenting several pigmented varieties. Red rice is distinguishable due to its great nutritional value compared to the regular white variety. Its red pericarp pigmentation is due to the bioactive compounds that are responsible for its health benefits. The objective of this study was to evaluate the physical-chemical characterization, antioxidant, antihyperglycemic and antihypertensive capacity of flours of three different red rice cultures (Rubi, Virgínia and Pequeno). All samples presented specific levels of carbohydrates for cereals with low fat content and excellent levels of protein and resistant starch. In addition, the samples had a high antioxidant, antihyperglycemic and antihypertensive capacity. Antihyperglycemic capacities were measured as percent inhibition for amylase (56.7-76.5%) and glycosidase (81.0-76.6%), respectively, and antihypertensive capacity as the percentage inhibition of the angiotensin converting enzyme (38.4-34.7%). In addition, Pequeno flour presented the best results for antioxidant and antihyperglycemic capacity in comparison to the two flours tested. Thus, all red rice flours can be a source of functional compounds when added to food.

El arroz integral (Oryza sativa L.) posee importantes cantidades de proteínas, vitaminas, minerales y fitoquímicos. El arroz rojo se destaca por su gran valor nutricional. La pigmentación roja del pericarpio está asociado al contenido de compuestos bioactivos, que están directamente relacionados a los beneficios de salud humana. Teniendo en cuenta lo antes expuesto se propuso evaluar las caracteristicas físico-químicas, capacidad antioxidante, anti-hiperglucémica y antihipertensiva de las harinas de tres diferentes cultivos de arroz rojo (Rubí, Virginia y Pequeño). Todas las muestras presentaron niveles específicos de carbohidratos para cereales con bajo contenido de grasa y altos contenidos de proteína y almidón resistente. Además, las muestras presentaron una alta capacidad antioxidante, anti-hiperglucémica y antihipertensiva. La capacidad anti-hiperglicémica se midió en porcentaje de inhibidores de α-amilasa (56.7-76.5%) y α-glucosidasa (81.0-76.6%), respectivamente; y capacidad antihipertensiva como el porcentaje de inhibición de la enzima convertidora de la angiotensina (38.4-34.7%). El cultivar Pequeño presentó mayor capacidad antioxidante y anti-hiperglucémica en comparación a los demás cultivares. Así, todas las harinas de arroz rojo pueden ser vehículos de compuestos funcionales en los alimentos.

HPLC method development for the simultaneous analysis of amlodipine and valsartan in combined dosage forms and in vitro dissolution studies

A simple, rapid and reproducible HPLC method was developed for the simultaneous determination of amlodipine and valsartan in their combined dosage forms, and for drug dissolution studies. A C18 column (ODS 2, 10 μm, 200 x 4.6 mm) and a mobile phase of phosphate buffer (pH 3.6 , 0.01 mol L-1):acetonitrile: methanol (46:44:10 v/v/v) mixture were used for separation and quantification. Analyses were run at a flow-rate of 1 mL min-1 and at ambient temperature. The injection volume was 20 μL and the ultraviolet detector was set at 240 nm. Under these conditions, amlodipine and valsartan were eluted at 7.1 min and 3.4 min, respectively. Total run time was shorter than 9 min. The developed method was validated according to the literature and found to be linear within the range 0.1 - 50 μg mL-1 for amlodipine, and 0.05 - 50 μg mL-1 for valsartan. The developed method was applied successfully for quality control assay of amlodipine and valsartan in their combination drug product and in vitro dissolution studies.

Desenvolveu-se método de HPLC rápido e reprodutível para a determinação simultânea de anlodipino e valsartana em suas formas de associação e para os estudos de dissolução dos fármacos. Utilizaram-se coluna C18 (ODS 2, 10 μm, 200 x 4,6 mm) e fase móvel tampão fosfato (pH 3,6, 0,01 mol L-1):acetonitrila: metanol para a separação e a quantificação. As análises foram efetuadas com velocidade de fluxo de 1 mL min-1 e à temparatura ambiente O volume de injeção foi de 20 μL e utilizou-se detector de ultravioleta a 240 nm. Sob essas condições, anlodipino e valsartana foram eluídas a 7,1 min e 3,4 min, respectivamente. O tempo total de corrida foi menor que 9 min. O método desenvolvido foi validado de acordo com a literatura e se mostrou linear na faixa de 0,1-50 μg mL-1 para anlodipino e de 0,05-50 μg mL-1 para valsartana. O método desenvolvido foi aplicado com sucesso para ensaios de controle de qualidade de associações de anlodipino e valsartana e nos estudos de dissolução in vitro.

[Separation and assay of some methyl biphenyl derivatives used as angiotensin II antagonists and antihypertensives by using high performance liquid chromatography reversed phase]

Angiotensin II antagonists are major development in hypertension management in over decade, because of their excellent lower side effects and their specific action, as well as their effectiveness. So the research purposed to develop HPLC reserved phase for separation and assay of some angiotensin II antagonists, Valsartan, Losartan and Irbesartan in, raw materials and tablets. Chromatographic separation was achieved on coloun C18 using isocratic elution [at flow rate 1.5 ml/min] by using 10 mM potassium dihydrogen, phosphate buffer [pH=3] and acetonetrile [60: 40 v/v] as the mobile phase and ultraviolet detector set at 254 nm. This method had been validated and accepted, then this method had applied on human serums after using solid-liquid extraction for determination therapeutic concentrations of valsartan in group of patients treated with it

S-metoprolol: the 2008 clinical review.

Metoprolol is a widely used cardioselective beta-blocker. However, like all other beta-blockers it is also a racemic mixture of R- and S- isomers. The beta 1 blocking activity (cardioselectivity) of metoprolol resides in S-isomer while R-isomer exhibits beta 2 blocking activity. As both these isomers have different pharmacological properties, racemic metoprolol can be considered a combination of two different drugs in a fixed 1:1 ratio. The needless administration of the non beta-blocking R-enantiomer that makes up 50% of racemate actually puts the patient at an increased risk of side-effects, drug interactions and loss of cardioselectivity with up-titration of dosing. Clinical experience with chirally pure S-metoprolol at half the dose of racemate has shown it to be as effective as racemate in the treatment of patients with hypertension and angina. S-metoprolol has been shown to be effective and well-tolerated in patients with coexisting diabetes, COPD, and hyperlipidaemia. This confirms higher cardioselectivity of S-metoprolol in clinical settings. Less interaction potential of S-metoprolol compared to R-isomer further makes it a sensible choice in patients taking CYP2D6 inhibitors or in patients with heart failure or hepatic insufficiency. This article reviews differing properties of two isomers of metoprolol with focus on clinical experience with S-metoprolol.

Synthesis and evaluation of novel phenacyl based carboxamide derivatives of piperidine as antihypertensive agents

The research in the field of piperidine has generally been related to the synthesis of useful medicinal drugs. In view of the pharmacological and medicinal importance of piperidine derivatives in different disciplines of medicines the present study has been carried out. A series of newly synthesized N-substituted phenacyl piperidine derivatives [II-VII and XIII-XIV] has been evaluated for hypotensive activity in normotensive anesthetized rats at the doses of 0.5 micro g/kg taking acetylcholine and noradrenaline [1 micro g/kg] as control. Mean arterial blood pressure and heart rate were compared to its respective control values obtained immediately before the administration of test compounds and expressed as percent change. The compounds II, III and XIV showed mild hypertensive activity while compound V, VII and XIII were found inactive at that dose level. However, compound IV showed more hypotensive effect than the starting molecule [I]. None of these derivatives affected the heart rate at the same dose. It was also revealed that the carboxamide group has no considerable effects on arterial blood pressure and plays no important role in the increase or decrease of blood pressure

Using bradykinin-potentiating peptide structures to develop new antihypertensive drugs

Angiotensin I-converting enzyme (ACE) is a dipeptidyl-carboxypeptidase expressed in endothelial, epithelial and neuroepithelial cells. It is composed of two domains, known as N- and C-domains, and it is primarily involved in blood pressure regulation. Although the physiological functions of ACE are not limited to its cardiovascular role, it has been an attractive target for drug design due to its critical role in cardiovascular and renal disease. We examined natural structures based on bradykinin-potentiating peptides (BPPs) extracted from Bothrops jararaca venom for ACE inhibition. Modeling, docking and molecular dynamics were used to study the conserved residues in the S2’, S1’ and S1 positions that allow enzyme-substrate/inhibitor contacts. These positions are conserved in other oligopeptidases, and they form tight and non-specific contacts with lisinopril, enalapril and BPP9a inhibitors. The only specific inhibitor for human somatic ACE (sACE) was BPP9a, which is instable in the N-sACE-BPP9a complex due to repulsive electrostatic interactions between Arg P4-Arg 412 residues. Specificity for the C-terminal domain in human sACE inhibition was confirmed by electrostatic interaction with the Asp 1008 residue. Peptide-like BPP structures, naturally developed by snakes across millions of years of evolution, appear to be good candidates for the development of domain-selec tive ACE inhibitors with high stability and improved pharmacological profiles.