Marcelo Augusto Vieira de Souza

Antihypertensive, vasodilator and antioxidant effects of a vinifera grape skin extract.

Cumulative evidence suggests that moderate wine consumption exerts a cardioprotective effect. We investigated the occurrence of an antihypertensive effect of an alcohol‐free hydroalcoholic grape skin extract (GSE) obtained from skins of a vinifera grape (Vitis labrusca) in experimental rodent hypertension models. The vasodilator effect of GSE (polyphenols concentration 55.5 mg g−1) was also assessed in the isolated mesenteric vascular bed of Wistar rats and the antioxidant effect was studied on lipid peroxidation of hepatic microsomes. Oral administration of GSE significantly reduced systolic, mean and diastolic arterial pressure in Wistar rats with desoxycorticosterone acetate‐salt and NG‐ nitro‐L‐arginine methyl ester (L‐NAME) induced experimental hypertension. In the rat isolated mesenteric vascular bed pre‐contracted with norepinephrine, bolus injections of GSE induced endothelium‐dependent vasodilatation that was substantially inhibited by L‐NAME, but not by indometacin, tetraethylammonium or glibenclamide. Lipid peroxidation of hepatic microsomes estimated as malondialdehyde production was concentration‐dependently inhibited by GSE. In conclusion, the antihypertensive effect of GSE might be owing to a combination of vasodilator and antioxidant actions of GSE. These findings also suggest that the beneficial effect of moderate red wine consumption could be owing to an antihypertensive action induced by compounds occurring in the skin of vinifera grapes.

Antihypertensive and endothelium-dependent vasodilator effects of Alpinia zerumbet, a medicinal plant.

Alpinia zerumbet (K. Schum), a medicinal plant originated from West Asia, is used in the northeast and southeast of Brazil as infusions or decoctions as a diuretic, antihypertensive, and antiulcerogenic. Experiments were undertaken to determine whether a hydroalcoholic extract obtained from leaves of Alpinia zerumbet (AZE) induces vasodilation in the mesenteric vascular bed (MVB), and an antihypertensive effect was also assessed in rats with DOCA-salt hypertension. In MVB precontracted with norepinephrine, AZE induces a long-lasting endothelium-dependent vasodilation that is not reduced by indomethacin. Inhibition of NO synthase by NG-nitro-L-arginine methyl ester (L-NAME) and guanylyl cyclase by 1H-[1,2,3]oxadiazolo [4,4-a]quinoxalin-1-one (ODQ) reduces the vasodilator effect of AZE. In vessels precontracted with norepinephrine, the vasodilator effect of AZE was not changed by 4-aminopyridine, glibenclamide, or by charybdotoxin plus apamin. Concentrations of atropine, pyrilamine, and yohimbine that significantly reduced the vasodilator effect of acetylcholine, histamine, and clonidine, respectively, did not change the vasodilator effect of AZE. HOE 140, which significantly reduced the vasodilator effect of bradykinin, induced a slight but significant reduction on the vasodilator effect of AZE. Chronic oral administration of AZE induced a significant reduction in systolic, mean, and diastolic arterial pressure in rats with DOCA-salt hypertension. Probably the vasodilator effect of AZE is dependent on the activation of the NO-cGMP pathway and independent of activation of ATP-dependent, voltage-dependent, and calcium-dependent K+ channels. Bradykinin receptors may also participate in the vasodilator effect of AZE. Finally, the vasodilator and antihypertensive effects of AZE demonstrated in the present study provide experimental support for the indication of Alpinia zerumbet as an antihypertensive medicinal plant.

Protective effect of Euterpe oleracea Mart (açaí) extract on programmed changes in the adult rat offspring caused by maternal protein restriction during pregnancy

This study examined the effect of açaí (Euterpe oleracea Mart.) seed extract (ASE) on cardiovascular and renal alterations in adult offspring, whose mothers were fed a low‐protein (LP) diet during pregnancy.

Effects of an extract obtained from fruits of Euterpe oleracea Mart. in the components of metabolic syndrome induced in C57BL/6J mice fed a high-fat diet.

Previously, we have demonstrated that the seed of Euterpe oleracea Mart. (açaí) from the Amazon region exerts vasodilator and antihypertensive actions. The aim of our study was to assess the effects of oral chronic treatment with açaí seed extract (ASE, 300 mg·kg−1·d−1) on high-fat (HF) diet-induced metabolic syndrome (MS) in C57BL/6J mice. Four groups of C57BL/6 mice were fed with control diet (10% fat), ASE (10% fat), HF (60% fat), and HF + ASE (60% fat plus ASE) for 12 weeks. The vasodilator effects of acetylcholine (ACh) and nitroglycerine (NG) were studied in perfused mesenteric arterial bed. Body weight, plasma total cholesterol, triglyceride, glucose and insulin levels, oral glucose tolerance test, and oxidative damage were determined, and the insulin resistance measured by Homeostatic Model Assessment (HOMA) index. Vasodilator response to ACh but not to NG was reduced in HF mice, and ASE restored the response. Increased plasma malondialdehyde levels, body weight, plasma triglyceride, total cholesterol, glucose levels, and insulin resistance were observed in HF mice and reduced by ASE. Treatment with ASE also reduced glucose intolerance observed by oral glucose tolerance test in HF mice. In conclusion, ASE protected C57BL/6J mice fed HF diet from phenotypic and metabolic characteristics of MS, providing an alternative nutritional resource for prevention of MS.

Antidiabetic effect of Euterpe oleracea Mart. (açaí) extract and exercise training on high-fat diet and streptozotocin-induced diabetic rats: A positive interaction

A growing body of evidence suggests a protective role of polyphenols and exercise training on the disorders of type 2 diabetes mellitus (T2DM). We aimed to assess the effect of the açaí seed extract (ASE) associated with exercise training on diabetic complications induced by high-fat (HF) diet plus streptozotocin (STZ) in rats. Type 2 diabetes was induced by feeding rats with HF diet (55% fat) for 5 weeks and a single dose of STZ (35 mg/kg i.p.). Control (C) and Diabetic (D) animals were subdivided into four groups each: Sedentary, Training, ASE Sedentary, and ASE Training. ASE (200 mg/kg/day) was administered by gavage and the exercise training was performed on a treadmill (30min/day; 5 days/week) for 4 weeks after the diabetes induction. In type 2 diabetic rats, the treatment with ASE reduced blood glucose, insulin resistance, leptin and IL-6 levels, lipid profile, and vascular dysfunction. ASE increased the expression of insulin signaling proteins in skeletal muscle and adipose tissue and plasma GLP-1 levels. ASE associated with exercise training potentiated the reduction of glycemia by decreasing TNF-α levels, increasing pAKT and adiponectin expressions in adipose tissue, and IR and pAMPK expressions in skeletal muscle of type 2 diabetic rats. In conclusion, ASE treatment has an antidiabetic effect in type 2 diabetic rats by activating the insulin-signaling pathway in muscle and adipose tissue, increasing GLP-1 levels, and an anti-inflammatory action. Exercise training potentiates the glucose-lowering effect of ASE by activating adiponectin-AMPK pathway and increasing IR expression.

Polyurethane Composite Membranes

Fibrous nanostructured polyurethane composite membranes were developed using electrospinning process. Membranes of polyurethane having silver and zinc oxide as additives were prepared by electrospinning of solutions having dimethylformamide (DMF) or its mixture with tetrahydrofuran (THF) (50:50 volume ratio) as solvent. Morphology of the fibers was characterized by using optical microscopy and scanning electron microscopy, showing fiber diameters from 200 to 800 nanometers. Antibacterial properties were tested by eluting solutions of E.coli at different concentrations through the membranes.