Modulation of neuropathic pain in experimental diabetes mellitus

The main objective of the current article is to investigate the diabetic polyneuropathy which represents a major preoccupation within the context of high incidence of diabetes mellitus (DM) and its complications. Moreover, neuropathy may develop despite intensive hyperglycaemic control. The effect of Zn and black grape seed polyphenols (BGSP) in streptozotocin diabetic rats was studied. Zn and BGSP were administered by gavage, daily, for 16 weeks to Wistar rats that have been rendered diabetic by a single i.v. injection of streptozotocin (55 mg/kg body weight). Dysalgesia was investigated under the conditions of nociceptive stimulation through the following tests: the thermoalgesic mechanism through the tail-flick test, the hot plate test and the plantar test, and the mechanoalgesic mechanism through the algesimetric test. Thermal hyperalgesia detected in the diabetic group is significantly reduced (p < 0.001) through the administration of polyphenols, or even better, of Zn. Diabetes-associated mechanical hyperalgesia decreased significantly (p < 0.001) probably through the inhibition of the NMDA receptors. Administration of Zn or BGSP to the diabetic group improves glycosylated haemoglobin (HbA1c) values but does not bring them to normal. The present data suggest a favourable effect of Zn and BGSP in inhibiting diabetic complications by several mechanisms

Effect of low molecular grape seed proanthocyanidins on blood pressure and lipid homeostasis in cafeteria diet-fed rats

Cardiovascular disease (CVD) and related pathologies are the leading cause of death worldwide. Fruits and vegetables are known to improve CVD, an effect that has been associated with flavonoid intake. The aim of this study was to simultaneously evaluate the acute effect of a low molecular grape seed proanthocyanidin extract (LM-GSPE) on two of the main risk factors of CVD, high blood pressure (BP) and dyslipidaemia, using high-fat diet-fed rats. Therefore, male Wistar rats that were cafeteria diet fed for 10 weeks were administered with 375 mg/kg of body weight of LM-GSPE, and the BP as well as plasmatic and hepatic parameters were determined at 6 h post-administration. The BP and plasmatic and hepatic lipid were decreased 6 h after the LM-GSPE administration. Moreover, the liver lipid peroxidation products decreased after the LM-GSPE treatment, indicating a reduction in oxidative stress. However, hepatic-reduced glutathione or plasma angiotensin converting enzyme activity was not altered by the LM-GSPE. In conclusion, grape proanthocyanidins is able to simultaneously reduce more than one risk factor for CVD by decreasing the BP and improving hypertriglyceridaemia at least in part due to an improvement in oxidative stress. These results open up the possibility of using grape proanthocyanidins in functional foods for CVD improvement

Resveratrol does not increase body fat loss induced by energy restriction

Resveratrol (RSV) is known to have an antiobesogenic effect because it mimics energy restriction. However, hardly any evidence exists concerning the combined effects of RSV and energy restriction on body fat reduction. So, the aim of the present study was to determine whether RSV increases body fat reduction induced by energy restriction. Male Wistar rats were fed a high-fat, high-sucrose diet for 6 weeks to obtain a diet-induced obesity model. Then they were submitted to a mild energy restriction (25 %) without or with RSV supplementation (30 mg/kg body weight/day) for 2 weeks. Final body weight, subcutaneous and intra-abdominal white adipose tissues weights, Adipose Index, and serum triacylglycerol, cholesterol, glucose, and insulin were assessed. Lipoprotein lipase (LPL), fatty acid synthase (FAS), and acetyl coenzyme A carboxylase (ACC) activities, as well as their genetic expressions, were measured in white adipose tissue. Final body weight, white adipose tissue weights, Adipose Index, and serum triacylglycerol, cholesterol, and insulin were reduced in both groups, but no differences were found among them. FAS, ACC, and LPL activities and expressions were also similar in both groups. These results suggest a lack of any adjuvant effect of RSV on energy restriction for obesity treatment purposes

Effect of selenium and grape seed extract on indomethacin-induced gastric ulcers in rats

Indomethacin (IND) is a non-steroid anti-inflammatory agent that is known to induce severe gastric mucosal lesions. In this study, we investigated the protective effect of selenium (SEL), grape seed extract (GSE), and both on IND-induced gastric mucosal ulcers in rats. Sprague–Dawley rats (200–250 g) were given SEL, GSE, and both by oral gavage for 28 days, and then gastric ulcers were induced by oral administration of 25 mg/kg IND. Malondialdehyde (MDA), non-enzymatic (reduced glutathione, GSH) and enzymatic (superoxide dismutase, catalase, and glutathione peroxidase) antioxidants, prostaglandin E2 (PGE2) in gastric mucosa, and serum tumor necrosis factor Alpha (TNF-Alpha) were measured. Moreover, gastric ulcer index and preventive index were determined. Indomethacin increased the gastric ulcer index, MDA, TNF-Alpha, and decreased PGE2 and non-enzymatic (GSH) and enzymatic (superoxide dismutase, catalase, and glutathione peroxidase) antioxidants. Pretreatment with SEL, GSE, and both significantly decreased the gastric ulcer index, MDA, and TNF and increased antioxidants and PGE2. Histopathological observations confirm the gastric ulcer index and biochemical parameters. Selenium and GSE have a protective effect against IND-induced gastric ulcers through prevention of lipid peroxidation, increase of GSH, activation of radical scavenging enzymes, PGE2 generation, and anti-inflammatory activity. Co-administration of GSE and SEL is more effective than GSE or SEL alone

Evaluación de la liberación de polifenoles desde vehículos cosméticos / An evaluation of polyphenol release from cosmetic formulations

La uvaterapia es una de las propuestas para atenuar las evidencias estéticas provocadas por el envejecimiento extrínseco en la piel, la que se fundamenta en el tratamiento con productos formulados con extracto vegetal y aceite de pepitas de uva, Vitis Vinífera L., ambos con propiedades antioxidantes. El objetivo de este trabajo fue evaluar la liberación de polifenoles presentes en el extracto y en el aceite de pepitas de uva incorporados en formulaciones cosméticas. La liberación de los ingredientes activos desde las formulaciones se evaluó utilizando celdas de difusión de Franz. Los polifenoles totales se cuantificaron mediante espectrofotometría visible por el método de Folin Denis. La liberación de polifenoles desde los vehículos formulados, gel y emulsión, se ajustó al modelo cinético de la raíz cuadrada del tiempo, siendo mayor la velocidad de liberación desde el gel (AU)

One of the proposed treatments for extrinsic skin aging processes is Grape therapy, whose active ingredients, known to possess antioxidant properties, are the vegetable and seed oil extracts from the Vitis Vinífera L. grape species. The objective of the present work was to evaluate the release of polyphenol compounds from these extracts, retained in gel and emulsion based cosmetic formulations, using Franz diffusion cells. A quantification of total active ingredient release was also carried out using the Folin Denis visible spectrophotometry method. Polyphenol release from both types of formulation was found to follow a square root of time kinetic model, but a higher rate of release was obtained from the gel formulation (AU)