No abstract

In some countries, leaves of Vitis vinifera grapes have been used for food and for treating many medical disorders. However, there are no studies on the leaves of Vitis labrusca, the main species used for wine and juice production in South America. In this work, the phenolic compounds and antioxidant activity of organic and conventional grape leaves extracts prepared from V. labrusca (var. Bordo) in brain tissues (in vitro model) have been evaluated. Both organic and conventional grape leaves extracts have similar total phenolic content, however, different patterns were observed for the main phenolic compounds of both kinds of leaves. The organic leaves extract showed about 10 times more resveratrol than the conventional one. Both extracts were able to reduce the lipid and protein damages induced by hydrogen peroxide in the brain of rats. This effect was accompanied by the reversion of the hydrogen peroxide-induced alterations in the superoxide dismutase and catalase activities. Negative correlations between lipid and protein damages and the levels of polyphenols were found, suggesting that these compounds contribute directly to the protective effect observed.

Moderate consumption of red wine reduces the risk of heart disease and extends lifespan, but the relative contribution of wine polyphenols to these effects is unclear. In this work, the capacity of resveratrol and catechin to protect the eukaryotic microorganism Saccharomyces cerevisiae against oxidative stress caused by different agents, hydrogen peroxide, carbon tetrachloride, and cadmium, was evaluated. Under all stress conditions, both polyphenols increased tolerance, although their protection was more evident under peroxide exposure. By using mutant strains deficient in specific antioxidant defense systems (superoxide dismutases, catalase, or glutathione), it was observed that increased H2O2 tolerance produced by both polyphenols was associated with catalase, as well as the rise in survival rates caused by resveratrol under CCl4. The acquisition of tolerance was correlated with a reduction in lipid peroxidation, indicating that the antioxidant property of resveratrol and catechin involves protection against membrane oxidation.

The aim of this study was to investigate the responses of creatine kinase (CK) and lactate dehydrogenase (LDH) after performing different resistance and aerobic exercise protocols. Twelve recreationally trained men (age, 23.2 ± 5.6 years; body mass, 84.3 ± 9.3 kg; body height, 178.9 ± 4.5 cm; and BMI, 26.3 ± 2.3 kg·m2) volunteered to participate in this study. All subjects were randomly assigned to four experimental protocols (crossover): (a) aerobic training at 60% of VO2max, (b) aerobic training at 80% of VO2max, (c) a resistance exercise (RE) session with a bi-set protocol, and (d) an RE session with a multiple sets protocol. Blood samples were collected before, immediately after and 24 hours following the experimental protocols. After 24 hours, there was a significant increase in CK for the 80% of VO2max protocol vs. the bi-set RE session (p = 0.016). Immediately after the protocols, we observed a significant increase in LDH among certain groups compared to others, as follows: multiple sets RE session vs. 60% of VO2max, bi-set RE session vs. 60% of VO2max, multiple sets RE session vs. 80% of VO2max, and bi-set RE session vs. 80% of VO2max (p = 0.008, p = 0.013; p = 0.002, p = 0.004, respectively). In conclusion, aerobic exercise performed at 80% of VO2max appears to elevate plasma CK levels more than bi-set RE sessions. However, the bi-set and multiple sets RE sessions appeared to trigger greater levels of blood LDH compared to aerobic protocols performed at 60% and 80% of VO2max.

The antioxidant properties of purple grape juice, organic and conventional, in brain tissues are not well known. In this study our objective was to evaluate the antioxidant activity in substantia nigra and striatum of rats chronically treated with organic or conventional purple grape juice and to correlate the results obtained with the polyphenol content (total polyphenolic content, resveratrol, and anthocyanins [malvidin, delphinidin, peonidin, and cyanidin]). We observed that CCl(4) damage decreased significantly in the grape juice-treated groups when compared with the control group. In the grape juice-treated groups we further observed a decrease of lipid (thiobarbituric acid-reactive substances assay) and protein (carbonyl) peroxidation, as well as a significant antioxidant protection through the increase of enzyme activity. Antioxidant activities were significantly correlated with polyphenol content. These findings demonstrated that both grape juices have potent antioxidant properties and these activities could be at least attributed to the high phenolic content present in these juices.

Grape juice is a source of polyphenols, as catechin, anthocyanidins, resveratrol, and others. Some health benefits have been attributed to these compounds (e.g., antioxidant and antitumorigenic properties). In this study, we investigated the possible antioxidant activity of two different grape juices: organic purple grape juice and conventional purple grape juice. The antioxidant activity of both grape juices was evaluated by an animal model of three groups: control and organic and conventional juices. After 30 days, all animals were sacrificed, and blood and liver were collected to evaluate lipid peroxidation level (thiobarbituric acid-reactive substances [TBARS] assay), protein oxidative level (carbonyl assay), and catalase (CAT) and superoxide dismutase (SOD) activities. The group treated with organic grape juice showed the highest SOD and CAT activities in both plasma and liver when compared with the conventional and control groups (P < .05). In plasma, we observed a positive correlation among SOD and CAT activities, resveratrol, and all anthocyanin contents, suggesting that these polyphenols may be, at least in part, responsible for this increased antioxidant defense. The grape juices were capable of reducing carbonyl and lipid peroxidation levels in plasma and liver. However, in plasma, the organic group showed lower carbonyl and TBARS levels when compared to the conventional grape juice group (P < .05). Our findings suggest that the intake of purple grape juice, especially of organic juice, induces a better antioxidant capacity when compared to conventional juice and that this may be an important issue for further investigations in the area of biochemical functional foods.

Epilepsy is the most common neurological disorder worldwide. Studies have shown that recurrent seizures may increase the concentration of reactive oxygen species, which can lead to oxidative stress and neuronal damage. These seizures result in substantial deleterious effects on an individual's health. Organic and conventional grape juices are rich in polyphenols, compounds with important antioxidant activity. However, these juices could have differences in their polyphenol content. The aim of this study was to investigate the neuroprotective and anticonvulsant effects of organic and conventional grape juice treatments in Wistar rats against pentylenetetrazole (a convulsant drug)-induced damage. In addition, we evaluated potential behavioral changes in rats treated with the juices and the polyphenolic profile of those samples. Animals (n=16 in each group) received treatment with saline, organic or conventional grape juice for 17 days. On the eighteenth day, behavioral changes were evaluated by an open field test. Afterwards, half of the rats from each group received pentylenetetrazole and were observed for 30 min to evaluate possible seizure characteristics. The animals were subsequently killed by decapitation and their hippocampus, cerebellum and cerebral cortex tissues were isolated. The results of this study showed that neither organic nor conventional grape juice altered the behavior parameters, and no statistical differences were observed in the seizure characteristics of the groups. Nevertheless, both juice types were able to protect from lipid and protein oxidative damage, decrease nitric oxide content and increase enzymatic (superoxide dismutase and catalase) and non-enzymatic (sulfhydryl protein) antioxidant defenses in brain tissues following pentylenetetrazole-induced seizures. In general, organic juice showed superior results in each test, probably due to its higher polyphenol content relative to conventional juice. These results indicate that grape juices can provide further insight into natural neuroprotective compounds and may lead to the development of new therapeutic strategies for epileptic patients.

The purpose of this study was to evaluate the beneficial effects of organic and conventional grapevine (Vitis labrusca L.) leaf extracts in reducing hydrogen peroxide-induced stress in the liver, heart and kidney of Wistar rats by measuring lipids and proteins damages (carbonyl assay), as well as the activity of the antioxidant enzymes superoxide dismutase and catalase. The preincubation with 5 mg/mL of organic and conventional grapevine (Vitis labrusca L.) leaf extracts prevented both lipids and proteins oxidative damages in all tissues analyzed. The organic leaf extract was able to restore superoxide dismutase (kidney and liver) and catalase (heart) activities, which were modified by the treatment with H 2 O 2 . The conventional extract was able to restore only the catalase activity in liver and heart tissues. The beneficial effects of the V. labrusca leaf extract shown in this study could probably be important for formulating dietary supplements, as well as for developing new ingredients with improved antioxidant properties from other plant sources.