Lívia S. Oliboni

Intake of purple grape juice as a hepatoprotective agent in Wistar rats.

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.

Phenolic content of grapevine leaves (Vitis labrusca var. Bordo) and its neuroprotective effect against peroxide damage.

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.

Antioxidant and Antigenotoxic Activities of Purple Grape Juice—Organic and Conventional—in Adult Rats

Oxidative damage to biomolecules occurs by the accumulation of molecular damage due to free radicals and/or a diminution of antioxidant protection. The aim of this study was to evaluate the protection of organic and conventional purple grape juices in brain, liver, and plasma from adult Wistar rats (7 months old) against the oxidative damage provoked by carbon tetrachloride (CCl(4)). Adult rats were divided into three groups (control, conventional purple grape juice, and organic purple grape juice). Half of the rats received CCl(4), and the other half received the vehicle (vegetable oil). The chemical analytical determination showed that the highest levels of total phenolic, resveratrol, and catechins were seen in organic purple grape juices. Considering the treatment groups, it was observed that in all tissues (brain structures and liver) and plasma, CCl(4) treatment increased the lipid peroxidation (LP) levels. Both grape juices were capable to reduce LP levels in cerebral cortex and hippocampus; however, in the striatum and substantia nigra only the organic grape juice reduced LP level. CCl(4) caused an increase in catalase activity in cerebral cortex, hippocampus, and substantia nigra and in superoxide dismutase activity in substantia nigra. This increase was reduced by both juices in substantia nigra and hippocampus structures (P < .05). In the alkaline version of the comet assay performed on whole blood, it was observed that CCl(4) was capable of inducing mainly DNA damage class 4 and 3 frequencies, which was significantly reduced in groups that received both purple grape juices. This implies that both grape juices have an important antigenotoxic activity.

Hepatoprotective, cardioprotective, and renal-protective effects of organic and conventional grapevine leaf extracts (Vitis labrusca var. Bordo) on Wistar rat tissues

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.

Antioxidant Activity and Phenolic and Mineral Content of Rose Grape Juice

There are many studies related to the antioxidant activity of grape products; however, they concern only purple and white grape varieties. Up to now, there are no reports of studies on the Goethe rose grape variety, either on its antioxidant activity or on its phenolic and mineral quantification. Thus, the purpose of this study was to evaluate in vitro and in vivo antioxidant activity, as well as to quantify total phenolic compounds, ascorbic acid, and mineral content, in a Goethe rose grape juice. The results obtained showed that the Goethe rose grape juice is a great polyphenol source, which contains catechin, epicatechin, and procyanidins (B(1), B(2), B(3), and B(4)). Of all metals analyzed, potassium, calcium, magnesium, and iron showed the highest values. We found that this rose grape juice shows an important antioxidant activity in in vitro (2,2-diphenyl-1-picrylhydrazyl radical scavenging activity) and in vivo (using the Saccharomyces cerevisiae yeast cells) assays. The antioxidant activity could be explained by the significant phenolic content and ascorbic acid levels found in the juice. The results showed that rose grape juice is an excellent antioxidant source, which could contribute to the prevention of many diseases related to oxidative stress, such as atherosclerosis and Parkinsons disease.

Effect of 3-butyl-1-phenyl-2-(phenyltelluro)oct-en-1-one on oxidative stress in cerebral cortex of rats.

The objective of this study was to verify the effect of the organochalcogen 3-butyl-1-phenyl-2-(phenyltelluro)oct-en-1-one on some parameters of oxidative stress in the brain of 10-day-old rats. Cerebral cortex was incubated for 1h in the presence or absence of 1, 10 or 30 microM of 3-butyl-1-phenyl-2-(phenyltelluro)oct-en-1-one and thiobarbituric acid reactive substances (TBARS), carbonyl, sulfhydryl, catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione S-transferase (GST), nitric oxide (NO) production and the release of the cytosolic enzyme lactate dehydrogenase (LDH) were measured. The organotellurium was not capable to alter TBARS and carbonyl assays. In contrast, the compound at 10 and 30 microM provoked a reduced of protein thiol groups measured by the sulfhydryl assay. Furthermore, the activity of the antioxidant enzyme CAT (10 and 30 microM) and GPx (1, 10 and 30 microM) was reduced by the organochalcogen. On the other hand, the activity of SOD and GST were enhanced respectively by 1, 10 and 30 microM of the compound. Furthermore, NO production was also increased by 30muM of this organochalcogen. Finally, we verified that the organotellurium was capable of enhance the LDH release at 30 microM concentration. Our findings indicate that this organotellurium compound induces in vitro oxidative stress in the cerebral cortex of rats being potentially toxic for the brain of rats.