title: Acute consumption of organic and conventional tropical grape juices (Vitis labrusca L.) increases antioxidants in plasma and erythrocytes, but not glucose and uric acid levels, in healthy individuals.
abstract: Bioactive polyphenols in grapes are influenced by grape variety and cultivation conditions. The Vitis labrusca L. varieties are cultivated in tropical regions and used for grape juice production. We hypothesized that polyphenols from tropical grape juices would beneficially affect redox homeostasis in humans. Therefore, the effects of acute consumption of organic and conventional grape juices from V labrusca L. on antioxidants biomarkers were investigated in healthy individuals. In a controlled, randomized, crossover, intervention trial, 24 individuals were assigned to drink 400 mL of conventional juice, organic juice, or water. Each intervention was followed by a 14-day washout period. Blood samples were obtained before and 1 hour after acute intake and analyzed for erythrocyte reduced glutathione, serum total antioxidant capacity, antioxidant enzymes in erythrocytes, and glucose and uric acid in serum. The ingestion of both grape juices resulted in elevated levels of reduced glutathione (P< .001) and serum total antioxidant capacity (P< .05) and increased activity of catalase (P< .001), superoxide dismutase (P< .001), and glutathione peroxidase (P< .05) compared with the control intervention, with no significant differences between grape juices (P< .05). The intake of juices did not affect significantly the concentrations of glucose or uric acid. Grape juice polyphenols were associated with increased antioxidants, and the chemical differences between organic and conventional juices were not predictive of the observed responses. The results suggest a bioactive potential of V labrusca L. juices to improve redox homeostasis, which is involved in defense against oxidative stress in humans.
authors.affiliation: Department of Food Science and Technology, Federal University of Santa Catarina, Admar Gonzaga Rd, 1346, Itacorubi, 88034-001, Florianópolis, SC, Brazil. Electronic address: bela.toaldo@gmail.com.
authors.forename: Isabela Maia
authors.initials: IM
authors.lastname: Toaldo
authors.affiliation: Department of Clinical Analysis, Federal University of Santa Catarina, Delfino Conti St, Trindade, 88040-370, Florianópolis, SC, Brazil. Electronic address: feralvescruz@gmail.com.
authors.forename: Fernanda Alves
authors.initials: FA
authors.lastname: Cruz
authors.affiliation: Department of Clinical Analysis, Federal University of Santa Catarina, Delfino Conti St, Trindade, 88040-370, Florianópolis, SC, Brazil. Electronic address: edson.silva@ufsc.br.
authors.forename: Edson Luiz
authors.initials: EL
authors.lastname: da Silva
authors.affiliation: Department of Food Science and Technology, Federal University of Santa Catarina, Admar Gonzaga Rd, 1346, Itacorubi, 88034-001, Florianópolis, SC, Brazil. Electronic address: marilde.bordignon@ufsc.br.
authors.forename: Marilde T
authors.initials: MT
authors.lastname: Bordignon-Luiz
mesh_terms: D000328:Adult; D000975:Antioxidants / Q000032:analysis*; D001628:Beverages; D001786:Blood Glucose / Q000032:analysis*; D002374:Catalase / Q000097:blood; D018592:Cross-Over Studies; D004912:Erythrocytes / Q000737:chemistry; D005260:Female; D058870:Food, Organic; D005638:Fruit / Q000737:chemistry*; D005978:Glutathione / Q000097:blood; D005979:Glutathione Peroxidase / Q000097:blood; D006801:Humans; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000187:drug effects; D013482:Superoxide Dismutase / Q000097:blood; D014329:Tropical Climate; D014527:Uric Acid / Q000097:blood*; D027843:Vitis / Q000737:chemistry*
chemical_list: D000975:Antioxidants; D001786:Blood Glucose; D014527:Uric Acid; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase; D005978:Glutathione
keywords: Erythrocyte enzyme; Glycemia; Grape polyphenol; Redox homeostasis; Tropical juice; V labrusca L.