title: Effect of free or protein-associated soy isoflavones on the antioxidant status in rats.
abstract: BACKGROUND
  The objective of this study was to investigate the effect of chronic ingestion of free and protein-associated soy isoflavones on the antioxidant status in male Wistar rats. Free isoflavone (iso), protein-associated soy isoflavone (iso + prot) and soy protein (prot) extracts were administered for 30 days by gavage to the rats at a dosage of 1 mg aglycone isoflavones per 200 g body weight, adjusted daily, and the prot group was given the same concentration of soy protein received by the iso + prot group. Antioxidant capacity of plasma, thiobarbituric acid-reactive substance (TBARS) and glutathione (GSH) levels and catalase (CAT), glutathione peroxidase (GPx) and superoxide dismutase (SOD) activities in plasma, erythrocytes and tissues and gene expression levels in liver and kidney were evaluated.
  
  
  RESULTS
  Chronic ingestion of free but not of protein-associated soy isoflavones nor of solely soy protein increased plasma antioxidant capacity and GPx activity in erythrocytes. Soy protein increased CAT activity and gene expression in liver. SOD activity in erythrocytes was increased by all treatments.
  
  
  CONCLUSIONS
  The overall results confirm that dietary soy isoflavones have a positive effect on antioxidant status, enhancing antioxidant capacity of plasma and antioxidant enzymes in various tissues, but the effects are dependent on the form of administration and on a complex mechanism of antioxidant status balance on the organism.
authors.affiliation: Laboratório de Química, Bioquímica e Biologia Molecular de Alimentos, Departamento de Alimentos e Nutrição Experimental, FCF, Universidade de Sao Paulo, Av. Prof. Lineu Prestes 580, Bloco 14, 05508-900 Sao Paulo, SP, Brazil.
authors.forename: Ana Cl
authors.initials: AC
authors.lastname: Barbosa
authors.forename: Franco M
authors.initials: FM
authors.lastname: Lajolo
authors.forename: Maria I
authors.initials: MI
authors.lastname: Genovese
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000378:metabolism* / Q000494:pharmacology; D002374:Catalase / Q000378:metabolism; D004798:Enzymes / Q000378:metabolism; D004912:Erythrocytes / Q000187:drug effects* / Q000201:enzymology; D005979:Glutathione Peroxidase / Q000097:blood; D007529:Isoflavones / Q000494:pharmacology*; D008099:Liver / Q000187:drug effects* / Q000201:enzymology; D008297:Male; D010936:Plant Extracts / Q000494:pharmacology*; D014674:Plant Proteins, Dietary / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D030262:Soybean Proteins / Q000494:pharmacology*; D013025:Glycine max / Q000737:chemistry*; D013482:Superoxide Dismutase / Q000097:blood; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism
chemical_list: D000975:Antioxidants; D004798:Enzymes; D007529:Isoflavones; D010936:Plant Extracts; D014674:Plant Proteins, Dietary; D030262:Soybean Proteins; D017392:Thiobarbituric Acid Reactive Substances; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase