title: Effects of flavonoids on α-glucosidase activity: potential targets for glucose homeostasis.
abstract: OBJECTIVE
  Flavonoids are naturally occurring compounds widely distributed in plants, which have hypoglycemic potential and have been described as glucosidase inhibitors. This study evaluated the effect of flavonoids on intestinal glucosidase activity after in vivo and in vitro treatment.
  
  
  METHODS
  For the in vivo studies animals received quercetin by gavage and for the in vitro assays a segment of the small intestine was used. To obtain the oral glucose tolerance curve fasted normal rats were loaded with glucose plus flavonoids. The glycemia was measured by the glucose oxidase method.
  
  
  RESULTS
  Quercetin reduced the effect of sucrase and maltase in the in vivo and in vitro treatments. It was observed in the in vitro studies that the maximum inhibitory effect of kaempferitrin was around 23% for maltase activity. Also, for the sucrose substrate the specific enzyme activity was significantly decreased. Aglycone, flavonoids, and kaempferol decreased significantly the maltase activity at all concentrations assayed. Finally, rutin reduced maltase-specific activity at all concentrations studied. According to the oral glucose tolerance curve, rutin reduced the serum glucose levels at 15, 30, and 60 min when administered by oral gavage 30 min before glucose overload in rats.
  
  
  CONCLUSIONS
  Based on these results, we can conclude that disaccharidases are targets of flavonoids in the regulation of glucose absorption and consequently glucose homeostasis.
authors.affiliation: Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Campus Universitário, Bairro Trindade, Florianópolis, SC, Brazil.
authors.forename: Danielle Fontana
authors.initials: DF
authors.lastname: Pereira
authors.forename: Luisa Helena
authors.initials: LH
authors.lastname: Cazarolli
authors.forename: Cristiane
authors.initials: C
authors.lastname: Lavado
authors.forename: Vanessa
authors.initials: V
authors.lastname: Mengatto
authors.forename: Maria Santos Reis Bonorino
authors.initials: MS
authors.lastname: Figueiredo
authors.forename: Alessandro
authors.initials: A
authors.lastname: Guedes
authors.forename: Moacir Geraldo
authors.initials: MG
authors.lastname: Pizzolatti
authors.forename: Fátima Regina Mena Barreto
authors.initials: FR
authors.lastname: Silva
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D001786:Blood Glucose / Q000032:analysis; D004186:Disaccharidases / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005215:Fasting; D005947:Glucose / Q000378:metabolism*; D005951:Glucose Tolerance Test; D065089:Glycoside Hydrolase Inhibitors; D006706:Homeostasis / Q000187:drug effects*; D007421:Intestine, Small / Q000187:drug effects / Q000201:enzymology; D044949:Kaempferols / Q000494:pharmacology*; D008297:Male; D011794:Quercetin / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D013393:Sucrase / Q000378:metabolism
chemical_list: D000975:Antioxidants; D001786:Blood Glucose; D004791:Enzyme Inhibitors; D065089:Glycoside Hydrolase Inhibitors; D044949:Kaempferols; D011794:Quercetin; D004186:Disaccharidases; D013393:Sucrase; D005947:Glucose; C042728:lespenefril