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. CONCLUSION: Based on these results, we can conclude that disaccharidases are targets of flavonoids in the regulation of glucose absorption and consequently glucose homeostasis.
Subject(s)
Antioxidants/pharmacology , Glucose/metabolism , Glycoside Hydrolase Inhibitors , Homeostasis/drug effects , Kaempferols/pharmacology , Quercetin/pharmacology , Animals , Blood Glucose/analysis , Disaccharidases/metabolism , Enzyme Inhibitors/pharmacology , Fasting , Glucose Tolerance Test , Intestine, Small/drug effects , Intestine, Small/enzymology , Male , Rats , Rats, Wistar , Sucrase/metabolismABSTRACT
The purpose of this review is to discuss the recent developments related to the chemistry and medicinal properties of flavonoids. Major flavonoids that show well categorized structures and well defined structure function-relationships are: flavans, flavanones, flavones, flavanonols, flavonols, catechins, anthocyanidins and isoflavone. The biological properties of flavonoids include antioxidant, anti-inflamatory, antitumoral, antiviral and antibacterial, as well as a direct cytoprotective effect on coronary and vascular systems, the pancreas and the liver. These characteristics place them among the most attractive natural substances available to enrich the current therapy options.
Subject(s)
Flavonoids/pharmacology , Flavonoids/pharmacokinetics , Flavonoids/therapeutic use , Animals , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/therapeutic use , Anti-Inflammatory Agents, Non-Steroidal/pharmacology , Antineoplastic Agents, Phytogenic/chemistry , Antineoplastic Agents, Phytogenic/pharmacology , Antineoplastic Agents, Phytogenic/therapeutic use , Antioxidants/pharmacology , Antiviral Agents/chemistry , Antiviral Agents/pharmacology , Antiviral Agents/therapeutic use , Flavonoids/chemistry , Flavonoids/classification , Humans , Intestinal AbsorptionABSTRACT
The purpose of this review is to discuss the cellular and molecular mechanisms of action of flavonoids focusing on carbohydrate metabolism. The beneficial effects of flavonoids have been studied in relation to diabetes mellitus, either through their capacity to avoid glucose absorption or to improve glucose tolerance. Furthermore, flavonoids stimulate glucose uptake in peripheral tissues, regulate the activity and/or expression of the rate-limiting enzymes in the carbohydrate metabolism pathway and act per se as insulin secretagogues or insulin mimetics, probably, by influencing the pleiotropic mechanisms of insulin signaling, to ameliorate the diabetes status.
