Influência De Chalconas Análogas, Xantonas E Monossacarídeos Na Glicemia Em Modelo Experimental Animal
Year: 2007
Type: dissertation
Abstract: INFLUENCE OF CHALCONE ANALOGUES, XANTHONES AND MONOSACCHARIDES ON GLYCEMIA IN AN EXPERIMENTAL ANIMAL MODEL The objective of this investigation was to study the effect of chalcone analogues (derived from 3,4-methylenedioxy-benzaldehyde, 2-naphthaldehyde or xanthoxylin), monosaccharides (gluconic and tartaric acids), the crude ethanolic extract of Polygala paniculata, and the ethyl acetate fraction (EtAc) of Polygala cyparissias (that contains xanthones) on glycemia in normoglycemic rats, hyperglycaemic rats, and in alloxan-induced diabetic rats. The glucose tolerance curve of the compounds being tested was compared with a curve obtained using substances with a known hypoglycaemic effect (insulin and tolbutamida). Glycemia was determined by the glucose-oxidase method. The chalcone analogues were administered at doses of 5, 10 and 15 mg/kg in hyperglycaemic rats. Blood was collected at time zero and at 15, 30, 60, 120 and 180 minutes (glucose tolerance curve). Three series of chalcones were tested, those derived from 3,4-methylenedioxy-benzaldehyde (compounds 03, 04, 05, 07, 09 and 10) and naphthaldehyde (compounds 12, 13 and 14) that presented hypoglycaemic activity, and chalcones derived from xanthoxylin, which did not present any effect on glycemia, suggesting that substituents in the 3’ and/or 4’ positions are essential for the hypoglycaemic activity of these compounds. Substituents in the A and B ring of the nucleus of the chalcones determine the potency and efficiency in hypoglycaemic activity of these new compounds compared to insulin and tolbutamide. Gluconic acid was administered by oral route at doses of 25, 50, 100, 200, 400 and 800 mg/kg body weight in normoglycemic rats, and via oral or intraperitoneal route in hyperglycaemic and diabetic rats. Tartaric acid was administered at doses of 100 mg/kg and 400 mg/kg via oral route in normoglycemic and hyperglycaemic rats. Blood was collected from normal and diabetic animals at time zero, and then at 1, 2 and 3 hours to construct a dose-response curve as a function of time, and at time zero, then at 15, 30, 60, 120 and 180 minutes to produce a glucose tolerance curve in hyperglycaemic rats. There was no significant change in the glycemia of normoglycemic rats treated with gluconic acid and tartaric acid compared to time zero. In the glucose tolerance curve for animals treated with gluconic acid (400 mg/kg) there was a significant increase in glycemia at 15, 30, 60 and 120 minutes, while in animals treated with tartaric acid (400 mg/kg) this was present at 120 and 180 minutes. Gluconic acid did not change the glycemia in alloxan-induced diabetic rats. These results suggest that gluconic and tartaric acids do not act as insulin secretagogues and do not possess an insulinomimetic action. The EBEtOH of P. paniculata was administered at doses of 400, 800 and 1200 mg/kg in diabetic and hyperglycaemic rats. The EtAc fraction of P. cyparissias was administered at a dose of 800 mg/kg in diabetic and hyperglycaemic rats. P. paniculata (EBEtOH) did not significantly alter glycemia in alloxan-induced diabetic rats nor did it affect the glucose tolerance curve at the doses tested. P. cyparissias (EtAc) did not reduce glycemia in diabetic rats, although it did cause a significant decrease in glycemia at 15 and 30 minutes when compared to the hyperglycaemic control. In summary, the xanthones-rich fraction of P. cyparissias exhibited potential hypoglycaemic activity, while P. paniculata (EBEtOH) did not present any antihyperglycaemic, anti-diabetic or insulinomimetic action in the tests.
Author: Elga Alberton
Language: Portuguese
Subfield: Endocrinology, Diabetes and Metabolism
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W2152923106