Yacon roots (Smallanthus sonchifolius) improve oxidative stress in diabetic rats

Context: Smallanthus sonchifolius (Poepp. and Endl.) H. Robinson, Asteraceae (yacon) roots are a natural product recognized by the traditional medicine to treat diabetes-related problems. There are no reports concerning the potential of yacon roots to reduce oxidative stress and ameliorate diabetes complications in diabetic animals. Objective: This work analyzes the in vivo antioxidant activity and beneficial effects of yacon roots, using a model of streptozotocin-induced diabetes in rats. Materials and methods: Lipid peroxidation and other indicators of oxidative stress were determined in liver and kidney homogenates from non-diabetic rats, untreated diabetic rats, and diabetic rats treated orally with yacon flour (340 mg fructooligosaccharide/kg/d) as a diet supplement for 90 d. Biochemical parameters were determined in liver, kidney, and blood at the end of the experimental period. Results: Yacon supplementation to diabetic rats produced a significant decrease in malondialdehyde levels in both liver (-30.97%) and kidney (-19.15%). Hepatic superoxide dismutase and catalase activities were significantly lower in diabetic-treated rats (-13.46 and-64.33%, respectively) compared with diabetic controls. Similar results were observed in kidney. The treatment of diabetic rats produced an increase of glutathione peroxidase and glutathione levels in liver (172.50 and 35.91%, respectively) and kidney (177.78 and 57.76%, respectively). Plasma cholesterol and triacylglycerol levels and liver fatty acid composition, which were altered in diabetic rats, reverted back to nearly normal with yacon treatment. Conclusions: These results indicate that yacon root flour is a potential diet supplement with high in vivo antioxidant activity.Fil: Habib, Natalia Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; ArgentinaFil: Serra Barcellona, Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; ArgentinaFil: Honore, Stella Maris. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; ArgentinaFil: Genta, Susana Beatriz de Fátima. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; ArgentinaFil: Sanchez, Sara Serafina del V.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; Argentin

Smallanthus macroscyphus: a new source of antidiabetic compounds

The aim of the present study was to analyze the in vivo hypoglycaemic effects of both decoction of Smallanthus macroscyphus leaves and pure crystalline polymatin A isolated from its leaves. Phytochemical analysis of the leaf decoction showed that its major constituents were caffeic, chlorogenic and three dicaffeoilquinic acids, together with the sesquiterpene lactone polymatin A. Oral glucose tolerance test in normal rats was performed to evaluate the hypoglycemic activity and to choose the minimum effective dose of the decoction and polymatin A. They have effective hypoglycemic activity at the minimum dose of 140 mg dry extract and 14 mg crystalline powder/kg body weight, respectively, and were selected for the following experiments. Oral administration of a single-dose of decoction produced a moderate lowering effect in fasting glycemia of normal rats, whereas polymatin A had no significant effect. We also assessed the effect of a single-dose on post-prandial blood glucose, resulting in an inhibition of the hyperglycemic peak after sucrose overload. Daily administration of decoction or polymatin A for 4 weeks produced an effective glycemic control in diabetic animals, with a decrease in urinary glucose excretion and a significant reduction in the HbA1c levels. Although there were no significant increases in plasma insulin levels, both treatments improved the fasting blood glucose/insulin ratio. In vivo acute toxicity studies were performed in adult Wistar rats. There were no deaths or signs of toxicity observed after oral administration of decoction or polymatin A at any dose level up to the highest dose tested (14.0 g /kg and 2.8 g /kg, respectively). The results presented here strongly support the notion that S. macroscyphus represents a new source of antidiabetic compounds that could help to manage diabetes more efficiently and safely.Fil: Serra Barcellona, Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Instituto Superior de Investigaciones Biológicas; ArgentinaFil: Coll Araoz, Maria Victoria. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto de Ecología Regional; ArgentinaFil: Cabrera, Wilfredo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Instituto Superior de Investigaciones Biológicas; ArgentinaFil: Habib, Natalia Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Instituto Superior de Investigaciones Biológicas; ArgentinaFil: Honore, Stella Maris. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Instituto Superior de Investigaciones Biológicas; ArgentinaFil: Catalan, Cesar Atilio Nazareno. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Instituto de Quimica del Noroeste; ArgentinaFil: Grau, Alfredo. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto de Ecología Regional; ArgentinaFil: Genta, Susana B.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Instituto Superior de Investigaciones Biológicas; ArgentinaFil: Sanchez, Sara Serafina del V.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Instituto Superior de Investigaciones Biológicas; Argentin

Enhydrin Regulates Postprandial Hyperglycemia in Diabetic Rats by Inhibition of α-Glucosidase Activity

During the last few years, numerous attempts were made to identify effective α-glucosidase inhibitors from natural sources in order to develop new alternatives for diabetes management. Smallanthus sonchifolius (yacon) leaves were found to be effective in controlling postprandial hyperglycemia. Enhydrin, a constituent of yacon leaves, was noted for its significant hypoglycemic properties in diabetic rats. These properties were also demonstrated for yacon leaves decoction, which is rich in phenolic compounds such as chlorogenic acid and its derivatives. The purpose of the present study was to evaluate the potential of yacon leaves decoction and the isolated compound enhydrin to inhibit α-glucosidase enzyme, a possible mechanism of the above antihyperglycemic effect. In vitro assays showed that both 10% decoction and enhydrin significantly inhibited the activity of the yeast α-glucosidase enzyme in a dose-dependent manner, IC50 values being 50.40 and 134.17 μg/ml, respectively. In vivo experiments showed a rapid decrease in the hyperglycemic peak after sucrose load (2 g/kg body weight) in normal rats treated with the 10% decoction (140 mg/kg) and enhydrin (0.8 mg/kg). Both treatments caused a significant decrease in blood glucose levels in diabetic rats after sucrose load compared to diabetic control. These results suggest that both products assayed could be effective in the management of postprandial hyperglycemia through inhibition of α-glucosidase in the small intestine.Fil: Serra Barcellona, Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; ArgentinaFil: Habib, Natalia Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; ArgentinaFil: Honore, Stella Maris. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; ArgentinaFil: Sanchez, Sara Serafina del V.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; ArgentinaFil: Genta, Susana Beatriz de Fátima. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; Argentin

Polymatin A from Smallanthus macroscyphus leaves: A safe and promising antidiabetic compound

Smallanthus macroscyphus is an herb native to South America whose leaves are a source of antidiabetic compounds, although complete information about their safe use is not available yet. This study was developed to evaluate the toxicity profile of both 10% decoction and the sesquiterpene lactone polymatin A from S. macroscyphus leaves through in vitro cytotoxicity assays and in vivo subchronic oral toxicity. Cell viability of Hep-G2, COS1, CHO-K1 and Vero cell lines decreased in a concentration-dependent manner when cells were incubated with 0.4–200 μg ml–1 of dry extract or 0.12–60 μg ml–1 of polymatin A. In subchronic studies, decoction was orally administered to Wistar rats for 90 days at daily doses of 70, 140 and 280 mg kg–1 of dry extract, whereas polymatin A was administered in the same way at doses of 7, 14 and 28 mg kg–1. No toxicity signs or deaths were observed. There were no changes in the behavior, body or organ weights, hematological, biochemical or urine parameters of the rats. No histopathological lesions were observed in the examined organs. The results indicate that the 10% decoction and polymatin A from S. macroscyphus leaves may be considered as non-toxic substances at a wide range of doses, including the effective hypoglycemic dose. Copyright © 2016 John Wiley & Sons, Ltd.Fil: Serra Barcellona, Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; ArgentinaFil: Honore, Stella Maris. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; ArgentinaFil: Cabrera, Wilfredo Marcelino. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; ArgentinaFil: Habib, Natalia Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; ArgentinaFil: Genta, Susana Beatriz de Fátima. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; ArgentinaFil: Sanchez, Sara Serafina del V.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; Argentin