title: Smallanthus macroscyphus: a new source of antidiabetic compounds.
abstract: 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 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.
authors.affiliation: Instituto Superior de Investigaciones Biológicas (INSIBIO), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de Tucumán, Chacabuco 461, 4000 San Miguel de Tucumán, Argentina.
authors.forename: Carolina
authors.initials: C
authors.lastname: Serra-Barcellona
authors.affiliation: Instituto de Ecología Regional (IER), Facultad de Ciencias Naturales, Universidad Nacional de Tucumán, 4107 Yerba Buena, Tucumán, Argentina.
authors.forename: Maria V
authors.initials: MV
authors.lastname: Coll Aráoz
authors.affiliation: Instituto Superior de Investigaciones Biológicas (INSIBIO), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de Tucumán, Chacabuco 461, 4000 San Miguel de Tucumán, Argentina.
authors.forename: Wilfredo M
authors.initials: WM
authors.lastname: Cabrera
authors.affiliation: Instituto Superior de Investigaciones Biológicas (INSIBIO), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de Tucumán, Chacabuco 461, 4000 San Miguel de Tucumán, Argentina.
authors.forename: Natalia C
authors.initials: NC
authors.lastname: Habib
authors.affiliation: Instituto Superior de Investigaciones Biológicas (INSIBIO), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de Tucumán, Chacabuco 461, 4000 San Miguel de Tucumán, Argentina.
authors.forename: Stella M
authors.initials: SM
authors.lastname: Honoré
authors.affiliation: INQUINOA (CONICET), Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán, Ayacucho 471, 4000 San Miguel de Tucumán, Argentina.
authors.forename: César A N
authors.initials: CA
authors.lastname: Catalán
authors.affiliation: Instituto de Ecología Regional (IER), Facultad de Ciencias Naturales, Universidad Nacional de Tucumán, 4107 Yerba Buena, Tucumán, Argentina.
authors.forename: Alfredo
authors.initials: A
authors.lastname: Grau
authors.affiliation: Instituto Superior de Investigaciones Biológicas (INSIBIO), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de Tucumán, Chacabuco 461, 4000 San Miguel de Tucumán, Argentina. Electronic address: sbgenta@fbqf.unt.edu.ar.
authors.forename: Susana B
authors.initials: SB
authors.lastname: Genta
authors.affiliation: Instituto Superior de Investigaciones Biológicas (INSIBIO), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de Tucumán, Chacabuco 461, 4000 San Miguel de Tucumán, Argentina. Electronic address: ssanchez@fbqf.unt.edu.ar.
authors.forename: Sara S
authors.initials: SS
authors.lastname: Sánchez
mesh_terms: D000284:Administration, Oral; D000818:Animals; D019659:Asteraceae / Q000737:chemistry*; D001786:Blood Glucose / Q000032:analysis / Q000187:drug effects*; D002851:Chromatography, High Pressure Liquid; D003921:Diabetes Mellitus, Experimental / Q000188:drug therapy; D004305:Dose-Response Relationship, Drug; D008401:Gas Chromatography-Mass Spectrometry; D007004:Hypoglycemic Agents / Q000737:chemistry / Q000494:pharmacology*; D007783:Lactones / Q000737:chemistry / Q000494:pharmacology*; D008297:Male; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D018515:Plant Leaves / Q000737:chemistry; D051381:Rats; D017208:Rats, Wistar; D012717:Sesquiterpenes / Q000737:chemistry / Q000494:pharmacology*
chemical_list: D001786:Blood Glucose; D007004:Hypoglycemic Agents; D007783:Lactones; D010936:Plant Extracts; D012717:Sesquiterpenes; C587733:polymatin A
keywords: Hypoglycemic activity; Polymatin A; Smallanthus macroscyphus leaves