Fructan degradation and hydrolytic activity in tuberous roots of Viguiera discolor Baker (Asteraceae), a herbaceous species from the cerrado

Fructans of the inulin type are the major reserve carbohydrates in tuberous roots of Viguiera discolor, a perennial herb native to the cerrado. Changes in molecular mass of the polymer, followed by releasing free fructose suggested that hydrolysis could be related to the sprouting of the buds after the dormant period, when aerial parts of the plant are naturally absent. Excision of aerial parts resulted in the increase of fructan 1-exohydrolase (1-FEH) activity in tuberous roots after sprouting. 1-FEH was partially purified from this material by binding to ConA-Sepharose and the highest activity was detected at pH 5.4 and between 20 and 40 °C. Values of Km for V. discolor inulin could not be determined since no saturation was observed up to 10%. The study of the kinetics of the 1-FEH activity showed that it does not follow Michaelis-Menten and apparently presents allosteric behaviour, as data fits in the Hill equation. The 1-FEH from V. discolor is a glycoprotein, more active on low molecular mass fructans than on high molecular mass inulin from the same species.

Synthesis of fructans by fructosyltransferase from the tuberous roots of Viguiera discolor (Asteraceae)

Sucrose:sucrose fructosyltransferase (SST) and fructan:fructan fructosyl-transferase (FFT) activities from crude extracts of tuberous roots of Viguiera discolor growing in a preserved area of cerrado were analyzed in 1995-1996. SST activity was characterized by the synthesis of 1-kestose from sucrose and FFT activity by the production of nystose from 1-kestose. The highest fructan-synthesizing activity was observed during early dormancy (autumn), when both (SST and FFT) activities were high. The increase in synthetic activity seemed to start during the fruiting phase in the summer, when SST activity was higher than in spring. During winter and at the beginning of sprouting, both activities declined. The in vitro synthesis of high molecular mass fructans from sucrose by enzymatic preparations from tuberous roots collected in summer showed that long incubations of up to 288 h produced consistently longer polymers which resembled those found in vivo with respect to chromatographic profiles.

Postharvest conservation of the tuberous roots of Pachyrhizus Ahipa (Wedd) Parodi

O objetivo deste trabalho foi avaliar o período de armazenamento em diferentes temperaturas e embalagens na conservação das raízes de Pachyrhizus ahipa. As raízes foram colhidas, lavadas e armazenadas em bandejas de isopor, no refrigerador, câmara fria e à temperatura ambiente. As embalagens utilizadas foram PVC, saco plástico e sem embalagem (controle). As bandejas foram retiradas do seu ambiente de armazenamento e analisadas quanto a acidez total titulável, sólidos solúveis totais, pH, teores de cinzas, lipídios, carboidrato total e proteínas em base seca. A menor perda de massa das raízes foi em câmara fria e em saco plástico. A ATT manteve-se maior nas raízes armazenadas em câmara fria e na embalagem de PVC; os menores teores de SST foram observados em câmara fria não variando entre as embalagens. em todos os tratamentos a porcentagem média de carboidratos foi 84,9%. A porcentagem de lipídios foi maior nas raízes armazenadas em temperatura ambiente, entretanto, o teor de proteína e cinzas foram maiores nas armazenadas na geladeira. A melhor condição para o armazenamento das raízes é em câmara fria e embaladas com saco plástico, onde as raízes mantiveram a qualidade apropriada para comercialização durante até 30 dias de armazenamento.

Effects of post-harvest treatments on the carbohydrate composition of yacon roots in the Peruvian Andes

Yacon (Smallanthus sonchifolius [Poepp. & Endl.] H. Robinson) is an under-exploited native root crop of the Andes, which stores oligofructans (fructo-oligosaccharides, FOS) as its main component of dry matter (DM). FOS are of increasing economic interest because of their low caloric value in human diets and bifidogenic benefits on colon health. Two on-farm experiments were conducted to: (i) determine the effect of shaded, short-term storage at 1990 and 2930 m a.s.l. in the Andean highlands; and (ii) address the effects of a traditional sunlight exposure (‘sunning’) on the carbohydrate composition in the DM of tuberous yacon roots. After a 6-day shade storage FOS concentrations were smaller at the lower (36–48% of DM) than at the higher altitude (39–58% of DM). After 12 days FOS concentrations were nearly equal at both sites (27–39% of DM). The concentration of free sugars (fructose, glucose, sucrose) increased accordingly from 29–34 to 48–52%. During the 6-day sunning experiment FOS concentrations decreased from 50–62 to 29–44% and free sugars increased from 29–34 to 45–51%. The results indicate that partial hydrolysis of oligofructans starts shortly after harvest. Storage in highland environments should wherever possible exploit the cooler temperatures at higher altitudes. Sunning of yacon’s tuberous roots effectively reduces much of the roots’ water content, in this experiment 40%, and thus allows energy to be saved if yacon is processed into dehydrated products.

Improvement of biochemical parameters in type 1 diabetic rats after the roots aqueous extract of yacon [Smallanthus sonchifolius (Poepp.& Endl.)] treatment

The aim of this study was to evaluate the effect of yacon (Smallanthus sonchifolius) (Poepp.& Endl.) on clinical parameters under diabetic conditions. The aqueous extract of yacon tuberous roots (YRAE; 0.76gfructankg-1 body weight) was prepared at the moment of each administration. Thirty-two male rats were divided into four groups (n=8): control group (C); group that received YRAE (Y); untreated diabetic group (DM1); and diabetic group treated with YRAE (Y-DM1). The diabetes mellitus was induced by streptozotocin (60mgkg-1 body weight). The animals from Y2 and Y-DM1 received YRAE by gavage, at 7-day intervals, for 30days. The aqueous extract of yacon roots decreased (p<0.05) the water and food intake in diabetic rats (Y-DM1). YRAE treatment reduced (p<0.05) glycaemia, total cholesterol, VLDL-c, LDL-c and triacylglycerol levels in diabetic rats (YRAE). HDL, urea and creatinine levels did not differ (p>0.05) between the Y and Y-DM1 groups. YRAE normalised alanine aminotransferase (ALT) activity, when comparing DM1 and Y-DM1 rats, but had no effect on lactate dehydrogenase activity (LDH). In conclusion, YRAE was sufficient for controlling water and food consumption, hyperglycaemia and dyslipidaemia, and promote the reduction of the ALT, suggesting a hepatoprotective effect in rats with STZ-induced DM1. © 2013 Elsevier Ltd.

Starch accumulation in cassava roots: spatial and temporal distribution

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Morfoanatomia da raiz tuberosa de Vernonia oxylepis Sch. Bip. in Mart. ex Baker - Asteraceae

Several native herbaceous and subshrub species native to the Cerrado in Brazil are geophytes, that is, they survive the unfavorable dry season and low temperatures, that sometimes coincide with fire, with only the underground system intact. Vernonia oxylepis is one of these species and the aim of this study was to describe the morpho-anatomy of the tuberous root and bud formation on this structure. The main axis of this root is perpendicular to the soil surface, and from which aerial shoots arise periodically throughout the life cycle. On the upper portion of the root, self-grafting of the shoots occurs. The root stores lipids and fructans, exhibits contraction and produces reparatory buds; adventitious buds arise from proliferated pericycle. These characteristics may be related to adaptation of this species to conditions in the Cerrado.

Underground systems of Asteraceae species from the Brazilian Cerrado

Underground systems of Asteraceac species from the Brazilian Cerrado. The aim or this study was to describe the underground systems structure, the origin of the shoot buds, and to identify the storage reserve of seven Asteraceae species in order to understand the adaptive strategies of these species in burned Cerrado areas and their higher frequency in the floristic Surveys for herbaceous and undershrub layers of this biome. The subterranean systems types-diffuse underground system, rhizophore, tuberous roots, and xylopodium-varied among the studied species, but all of them have high shoot bud-forming potential. Fructans of the inulin type were detected as storage substances. The presence of these characteristics on the underground systems Could explain the frequency of these species in the floristic surveys from the Brazilian Cerrado, in which Fire and seasonal drought are frequent. It is possible that the belowground bud banks in the Cerrado biome are as important as demonstrated in North American prairies where fire is also frequent. However, in the Cerrado, as demonstrated here, there are types of underground systems other than rhizomes that are usually described in the prairie. Understanding the anatomical features of these plants is one of the steps to appropriate conservation management of these species in the Cerrado.

Phylogeny of South American Pogonieae (Orchidaceae, Vanilloideae) based on sequences of nuclear ribosomal (ITS) and chloroplast (psaB, rbcL, rps16, and trnL-F) DNA, with emphasis on Cleistes and discussion of biogeographic implications

Tribe Pogonieae (Orchidaceae), as Currently known, comprises live genera distributed from South to North America and Eastern Asia. Phylogenetic inferences within Cleistes and among genera of tribe Pogonieae were made based oil nrDNA (ITS) and cpDNA (trnL-F, rps16, rbcL, and psaB) Sequence data and maximum parsimony. Eighteen species of Cleistes, members of all other genera of Pogonieae, and outgroups were sampled. Analyses based oil individual DNA regions provided similar topologies. All evidence indicates that Cleistes is paraphyletic. The North American C. divaricata and C bifaria are more closely related to the temperate genera Isotria and Pogonia than to their Central and South American congeners, the latter Constituting a monophyletic group characterized by the production of nectar as reward, tuberous roots, and their distribution in Central and South America. The Amazonian Duckeella is sister to the remainder of Pogonieae. Taxonomic and biogeographic implications are discussed, and morphological synapomorphies are given For clades obtained in the inferred molecular phylogeny. (C) 2008 Gesellschaft fur Biologische Systematik. Published by Elsevier GmbH. All rights reserved.

Morfoanatomia do sistema subterrâneo de Smallanthus sonchifolius (Poepp. & Endl.) H. Robinson (Asteraceae)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

O cultivo de yacon no Brasil

O yacon (Polymnia sonchifolia Poep. Endl.) é uma espécie da família Asteraceae que apresenta um complexo sistema subterrâneo. Suas raízes tuberosas e rizóforos contêm grandes quantidades de frutose e glicose livres, além de fruto-oligossacarídeos do tipo inulina como carboidrato de reserva. Vem despertando interesse principalmente por suas propriedades medicinais, sendo utilizado como auxiliar no tratamento contra diabetes e colesterol. Foi introduzido no Brasil por volta de 1989, porém somente em 1994 iniciaram-se os primeiros cultivos comerciais. Atualmente é cultivado na região de Capão Bonito (SP), a partir de rizóforos pesando de 60 a 80 g. Estes são plantados em canteiros de 0,30 - 0,40 m de altura por 1,0 m de base, em um espaçamento de 1,00 x 0,90 m. O pH do solo é ajustado para 6,0 e a fertilização básica é realizada com NPK + Zn, de acordo com análise e a recomendação utilizada para batata doce. Posteriormente são aplicados 40 kg.ha-1 de N em duas parcelas. A irrigação é feita por aspersão e a colheita realizada entre os 8 e 10 meses após o plantio, obtendo-se um rendimento médio de 80 t.ha-1 de raízes e 1 t.ha-1 de folhas desidratadas. Tanto as raízes como as folhas podem ser consumidas frescas ou desidratadas em estufas com ventilação forçada, à temperatura máxima de 50°C, para se evitar a degradação dos carboidratos de reserva e das substâncias do metabolismo secundário.

Avaliações bioquímicas séricas e hepáticas do extrato de yacon (Polymnia sonchifolia) Poepp. & Endl.

Yacon is a medicinal plant, the tuberous roots of which have been thought to contain a large amount of fructan (oligosaccharides). Purpose - The aim of paper was to study the effect of aqueous extracts of yacon on biochemical parameters of clinical importance in rats. The animals (male, wistar, weighing approximately 300g) were divided in 3 groups: G1(n=8)= water control; G2(n=8)= aqueous extract of roots (0,17g/100g/day); G3(n=8)= aqueous extract of leaves (25mg/100g/day). The serum samples were obtained after 30 days, and the biochemical parameters were measured. The livers were removed and homogenized in 0,01M phosphate buffer pH 7,0 and then the supernatant fractions were used for enzyme assay. Significantly increased serum glucose was observed in G2 (206,72±91,27 mg/dL). The groups G2 and G3 rats had higher (p<0,05) urea concentration, while creatinin level decreased (p<0,05). The serum albumin concentration showed a tendency to remain in G2 (2,44±0,45 g/dL) and G3 (2,84±0,50 g/dL). Aqueous extracts administration markedly decreased (p<0,05) the activities of ALT in the liver and greatly increased these enzymatic activities in blood. The serum alkaline phosphatase activity increased (p<0,05) in rats receiving the aqueous extract of root (192,75±20,95 U/dL), while aqueous extract of leaves reduced it (129,57±19,93 U/dL). The results indicated that the extract of yacon promoted changes of the biochemical parameters.

Atividades de peroxidase e polifenoloxidase durante o armazenamento pós - Colheita de yacon (polymnia sonchifolia poep & endl)

The purpose of this study was to investigate the peroxidase and polyphenoloxidase activities during the refrigeration at 4oC of yacon tuberous roots with and without polyethylene packing and compared with untreated roots at regular conditions. It was concluded that refrigeration treatment maintains a low activity of these enzymes and keeps good appearance of the roots.

Morfo-anatomia de raízes tuberosas de mandioca (Manihot esculenta Crantz) cultivar IAC 576-70 em diferentes preparos do solo

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Yacon (Smallanthus sonchifolius): compostos fenólicos totais e efeitos sobre a glicemia e estresse oxidativo em ratos diabéticos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)