Silvio Claudio da Costa

The anionic glycan from the cactus Cereus peruvianus : structural features and potential uses

The columnar cactusCereus peruvianus provides various compounds of interest that account for most of its 10% dry wt content. Included are acidic gum and cellulose as the highly polymerized carbohydrate components, and a complex waxy lipid fraction. The major gum fraction (1.5 g% of the fresh phytobiomass on single aqueous extraction) is an uronylated rhamnoarabinogalactan whose intrinsic viscosity may exceed 1000 mL/g. Its rheological behavior is, in part, influenced by the nativeo-acetyl and cation components, mainly Ca2+. A pigment-free powdered gum was obtained by precipitating and washing the fresh mucilage with 2–3 vol of ethanol. The almost protein-free polysaccharide forms viscous solution upon redissolution. The possible uses to be investigated for the pretreated cactus gum will be as an adjuvant in the flocculation of water impurities and in formulation of cosmetics.

The cuticle of the cactusCereus peruvianus as a source of a homo-α-d-galacturonan

The waxy pecto-cellulosic cuticle of cladodes of the columnar cactusCereus peruvianus (19% of the whole phytobiomass; dry wt) is a source of an α-d-polygalacturonic or pectic acid (35–40% yield, on a dry wt based on the wax-free pectocellulose layer). Warm EDTA/oxalate or room temperature strong acid/alkali cycles are efficient for pectic acid extraction, since divalent cation (mainly Ca2+) is a barrier to be removed within the native and compact architecture of the cuticle. Despite some molecular dispersion arising from the application of strong mineral acid in the first extraction step, the pectic material appears to be quite homogeneous and, on acid or enzymatic analyses, was shown to contain onlyd-galacturonic acid as its monomer.Cereus cuticle pectate (sodium salt) tends to gel above a concentration of 1%, a useful property that can be more easily obtained by the inclusion of sucrose, light addition of calcium salt, and/or mild acidification.

Evaluation of the potential use of rebaudioside-A as sweetener for diet jam

Sweeteners based on stevia extract contain a series of diterpene glycosides derivatives from steviol, standing out the rebaudioside-A. There is no tabletop sweeteners in the market formulated purely with rebaudioside-A yet, so its use in foods depends on the development of new products followed by physicochemical and sensory evaluations. This work presents the formulation of a diet strawberry jam dyed with cranberry juice and sweetened with rebaudioside-A purified from stevia plants of the lineage UEM-320 developed in the Centro de Estudos de Produtos Naturais da Universidade Estadual de Maringa. Evaluations of physicochemical properties, microbiological and sensory characteristics were carried out for the product in comparison with a control sweetened with equal amount of sucralose. The results showed that the physicochemical characteristics of the sample and the control are not significantly different and the supplementation with cranberry juice increased both color and total phenolic content in both samples. The sensory acceptability indicated a significant preference for the formulation sweetened with 100% of rebaudioside-A, only in the items flavor and purchase intent. We concluded that rebaudioside-A has a better sensory performance than sucralose, even this last one being 1.33 fold sweeter than rebaudioside-A.

Pentachlorophenol removal by Pleurotus pulmonarius in submerged cultures

Pentachlorophenol (PCP) removal by Pleurotus pulmonarius grown in submerged cultures in the presence and absence of laccase inducers was studied in this work. When PCP was added to a final concentration of 25 mg·L-1 in submerged cultures actively producing laccase, 70% of the PCP was removed after 96 h. The removal of PCP was less than 20% in the cultures with low laccase activity. The results suggested that laccase played an important role in the biodegradation of PCP by P. pulmonarius and that for bioremediation purposes the fungus must be cultured under the conditions of active laccase production.

Pretreatment with ethanol as an alternative to improve steviol glycosides extraction and purification from a new variety of stevia

Leaves of a new variety of Stevia rebaudiana with a high content of rebaudioside A were pretreated with ethanol. The ethanolic extract showed high antioxidant potential and 39 compounds were identified, by UPLC/HRMS, among them one not yet mentioned in the literature for stevia leaves. From the in natura leaves and pretreated leaves, the conditions of aqueous extraction of steviol glycosides were investigated using response surface methodology. The aqueous extracts obtained were purified by ion exchange chromatography techniques and membrane separation methods. The recuperation of steviol glycosides was 4.02g for pretreated leaves and 2.20g for in natura leaves. The level of purity was, respectively, 87% and 84.8%. The results obtained demonstrate that pretreatment increases the yield and purity level of stevia sweeteners by the use of environmentally friendly methodologies and the final product presented acceptable sensory characteristics.

Fortification of the whey protein isolate antioxidant and antidiabetic activity with fraction rich in phenolic compounds obtained from Stevia rebaudiana (Bert.). Bertoni leaves

AbstractA stevia fraction (ASF) free of steviol glycosides was extracted from Stevia rebaudiana leaves (Stevia UEM-13). ASF essentially constitutes phenolic compounds (52.42%), which were identified by liquid chromatography tandem mass spectrometry (LC–MS/MS) as caffeic acid, quercetin-3-o-glycoside, cyanidin-3-glucoside, kaempferol, quercetin, apigenin, rozmarinic acid, chlorogenic acid and dicaffeoylquinic acid. ASF was used as a multi-functional source of phenolic compounds to fortify the whey protein isolate (WPI) obtained by membrane separation. WPI fortified with 0.2% ASF showed an 80% increase in its antioxidant activity and more pronounced antidiabetic effects than the unfortified WPI, mainly in the glycemic control of diabetic animals induced by streptozotocin. The in vitro and in vivo antioxidant effects of ASF may enhance the effects of WPI. Indeed, this pioneering study revealed that ASF can be used to enrich the antioxidant and antidiabetic properties of WPI.

Functional properties and sensory testing of whey protein concentrate sweetened with rebaudioside A

Objective: To develop a natural dietary product with functional benefits for diabetic patients. Whey protein concentrate was obtained through the separation membrane processes and sweetened with rebaudioside A. This product was submitted to sensory testing in humans and used to evaluate possible functional properties in male Wistar rats models with diabetesMellitus induced by streptozotocin. Methods: Two concentrates were produced. Only the second showed protein content of 74.3 and 17.3% of lactose was used as supplementation in induced diabetic rats. This concentrate was obtained from the concentration by reverse osmosis system (180 k Daltons), followed by nanofiltration in a 500 k Daltons membrane and spray drying at 5.0% solution of the first concentrate developed. The concentrate was sweetened with rebaudioside A (rebaudioside A 26 mg/100 g concentrate). All procedures were performed at the Center for Studies in Natural Products, at the Universidade Estadual de Maringa. Three experimental groups were established (n=6): two groups of diabetic animals, one control group and one supplemented group; and a control group of normal mice (non-diabetic). The supplemented group received concentrates sweetened with rebaudioside A in a dose of 100 mg/kg bw/day by an esophageal tube for 35 days. Fasting, the fed state and body weight were assessed weekly for all groups. At the end of the supplementation period, the following were analyzed: plasma parameters of glucose, total cholesterol, triglycerides and fructosamine; the serum levels of aspartate aminotransferase and alanine aminotransferase, water and food intake. Organs and tissues were removed and weighed to assess mass and anatomical changes. Results: The product presented 74% of proteins and 17% of lactose and showed satisfactory sensory testing by the addition of 26 mg of rebaudioside A/100 g concentrate. Supplementation of the product reduced hyperglycemia, plasma fructosamine levels, triglycerides and total cholesterol, and improved body weight gain of streptozotocin-induced diabetic rats. Conclusion: Whey protein concentrate with substantial content of protein (above 70%) and low lactose was obtained through the membrane separation processes. The addition of rebaudioside A at the concentration of 26 mg/100 g rebaudioside A proved to be as sweet as sucralose with satisfactory sensory testing, which indicates that this is a non-caloric natural sweetener that can replace artificial sweeteners. The product (whey protein concentrate sweetened with rebaudioside A) presented important functional properties and reduced the metabolic disorders caused by the syndrome.

DETERMINAÇÃO DE TEORES DE ISOFLAVONAS COMERCIALIZADAS NA FORMA DE EXTRATO SECO E MANIPULADAS POR FARMÁCIAS

O consumo de produtos naturais, fitoterapicos e suplementos, contendo isoflavonas, aumentaram na ultima decada, especialmente pelas descobertas dos efeitos beneficos causados por estes compostos associados com o alivio de sintomas, principalmente aos causados pela menopausa em mulheres que apresentam a perda hormonal. Como nao ha trabalhos relatando quantidades minimas de isoflavonas nas formas glicosidicas (daidzina, glicitina e genistina) e agliconas (daidzeina, gliciteina e genisteina), contidas nos extratos secos e capsulas manipuladas por farmacias denominadas de manipulacao, ou ate mesmo metodologia oficial para o controle de qualidade. O presente estudo objetivou, desenvolver um metodo quantitativo de analise de isoflavonas em extrato seco de soja, utilizados como materias primas, para obtencao de capsulas fitoterapicas, comercializadas livremente sem qualquer fiscalizacao do comercio brasileiro. A analise quantitativa de isoflavonas em extrato seco de soja e manipulados foi realizada utilizando a cromatografia liquida de alta eficiencia (CLAE) revelando grandes variacoes nos teores de isoflavonas, dependendo do fornecedor e manipulador. As variacoes ocorreram para os lotes padronizados a 40% de isoflavonas em 100g de extrato e para as formas manipuladas, que sao comercializadas com rotulos de 20 mg de isoflavonas. As maiores distorcoes nos valores foram encontrados para os compostos daidzeina 60,5% e genisteina 451%. Portanto, e necessario a adocao de metodos de padronizacao e caracterizacao das materias- primas, bem como certificacao das empresas comercializadoras, uma vez que esses fitoterapicos sao, em muitas vezes, indicado seu consumo por profissionais da area medica.

Efeito do Ginseng-Brasileiro Pfaffia glomerara(spreng) Pedersen (Amaranthaceae) no Controle do Diabetes Experimental em Ratos

Este trabalho procurou investigar o efeito do tratamento de ratos diabeticos aloxânicos com o extrato aquoso das raizes da Pfaffia glomerata (Spreng) Pedersen, conhecidas popularmente como ginseng-brasileiro. Foram analisados os seguintes parâmetros: peso corporal, ingestao hidrica, diurese, ingestao alimentar, glicosuria/24hs, ureia urinaria/24hs e peso da gordura retroperitoneal e periepididimal. Os resultados obtidos nao mostraram diferencas significativas entre os grupos de ratos tratados e controle, no entanto, o grupo que recebeu o tratamento apresentou uma maior taxa de sobrevivencia.

Stevia Nonsweetener Fraction Displays an Insulinotropic Effect Involving Neurotransmission in Pancreatic Islets

Stevia rebaudiana (Bert.) Bertoni besides being a source of noncaloric sweeteners is also an important source of bioactive molecules. Many plant extracts, mostly obtained with ethyl acetate solvent, are rich in polyphenol compounds that present insulinotropic effects. To investigate whether the nonsweetener fraction, which is rich in phenolic compounds isolated from Stevia rebaudiana with the solvent ethyl acetate (EAF), has an insulinotropic effect, including interference at the terminals of the autonomic nervous system of the pancreatic islets of rats. Pancreatic islets were isolated from Wistar rats and incubated with EAF and inhibitory or stimulatory substances of insulin secretion, including cholinergic and adrenergic agonists and antagonists. EAF potentiates glucose-stimulated insulin secretion (GSIS) only in the presence of high glucose and calcium-dependent concentrations. EAF increased muscarinic insulinotropic effects in pancreatic islets, interfering with the muscarinic receptor subfamily M3. Adrenergic inhibitory effects on GSIS were attenuated in the presence of EAF, which interfered with the adrenergic α 2 receptor. Results suggest that EAF isolated from stevia leaves is a potential therapy for treating type 2 diabetes mellitus by stimulating insulin secretion only in high glucose concentrations, enhancing parasympathetic signal transduction and inhibiting sympathetic signal transduction in beta cells.