114 resultados para Hydrolyzable tannins


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Pyrostegia venusta (Ker-Gawl.) Miers (Bignoniaceae) is a species with a wide distribution in nearly all of Southern and Southeastern Brazil, has long been used in folk medicine and is considered an invasive plant. The phytotoxic potential of a hydroalcoholic extract of the flowers of P. venusta was evaluated by the germination (pre and post-emergence) and the phytotoxicity bioassays (mitotic index) on the test plant Lactuca sativa (Asteraceae) (lettuce). A phytochemical screening was performed to identify the components of the floral extract. Different concentrations of the extract caused changes in the germination parameters, the root length and the mitotic index. The phytochemical screening indicated the presence of substances such as terpenes, sterols, flavonoids, tannins and saponins, which are compounds that may be associated directly with the results of cytotoxicity and phytotoxicity observed. P. venusta has allelochemical components capable of impairing the germination and root growth of lettuce.

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Cassava leaves have been widely used as a protein source for ruminants in the tropics. However, these leaves contain high level of hydro-cyanic acid (HCN) and condensed tannins (CT). There are evidences that making hay can eliminate more than 90% of HCN and that long-term storage can reduce CT levels. A complete randomized design with four replicates was conducted to determine the effect of different storage times (0-control, 60, 90 and 120 days) on chemical composition, in vitro rumen fermentation kinetics, digestibility and energy value of cassava leaves hay. Treatments were compared by analyzing variables using the GLM procedure (SAS 9.1, SAS Institute, Inc., Cary, NC). Crude protein (CP) and ether extract (EE) of the cassava hay were not affected (P > 0.05) by storage time (17.7% and 3.0%, respectively). Neutral detergent fiber, acid detergent fiber, total carbohydrate and non-fiber carbohydrate were not affected either (P>0.05) by storage time (47.5, 32.6, 72.3 and 25.8% respectively). However, other parameters were influenced. CT was lower (P<0.05) in hay after 120 days of storage compared with control (1.75% versus 3.75%, respectively). Lignin and insoluble nitrogen in neutral detergent, analyzed without sodium sulfite, were higher (P<0.01) after 120 days of storage, compared with the control (11.22 versus 13.57 and 1.65 versus 3.81% respectively). This suggests that the CT has bound to the fiber or CP and became inactive. Consequently, the in vitro digestibility of organic matter (50.36%), total digestible nutrients (44.79%) and energy (1.61 Mcal/KgMS), obtained from gas production data at 72 h of incubation, has increased (P<0.05) with storage times (56.83%, 51.53% and 1.86 Mcal/KgMS, respectively). The chemical composition and fermentative characteristics of cassava hay suffered variations during the storage period. The best values were obtained after 90 days of storage. This is probably due to the reduction in condensed tannins.

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Moringa oleifera Lam, is a leguminous plant, originally from Asia, which is cultivated in Brazil because of its low production cost. Although some people have used this plant as food, there is little information about its chemical and nutritional characteristics. The objective of this study was to characterise the leaves of M. oleifera in terms of their chemical composition, protein fractions obtained by solubility in different systems and also to assess their nutritional quality and presence of bioactive substances. The whole leaf flour contained 28.7% crude protein, 7.1% fat, 10.9% ashes, 44.4% carbohydrate and 3.0 mg 100 g(-1) calcium and 103.1 mg 100 g(-1) iron. The protein profile revealed levels of 3.1% albumin, 0.3% globulins, 2.2% prolamin, 3.5% glutelin and 70.1% insoluble proteins. The hydrolysis of the protein from leaf flour employing sodium dodecyl sulfate (SDS) and 2-mercaptoethanol (ME) resulted in 39.5% and 29.5%, respectively. The total protein showed low in vitro digestibility (31.8%). The antinutritional substances tested were tannins (20.7 mg g(-1)), trypsin inhibitor (1.45 TIU mg g(-1)), nitrate (17 mg g(-1)) and oxalic acid (10.5 mg g(-1)), besides the absence of cyanogenic compounds. beta-Carotene and lutein stood out as major carotenoids, with concentrations of 161.0 and 47.0 mu g g(-1) leaf, respectively. Although M. oleifera leaves contain considerable amount of crude protein, this is mostly insoluble and has low in vitro digestibility, even after heat treatment and chemical attack. In vivo studies are needed to better assess the use of this leaf as a protein source in human feed. (C) 2013 Elsevier Ltd. All rights reserved.

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Herbal medicines have been widely used around the world since ancient times. The advancement of phytochemical and phytopharmacological sciences has enabled elucidation of the composition and biological activities of several medicinal plant products. The effectiveness of many species of medicinal plants depends on the supply of active compounds. Most of the biologically active constituents of extracts, such as flavonoids, tannins, and terpenoids, are highly soluble in water, but have low absorption, because they are unable to cross the lipid membranes of the cells, have excessively high molecular size, or are poorly absorbed, resulting in loss of bioavailability and efficacy. Some extracts are not used clinically because of these obstacles. It has been widely proposed to combine herbal medicine with nanotechnology, because nano-structured systems might be able to potentiate the action of plant extracts, reducing the required dose and side effects, and improving activity. Nanosystems can deliver the active constituent at a sufficient concentration during the entire treatment period, directing it to the desired site of action. Conventional treatments do not meet these requirements. The purpose of this study is to review nanotechnology- based drug delivery systems and herbal medicines.

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In the present study it was investigated, in plant and population scale, the relationship between the amount of resource and body size, species diversity and abundance and biomass of bruchids and their parasitoids. Possible effects of resource quality (soil quality and concentration of tannins in seeds) in response to the variables mentioned above were also analyzed. Mimosa bimucronata fruits were collected in two areas during the occurrence of bruchids during the years 2009 and 2010. Only the species of bruchid Acanthoscelides schrankiae was found infesting the fruits of M. bimucronata. The parasitoids belong to families Braconidae, Encyrtidae, Eulophidae, Eupelmidae, Eurytomidae and Pteromalidae. Most local-level analysis showed no significant results for both years of collection and study areas. There was only significant result for the relationship between the biomass of parasitoids and the concentration of tannins considering the year 2009 (negative trend). The soil from Lageado showed higher percentages of silt and clay. With respect to chemical analysis, pH, cation exchange capacity, and concentrations of organic matter, potassium, calcium and magnesium were all significantly higher in soil from Lageado. Therefore, it was found that the plants from Lageado are growing in more fertile soils. However, it was found that the amount of fruits and seeds was significantly higher in Rubião. Comparisons of the abundance of bruchids and parasitoids diversity among the areas that showed the highest values were observed in Rubião. In this study it was found that the abundance of bruchids and parasitoids, as well as the diversity of parasitoids was greatest in the area that had higher amounts of fruits and seeds, suggesting a significant relationship between the amount of resources and the abundance and diversity. However, it is possible that ...(Complete abstract click electronic access below)

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Pós-graduação em Ciência dos Materiais - FEIS

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Natural rubber latex from Hevea brasiliensis has interesting characteristics related to this work such as: it is easy to manipulate, low cost, can stimulate the natural angiogenesis, is a biocompatible material and presents high mechanical resistance. The aim of this study was to develop a novel sustained delivery system for Stryphnodendron sp. based on Natural Rubber Latex (NRL) membranes and to study the Stryphnodendron sp. delivery system behavior. Stryphnodendron sp., commonly known as barbatimao is extensively used in folk medicine for the treatment of diarrhoea, gynaecological problems and for healing wounds. The stem bark of this species is mentioned in the Brazilian Pharmacopeia with a content of at least 20% of tannins. Previous studies showed significant cicatrizant properties, anti-inflammatory activity and gastric anti-ulcerogenic effects for the stem bark crude extract. One possible way to accelerate the tissue repair process, it was incorporated the Stryphnodendron sp. extract in NRL membranes. Stryphnodendron sp extract was incorporated into the NRL, by mixing it in solution for in vitro protein delivery experiments. Results show that the NRL membrane can release Stryphnodendron sp. for up to 49.89% of its Stryphnodendron sp. content for up 400 h. The kinetics of the extract release could be fitted with double exponential function, with two characteristic times of 0.78 and 133.22 h. In this study, we demonstrated that the induced angiogenesis provided by NRL membranes combined with a controlled release of extract is relevant for biomedical applications.

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