Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 2.781
Filtrar
1.
Food Chem ; 367: 130738, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34384978

RESUMO

A homogeneous galactoglucan was purified from the alkali-extracted polysaccharides from the basidioma of Macrolepiota albuminosa by gradient ethanol precipitation, whose proposed structure was given for the first time. Results showed it had a molecular weight of 210 kDa, and mainly consisted of glucose and galactose. There were abundant filaments, randomly distributed sheet-like and flaky appearance in its surface by SEM observation. Its backbone comprised ß-(1 â†’ 6)-Glcp, α-(1 â†’ 6)-Galp and ß-(1 â†’ 3,6)-Glcp residues at 4:1:1, terminated by ß-(1 â†’ 3)-Glcp and T-Glcp residues. Rheological measurements suggested its steady flow behavior was highly dependent on concentrations. Newtonian behavior was evident at low concentrations, whereas pseudoplastic behavior was observed at high concentrations. Besides, the X-ray diffraction patterns proved the presence of amorphous structure. The conformational parameters were detected by HPSEC-MALLS-RI, revealing a random coil conformation in NaNO3 aqueous solution. This work provides a theoretical basis for the application of polysaccharides from M. albuminosa in food- and drug-based therapies.


Assuntos
Galactanos , Polissacarídeos Bacterianos , Glucanos , Peso Molecular , Polissacarídeos
2.
Molecules ; 26(17)2021 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-34500801

RESUMO

The process of sulfation of arabinogalactan-a natural polysaccharide from Larix sibirica Ledeb.-with sulfamic acid in 1,4-dioxane using different activators has been studied for the first time. The dynamics of the molecular weight of sulfated arabinogalactan upon variation in the temperature and time of sulfation of arabinogalactan with sulfamic acid in 1,4-dioxane has been investigated. It has been found that, as the sulfation time increases from 10 to 90 min, the molecular weights of the reaction products grow due to the introduction of sulfate groups without significant destruction of the initial polymer and sulfation products. Sulfation at 95 °C for 20 min yields the products with a higher molecular weight than in the case of sulfation at 85 °C, which is related to an increase in the sulfation rate; however, during the further process occurring under these conditions, sulfation is accompanied by the destruction and the molecular weight of the sulfated polymer decreases. The numerical optimization of arabinogalactan sulfation process has been performed. It has been shown that the optimal parameters for obtaining a product with a high sulfur content are a sulfamic acid amount of 20 mmol per 1 g of arabinogalactan, a process temperature of 85 °C, and a process time of 2.5 h.


Assuntos
Galactanos/isolamento & purificação , Larix/química , Sulfatos/química , Configuração de Carboidratos , Galactanos/química , Modelos Moleculares , Peso Molecular , Temperatura
3.
PLoS One ; 16(9): e0257692, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34547054

RESUMO

The growth period, phenology, grain yield and gum content of two different guar ecotypes were studied in response to different sowing dates and plant densities. A two-year field experiment was conducted as a split-factorial in a randomized complete block design (RCBD) with three replicates in the research field of Tarbiat Modares University during 2016 and 2017 growing season. Main plots consisted of four sowing dates (May 21, June 4, June 21 and July 5 in 2016 and May 10, May 26, June 10 and June 26 in 2017), and subplots including three plant densities (13, 20 and 40 plants m-2) and two ecotypes (Pakistani and Indian). Based on findings, the phenological traits, plant height, grain yield and harvest index were significantly affected by plant density. The effect of ecotypes was statistically significant (p<0.05) on all traits except harvest index in the first year. Furthermore, the seed sowings on May 21 and May 26 with 13 plants m-2 led to highest grain yield (3004.8 and 2826.10 kg.ha-1 for two consecutive years). The high gum content (33.68 and 33.78% for two consecutive years) was also recorded for Pakistani ecotype while for gravity, Indian ecotype showed higher value in both crop years. By and large, the Pakistani ecotype showed better response compared to the Indian one in both years, especially in 1st and 2nd sowing dates.


Assuntos
Produção Agrícola/métodos , Cyamopsis/crescimento & desenvolvimento , Ecossistema , Galactanos/isolamento & purificação , Mananas/isolamento & purificação , Gomas Vegetais/isolamento & purificação , Solo
4.
Langmuir ; 37(35): 10547-10559, 2021 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-34427446

RESUMO

Adsorption of five different hyperbranched arabinogalactan-protein (AGP) fractions from Acacia senegal gum was thoroughly studied at the solid-liquid interface using a quartz crystal microbalance with dissipation monitoring (QCM-D), surface plasmon resonance (SPR), and atomic force microscopy (AFM). The impact of the protein/sugar ratio, molecular weight, and aggregation state on the adsorption capacity was investigated by studying AGP fractions with different structural and biochemical features. Adsorption on a solid surface would be primarily driven by the protein moiety of the AGPs through hydrophobic forces and electrostatic interactions. Increasing ionic strength allows the decrease in electrostatic repulsions and, therefore, the formation of high-coverage films with aggregates on the surface. However, the maximum adsorption capacity was not reached by fractions with a higher protein content but by a fraction that contains an average protein quantity and presents a high content of high-molecular-weight AGPs. The results of this thorough study highlighted that the AGP surface adsorption process would depend not only on the protein moiety and high-molecular-weight AGP content but also on other parameters such as the structural accessibility of proteins, the molecular weight distribution, and the AGP flexibility, allowing structural rearrangements on the surface and spreading to form a viscoelastic film.


Assuntos
Acacia , Adsorção , Galactanos , Mucoproteínas , Proteínas de Plantas , Técnicas de Microbalança de Cristal de Quartzo , Senegal , Propriedades de Superfície
5.
J Environ Manage ; 299: 113591, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34455350

RESUMO

An annular bioreactor (ABR) with wide gap was used for PHB production from Ralstonia eutropha. Hydrodynamic studies demonstrated the uniform distribution of fluid in the ABR due to the Taylor-Couette flow. Thereafter, the ABR was operated at different agitation and sparging rates to study its effect on R. eutropha growth and PHB production. The ABR operated at 500 rpm with air sparge rate of 0.8 vvm yielded a maximum PHB concentration of 14.89 g/L, which was nearly 1.4 times that obtained using a conventional stirred-tank bioreactor (STBR). Furthermore, performances of the bioreactors were compared by operating the reactors under fed-batch mode. At the end of 90 h of operation, the ABR resulted in a very high PHB production of 70.8 g/L. But STBR resulted in a low PHB concentration of 44.2 g/L. The superior performance was due to enhanced oxygen and nutrient mass transfer in the ABR.


Assuntos
Cupriavidus necator , Reatores Biológicos , Galactanos , Hidroxibutiratos , Mananas , Extratos Vegetais , Gomas Vegetais , Poliésteres
6.
Biomacromolecules ; 22(9): 3731-3745, 2021 09 13.
Artigo em Inglês | MEDLINE | ID: mdl-34436877

RESUMO

Local delivery of anticancer agents via injectable hydrogels could be a promising method for achieving spatiotemporal control on drug release as well as minimizing the disadvantages related to the systemic mode of drug delivery. Keeping this in mind, we report the development of N,O-carboxymethyl chitosan (N,O-CMCS)-guar gum-based injectable hydrogels for the sustained delivery of anticancer drugs. The hydrogels were synthesized by chemical crosslinking of multialdehyde guar gum (MAGG) and N,O-CMCS through dynamic Schiff base linkages, without requiring any external crosslinker. Fabrication of injectable hydrogels, involving N,O-CMCS and MAGG via Schiff base crosslinking, is being reported for the first time. The hydrogels exhibited pH-responsive swelling behavior and good mechanical properties with a storage modulus of about 1625 Pa. Due to the reversible nature of Schiff base linkages, hydrogels displayed excellent self-healing and thixotropic properties. Doxorubicin (Dox), an anticancer agent, was loaded onto these hydrogels and its release studies were conducted at pH 7.4 (physiological) and pH 5.5 (tumoral). A sustained release of about 67.06% Dox was observed from the hydrogel after 5 days at pH 5.5 and about 32.13% at pH 7.4. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay on the human embryonic kidney cell line (HEK-293) and the hemolytic assay demonstrated the biocompatible nature of the hydrogels. The Dox-loaded hydrogel exhibited a significant killing effect against breast cancer cells (MCF-7) with a cytotoxicity of about 72.13%. All the data presented support the efficiency of the synthesized N,O-CMCS/MAGG hydrogel as a biomaterial that may find promising applications in anticancer drug delivery.


Assuntos
Antineoplásicos , Quitosana , Antineoplásicos/farmacologia , Liberação Controlada de Fármacos , Galactanos , Células HEK293 , Humanos , Hidrogéis , Concentração de Íons de Hidrogênio , Mananas , Gomas Vegetais
7.
Cells ; 10(8)2021 07 30.
Artigo em Inglês | MEDLINE | ID: mdl-34440704

RESUMO

Novel molecular pinball machines of the plasma membrane control cytosolic Ca2+ levels that regulate plant metabolism. The essential components involve: 1. an auxin-activated proton pump; 2. arabinogalactan glycoproteins (AGPs); 3. Ca2+ channels; 4. auxin-efflux "PIN" proteins. Typical pinball machines release pinballs that trigger various sound and visual effects. However, in plants, "proton pinballs" eject Ca2+ bound by paired glucuronic acid residues of numerous glycomodules in periplasmic AGP-Ca2+. Freed Ca2+ ions flow down the electrostatic gradient through open Ca2+ channels into the cytosol, thus activating numerous Ca2+-dependent activities. Clearly, cytosolic Ca2+ levels depend on the activity of the proton pump, the state of Ca2+ channels and the size of the periplasmic AGP-Ca2+ capacitor; proton pump activation is a major regulatory focal point tightly controlled by the supply of auxin. Auxin efflux carriers conveniently known as "PIN" proteins (null mutants are pin-shaped) pump auxin from cell to cell. Mechanosensitive Ca2+ channels and their activation by reactive oxygen species (ROS) are yet another factor regulating cytosolic Ca2+. Cell expansion also triggers proton pump/pinball activity by the mechanotransduction of wall stress via Hechtian adhesion, thus forming a Hechtian oscillator that underlies cycles of wall plasticity and oscillatory growth. Finally, the Ca2+ homeostasis of plants depends on cell surface external storage as a source of dynamic Ca2+, unlike the internal ER storage source of animals, where the added regulatory complexities ranging from vitamin D to parathormone contrast with the elegant simplicity of plant life. This paper summarizes a sixty-year Odyssey.


Assuntos
Sinalização do Cálcio , Cálcio/metabolismo , Membrana Celular/metabolismo , Mecanotransdução Celular , Proteínas de Membrana Transportadoras/metabolismo , Mucoproteínas/metabolismo , Reguladores de Crescimento de Plantas/metabolismo , Plantas/metabolismo , Canais de Cálcio/metabolismo , Galactanos/metabolismo , Ácidos Indolacéticos/metabolismo , Desenvolvimento Vegetal , Proteínas de Plantas/metabolismo , Bombas de Próton/metabolismo , Espécies Reativas de Oxigênio , Estresse Mecânico
8.
Cells ; 10(8)2021 07 24.
Artigo em Inglês | MEDLINE | ID: mdl-34440649

RESUMO

Arabinogalactan proteins (AGPs) are a class of heavily glycosylated proteins occurring as a structural element of the cell wall-plasma membrane continuum. The features of AGPs described earlier suggest that the proteins may be implicated in plant adaptation to stress conditions in important developmental phases during the plant reproduction process. In this paper, the microscopic and immunocytochemical studies conducted using specific antibodies (JIM13, JIM15, MAC207) recognizing the carbohydrate chains of AGPs showed significant changes in the AGP distribution in female and male reproductive structures during the first stages of Bellis perennis development. In typical conditions, AGPs are characterized by a specific persistent spatio-temporal pattern of distribution. AGP epitopes are visible in the cell walls of somatic cells and in the megasporocyte walls, megaspores, and embryo sac at every stage of formation. During development in stress conditions, the AGP localization is altered, and AGPs entirely disappear in the embryo sac wall. In the case of male development, AGPs are present in the tapetum, microsporocytes, and microspores in normal conditions. In response to development at lower temperature, AGPs are localized in the common wall of microspores and in mature pollen grains. Additionally, they are accumulated in remnants of tapetum cells.


Assuntos
Asteraceae/metabolismo , Temperatura Baixa , Galactanos/metabolismo , Gametogênese Vegetal , Mucoproteínas/metabolismo , Óvulo Vegetal/metabolismo , Processamento de Proteína Pós-Traducional , Asteraceae/embriologia , Asteraceae/crescimento & desenvolvimento , Glicosilação , Imuno-Histoquímica , Microscopia Confocal , Óvulo Vegetal/embriologia , Óvulo Vegetal/crescimento & desenvolvimento , Proteínas de Plantas/metabolismo , Fatores de Tempo
9.
J Dairy Res ; 88(3): 343-350, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34289915

RESUMO

The beneficial effects of a healthy diet on the quality of life have prompted the food industry to develop low-fat variants, but fat content directly affects the physicochemical and sensory properties of food products. The utilization of high-pressure homogenization (HP) and incorporation of hydrocolloids have been suggested as strategies to improve the physical stability and rheological properties of light cream. Thus, this study aims to analyze the associated effect of high-pressure homogenization (80 MPa) and three different hydrocolloids: microcrystalline cellulose, locust bean gum and xanthan gum, on emulsion stability and rheological properties of ultra-high-temperature (UHT) light cream (ULC) with a 15% w/w fat content. The stability of ULC was determined by the ζ potential of oil droplets and emulsion stability percentage. Rheological characterization was based on flow behavior tests and dynamic oscillatory measurements, which were carried out in a rheometer. Results showed that the high-pressure homogenization process did not influence the emulsion stability of the treatments. Moreover, the hydrocolloids added to systems present weak interactions with milk proteins since all ULC showed macroscopical phase separation. The samples presented the same rheological behavior and were classified as pseudoplastic fluids (n < 1). ULC treated at 80 MPa was significantly (P ≤ 0.05) more consistent than the treatments at 20 MPa. All ULC showed a predominant elastic behavior (G' > G″), and a remarkable increase in both G' and G″ at 80 MPa. The results presented in this study highlight the potential of HP for altering some rheological characteristics of UHT light cream, for example, to increase its consistency. These results are important for the dairy industry and ingredient suppliers, in the standardization of UHT light cream and/or to develop low-fat products.


Assuntos
Coloides/administração & dosagem , Laticínios , Gorduras na Dieta/análise , Manipulação de Alimentos/métodos , Temperatura Alta , Leite/química , Animais , Celulose , Fenômenos Químicos , Dieta com Restrição de Gorduras , Emulsões , Galactanos , Mananas , Gomas Vegetais , Polissacarídeos Bacterianos , Pressão , Reologia
10.
Carbohydr Polym ; 269: 118331, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34294341

RESUMO

This study aimed to extract polysaccharides from citron and analyze their structures and potential bioactivities. Two novel polysaccharides CM-1 and CM-2 were purified from citron by DEAE-Sepharose Fast Flow and Sephadex G-100 column chromatography. Monosaccharide composition, linkage and NMR data were used to infer their sugar chains composition. The anti-breast cancer cells and immunoregulatory activities of CM-1 and CM-2 were investigated. Results indicated that CM-1 (Mw = 21,520 Da), composed of arabinose, xylose, mannose and glucose in a molar ratio of 10.78:11.53:1.00:1.70, was arabinoxylan (AX) with (1 â†’ 4)-linked ß-d-Xylp skeleton monosubstituted with α-l-Araf units at O-3 position. While CM-2 (Mw = 22,303 Da), composed of arabinose, mannose, glucose and galactose in a molar ratio of 25.46:1.45:1.00:6.57, was galactoarabinan (GA) with (1 â†’ 5)-linked α-l-Araf backbone substituted by ß-d-Galp units at O-2 and/or O-3 positions. Both polysaccharides exhibited potential inhibiting cancer and immunostimulatory activities in vitro, especially CM-1. These results provide a basis for further research on citron polysaccharides.


Assuntos
Antineoplásicos/farmacologia , Citrus/química , Galactanos/farmacologia , Fatores Imunológicos/farmacologia , Xilanos/farmacologia , Animais , Antineoplásicos/química , Antineoplásicos/isolamento & purificação , Antineoplásicos/toxicidade , Sequência de Carboidratos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Galactanos/química , Galactanos/isolamento & purificação , Galactanos/toxicidade , Humanos , Fatores Imunológicos/química , Fatores Imunológicos/isolamento & purificação , Fatores Imunológicos/toxicidade , Interleucina-6/metabolismo , Camundongos , Peso Molecular , Óxido Nítrico Sintase Tipo II/metabolismo , Células RAW 264.7 , Fator de Necrose Tumoral alfa/metabolismo , Xilanos/química , Xilanos/isolamento & purificação , Xilanos/toxicidade
11.
Molecules ; 26(13)2021 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-34209325

RESUMO

Polysaccharides can form interfacial complexes with proteins to form emulsions with enhanced stability. We assessed the effect of adding gum guar or gum arabic to egg yolk/fish oil emulsions. The emulsions were produced using simple or high-pressure homogenization, stored for up to 10 days at 45 °C, and characterized for their particle size and distribution, viscosity, encapsulation efficiency, oxidative stability, and cytotoxicity. Emulsions containing gum guar and/or triglycerides had the highest viscosity. There was no significant difference in the encapsulation efficiency of emulsions regardless of the polysaccharide used. However, emulsions containing gum arabic displayed a bridging flocculation effect, resulting in less stability over time compared to those using gum guar. Emulsions produced using high-pressure homogenization displayed a narrower size distribution and higher stability. The formation of peroxides and propanal was lower in emulsions containing gum guar and was attributed to the surface oil. No significant toxicity toward Caco-2 cells was found from the emulsions over time. On the other hand, after 10 days of storage, nonencapsulated fish oil reduced the cell viability to about 80%. The results showed that gum guar can increase the particle stability of egg yolk/fish oil emulsions and decrease the oxidation rate of omega-3 fatty acids.


Assuntos
Gema de Ovo/química , Óleos de Peixe/química , Galactanos/química , Goma Arábica/química , Mananas/química , Gomas Vegetais/química , Polissacarídeos/química , Células CACO-2 , Emulsões , Óleos de Peixe/farmacologia , Galactanos/farmacologia , Goma Arábica/farmacologia , Humanos , Mananas/farmacologia , Oxirredução , Gomas Vegetais/farmacologia , Polissacarídeos/farmacologia
12.
J Biotechnol ; 335: 47-54, 2021 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-34118331

RESUMO

Haloalkane dehalogenase DhaA can catalyze the hydrolytic cleavage of carbonhalogen bonds, along with production of the corresponding alcohol, a proton and a halide. However, DhaA suffers from poor environmental tolerance, such as sensitivity to high temperature, low pH and hypersaline. Arabinogalactan (AG) is a hydrophilic polysaccharide with highly branched long chains. DhaA was conjugated with AG to improve the environmental stability of DhaA in the present study. Each DhaA was averagely conjugated with 4∼5 AG molecules. Conjugation of AG essentially maintained the enzymatic activity of DhaA (91.4 %) without apparent structural alteration. The hydration layer formed by AG could reduce the solvent accessible area of DhaA and slow the protonation process, thereby improving the pH and high salt stability of DhaA. In particular, the remaining activities of the conjugate (AG-DhaA) were 35.3 % after treatment at pH4.0 for 1 h, and 80.8 % in 1 M NaCl after treatment for 16 h. As compared with DhaA, AG-DhaA showed slightly different kinetic parameters (K M of 1.90 µmol/L and k cat of 2.60 s -1).


Assuntos
Rhodococcus , Galactanos , Hidrolases
13.
Carbohydr Polym ; 267: 118172, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34119144

RESUMO

The fruit of Lycium ruthenicum Murr is used as traditional medicine and functional food. Previously we reported that one RG-I pectin from this fruit might inhibit pancreatic cancer cells growth. We further hypothesized that there might be other type of polysaccharides in this fruit also have anti-tumor effect. Here, we showed novel structure of a homogeneous polysaccharide named LRP1-S2 from this fruit and its anti-pancreatic cancer effect. Structure analyses suggested that LRP1-S2 was a novel arabinogalactan with the molecular weight (Mw) of 17.0 kDa. Bioactivity test showed that LRP1-S2 might attenuate the proliferation of pancreatic cancer cells in vitro and in vivo without significant cytotoxicity to normal pancreatic HPDE6-C7 cells and LO2 liver cells. Mechanism study indicated that it might induce apoptosis of BxPC-3 by inactivating P38 MAPK/NF-κB and GSK-3ß/ß-Catenin signaling pathways. These results suggested that LRP1-S2 could be a potential anti-tumor leading compound for functional food and new drug development. CHEMICAL COMPOUNDS: arabinogalactan, pectin, galactan, arabinan, RN-1, HH1-1, LRP1-S2, LRP3-S1.


Assuntos
Antineoplásicos/uso terapêutico , Galactanos/uso terapêutico , Neoplasias Pancreáticas/tratamento farmacológico , Animais , Antineoplásicos/química , Antineoplásicos/isolamento & purificação , Antineoplásicos/toxicidade , Apoptose/efeitos dos fármacos , Sequência de Carboidratos , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Frutas/química , Galactanos/química , Galactanos/isolamento & purificação , Galactanos/toxicidade , Humanos , Lycium/química , Camundongos Endogâmicos BALB C , Camundongos Nus , Transdução de Sinais/efeitos dos fármacos , Ensaios Antitumorais Modelo de Xenoenxerto
14.
Carbohydr Polym ; 267: 118183, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34119151

RESUMO

Fluorescence probing was used to study hydrophobic interactions of galactomannan (GM) obtained from fenugreek gum (FG), guar gum (GG), and locust bean gum (LBG) at different M/G ratios. The I1/I3 ratio of pyrene changed from 1.73 to 1.29, 1.22, and 1.29 for FG, GG and LBG, respectively, as the concentration of GM increased from 0.01 to 8.0 g/L at 30 °C. The critical aggregation concentration of FG, GG, and LBG increased from 1.04 to 3.84 g/L, 1.15 to 3.73 g/L, and 0.94 to 3.63 g/L, respectively, as temperature increased from 10 to 70 °C. Addition of Na2SO4 and NaSCN increased the I1/I3 ratio in dilute solution, but reduced it in semi-dilute solution, whereas adding urea reduced I1/I3 in dilute solution but increased it in semi-dilute solution. These results indicated that the CAC of GM, polarity and number of hydrophobic microdomains were highly dependent on the M/G ratio and galactose distribution.


Assuntos
Interações Hidrofóbicas e Hidrofílicas , Mananas/química , Sequência de Carboidratos , Corantes Fluorescentes/química , Galactanos/química , Gomas Vegetais/química , Pirenos/química , Sulfatos/química , Temperatura , Tiocianatos/química , Trigonella/química , Ureia/química
15.
Carbohydr Polym ; 267: 118190, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34119158

RESUMO

Cryotropic gelation is one of the most common approaches to design novel hydrogels with multifaceted technological and biological functionalities. In the present paper, we studied the ability of highly galactosyl-substituted galactomannans, i.e. fenugreek and alfalfa gum, to form physically crosslinked hydrogels via cryogenic processing. Cycling of the galactomannan solutions (0.25 to 4% wt) from 25 to -20 to 25 °C induced the physical crosslinking of the galactomannan chains leading to the formation of different cryogel structures, i.e. filamentous aggregates (c* < c < 1%), cellular-like gel networks (1 ≤ c < 4%) or a homogeneously swollen gel (c ≥ 4%), depending on the total biopolymer content. Alfalfa gum-based cryogels exhibited higher elasticity and stiffness, better uniformity of the structure and a lower macropore size than their fenugreek counterparts. The physical blending of alfalfa or fenugreek gum with locust bean gum (2% total biopolymer) led to the reinforcement of the mechanical properties of the cryogels without significantly altering their microstructural aspects.


Assuntos
Criogéis/química , Mananas/química , Medicago sativa/química , Sementes/química , Trigonella/química , Módulo de Elasticidade , Fabaceae/química , Galactanos/química , Gomas Vegetais/química , Porosidade
16.
Carbohydr Polym ; 267: 118212, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34119167

RESUMO

Cranberries of Stevens variety, mainly used for juice production, were processed into pomace, from which alcohol insoluble solids (AIS) were obtained. The cell wall polysaccharides were sequentially extracted from AIS, and characterized in terms of monosaccharide profile, sugar linkage and molecular weight distribution. Pectic polysaccharides represented more than 90% of the carbohydrates contained in hot buffer (HA), chelating agents (CH) and diluted alkali (DA) extracts. HA extract contained homogalacturonan with 75% being methyl esterified, and pectic arabinan with traces of pectic galactan, type II arabinogalactan and 1,4-ß-glucan. CH extract, recovered with the highest yield (11.0% w/w), was composed mainly of homogalacturonan. DA extract included homogalacturonan with 2% methyl esterification, abundant arabinan and galactans and traces of 1,4-ß-glucan. Glucomannan, xylan and xyloglucan represented 66% of the carbohydrates present in the last concentrated alkali extract (CA), the rest being pectic arabinan and galactan. High molecular weight polysaccharides (>102 kDa) were identified in all extracts.


Assuntos
Parede Celular/química , Galactanos/química , Pectinas/química , Vaccinium macrocarpon/química , Frutas/química , Galactanos/isolamento & purificação , Ácidos Hexurônicos/química , Peso Molecular , Pectinas/isolamento & purificação
17.
Carbohydr Polym ; 267: 118219, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34119173

RESUMO

Polygonatum cyrtonema is a known tonic herb in Chinese Materia Medica, extensively consumed in China, but the structure and activity of its polysaccharide components remain to be clarified. Herein, two new polysaccharides (a fructan and a galactan) were purified from the dried and the processed P. cyrtonema rhizome, respectively. Structural analysis suggested that the fructan consisted of a (2 â†’ 6) linked ß-d-Fruf residues backbone with an internal α-d-Glcp residue and two (2 â†’ 1) linked ß-d-Fruf residues branches, and that the galactan was a (1 â†’ 4)-ß-d-galactan branched with a single ß-d-galactose at C-6 at about every nine residues in its main chain. The bioactive assay showed that the fructan and the galactan remarkably promoted growth of Bifidobacterium and Lactobacillus strains, indicating that they possess prebiotic activity. These findings may help expand the application of the polysaccharides from the tonic herb P. cyrtonema as functional ingredients in food products.


Assuntos
Frutanos/química , Frutanos/metabolismo , Galactanos/química , Galactanos/metabolismo , Polygonatum/química , Bifidobacterium/metabolismo , Sequência de Carboidratos , Frutanos/isolamento & purificação , Galactanos/isolamento & purificação , Lactobacillus/metabolismo , Peso Molecular , Prebióticos
18.
Int J Biol Macromol ; 183: 1987-2000, 2021 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-34087302

RESUMO

The aim of the present study was to obtain a better and safer galactomannan-based material for drug release applications. A novel epoxy-crosslinked galactomannan hydrogel (EGH) was prepared from guar gum using 1,4-butanediol diglycidyl ether as a crosslinking agent. The diffusion rate constant of water molecules in freeze-dried EGH positively correlated with water uptake/equilibrium swelling rate (WU/ESR), and the water molecules participated in Fickian diffusion. The ESR, WU/ESR, and bovine serum albumin (BSA) loading capacity of a customized EGH with a crosslinking density of 48.9% were 48.7 ± 0.15 g/g, 95.3%, and 56.4 mg/g, respectively. The release of BSA from freeze-dried EGH was affected by the WU/ESR and the pH; the release equilibrium time was ~40 h at pH 1.2, decreasing to ~24 h at pH 7.4. Furthermore, the cumulative release rate increased from 63.5% to 80.7% and the t50 decreased from 59 to 41 min upon changing from the acidic to basic pH. The release process conformed to the Ritger-Peppas and Hixson-Crowell models, and represented Fickian diffusion and chain relaxation. The EGH showed no cytotoxicity toward HeLa cells. Together, these results demonstrate the properties of a novel galactomannan-based hydrogel that can potentially be employed as a vehicle for drug delivery.


Assuntos
Butileno Glicóis/química , Hidrogéis/química , Mananas/química , Soroalbumina Bovina/química , Sistemas de Liberação de Medicamentos , Liberação Controlada de Fármacos , Liofilização , Galactanos/química , Células HeLa , Humanos , Concentração de Íons de Hidrogênio , Gomas Vegetais/química , Água
19.
Int J Biol Macromol ; 183: 2174-2183, 2021 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-34102237

RESUMO

Guar gum (plant-based polysaccharide) is a promising candidate with immense potential. It is used as emulsifier, thickener, stabilizer, and as binding agent in many industries. In the present project, it was planned to synthesize guar gum based polyurethanes by varying the amount of guar gum. Guar gum (GG) was used along with hydroxyl-terminated polybutadiene (HTPB) as soft segment, which was then reacted with isophorone diisocyanate (IPDI) to form PU pre-polymers. In last step, these -NCO terminated pre-polymers were extended with 1,4 butane diol as chain extender. The prepared polyurethane samples were then characterized by using FTIR, solid-state 1HNMR and X-ray diffraction (XRD). Thermal behavior of the samples was studied by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Results indicated that the incorporation of guar gum in PU backbone improved its thermal behavior and crystallinity.


Assuntos
Galactanos/química , Mananas/química , Gomas Vegetais/química , Poliuretanos/química , Butadienos/química , Butileno Glicóis/química , Cristalização , Elastômeros/química , Isocianatos/química , Estrutura Molecular , Relação Estrutura-Atividade , Temperatura
20.
Ultrason Sonochem ; 76: 105630, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34146974

RESUMO

Polyphenols in carobs have recently attracted great attention due to their wide range of biological and health promoting effects. A comprehensive study was conducted to find an optimum method for the extraction, purification and characterization of these valuable bioactive substances. Under this framework, the ultrasound-assisted extraction (UAE) of polyphenols from carob pulp was optimized by the maximization of the yield in total phenolics using response surface methodology. In particular, the effects of solid-solvent ratio, solvent concentration, extraction time, sonication amplitude, and sonication mode were investigated and optimized using a complete experimental design. In comparison to conventional extraction techniques, UAE offered a higher yield of antioxidants and a shorter processing time. Solid-phase extraction was evaluated as a clean-up strategy prior to the electrophoretic analysis of extracts. The results from the analysis of real samples revealed the predominance of gallic acid and highlighted the great influence of the ripening stage on carobs composition.


Assuntos
Antioxidantes/química , Antioxidantes/isolamento & purificação , Fracionamento Químico/métodos , Galactanos/química , Mananas/química , Gomas Vegetais/química , Polifenóis/análise , Ondas Ultrassônicas , Solventes/química
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...