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1.
J Ethnopharmacol ; 247: 112281, 2020 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-31600559

RESUMO

ETHNOPHARMACOLOGICAL RELEVANCE: Artemisia annua L. is a heat-clearing Chinese medicine and well-known for its antimalarial constituent, artemisinin. It has gained increasing attention for its anti-inflammatory and immunoregulatory activities. Interestingly, the crude polysaccahrides of A. annua exhibited potent anticomplement activity. This study was to isolate and characterize its anticomplement homogeneous polysaccharides from A. annua, and reveal the relationship between structures and anticomplement activities of the isolated polysaccharides. MATERIALS AND METHODS: Water-soluble crude polysaccharides from the aerial parts of A. annua were extracted and fractionated by DEAE-cellulose and Sephacryl S-300 gel permeation chromatography. Homogeneity, molecular weight, monosaccharide composition, methylation and NMR analysis were performed to characterize the structures of homogeneous polysaccharides. Their anticomplement activities and targeting components in the complement activation cascade were evaluated by hemolytic assays. RESULTS: Three homogeneous polysaccharides (AAP01-1, AAP01-2 and AAP01-3) were obtained from A. annua. AAP01-1 was composed of seven monosaccharides, including mannose, rhamnose, glucuronic acid, galacturonic acid, glucose, galactose and arabinose. AAP01-2 and AAP01-3 had similar monosaccharides with AAP01-1, except the absence of glucuronic acid. They were all branched acidic heteropolysaccharides with different contents of galacturonic acid (8%, 28% and 15% for AAP01-1, AAP01-2 and AAP01-3, respectively). AAP01-2 showed potent anticomplement activity with CH50 value of 0.360 ±â€¯0.020 mg/mL through the classical pathway and AP50 value of 0.547 ±â€¯0.033 mg/mL through the alternative pathway. AAP01-3 exhibited slightly weaker activity (CH50: 1.120 ±â€¯0.052 mg/mL, AP50: 1.283 ±â€¯0.061 mg/mL), while AAP01-1 was inactive. Moreover, AAP01-2 acted on C1q, C3, C4, C5 and C9 components and AAP01-3 interacted with C3, C4 and C5 components in the activation cascade of complement system. CONCLUSION: These results indicated that the relatively high contents of galacturonic acid were important for anticomplement activities of the polysaccharides from A. annua. The anticomplement polysaccharides are another kind of bioactive constituents conferring heat-clearing effects of A. annua.


Assuntos
Artemisia annua/química , Ativação do Complemento/efeitos dos fármacos , Inativadores do Complemento/farmacologia , Medicamentos de Ervas Chinesas/farmacologia , Polissacarídeos/farmacologia , Animais , Bioensaio , Inativadores do Complemento/química , Inativadores do Complemento/isolamento & purificação , Proteínas do Sistema Complemento , Medicamentos de Ervas Chinesas/química , Medicamentos de Ervas Chinesas/isolamento & purificação , Cobaias , Hemólise/efeitos dos fármacos , Ácidos Hexurônicos/química , Ácidos Hexurônicos/isolamento & purificação , Ácidos Hexurônicos/farmacologia , Modelos Animais , Estrutura Molecular , Componentes Aéreos da Planta/química , Coelhos , Relação Estrutura-Atividade
3.
Molecules ; 24(11)2019 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-31181702

RESUMO

: Pectin was extracted from apple (Malus domestica 'Falticeni') pomace with Celluclast 1.5L, at doses of 20, 40, and 60 µL/g of material. The temperature and time of extraction were varied on three levels-temperature-40, 50, and 60 °C; time-12, 18, and 24 h. For each experiment, the extraction yield (R2 = 0.8905), the galacturonic acid content (R2 = 0.9866), and the degree of esterification (R2 = 0.9520) of pectin was determined. Response surface methodology (RSM) was implemented via a Box-Behnken design, to optimize pectin extraction. In the optimum extraction conditions (temperature of 48.3 °C, extraction time of 18 h 14 min, and enzyme dose of 42.5 µL/g of pomace), the design predicted a 6.76% yield with a galacturonic acid content of 97.46 g/100 g of pectin and a degree of esterification of 96.02%. FT-IR analysis of the pectin sample obtained in these conditions showed a chemical structure similar to that of commercial apple and citrus pectin.


Assuntos
Enzimas/metabolismo , Malus/química , Pectinas/isolamento & purificação , Ácido Acético/química , Fracionamento Químico , Esterificação , Ácidos Hexurônicos/química , Concentração de Íons de Hidrogênio , Cinética , Temperatura Ambiente
4.
An Acad Bras Cienc ; 91(2): e20180333, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31038537

RESUMO

Abstract: The present work investigated what the appropriate methods of hydrolysis of pectin for reducing compounds (RCs) production, employed as a substrate for cell growth of Cupriavidus necator. This microorganism has great importance industrial, because besides potential single cell protein (SCP), is the most studied microorganism for production of polyhydroxybutyrate (PHB), and both processes require high cell concentration with inexpensive substrates For this, it was compared to acid and enzymatic hydrolysis procedures, through rotational central composite experimental design, using pectin concentration (1.0%). It was analyzed as a variable response for both experimental design, the RCs' production. The best conditions of each procedure were used in study kinetics of RCs' production and as a substrate for cell growth of C. necator. The results indicated that the enzymatic hydrolysis method was the most efficient, with a 93.0% yield of RCs, while the yield for acid hydrolysis was 60.0%. The optimum conditions for enzymatic hydrolysis were an enzyme concentration of 10.01 UI/g (International Unit of enzyme per gram of pectin) and an agitation speed of 230.3 rpm. C. necator showed satisfactory growth in the media containing pectin hydrolysates, with specific growth rates (µMax) similar to those reported for other substrates.


Assuntos
Meios de Cultura/química , Cupriavidus necator/crescimento & desenvolvimento , Pectinas/química , Análise de Variância , Técnicas de Cultura de Células/métodos , Proliferação de Células/fisiologia , Ácidos Hexurônicos/química , Hidrólise , Cinética , Valores de Referência , Reprodutibilidade dos Testes , Espectrofotometria/métodos , Temperatura Ambiente , Fatores de Tempo
5.
Food Chem ; 294: 339-346, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31126472

RESUMO

In the present study, the various properties of pectin extracted using microwave-assisted extraction (MAE) from eggplant peel and eggplant calyx (as food processing wastes of eggplant) were compared with each other. The eggplant peel pectin (EPP) exhibited higher extraction yield (29.17%) than eggplant calyx pectin (ECP; 18.36%). Both of EPP and ECP were high in methoxyl and rich in galacturonic acid. HPLC analysis showed that EPP was high in HG (homogalacturonan) (58.6%), while ECP was high in RG-I (rhamnogalacturonan-I) (44.9%). Also, higher phenolic contents were observed for EPP in comparing with ECP. Approximately in all of the functionalities (WHC (water holding capacity) and OHC (oil holding capacity), emulsifying and foaming properties, and antioxidant activity), EPP showed higher value rather than ECP. 1H NMR (hydrogen-1 nuclear magnetic resonance), FT-IR (Fourier transform-infrared) and XRD (x-ray diffraction) spectra confirmed the presence of high methylated crystalline pectin in both EPP and ECP.


Assuntos
Pectinas/química , Solanum melongena/metabolismo , Cromatografia Líquida de Alta Pressão , Manipulação de Alimentos , Ácidos Hexurônicos/química , Espectroscopia de Ressonância Magnética , Micro-Ondas , Pectinas/análise , Pectinas/isolamento & purificação , Fenóis/química , Espectroscopia de Infravermelho com Transformada de Fourier , Água/química
6.
J Mater Sci Mater Med ; 30(6): 60, 2019 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-31127386

RESUMO

Implantable membranes based on alginate and hyaluronic acid (HA) were manufactured to obtain a rapidly resorbing pliable mesh for the in situ administration of HA to intestinal tissue. Morphological analyses of this interpenetrated matrix pointed out a homogeneous polymeric texture while degradation studies demonstrated that the material is able to dissolve in physiological solutions within few days. Biological studies in vitro showed that the membrane is biocompatible towards human dermal fibroblasts and that liquid extracts from the HA-containing membrane can stimulate wound healing. A preliminary in vivo biocompatibility study on rats showed that the membranes in direct contact with the intestine did not elicit any acute adverse reaction or immune response, while only a mild inflammatory reaction was noticed at the mesenteric or serosal region. Overall, these results appear to support the application of these polysaccharide-based materials for intestinal wound healing.


Assuntos
Materiais Biocompatíveis/química , Ácido Hialurônico/química , Ferida Cirúrgica/terapia , Cicatrização , Alginatos/química , Animais , Sobrevivência Celular , Fibroblastos/metabolismo , Ácidos Hexurônicos/química , Humanos , Inflamação , Teste de Materiais , Camundongos , Células NIH 3T3 , Polímeros , Polissacarídeos/química , Ratos , Pele/metabolismo
7.
Food Chem ; 289: 351-359, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-30955623

RESUMO

The ultrasound-microwave assisted HCl extraction of pectin from potato pulp was optimized using the response surface methodology. Effects of extraction temperature, pH, and time on the yield were evaluated, and structural characteristics of pectin extracted under optimal conditions were determined. The yield was 22.86 ±â€¯1.29% under optimal conditions of temperature 93 °C, pH 2.0, and time 50 min. The obtained pectin was rich in branched rhamnogalacturonan I (61.54 mol%). Furthermore, the pectin was a low-methoxyl (degree of methylation, 32.58%) but highly acetylated (degree of acetylation, 17.84%) pectin and the molecular weight was 1.537 × 105 g/mol. Fourier transform infrared spectroscopy and 1H nuclear magnetic resonance indicated that pectin had a linear region of α-1, 4-linked galacturonic acids which could be methyl and acetyl-esterified, and rhamnose linked with galacturonic acid to form rhamnogalacturonan which was branched with side chains. Scanning electron microscopy showed most of pectin had a lamellae structure.


Assuntos
Pectinas/isolamento & purificação , Extratos Vegetais/química , Solanum tuberosum/química , Acetilação , Ácidos Hexurônicos/química , Metilação , Microscopia Eletrônica de Varredura , Micro-Ondas , Pectinas/análise , Pectinas/química , Tubérculos/química , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura Ambiente , Ultrassom
8.
J Biol Chem ; 294(19): 7711-7721, 2019 05 10.
Artigo em Inglês | MEDLINE | ID: mdl-30877196

RESUMO

The metabolism of carbohydrate polymers drives microbial diversity in the human gut microbiome. The selection pressures in this environment have spurred the evolution of a complex reservoir of microbial genes encoding carbohydrate-active enzymes (CAZymes). Previously, we have shown that the human gut bacterium Bacteroides thetaiotaomicron (Bt) can depolymerize the most structurally complex glycan, the plant pectin rhamnogalacturonan II (RGII), commonly found in the human diet. Previous investigation of the RGII-degrading apparatus in Bt identified BT0997 as a new CAZyme family, classified as glycoside hydrolase 138 (GH138). The mechanism of substrate recognition by GH138, however, remains unclear. Here, using synthetic substrates and biochemical assays, we show that BT0997 targets the d-galacturonic acid-α-1,2-l-rhamnose linkage in chain A of RGII and that it absolutely requires the presence of a second d-galacturonic acid side chain (linked ß-1,3 to l-rhamnose) for activity. NMR analysis revealed that BT0997 operates through a double displacement retaining mechanism. We also report the crystal structure of a BT0997 homolog, BPA0997 from Bacteroides paurosaccharolyticus, in complex with ligands at 1.6 Å resolution. The structure disclosed that the enzyme comprises four domains, including a catalytic TIM (α/ß)8 barrel. Characterization of several BT0997 variants identified Glu-294 and Glu-361 as the catalytic acid/base and nucleophile, respectively, and we observed a chloride ion close to the active site. The three-dimensional structure and bioinformatic analysis revealed that two arginines, Arg-332 and Arg-521, are key specificity determinants of BT0997 in targeting d-galacturonic acid residues. In summary, our study reports the first structural and mechanistic analyses of GH138 enzymes.


Assuntos
Proteínas de Bactérias/química , Bacteroides thetaiotaomicron/enzimologia , Glicosídeo Hidrolases/química , Ácidos Hexurônicos/química , Proteínas de Bactérias/genética , Bacteroides thetaiotaomicron/genética , Domínio Catalítico , Cristalografia por Raios X , Glicosídeo Hidrolases/genética , Relação Estrutura-Atividade , Especificidade por Substrato
9.
Food Chem ; 286: 1-7, 2019 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-30827581

RESUMO

Surfactant and microwave assisted extraction (S-MAE) was used for pectin extraction from orange peel. First, we optimized the conditions of microwave assisted extraction (MAE), e.g., irradiation time, liquid-to-solid ratio (LSR), and pH on pectin yield (PY), galacturonic acid (GA) content, and degree of esterification (DE) using a Box-Behnken design. Under optimal conditions (pH 1.2, 7.0 min, and 21.5 v/w LSR), we obtained a PY of 28.0 ±â€¯0.5%, which was close to the predicted value (31.1%). Second, we analyzed the effect of surfactant on microwave extraction of pectin. Among the surfactants investigated, Tween-80 (8 g/L, w/v) increased PY by 17.0%. Compared with conventional solvent extraction, S-MAE is a novel and efficient method for pectin extraction, which generated a higher (p < 0.05) PY (32.8%), GA content (78.1%), DE (69.8%), and Mw (286.3 kDa).


Assuntos
Citrus sinensis/metabolismo , Micro-Ondas , Pectinas/química , Tensoativos/química , Cromatografia Líquida de Alta Pressão , Esterificação , Ácidos Hexurônicos/química , Concentração de Íons de Hidrogênio , Pectinas/isolamento & purificação , Espectroscopia de Infravermelho com Transformada de Fourier
10.
Molecules ; 24(2)2019 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-30669480

RESUMO

In this study, we investigated changes in the structural and immunological features of polysaccharides (S1-PLE0, S2-PLE0, and S3-PLE0) extracted from persimmon leaves at three different growth stages. Physicochemical analyses revealed that their chemical compositions, molecular weight distributions, and linkage types differed. High-performance size-exclusion chromatograms showed that the molecular weights of the polysaccharides increased during successive growth stages. In addition, seasonal variation of persimmon leaves affected the sugar compositions and glycosidic linkages in the polysaccharides. S2-PLE0 was composed of comparatively more galactose, arabinose, rhamnose, xylose, and galacturonic acid, showing the presence of ß-glucopyranoside linkages. Significant differences also occurred in their immunostimulatory effects on RAW264.7 macrophages, with respect to which their activities could be ordered as S2-PLE0 > S3-PLE0 > S1-PLE0. Evidently, S2-PLE0 showed the greatest immunostimulatory activity by enhancing the phagocytic capacity and promoting nitric oxide (NO) and cytokines secretion through the upregulation of their gene expression in macrophages. These results suggest that differences in the structural features of polysaccharides according to the different maturity of persimmon leaves might impact their immunostimulatory properties. The results also provide a basis for optimizing persimmon leaf cultivation strategies for food and medical uses of the polysaccharides.


Assuntos
Diospyros/química , Extratos Vegetais/química , Folhas de Planta/química , Polissacarídeos/química , Polissacarídeos/imunologia , Adjuvantes Imunológicos/química , Animais , Citocinas/metabolismo , Frutas/química , Ácidos Hexurônicos/química , Camundongos , Peso Molecular , Células RAW 264.7 , Açúcares/química
11.
Ultrason Sonochem ; 50: 208-217, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30249371

RESUMO

Flaxseed oil is one of the richest sources of α-linolenic acid (ALA). However, the susceptibility of ALA to oxidation and also lack of the convenient methods to deliver these invaluable compound into the lower sections of gastrointestinal tract (GIT) are still unknown. The objective of the current study was to establish a method for ALA targeted delivery into the lower sections of GIT to enrich broiler meat. An in vitro study was performed to use ultrasound to produce oil-in-water nanoemulsions of flaxseed oil stabilized by different wall materials for controlled release of ALA in GIT. The fabricated nanoemulsions were assessed in terms of particle size distribution, zeta-potential, encapsulation efficiency, field emission scanning electron microscopy (FESEM), and in vitro gastric and intestinal digestions. Results indicated that the nanoemulsions coated by a combination of whey protein-sodium alginate (WP/SA) had a relatively uniform distribution and all particles distributed in less than 1000 nm. The values of zeta-potential for nanoemulsions stabilized by whey protein (WP), sodium alginate (SA) and WP/SA were -31.4, -29.3 and -45.5 mV, respectively. The wall combination of WP/SA showed the best encapsulation efficiency followed by WP. The FESEM results indicated spherical and non-aggregated structures for three types of nanoemulsions. The nanoemulsions stabilized by WP/SA showed a high resistance to in vitro gastric digestion but a relatively rapid release during intestinal digestion. An in vivo study was conducted to enrich broiler meat with ALA, using the best wall material from the in vitro study. In total, 300 one-day-old broilers (Ross, 308) were assigned into 5 experimental treatments including: basal diet (BD), basal diet plus flaxseed oil (BD + FO, 1 mL/kg body weight), basal diet plus ultrasonicated flaxseed oil nanoemulsions stabilized by WP/SA (BD + FON, 1 mL/kg body weight), basal diet plus flaxseed oil and vitamin E (BD + FO + E, 1 mL/kg body weight and 200 mg/kg diet vitamin E) and basal diet plus ultrasonicated flaxseed oil nanoemulsions stabilized by WP/SA and vitamin E (BD + FON + E, 1 mL/kg body weight of nanoemulsion and 200 mg/kg diet vitamin E). Each experimental treatment included 4 replicates in a completely randomized design. Results showed a better feed conversion ratio (FCR) in birds treated with dietary treatments compared with those received basal diet. A greater incorporation of ALA and total poly unsaturated fatty acids (PUFA) omega-3 were observed in thigh and breast meat of birds fed by ultrasonicated flaxseed oil nanoemulsions. In comparison to birds fed with BD, a favourably lower PUFA omega-6/omega-3 ratio was observed in birds received nanoemulsions of flaxseed oil. In general, the current study showed that using ultrasound to produce nanoemulsions stabilized by WP/SA has potential to protect ALA of flaxseed oil from gastric digestion and could be used as delivery carriers of ALA omega-3 fatty acid to the posterior sections of chicken GIT. Moreover, ultrasonic fabrication of nanoemulsion has potential to enrich broiler meat by ALA fatty acid.


Assuntos
Alginatos/química , Emulsões , Ácidos Graxos Ômega-3/administração & dosagem , Alimentos Fortificados , Trato Gastrointestinal/metabolismo , Óleo de Semente do Linho/administração & dosagem , Óleo de Semente do Linho/química , Nanotecnologia , Produtos Avícolas , Sonicação , Proteínas do Soro do Leite/química , Animais , Galinhas , Ácido Glucurônico/química , Ácidos Hexurônicos/química , Microscopia Eletrônica de Varredura , Tamanho da Partícula
12.
Food Chem ; 274: 494-499, 2019 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-30372970

RESUMO

A novel acidic polysaccharide fraction (PZMP2-2) was isolated from Ziziphus Jujuba cv. Muzao fruit via hot water extraction and purified by DEAE-Sepharose FF and Sephacryl S-300 column chromatography. PZMP2-2 consisted of rhamnose, arabinose, xylose, galactose, and galacturonic acid in a ratio of 1.18: 5.23: 0.22: 2.68: 2.20, with a molecular weight of 62.73 kDa. Structural features of PZMP2-2 were investigated using FT-IR, SEM, AFM, GC-MS analysis and NMR spectroscopy. Methylation and GC-MS analysis revealed that the main glycosidic bonds in PZMP2-2 comprised 1-linked Galp, 1,3-linked Araf, 1,2,4-linked Rhap, 1,3-linked Galp, 1,4-linked GalpA and 1,3,5-linked Araf. NMR analysis indicate that PZMP 2-2 has a linear backbone of (1 → 4)-linked GlcpA and (1 → 2,4)-linked Rhap residues, with branches at the O-4 position, consisting of Araf and Galp residues.


Assuntos
Polissacarídeos/química , Ziziphus/metabolismo , Cromatografia por Troca Iônica , Frutas/metabolismo , Galactose/química , Cromatografia Gasosa-Espectrometria de Massas , Ácidos Hexurônicos/química , Espectroscopia de Ressonância Magnética , Microscopia de Força Atômica , Peso Molecular , Polissacarídeos/isolamento & purificação , Ramnose/química , Espectroscopia de Infravermelho com Transformada de Fourier
13.
Int J Biol Macromol ; 124: 346-353, 2019 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-30465842

RESUMO

Enzyme-assisted extraction (EAE) possesses the advantages of being environmentally friendly and easily operated owing to relatively mild reaction conditions. Thus, mucilage from Asplenium australasicum was extracted with xylanase, glucanase and simultaneous application of both enzymatic preparations then investigated for their physicochemical properties. It was observed that compared to the control, the yield of mucilage increased significantly by EAE (from 3.64% to 6.04-6.86%), while the average molecular weight also increased slightly. SEM results showed that enzymes can erode the raw material which contributed to the higher extraction efficiency of polysaccharide. Furthermore, EAE modified the monosaccharide composition profile of A. australasicum mucilage considerably, especially there was a significant increase in glucose and galacturonic acid content. Although the FT-IR fingerprint did not change pronouncedly due to the action of the enzymes, but the degree of polysaccharide branching seemed to be more complicated, thus significantly reducing the intrinsic viscosity and water holding capacity of mucilage.


Assuntos
Glicosídeo Hidrolases/química , Mucilagem Vegetal/química , Polissacarídeos/química , Traqueófitas/química , Glucose/química , Ácidos Hexurônicos/química , Peso Molecular , Polissacarídeos/isolamento & purificação , Sementes/química , Espectroscopia de Infravermelho com Transformada de Fourier , Viscosidade , Água/química
14.
Int J Biol Macromol ; 125: 621-629, 2019 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-30543886

RESUMO

In this work, a Box-Behnken design (BBD) with three variables (ultrasound power, irradiation time and pH) in three levels was applied for pectin extraction optimization. The optimization process showed that the maximum extraction yield was 28.07 ±â€¯0.67% in ultrasound power of 150 W, irradiation time of 10 min and pH of 1.5 (as optimum conditions). In these conditions, ash, moisture and protein contents of SOPP were 1.89 ±â€¯0.51, 8.81 ±â€¯0.68 and 1.45 ±â€¯0.23%, respectively. HPLC analysis indicated that 65.3% of the extracted pectin was galacturonic acid and approximately 72% of total neutral sugars was galactose. The optimized pectin had a total phenolic content of 39.95 ±â€¯3.13 mg gallic acid equivalents/g pectin, the surface tension of 46.56 ±â€¯0.23 and 42.14 ±â€¯0.61 mN/m in concentrations of 0.1 and 0.5%w/v, water holding capacity and oil holding capacity of 3.10 ±â€¯0.12 and 1.32 ±â€¯0.21 g water or oil/g pectin with a suitable emulsifying and antioxidant properties. In addition, SOPP with degree of esterification of 6.77 ±â€¯0.43% was classified as low methoxyl pectin, which confirmed by FTIR and 1H NMR analysis.


Assuntos
Citrus sinensis/química , Citrus/química , Pectinas/química , Extratos Vegetais/química , Antioxidantes/química , Cromatografia Líquida de Alta Pressão/métodos , Emulsificantes/química , Emulsões/química , Esterificação , Galactose/química , Ácido Gálico/química , Ácidos Hexurônicos/química , Concentração de Íons de Hidrogênio , Açúcares/química , Tensão Superficial , Ondas Ultrassônicas
15.
J Agric Food Chem ; 66(43): 11407-11413, 2018 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-30295036

RESUMO

Aqueous d-galacturonic acid (d-GalA) model systems treated at 130 °C at different pH values show an intense color formation, whereas other reducing sugars, such as d-galactose (d-Gal), scarcely react. GC-MS measurements revealed the presence of several phenolic compounds: e.g., 3,8-dihydroxy-2-methyl-4 H-chromen-4-one (chromone) and 2,3-dihydroxybenzaldehyde (2,3-DHBA). These phenolic compounds, especially 2,3-DHBA, possess an intense browning potential and cannot be found within heated model solutions of reducing sugars. Investigations regarding the formation of these substances show that α-ketoglutaraldehyde plays an important role as an intermediate product. In addition, MS analysis of model systems of norfuraneol in combination with 2,3-DHBA showed the formation of oligomers that could also be detected in d-GalA model systems, leading to the assumption that, in addition to reductic acid, these compounds are jointly responsible for the strong color formation during the heat treatment of d-GalA.


Assuntos
Ácidos Hexurônicos/química , Polifenóis/química , Benzaldeídos/química , Catecóis/química , Manipulação de Alimentos , Cromatografia Gasosa-Espectrometria de Massas , Temperatura Alta , Espectrometria de Massas por Ionização por Electrospray , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
16.
J Agric Food Chem ; 66(44): 11784-11796, 2018 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-30346766

RESUMO

Insulin entrapped alginate-gum tragacanth (ALG-GT) hydrogels at different ALG replacement ratios (100, 75, 50, 25) were prepared through an ionotropic gelation method, followed by chitosan (CH) polyelectrolyte complexation. A mild gelation process without the use of harsh chemicals was proposed to improve insulin efficiency. Retention of almost the full amount of entrapped insulin in a simulated gastric environment and sustained insulin release in simulated intestinal buffer indicated the pH sensitivity of the gels. Insulin release from hydrogels with different formulations showed significant differences ( p < 0.05). Time domain (TD) NMR relaxometry experiments also showed the differences for different formulations, and the presence of CH revealed that ALG-GT gel formulation could be used as an oral insulin carrier at optimum concentrations. The hydrogels formulated from biodegradable, biocompatible, and nontoxic natural polymers were seen as promising devices for potential oral insulin delivery.


Assuntos
Sistemas de Liberação de Medicamentos/métodos , Insulina/administração & dosagem , Insulina/química , Alginatos/química , Portadores de Fármacos , Sistemas de Liberação de Medicamentos/instrumentação , Ácido Glucurônico/química , Ácidos Hexurônicos/química , Hidrogéis/química , Concentração de Íons de Hidrogênio , Polímeros/química , Tragacanto
17.
Carbohydr Res ; 470: 36-41, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30366185

RESUMO

Alginate oligosaccharides are depolymerization products of alginate by enzymatic degradation or physicochemical treatments. Alginate lyase has received great interests due to its use in oligosaccharide preparation. The substrate specificity of alginate lyase directly determines the type and degree of polymerization of alginate oligosaccharides. In this paper, the degradation products of Alginate lyase from Isoptericola halotolerans CGMCC 5336 were size-fractionated by gel filtration chromatography and the fractions were characterized by TLC, HPLC, MS and 1H NMR spectroscopy. The Mw values for these fractions were 352, 528, 704 Da which represented di-, tri-, and tetrasaccharide fragments, respectively. The 1H NMR revealed that the non-reducing ends of these oligosaccharides were 4-deoxy-L-erythro-hex-4-enepyranosyluronate and the reducing ends of these oligosaccharides were all guluronic acid. Therefore, it is believed that the alginate lyase produced by Isoptericola halotolerans CGMCC 5336 was capable of performing ß elimination on guluronic acid residue so that low molecular weight oligosaccharides with guluronic acid on the reducing end could be obtained in this way.


Assuntos
Actinomycetales/enzimologia , Alginatos/metabolismo , Ácidos Hexurônicos/metabolismo , Oligossacarídeos/biossíntese , Polissacarídeo-Liase/metabolismo , Alginatos/química , Ácidos Hexurônicos/química , Oligossacarídeos/química , Polissacarídeo-Liase/química , Polissacarídeo-Liase/isolamento & purificação
18.
Int J Biol Macromol ; 120(Pt A): 1149-1155, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30171958

RESUMO

Two polysaccharides JCS-1 and JCS-2 were successfully purified by DEAE-52 Cellulose chromatography from Zizyphus jujuba cv. Jinchangzao. Their structures were analyzed by high performance liquid chromatography (HPLC), high-performance gel permeation chromatography (HPGPC), nuclear magnetic resonance (NMR), and fourier transform infrared (FT-IR) spectroscopy. Further, eight sulfated derivatives are prepared by chlorosulfonic acid-pyridine (CSA-Pyr). Structural analysis revealed that both JCS-1 and JCS-2 were size uniform polysaccharides with the average molecular weight (Mw) of 71.75 kDa and 357.39 kDa, respectively. JCS-1 mainly has galacturonic acid (GalA) composition, and also contains a small amount of galactose (Gal) and arabinose (Ara), and their molar ratio is 39.04:1.26:1.39. JCS-2 was composed of GalA, mannose (Man), rhamnose (Rha), Ara and Gal, at a molar ratio of 19.87:2.07:1.77:1.65:1.16. Activity studies indicate that both natural polysaccharides and sulfated modified polysaccharides have immunomodulatory activity, while sulfated modified polysaccharides are stronger. Moreover, the sulfated polysaccharides significantly prolonged partial thromboplastin time (APTT) and thrombin time (TT) clotting times, but did not alter prothrombin time (PT) clotting time. The degree of substitution of polysaccharides seemed to be closely related to their biological characteristics. Sulfated modification represents an effective method of enhancing the immunomodulatory and anticoagulant activities of jujuba polysaccharides.


Assuntos
Anticoagulantes/química , Fatores Imunológicos/química , Polissacarídeos/química , Ziziphus/química , Anticoagulantes/imunologia , Anticoagulantes/isolamento & purificação , Anticoagulantes/farmacologia , Arabinose/química , Galactose/química , Ácidos Hexurônicos/química , Humanos , Fatores Imunológicos/isolamento & purificação , Fatores Imunológicos/farmacologia , Espectroscopia de Ressonância Magnética , Manose/química , Tempo de Tromboplastina Parcial , Polissacarídeos/imunologia , Polissacarídeos/isolamento & purificação , Polissacarídeos/farmacologia , Tempo de Protrombina , Ramnose/química , Espectroscopia de Infravermelho com Transformada de Fourier , Sulfatos/química , Ácidos Sulfônicos/química , Tempo de Trombina
19.
Carbohydr Polym ; 201: 246-256, 2018 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-30241817

RESUMO

In gene therapy, the stability of gene delivery system is essential during the systemic circulation. To improve the stability of PEI/DNA complexes, sodium alginate (Alg) was chosen as the optimal shielding material from four different polysaccharides. Then Alg/PEI/DNA complexes were further crosslinked by calcium ions (Ca2+) to form Ca2+/(Alg/PEI/DNA) nanoparticles. Compared to PEI/DNA complexes and Alg/PEI/DNA complexes, Ca2+/(Alg/PEI/DNA) nanoparticles exhibited enhanced stability, which was confirmed by the in vitro and in vivo evaluations. Furthermore, the pharmacokinetic study indicated that Ca2+/(Alg/PEI/DNA) nanoparticles exhibited longer circulation time in blood, which would be beneficial to the enhanced permeability and retention (EPR) effect of nanoparticles and could realize improved nanoparticles accumulation at tumor site. Overall, the Ca2+/(Alg/PEI/DNA) nanoparticles based on alginate shielding and Ca2+ crosslinking might be a promising platform in gene delivery and tumor treatment.


Assuntos
Alginatos/química , DNA/química , Técnicas de Transferência de Genes , Nanopartículas/química , Polietilenoimina/química , Ácido Glucurônico/química , Células HeLa , Células Hep G2 , Ácidos Hexurônicos/química , Humanos
20.
Mater Sci Eng C Mater Biol Appl ; 92: 184-195, 2018 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-30184741

RESUMO

Remotely assisted drug delivery by means of magnetic biopolymeric nanoplatforms has been utilized as an important tool to improve the delivery/release of hydrophobic drugs and to address their low cargo capacity. In this work, MnFe2O4 magnetic nanoparticles (MNPs) were synthesized by thermal decomposition, coated with citrate and then functionalized with the layer-by-layer (LbL) assembly of polyelectrolyte multilayers, with chitosan as polycation and sodium alginate as polyanion. Simultaneous conductimetric and potentiometric titrations were employed to optimize the LbL deposition and to enhance the loading capacity of nanoplatforms for curcumin, a hydrophobic drug used in cancer treatment. ~200 nm sized biopolymer platforms with ~12 nm homogeneously embedded MNPs were obtained and characterized by means of XRD, HRTEM, DLS, TGA, FTIR, XPS and fluorescence spectroscopy techniques to access structural, morphological and surface properties, to probe biopolymer functionalization and to quantify drug-loading. Charge reversals (±30 mV) after each deposition confirmed polyelectrolyte adsorption and a stable LbL assembly. Magnetic interparticle interaction was reduced in the biopolymeric structure, hinting at an optimized performance in magnetic hyperthermia for magneto-assisted drug release applications. Curcumin was encapsulated, resulting in an enhanced payload (~100 µg/mg). Nanocytotoxicity assays showed that the biopolymer capping enhanced the biocompatibility of nanoplatforms, maintaining entrapped curcumin. Our results indicate the potential of synthesized nanoplatforms as an alternative way of remotely delivering/releasing curcumin for medical purposes, upon application of an alternating magnetic field, demonstrating improved efficiency and reduced toxicity.


Assuntos
Alginatos/química , Quitosana/química , Curcumina/química , Compostos Férricos/química , Nanopartículas de Magnetita/química , Compostos de Manganês/química , Materiais Biocompatíveis/química , Sobrevivência Celular/efeitos dos fármacos , Curcumina/metabolismo , Curcumina/farmacologia , Portadores de Fármacos/química , Liberação Controlada de Fármacos , Ácido Glucurônico/química , Ácidos Hexurônicos/química , Humanos , Concentração de Íons de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Células MCF-7 , Tamanho da Partícula
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