Xylan glucuronic acid side chains fix suberin-like aliphatic compounds to wood cell walls.

Wood is the most important repository of assimilated carbon in the biosphere, in the form of large polymers (cellulose, hemicelluloses including glucuronoxylan, and lignin) that interactively form a composite, together with soluble extractives including phenolic and aliphatic compounds. Molecular interactions among these compounds are not fully understood. We have targeted the expression of a fungal α-glucuronidase to the wood cell wall of aspen (Populus tremula L. × tremuloides Michx.) and Arabidopsis (Arabidopsis thaliana (L.) Heynh), to decrease contents of the 4-O-methyl glucuronopyranose acid (mGlcA) substituent of xylan, to elucidate mGlcA's functions. The enzyme affected the content of aliphatic insoluble cell wall components having composition similar to suberin, which required mGlcA for binding to cell walls. Such suberin-like compounds have been previously identified in decayed wood, but here, we show their presence in healthy wood of both hardwood and softwood species. By contrast, γ-ester bonds between mGlcA and lignin were insensitive to cell wall-localized α-glucuronidase, supporting the intracellular formation of these bonds. These findings challenge the current view of the wood cell wall composition and reveal a novel function of mGlcA substituent of xylan in fastening of suberin-like compounds to cell wall. They also suggest an intracellular initiation of lignin-carbohydrate complex assembly.

Identification of xylan arabinosyl 2-O-xylosyltransferases catalyzing the addition of 2-O-xylosyl residue onto arabinosyl side chains of xylan in grass species.

Grass xylan, the major hemicellulose in both primary and secondary cell walls, is heavily decorated with α-1,3-linked arabinofuranosyl (Araf) residues that may be further substituted at O-2 with xylosyl (Xyl) or Araf residues. Although xylan 3-O-arabinosyltransferases (XATs) catalyzing 3-O-Araf addition onto xylan have been characterized, glycosyltransferases responsible for the transfer of 2-O-Xyl or 2-O-Araf onto 3-O-Araf residues of xylan to produce the Xyl-Araf and Araf-Araf disaccharide side chains remain to be identified. In this report, we showed that a rice GT61 member, named OsXAXT1 (xylan arabinosyl 2-O-xylosyltransferase 1) herein, was able to mediate the addition of Xyl-Araf disaccharide side chains onto xylan when heterologously co-expressed with OsXAT2 in the Arabidopsis gux1/2/3 (glucuronic acid substitution of xylan 1/2/3) triple mutant that lacks any glycosyl substitutions. Recombinant OsXAXT1 protein expressed in human embryonic kidney 293 cells exhibited a xylosyltransferase activity catalyzing the addition of Xyl from UDP-Xyl onto arabinosylated xylooligomers. Consistent with its function as a xylan arabinosyl 2-O-xylosyltransferase, CRISPR-Cas9-mediated mutations of the OsXAXT1 gene in transgenic rice plants resulted in a reduction in the level of Xyl-Araf disaccharide side chains in xylan. Furthermore, we revealed that XAXT1 close homologs from several other grass species, including switchgrass, maize, and Brachypodium, possessed the same functions as OsXAXT1, indicating functional conservation of XAXTs in grass species. Together, our findings establish that grass XAXTs are xylosyltransferases catalyzing Xyl transfer onto O-2 of Araf residues of xylan to form the Xyl-Araf disaccharide side chains, which furthers our understanding of genes involved in xylan biosynthesis.

Analysis of the biosynthetic flux in bovine milk oligosaccharides reveals competition between sulfated and sialylated species and the existence of glucuronic acid-containing analogues.

We previously observed that sialylated bovine milk oligosaccharides (BMOs) decline in both absolute and relative abundances over the initial stages of bovine lactation, with initial evidence suggesting that this decline occurred due to increased concentrations of unique sulfated BMOs. Since both sulfated and sialylated BMOs have distinct bioactivites, a follow up study was launched in order to more clearly define relative changes in these classes of BMOs over the first week of lactation in dairy cattle. Capillary electrophoresis (CE) and several liquid chromatography mass spectrometry (LC-MS) methods, including a novel multiplexed tandem MS method, were used to profile the BMOs extracted from milk collected from the same 20 Holstein cows at milkings 1, 2, 3, 4, 8, and 14 post-partum. In addition to clearly validating that sulfated and sialylated BMOs exist in direct biosynthetic completion, our study has identified over 170 unique BMOs including 14 unique glucuronic acid-containing trisaccharides.

Using a novel polysaccharide BM2 produced by Bacillus megaterium strain PL8 as an efficient bioflocculant for wastewater treatment.

In this study, the purification and characterization of a novel polysaccharide-based bioflocculant BM2 produced by a bacterium Bacillus megaterium strain PL8 with self-flocculating property were investigated. The results showed that BM2 was an acidic polysaccharide composed of Gal, GalUA, Glc, GlcUA and Man at a molar ratio of 45.1: 33.8:9.3:9.2:2.4, respectively. The molecular weight of BM2 was 4.55 × 106 Da. BM2 had high flocculation efficiencies across a wide pH ranged from 4 to 11 and a wide temperature ranged from 20 to 100 °C towards kaolin clay. BM2 was a cation-independent bioflocculant which could achieve high flocculation activity without the addition of other cations. Adsorption bridging was the main mechanism in the flocculation process of BM2 towards kaolin clay. The BM2 also displayed a high removal efficiency in terms of Congo red (88.14%) and Pb2+ ions (82.64%). These results suggested that BM2 had a great potential as an efficient bioflocculant candidate in wastewater treatment.

The protective effects of walnut green husk polysaccharide on liver injury, vascular endothelial dysfunction and disorder of gut microbiota in high fructose-induced mice.

This study aimed to investigate the protective effects of walnut green husk polysaccharide (WGHP) on liver injury, vascular endothelial dysfunction and disorder of gut microbiota in mice induced by high fructose (HF) diet. The chemical analysis results show that the walnut green husk polysaccharide is a low molecular weight acidic heteropolysaccharide, composed mainly of glucuronic acid, arabinose and galactose. Biochemical analysis showed that WGHP significantly improved glucose metabolism and lipid metabolism and decreased oxidative stress in HF-diet induced obesity mice. Histopathological observation of liver and cardiovascular aorta confirmed the protective effects of WGHP on hepatic steatosis and vascular endothelial dysfunction. Furthermore, 16S rRNA sequencing results demonstrated that WGHP reversed the disorders of gut microbiota caused by HF, decreased the relative abundance of Verrucomicrobia and increased the relative abundance of Deferribacteres at the phylum level, decreased the relative abundance of Akkermansia, Lachnoclostridium and norank_f__Muribaculaceae and increased the relative abundance of Prevotellaceae_UCG-001, Helicobacter, Alloprevotella and Allobaculum at the genus levels. Our results indicate that WGHP may act as a functional polysaccharide for protecting liver and cardiovascular in HF-fed mice.

Enzymatic hydrolysis of polysaccharide from Auricularia auricula and characterization of the degradation product.

An efficient enzymatic hydrolysis method was developed and optimized for the degradation of auricularia auricula polysaccharide (AAP) and the degradation product of AAP was characterized. Cellulase was used for the degradation of AAP. The yield of reducing sugar and the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging rate were used as indices to optimize the enzymatic hydrolysis of AAP, based on response surface methodology (RSM). The resulting optimal enzymolysis conditions were as follows: enzyme dosage, 13,500 U/g; enzymolysis temperature, 50 °C; and pH, 4.2. Under these conditions, the actual yield of reducing sugar was 16.50 mg/mL and the DPPH radical scavenging rate was 87.97%. The degradation product of AAP (C-EAAP) was homogeneous and contained alpha and beta glycoside bonds, but did not contain protein or nucleic acid. The molecular weight of the degradation product was 5.94 × 105 Da. Monosaccharide composition analysis revealed that C-EAAP was composed of mannose (57.1%), glucuronic acid (10.0%), rhamnose (0.4%), glucose (22.5%), galactose (2.9%), xylose (6.0%), and fucose (1.1%). The antioxidant activity of the polysaccharide indicated that C-EAAP had better antioxidant activity than AAP. The scavenging rates of C-EAAP for hydroxyl radicals (·OH) and superoxide anion radicals (O2-·) were 1.65 and 1.90 times those of AAP.

Optimization of synthesis of carbohydrates and 1-phenyl-3-methyl-5-pyrazolone (PMP) by response surface methodology (RSM) for improved carbohydrate detection.

Reducing sugars can react with 1-phenyl-3-methyl-5-pyrazolone (PMP) to form sugar-PMP derivatives, which can be detected by HPLC-UV or HPLC-DAD due to their high UV absorbance at 248 nm. Six different sugars were synthesized with PMP with aid of response surface methodology (RSM), by which the parameters of the synthesis were designed within temperature ranged between 60 °C and 90 °C, and time from 60 to 180 min, respectively. Consequently, optimal conditions of the glucose (Glu)-, glucosamine (GluN)-, galactose (Gal)-, glucuronic acid (GluA), galacturonic acid (GalA) and glucose-6-phosphate (G6P-PMP) reactions were determined at 71 °C for 129 min, 73 °C for 96 min, 70 °C for 117 min, 75 °C for 151 min, 76 °C for 144 min, and 70 °C for 154 min, respectively. Experiments demonstrated that unique functional groups and delicate differences of carbohydrates' inner pH environment could significantly influence the sugar-PMP reactions. However, sugar stereoisomers did not have remarkable impacts on the reactions.

DNA methylation patterns in bladder tumors of African American patients point to distinct alterations in xenobiotic metabolism.

Racial/ethnic disparities have a significant impact on bladder cancer outcomes with African American patients demonstrating inferior survival over European-American patients. We hypothesized that epigenetic difference in methylation of tumor DNA is an underlying cause of this survival health disparity. We analyzed bladder tumors from African American and European-American patients using reduced representation bisulfite sequencing (RRBS) to annotate differentially methylated DNA regions. Liquid chromatography-mass spectrometry (LC-MS/MS) based metabolomics and flux studies were performed to examine metabolic pathways that showed significant association to the discovered DNA methylation patterns. RRBS analysis showed frequent hypermethylated CpG islands in African American patients. Further analysis showed that these hypermethylated CpG islands in patients are commonly located in the promoter regions of xenobiotic enzymes that are involved in bladder cancer progression. On follow-up, LC-MS/MS revealed accumulation of glucuronic acid, S-adenosylhomocysteine, and a decrease in S-adenosylmethionine, corroborating findings from the RRBS and mRNA expression analysis indicating increased glucuronidation and methylation capacities in African American patients. Flux analysis experiments with 13C-labeled glucose in cultured African American bladder cancer cells confirmed these findings. Collectively, our studies revealed robust differences in methylation-related metabolism and expression of enzymes regulating xenobiotic metabolism in African American patients indicate that race/ethnic differences in tumor biology may exist in bladder cancer.

A simplified and miniaturized glucometer-based assay for the detection of ß-glucosidase activity.

ß-Glucosidase activity assays constitute an important indicator for the early diagnosis of neonatal necrotizing enterocolitis and qualitative changes in medicinal plants. The drawbacks of the existing methods are high consumption of both time and reagents, complexity in operation, and requirement of expensive instruments and highly trained personnel. The present study provides a simplified, highly selective, and miniaturized glucometer-based strategy for the detection of ß-glucosidase activity. Single-factor experiments showed that optimum ß-glucosidase activity was exhibited at 50 °C and pH 5.0 in a citric acid-sodium citrate buffer when reacting with 0.03 g/mL salicin for 30 min. The procedure for detection was simplified without the need of a chromogenic reaction. Validation of the analytical method demonstrated that the accuracy, precision, repeatability, stability, and durability were good. The linear ranges of ß-glucosidase in a buffer solution and rat serum were 0.0873-1.5498 U/mL and 0.4076-2.9019 U/mL, respectively. The proposed method was free from interference from ß-dextranase, snailase, ß-galactosidase, hemicellulase, and glucuronic acid released by baicalin. This demonstrated that the proposed assay had a higher selectivity than the conventional dinitrosalicylic acid (DNS) assay because of the specificity for salicin and unique recognition of glucose by a personal glucose meter. Miniaturization of the method resulted in a microassay for ß-glucosidase activity. The easy-to-operate method was successfully used to detect a series of ß-glucosidases extracted from bitter almonds and cultured by Aspergillus niger. In addition, the simplified and miniaturized glucometer-based assay has potential application in the point-of-care testing of ß-glucosidase in many fields, including medical diagnostics, food safety, and environmental monitoring.

Analyses of active antioxidant polysaccharides from four edible mushrooms.

Four water-soluble polysaccharides were extracted from Pleurotus eryngii, Flammulina velutipes, Pleurotus ostreatus and white Hypsizygus marmoreus. Using anion exchange and gel permeation chromatography, a neutral and an acidic fraction were purified from each water-soluble polysaccharide. Their molecular weights were all around 20 kDa except that the acidic polysaccharide from Pleurotus ostreatus (named WPOPA) had a lower molecular weight of 5 kDa. Four neutral polysaccharides were mainly composed of galactose (42.7%-69.1%), followed by Man (19.4%-39.3%) and Glc (1.1%-15.9%). Four acidic polysaccharides contained glucose (59.0%-81.8%) as major sugar and minor glucuronic acid (4.5%-9.5%). Acidic polysaccharides exhibited stronger antioxidant activities than neutral fractions, and WPOPA showed the best antioxidant effects. Structural analysis indicated WPOPA had ß-(1 → 6)-glucan backbone branched at O-3 by ß-1,3-d-Glcp, t-ß-d-Glcp and t-ß-d-GlcpA. This investigation would be useful for screening natural antioxidants and significant in developing mushroom polysaccharides as functional foods.

A simplified and miniaturized glucometer-based assay for the detection of β-glucosidase activity / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

β-Glucosidase activity assays constitute an important indicator for the early diagnosis of neonatal necrotizing enterocolitis and qualitative changes in medicinal plants. The drawbacks of the existing methods are high consumption of both time and reagents, complexity in operation, and requirement of expensive instruments and highly trained personnel. The present study provides a simplified, highly selective, and miniaturized glucometer-based strategy for the detection of β-glucosidase activity. Single-factor experiments showed that optimum β-glucosidase activity was exhibited at 50 °C and pH 5.0 in a citric acid-sodium citrate buffer when reacting with 0.03 g/mL salicin for 30 min. The procedure for detection was simplified without the need of a chromogenic reaction. Validation of the analytical method demonstrated that the accuracy, precision, repeatability, stability, and durability were good. The linear ranges of β-glucosidase in a buffer solution and rat serum were 0.0873-1.5498 U/mL and 0.4076-2.9019 U/mL, respectively. The proposed method was free from interference from β-dextranase, snailase, β-galactosidase, hemicellulase, and glucuronic acid released by baicalin. This demonstrated that the proposed assay had a higher selectivity than the conventional dinitrosalicylic acid (DNS) assay because of the specificity for salicin and unique recognition of glucose by a personal glucose meter. Miniaturization of the method resulted in a microassay for β-glucosidase activity. The easy-to-operate method was successfully used to detect a series of β-glucosidases extracted from bitter almonds and cultured by Aspergillus niger. In addition, the simplified and miniaturized glucometer-based assay has potential application in the point-of-care testing of β-glucosidase in many fields, including medical diagnostics, food safety, and environmental monitoring.

High precision microfluidic microencapsulation of bacteriophages for enteric delivery.

A Salmonella specific bacteriophage Felix O1 (Myoviridae) was microencapsulated in a pH responsive polymer formulation. The formulation incorporated a pH responsive methacrylic acid copolymer Eudragit® S100 (10% (w/v)) with the addition of the biopolymer sodium alginate, the composition of which was varied in the range (0.5% (w/v)-2% (w/v)). The microencapsulation process employed commercially available microfluidic droplet generation devices. We have used readily available low cost microfluidic chips instead of bespoke in-house fabricated glass capillary devices which are accessible only in specialist research facilities. We show that these co-flow microfluidic devices can easily be used to prepare phage encapsulated microparticles making them suitable for use by both the phage research community and industry in order to evaluate and optimise phage compatible formulations for microencapsulation. A novelty of the work reported here is that the size of the generated monodispersed droplets could be precisely controlled in the range 50 µm-200 µm by varying the flow rates of the dispersed and continuous phases. Consequently, alginate concentration and microparticle size were shown to influence the phage release profile and the degree of acid protection afforded to phages upon exposure to simulated gastric fluid (SGF). Bigger microparticles (∼100 µm) showed better acid protection compared with smaller beads (∼50 µm) made from the same formulation. Increasing the alginate composition resulted in improved acid protection of phages for similar particle sizes. The high viscosity formulations containing higher amounts of alginate (e.g. 2% (w/v)) negatively affected ease of droplet generation in the microfluidic device thereby posing a limitation in terms of process scale-up. Felix O1 encapsulated in the formulation containing 10% (w/v) ES100 and 1% (w/v) alginate showed excellent protection upon exposure of the gelled microparticles to SGF (pH 1 for 2 h) without the use of any antacids in the encapsulation matrix. Encapsulated phages previously exposed to SGF (pH 1 for 2 h) were released at elevated pH in simulated intestinal fluid (SIF) and were shown to arrest bacterial growth in the log growth phase. We have therefore demonstrated the microencapsulation of phages using readily available microfluidic chips to produce solid dosage microcapsule forms with a rapid pH triggered release profile suitable for targeted delivery and controlled release in the gastrointestinal tract.

Layer-by-Layer Alginate and Fungal Chitosan Based Edible Coatings Applied to Fruit Bars.

Food waste is currently being generated at an increasing rate. One proposed solution would be to convert it to biopolymers for industrial applications. We recovered chitin from mushroom waste and converted it to chitosan to produce edible coatings. We then used layer-by-layer (LbL) electrostatic deposition of the polycation chitosan and the polyanion alginate to coat fruit bars enriched with ascorbic acid. The performance of the LbL coatings was compared with those containing single layers of fungal chitosan, animal origin chitosan and alginate. Bars containing alginate-chitosan LbL coatings showed increased ascorbic acid content, antioxidant capacity, firmness and fungal growth prevention during storage. Also, the origin of the chitosan did not affect the properties of the coatings. PRACTICAL APPLICATION: Mushroom stalk bases could be an alternative source for isolating chitosan with similar properties to animal-based chitosan. Also, layer-by-layer assembly is a cheap, simple method that can improve the quality and safety of fruit bars.

Attenuation of quorum sensing controlled virulence factors and biofilm formation in Pseudomonas aeruginosa by pentacyclic triterpenes, betulin and betulinic acid.

The production of virulence determinants and biofilm formation in numerous pathogens is regulated by the cell-density-dependent phenomenon, Quorum sensing (QS). The QS system in multidrug resistant opportunistic pathogen, P. aeruginosa constitutes of three main regulatory circuits namely Las, Rhl, and Pqs which are closely linked to its pathogenicity and establishment of chronic infections. In spite intensive antibiotic therapy, P. aeruginosa continue to be an important cause of nosocomial infections and also the major cause of mortality in Cystic Fibrosis patients with 80% of the adults suffering from chronic P. aeruginosa infection. Hence, targeting QS circuit offers an effective intervention to the ever increasing problem of drug resistant pathogens. In the present study, the pentacyclic triterpenes i.e. Betulin (BT) and Betulinic acid (BA) exhibited significant attenuation in production of QS-regulated virulence factors and biofilm formation in P. aeruginosa, at the sub-lethal concentration. The test compound remarkably interfered in initial stages of biofilm development by decreasing the exopolysaccharide production and cell surface hydrophobicity. Based on the in vivo studies, the test compounds notably enhanced the survival of Caenorhabditis elegans infected with P. aeruginosa. Furthermore, molecular docking analysis revealed that BT and BA can act as a strong competitive inhibitor for QS receptors, LasR and RhlR. The findings suggest that BT and BA can serve as potential anti-infectives in the controlling chronic infection of P. aeruginosa.

Structural Elucidation and Biological Activity of a Highly Regular Fucosylated Glycosaminoglycan from the Edible Sea Cucumber Stichopus herrmanni.

Edible sea cucumbers are widely used as a health food and medicine. A fucosylated glycosaminoglycan (FG) was purified from the high-value sea cucumber Stichopus herrmanni. Its physicochemical properties and structure were analyzed and characterized by chemical and instrumental methods. Chemical analysis indicated that this FG with a molecular weight of ∼64 kDa is composed of N-acetyl-d-galactosamine, d-glucuronic acid (GlcA), and l-fucose. Structural analysis clarified that the FG contains the chondroitin sulfate E-like backbone, with mostly 2,4-di-O-sulfated (85%) and some 3,4-di-O-sulfated (10%) and 4-O-sulfated (5%) fucose side chains that link to the C3 position of GlcA. This FG is structurally highly regular and homogeneous, differing from the FGs of other sea cucumbers, for its sulfation patterns are simpler. Biological activity assays indicated that it is a strong anticoagulant, inhibiting thrombin and intrinsic factor Xase. Our results expand the knowledge on structural types of FG and illustrate its biological activity as a functional food material.

Chemical Characterization and Determination of the Anti-Oxidant Capacity of Two Brown Algae with Respect to Sampling Season and Morphological Structures Using Infrared Spectroscopy and Multivariate Analyses.

Brown algae biomass has been shown to be a highly important industrial source for the production of alginates and different nutraceutical products. The characterization of this biomass is necessary in order to allocate its use to specific applications according to the chemical and biological characteristics of this highly variable resource. The methods commonly used for algae characterization require a long time for the analysis and rigorous pretreatments of samples. In this work, nondestructive and fast analyses of different morphological structures from Lessonia spicata and Macrocystis pyrifera, which were collected during different seasons, were performed using Fourier transform infrared (FT-IR) techniques in combination with chemometric methods. Mid-infrared (IR) and near-infrared (NIR) spectral ranges were tested to evaluate the spectral differences between the species, seasons, and morphological structures of algae using a principal component analysis (PCA). Quantitative analyses of the polyphenol and alginate contents and the anti-oxidant capacity of the samples were performed using partial least squares (PLS) with both spectral ranges in order to build a predictive model for the rapid quantification of these parameters with industrial purposes. The PCA mainly showed differences in the samples based on seasonal sampling, where changes were observed in the bands corresponding to polysaccharides, proteins, and lipids. The obtained PLS models had high correlation coefficients (r) for the polyphenol content and anti-oxidant capacity (r > 0.9) and lower values for the alginate determination (0.7 < r < 0.8). Fourier transform infrared-based techniques were suitable tools for the rapid characterization of algae biomass, in which high variability in the samples was incorporated for the qualitative and quantitative analyses, and have the potential to be used on an industrial scale.

Magnetic alginate microspheres detected by MRI fabricated using microfluidic technique and release behavior of encapsulated dual drugs.

Alginate microspheres loaded with superparamagnetic iron oxide nanoparticles (SPIO NPs) have been fabricated by a T-junction microfluidic device combined with an external ionic crosslinking. The obtained microspheres possess excellent visuality under magnetic resonance due to the presence of only 0.6 mg/mL SPIO NPs. The microspheres also show uniform size with narrow distribution and regular spherical shape characterized by optic microscope and environmental scanning electron microscope. Furthermore, dual drugs (5-fluorouracil and doxorubicin hydrochloride) have been loaded within the microspheres. The release behavior of dual drugs from the microspheres show typical sustained release profiles. As a novel embolic agent, such microspheres in blood vessels can be tracked by magnetic resonance scanner. Thus, the integration of embolotherapy, chemotherapy, and postoperative diagnosis can be realized.

Cell and Tissue Imaging with Molecularly Imprinted Polymers.

Advanced tools for cell imaging are of particular interest as they can detect, localize and quantify molecular targets like abnormal glycosylation sites that are biomarkers of cancer and infection. Targeting these biomarkers is often challenging due to a lack of receptor materials. Molecularly imprinted polymers (MIPs) are promising artificial receptors; they can be tailored to bind targets specifically, be labeled easily, and are physically and chemically stable. Herein, we demonstrate the application of MIPs as artificial antibodies for selective labeling and imaging of cellular targets, on the example of hyaluronan and sialylation moieties on fixated human skin cells and tissues. Thus, fluorescently labeled MIP nanoparticles templated with glucuronic acid (MIPGlcA) and N-acetylneuraminic acid (MIPNANA) are respectively applied. Two different fluorescent probes are used: (1) MIPGlcA particles, ~400 nm in size are labeled with the dye rhodamine that target the extracellular hyaluronan on cells and tissue specimens and (2) MIP-coated InP/ZnS quantum dots (QDs) of two different colors, ~125 nm in size that target the extracellular and intracellular hyaluronan and sialylation sites. Green and red emitting QDs are functionalized with MIPGlcA and MIPNANA respectively, enabling multiplexed cell imaging. This is a general approach that can also be adapted to other target molecules on and in cells.

pH responsive controlled release of anti-cancer hydrophobic drugs from sodium alginate and hydroxyapatite bi-coated iron oxide nanoparticles.

Developing a drug carrier system which could perform targeted and controlled release over a period of time is utmost concern in the pharmaceutical industry. This is more relevant when designing drug carriers for poorly water soluble drug molecules such as curcumin and 6-gingerol. Development of a drug carrier system which could overcome these limitations and perform controlled and targeted drug delivery is beneficial. This study describes a promising approach for the design of novel pH sensitive sodium alginate, hydroxyapatite bilayer coated iron oxide nanoparticle composite (IONP/HAp-NaAlg) via the co-precipitation approach. This system consists of a magnetic core for targeting and a NaAlg/HAp coating on the surface to accommodate the drug molecules. The nanocomposite was characterized using FT-IR spectroscopy, X-ray diffraction, scanning electron microscopy, transmission electron microscopy and thermogravimetric analysis. The loading efficiency and loading capacity of curcumin and 6-gingerol were examined. In vitro drug releasing behavior of curcumin and 6-gingerol was studied at pH 7.4 and pH 5.3 over a period of seven days at 37°C. The mechanism of drug release from the nanocomposite of each situation was studied using kinetic models and the results implied that, the release is typically via diffusion and a higher release was observed at pH 5.3. This bilayer coated system can be recognized as a potential drug delivery system for the purpose of curcumin and 6-gingerol release in targeted and controlled manner to treat diseases such as cancer.

Anatomy, nutritional value and cell wall chemical analysis of foliage leaves of Guadua chacoensis (Poaceae, Bambusoideae, Bambuseae), a promising source of forage.

BACKGROUND: The present study combines morphological and anatomical studies, cell wall chemical composition analysis, as well as assessment of the nutritional value of Guadua chacoensis foliage leaves. RESULTS: Foliage leaves of G. chacoensis are a promising source of forage because: (a) as a native woody bamboo, it is adapted to and helps maintain environmental conditions in America; (b) leaf anatomical studies exhibit discontinuous sclerenchyma, scarcely developed, while pilose indumentum, silica cells, prickles and hooks are also scarce; (c) it has a high protein content, similar to that of Medicago sativa, while other nutritional parameters are similar to those of common forages; and (d) glucuronoarabinoxylan, the major extracted polysaccharide, has one-third of the 4-linked ß-d-xylopyranosyl units of the backbone substituted mainly with α-l-arabinofuranose as single stubs or non-reducing end of short chains, but also 5-linked α-l-arabinofuranose units, terminal ß-d-xylopyranose and d-galactopyranose units, as well as α-d-glucuronic acid residues and small amounts of its 4-O-methylated derivative. CONCLUSION: These results constitute the first report on this species, and as culms are utilized in constructions and crafts, the remaining leaves, when used as forage, constitute a byproduct that allows an additional income opportunity. © 2016 Society of Chemical Industry.