Partial Acid Hydrolysis Research Articles

Structural characterization of a polysaccharide from Scutellaria baicalensis Georgi and its immune-enhancing properties on RAW264.7 cells

A novel polysaccharide SPS01-2 (87.5 kDa) was isolated from the roots of Scutellaria baicalensis Georgi. Monosaccharide composition revealed that SPS01-2 consists of rhamnose, arabinose, galactose, galacturonic acid, and glucuronic acid in ratio of 4.4: 67.1: 22.2: 6.3: 1.2. Further investigations using methylation, NMR, and mass spectrometry indicated that SPS01-2 is classified as a type II arabinogalactan (AG-II) with a minor presence of type I rhamnogalacturonan (RG-I). The core structure alternates between 1,2/1,2,4-α-L-Rhap and 1,4-α-D-GalpA, with branches including 1,3,6-β-D-Galp, 1,3-β-D-Galp, T-β-D-Galp, and T-α-L-Rhap. The RG-I regions are linked to 1,6-β-D-Galp, and 1,3,6-β-D-Galp units. Numerous arabinan branches, featuring multiple branching points, are attached to the O-3 position of galactose. Additionally, T-β-D-Galp, 1,6-β-D-Galp, and T-β-D-4-OMe-GlcpA are also linked to galactose in the backbone. Furthermore, SPS01-2 demonstrated potential immune-enhancing properties by dose-dependently increasing proliferation, phagocytosis, and the production of nitric oxide and cytokines (TNF-α, IL-6, and IL-1β) in RAW264.7 cells. It also enhanced the expression of CD80, CD86, and MHC-II at concentrations ranging from 5 to 200 μg/mL. Moreover, the immunostimulatory activity of SPS01-2 was significantly reduced when branch linkages were removed through partial acid hydrolysis. Our findings indicate that SPS01-2 could serve as a natural immunostimulant in the food and pharmaceutical sectors.

Ultrasound-assisted low-temperature extraction of polysaccharides from Lavandula angustifolia Mill.: optimization, structure characterization, and anti-inflammatory activity

Lavandula angustifolia Mill. is a traditional Chinese medicinal herb with high economic and pharmacological value. In this study, we optimized the conditions for low-temperature ultrasound-assisted extraction of L. angustifolia Mill. polysaccharides using response surface methodology (RSM), and two homopolysaccharides LAPW1 (33.6 kDa) and LAPS1 (95.9 kDa) were obtained after isolation and purification by DEAE-650 M and Superdex™ 200 chromatography. The primary structure of LAPS1 was determined using “partial acid hydrolysis, methylation, two-dimensional (2D NMR) spectroscopy” as the core method. The results revealed that LAPS1 is a heteropolysaccharide whose main chain consists of [-1)-β-Galp-(6→1)-α-Araf-(5→]3-1-α-Araf-(3→1)-α-Araf-(5→[1)-β-Galp-(6→1)-α-Araf-(5→]3-1-α-Araf-(5→1)-α-Araf-(5→[-1)-β-Galp-(6→1)-α-Araf-(5→]3. In vitro experiments revealed that LAPW1 and LAPS1 significantly reduced the production of the inflammatory cytokines Interleukin-1β (IL-1β), Interleukin-6 (IL-6), and Tumor Necrosis Factor (TNF), as well as the expression of Nitric Oxide Synthase 2 (NOS2) and release of nitric oxide (.NO) free radical in the inflammatory model established by lipopolysaccharide (LPS) stimulated RAW264.7. Besides, the zebrafish inflammatory model, stimulated by CuSO4, was employed to assess the impact of polysaccharides on neutrophil migration, indicating a notable decrease in zebrafish neutrophils and confirming their potential anti-inflammatory activity. These results indicate that polysaccharides from L. angustifolia Mill. be used in the development of functional foods and pharmaceutical products.

Pectin-like heteroxylans in the early-diverging charophyte Klebsormidium fluitans.

The cell walls of charophytic algae both resemble and differ from those of land plants. Cell walls in early-diverging charophytes (e.g. Klebsormidiophyceae) are particularly distinctive, in ways that may enable survival in environments that are incompatible with land-plant polymers. This study therefore investigates the structure of Klebsormidium polysaccharides. The 'pectin' fraction (defined by extractability) of Klebsormidium fluitans, solubilised by various buffers from alcohol-insoluble residues (AIRs), was digested with several treatments that (partially) hydrolyse land-plant cell-wall polysaccharides. Products were analysed by gel-permeation and thin-layer chromatography. The Klebsormidium pectic fraction made up ~30-50% of its AIR, was optimally solubilised at pH 3-4 at 100°C, and contained residues of xylose ≈ galactose > rhamnose > arabinose, fucose, mannose, glucose. Uronic acids were undetectable and the pectic fraction was more readily solubilised by formate than by oxalate, suggesting a lack of chelation. Some land-plant-targeting hydrolases degraded the Klebsormidium pectic fraction: digestion by α-l-arabinanase, endo-β-(1⟶4)-d-xylanase, and α-d-galactosidase suggests the presence of β-(1⟶4)-xylan with terminal α-l-arabinose, α-d-galactose and (unexpectedly) rhamnose. 'Driselase' released oligosaccharides of xylose and rhamnose (~1:1) and graded acid hydrolysis of these oligosaccharides indicated a 'rhamnoxylan' with rhamnose side-chains. Partial acid hydrolysis of Klebsormidium pectic fraction released rhamnose plus numerous oligosaccharides, one of which comprised xylose and galactose (~1:2 Gal/Xyl), suggesting a galactoxylan. Lichenase was ineffective, as were endo-β-(1⟶4)-d-galactanase, endo-β-(1⟶4)-d-mannanase, β-d-xylosidase and β-d-galactosidase. Klebsormidium pectic fraction possesses many land-plant-like linkages but is unusual in lacking uronic acid residues and in containing rhamnoxylan and galactoxylan domains. Uronic acids allow land-plant and late-diverging charophyte pectins to form Ca2+-bridges, facilitating cell-wall polymer association; their absence from Klebsormidium suggests that neutral heteroxylans rely on alternative cross-linking mechanisms. This lack of dependency on Ca2+-bridges may confer Klebsormidium's ability to grow in the acidic, metal-rich environments which it tolerates.

Enhancement of Candida albicans phagocytosis and inhibitory potency of Alternative Complement Pathway by an arabinoxylan extracted from Plantago ciliata Desf. Seeds and its oligosaccharides

Leveraging bioactive compounds with immunomodulatory effects to boost immune functions represents a promising strategy for therapeutic intervention. The main objective of this work was to investigate the influence of the partial acid hydrolysis of an arabinoxylan extracted from Plantago ciliata Desf. seeds into oligosaccharides on its immunomodulatory effect. The resulting oligosaccharides and their polymer were evaluated for their potential to improve the phagocytic capacity (PC) and the phagocytic activity (PA) of polymorphonuclear neutrophils (PMNs) through the uptake of Candida albicans and to moderate alternative complement pathway (ACP) activation. As a result, the arabinoxylan derived from P. ciliata seeds (AXPCs) and its oligosaccharides (AXOPCs) significantly enhanced the PC of PMN cells, with EC50 values of 0.14 ± 0.23 and 0.12 ± 0.10 mg/mL, respectively. Zymosan used as a reference exhibited the highest PC with an EC50 0.07 ± 0.08 mg/mL. However, for PA, zymosan still demonstrated the highest activity with an EC50 of 0.22 ± 0.46 mg/mL compared to 0.33 ± 1.36 and 0.30 ± 0.74 mg/mL for AXPCs and AXOPCs, respectively. Moreover, AXPCs and AXOPCs were tested as moderator inhibitors of the complement system, showing maximum inhibition percentages of 40.11 ± 8.38% and 50.57 ± 10.45% at 1 mg/mL, with IC50 values of 1.49 ± 0.40 and 1.02 ± 0.20 mg/mL, respectively, compared to 61.52 ± 7.17% and 70.89 ± 5.78% for heparin used as a reference. These results suggest that AXPCs and AXOPCs can serve as relevant therapeutic immunomodulatory factors.

Structural identification, rheological properties and immunological receptor of a complex galacturonoglucan from fruits of Schisandra chinensis (Turcz.) Baill

A complex heteropolysaccharide SCP-2 named schisanan B (Mw = 1.005 × 105 g/mol) was obtained from water extracts of Schisandra chinensis fruits, and its planar structure was finally deduced as a galacturonoglucan by a combination of monosaccharide compositions, methylation analysis, partial acid hydrolysis, enzymatic hydrolysis and 1D/2D-nuclear magnetic resonance spectroscopy. The conformation of SCP-2 exhibited a globular shape with branching in ammonium formate aqueous solutions. The rheological properties of SCP-2 were investigated on concentrations, temperature, pH and salts. The in vitro immunomodulatory activity assay demonstrated that SCP-2 significantly enhanced the production of nitric oxide (NO) and stimulated the secretion of tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) in macrophages. Through a combination of high-resolution live-cell imaging, surface plasmon resonance, and molecular docking techniques, SCP-2 exhibited a strong binding affinity with the Toll-like receptor 4 (TLR4). Moreover, western blot analysis revealed that SCP-2 effectively induced downstream signaling proteins associated with TLR4 activation, thereby promoting macrophage activation. The evidence strongly indicates that TLR4 functions as a membrane protein target in the activation of macrophages and immune regulation induced by SCP-2.

Structural elucidation a complex galactosyl andglucosyl-rich pectin from the pericarp of immature fruits of Juglans mandshurica Maxim.

A glucosyl-rich pectin, JMMP-3 (Mw, 2.572 × 104g/mol, O-methyl % = 3.62%), was isolated and purified from the pericarp of the immature fruit of Juglans mandshurica Maxim. (QingLongYi). The structure of JMMP-3 was studied systematically by infrared spectroscopy, monosaccharide compositions, methylation analysis, partial acid hydrolysis, and 1/2D-NMR. The backbone of JMMP-3 possessed a smooth region (→ 4GalA1 →) and a hairy region (→ 4GalA1 → 2Rha1 →) with a molar ratio of 2: 5. The substitution of four characteristic side chains (R1-R4) occurs at C-4 of → 2,4)-α-Rhap-(1→, where R1 is composed of → 5)-α-Araf-(1→, R2 is composed of → 4)-β-Galp-(1 → and β-Galp-(1→, R3 is composed of α-Glcp-(1→, →4)-α-Glcp-(1 → and → 4,6)-α-Glcp-(1→, and R4 is composed of → 5)-α-Araf-(1→, β-Galp-(1→, → 4)-β-Galp-(1→, → 3,4)-β-Galp-(1→, → 4,6)-β-Galp-(1 → and → 2,4)-β-Galp-(1 → . In addition, the antitumor activity of JMMP-3 on HepG2 cells was preliminarily investigated.

The study of galactomannans with different molecular weights and their ability to form microparticles suitable for pulmonary delivery

The influence of locust bean gum (LBG) galactomannans (GMs) molecular weight (Mw) to assemble microparticulate systems was evaluated, and carriers for deep lung delivery were developed. A commercial batch of LBG with a mannose/galactose (M/G) ratio of 2.4 (batch 1) was used to study the influence of different microwave partial acid hydrolysis conditions on carbohydrate composition, glycosidic linkages, and aqueous solutions viscosity. The microwave treatment did not affect the composition, presenting 4-Man (36–42 %), 4,6-Man (27–35 %), and T-Gal (24–25 %) as the main glycosidic linkages. Depolymerization led to a viscosity reduction (≤0.005 Pa·s) with no major impact on polysaccharide debranching. The structural composition of the LBG galactomannans were further elucidated with sequence-specific proteins using carbohydrate microarray technologies. A second batch of LBG (M/G 3.3) was used to study the impact of GMs with different Mw on microparticle assembling, characteristics, and insulin release kinetics. The low-Mw GMs microparticles led to a faster release (20 min) than the higher-Mw (40 min) ones, impacting the release kinetics. All microparticles exhibited a safety profile to cells of the respiratory tract. However, only the higher-Mw GMs allowed the assembly of microparticles with sizes suitable for this type of administration.

Structural characterization of a galactoglucomannan with anti-neuroinflammatory activity from Ganoderma lucidum

According to traditional Chinese medicine theory, Ganoderma lucidum (G. lucidum) presents certain effects for nourishing nerves and calming the mind. G. lucidum polysaccharides (GLPs) have various biological activities; however, the structural characterization and the structure-activity relationship in anti-neuroinflammation of GLPs needs to be further investigated. In this work, the crude polysaccharide GL70 exhibited a remarkable impact on enhancing the spatial learning and memory function, as well as reducing the anxiety symptoms of the lipopolysaccharide (LPS)-induced rat model of Alzheimer's disease (AD). A galactoglucomannan (GLP70-1-2) was isolated from GL70, and characterized by monosaccharide composition, partial acid hydrolysis, methylation, and NMR analysis. The backbone of GLP70-1-2 was →6)-α-D-glcp-(1 → 6)-β-D-galp-(1 → [6)-β-D-manp-(1]3 → 4)-α-D-Glcp-(1 → 6)-α-D-glcp-(1 → 2)-β-D-galp-(1 → [4)-α-D-glcp-(1 → 6)-β-D-manp-(1 → 2)-β-D-galp-(1]2 → 6)-β-D-glcp-(1 → 6)-β-D-glcp-(1→ with two side chains attached to O-4 of →6)-β-D-galp-(1→ and O-3 of →6)-β-D-glcp-(1→, respectively. In addition, GLP70-1-2 exhibited remarkable efficacy in decreasing the level of pro-inflammatory factors in LPS-activated BV2 cells through the TLR4/MyD88/NF-κB pathway. Collectively, GLP70-1-2 exhibited significant anti-neuroinflammatory activity and may have the potential for developing as a drug for AD.

Process modelling and techno-economic analysis of anaerobic digestion of sewage sludge integrated with wet oxidation using a gravity pressure vessel and thermal hydrolysis

Anaerobic digestion (AD) of sewage sludge is used to biodegrade sewage sludge into biomethane and digestate. With the addition of thermal processes such as thermal hydrolysis (TH) and wet oxidation (WO), AD biodegradability generally improves. Implementation of additional treatment is challenging due to the limitation in the mass and energy balances. Hence, tools such as process simulation can be utilized to predict the input and output around the process. In addition, an economic analysis needs to be conducted to check the economic feasibility. The techno-economic analysis (TEA), an integrated method to evaluate a process scheme through simulation and subsequent economic analysis, is effective in providing a systematic understanding of economic implications and the feasibility of a process by identifying the bottlenecks and uncertainties that have a significant impact on the technology. TEA of AD, especially incorporating the TH or WO using gravity pressure vessel (GPV) technology, is limited in the literature. A comprehensive TEA of the AD and the pre- and post-treatment schemes can be utilized to determine the most feasible pathway for sludge treatment for implementation in the wastewater industry. In this study, TEA for four different scenarios of AD was conducted using Aspen Plus and economic analysis tools: (1) without any pre- or post-treatment, (2) with TH pre-treatment, (3) with 100 % WO post-treatment, and (4) with 20 % partial wet oxidation (PWO) and acid hydrolysis pre- or post-treatment. A simulation model (GPVM) was developed using Aspen Plus to mimic the GPV reactor. The study outcomes showed that Scenario 3 with 100 % WO post-treatment was the most suitable for processing parameters and sludge treatment cost. The sensitivity analysis concluded that operating cost and plant capacity are the dominant factors that impact the plant feasibility significantly.

Facile fabrication and antibacterial properties of chitosan/acrylamide/gold nanocomposite hydrogel incorporated with Chaetomium globosium extracts from Gingko biloba leaves

Microorganisms are a unique part of our ecosystem because they affect the survival of living organisms. Although pathogenic microorganisms could be detrimental to the plants, animals, and humans, beneficial microbes have provided significant improvement in the growth and development of living organisms. In this study, the fungus Chaetomium globosium was isolated from the medicinal tree Gingko biloba, and then incorporated into a polymerization system to fabricate chitosan/acrylamide/gold (CS/Am/Au) nanocomposite hydrogels. The as-prepared hydrogel displayed increased mechanical strength due to the reinforcement of Au (gold) nanocomposites within the hydrogel matrix. Also, the equilibrium pH responsive swelling rates of the hydrogels gradually increased as the pH increases due to partial acid and basic hydrolysis occurring in the hydrogel as well as formation of hydrogen bond. In addition, the hydrogel demonstrated promising antibacterial activities against selected gram-positive (Staphylococcus epidermidis and Staphylococcus aureus) and gram-negative (Pseudomonas aeruginosa) bacterial strains with an average MIC90 of 0.125 mg/mL at a dosage of 1.0 mg/L. The obtained results are quite promising towards resolving several health challenges and advancing the pharmaceutical industries.

Conformational properties of heterogeneous arabinoxylan protein gums from corn bran and distillers grains in comparison with gum arabic

The molecular structure and conformation of arabinoxylan-protein gum, commonly referred as corn fiber gum (CFG) were analyzed by high-performance size-exclusion chromatography (HPSEC) coupled with RI, UV, light scattering and viscometer detectors. CFG had a heterogeneous structure. The detailed conformation of CFG at different molecular weights was compared with that of hemicellulose fiber gum (HFG) from dried distiller's grains with solubles and gum arabic. The CFG molecules mainly had random coil conformation; only 10 % of them exhibited rigid rod conformation. Approximately 80 % of the CFG had a molecular weight between 105 and 105.4 Da, while the other 20 % of molecules were between 105.4 and 1.5 × 107.7 Da. The overall conformational properties of CFG and HFG were closer but differed from that of gum arabic. The intrinsic viscosity and radius of gyration of both CFG and HFG were greater than those of gum arabic although the average molecular weight of CFG and HFG was lower. The protein and carbohydrate were covalently linked in CFG molecules as shown by the HPSEC-multiple detectors combined with partial acid hydrolysis. Based on the detailed conformation of CFG and the methylation analysis, 1D and 2D NMR spectroscopy results, the molecular structure of CFG was proposed.

Fine structure and hypoglycemic effect of a galactoglucan from the bulbs of Lanzhou lily

The present research aimed to further identify the fine structure, morphology, and thermal behaviors of a galactoglucan BHP-2 derived from Lanzhou lily bulbs through partial acid hydrolysis, methylation, 2D NMR (1H1H COSY, HSQC, and HMBC), scanning electron microscopy (SEM) and thermogravimetric-differential thermal analysis (TG-DTA). Additionally, the study assessed the potential in vitro hypoglycemic effect of BHP-2 by examining its inhibitory effect on α-glucosidase and α-amylase. The results indicated that the main backbone composition of BHP-2 consisted of →4)-α-D-Glcp-(1→, →3)-β-D-Glcp-(1 → and →6)-β-D-Galp-(1→, while the side chain composition predominantly featured →4)-α-D-Glcp-(1→, →3,5)-α-L-Araf-(1 → and →3)-β-D-Galp-(1→, attached to the C-2 and/or C-3 positions of →4)-α-D-Glcp-(1→. Terminal residues consisted of α-D-Glcp-(1 → and β-L-Araf-(1→. BHP-2 exhibited excellent thermal stability, with a microscopic surface characterized by tightly packed sheets and numerous spiral depressions, which might contribute to its remarkable in vitro hypoglycemic effect. BHP-2 showed competitive inhibition of α-amylase and mixed non-competitive inhibition of α-glucosidase, with respective IC50 values of 0.31 and 0.18 mg/mL, closely resembling to those of acarbose (0.27 and 0.12 mg/mL). These findings suggested that BHP-2 had potential as an additive for glycemic intervention.

A pectic polysaccharide isolated from Achyranthes bidentata is metabolized by human gut Bacteroides spp.

Achyranthes bidentata (A. bidentata) is a famous traditional Chinese medicine (TGM) for treatment osteoporosis. Polysaccharides, a major factor for shaping the gut microbiota, are the primary ingredients of A. bidentata. However, bioactivity of A. bidentata polysaccharide on human gut microbiota (HGM) remains unknown. Here, a homogeneous pectic polysaccharide A23–1 with average molecular weight of 93.085 kDa was extracted and purified from A. bidentata. And A23–1 was compsed of rhamnose, glucuronic acid, galacturonic acid, glucose, galactose and arabinose in a molar ratio of 7.26: 0.76: 5.12: 2.54: 23.51: 60.81. GC–MS, partial acid hydrolysis and NMR results indicated the backbone of A23–1 was composed of 1, 2, 4-Rhap and 1, 4-GlapA, while the branches were composed of galactose, arabinose, glucose and glucuronic acid. Further, A23–1 was found to be degraded into monosaccharides and fragments. Taking Bacteroides thetaiotaomicron (BT) as a model, we suggested three polysaccharide utilization loci (PULs) might be involved in the A23–1 degradation. Degraded products generated by BO might not support the growth of probiotics. Besides, acetate and propionate as the main end products were generated by Bacteroides spp. and probiotics utilizing A23–1. These findings suggested A23–1 was possible one of food sources of human gut Bacteroides spp.

Structural characterization and anti-inflammatory activities of anti-complementary polysaccharides from Rhododendron principis.

Rhododendron principis leaves have been used as "Dama", a Traditional Tibetan Medicine for treating inflammatory diseases. R. principis crude polysaccharides (CZND) with anti-complementary activity demonstrated promising anti-inflammatory effects on acute lung injury (ALI) induced by lipopolysaccharide (LPS). CZND significantly decreased the levels of TNF-α and IL-6 in both serum and BALF (blood and bronchoalveolar lavage fluid) in LPS-induced ALI mice by intragastric administration (100 mg/kg). A heteropolysaccharide, ZNDHP, was obtained from CZND with successive anti-complementary activity-guided separation. ZNDHP was characterized as a branched neutral polysaccharide with a backbone composed of →2)-β-Glcp-(1→, →2,6)-α-Glcp-(1→, →6,3)-β-Galp-(1→, →2,6)-α-Galp-(1→, →6,2)-β-Glcp-(1→, →4)-α-Glcp-(1→, →5)-β-Araf-(1→, →3,5)-α-Araf-(1→, and →4,6)-β-Manp-(1→, and the backbone structure was further confirmed by partial acid hydrolysis. In addition to anti-complementary and antioxidant activities, ZNDHP exhibited potent anti-inflammatory activity by significantly inhibiting the secretion of NO, TNF-α, IL-6, and IL-1β of LPS treated RAW264.7 cells. However, all of these activities decreased greatly after partially hydrolyzing, indicating the importance of the multi-branched structure for its bioactivity. Therefore, ZNDHP might be an important component of R. principis for treating inflammation.

A New Galactoglucomannan from the Mycelium of the Medicinal Parasitic Fungus Cordyceps cicadae and Its Immunomodulatory Activity In Vitro and In Vivo.

A new galactoglucomannan (C-0-1) was purified from the medicinal parasitic fungus of Cordyceps cicadae using an anion-exchange column and gel permeation column. The results of high-performance liquid chromatography and high-performance gel permeation chromatography indicated that C-0-1 consists of galactose, glucose, and mannose in a ratio of 5:1:4 and has a molecular weight of 23.3 kDa. The combined structural elucidation analysis methods including partial acid hydrolysis, methylation analysis, and NMR experiments revealed that C-0-1 was a comb-like polysaccharide with a core structure including (1→2)-α-D-Manp residues in the backbone and branches at O-6 of the main chain. (1→4)-α-D-Glcp, (1→2)-β-D-Galf, (1→2,6)-β-D-Galf, and terminal β-Galf were located at the side chains. An in vitro experiment using RAW 264.7 cells indicated that C-0-1 exhibits good immunomodulatory activity by enhancing inducible nitric oxide synthase secretion and the production of some major inflammatory cytokines. On inhibiting the cytokine production using anti-pattern recognition receptors antibodies, it was revealed that the activation of macrophages is mainly carried out by C-0-1 through the mannose receptor. Toll-like receptor 4 and Toll-like receptor 2 were also involved in this identification process. An in vivo experiment on immunosuppressive mice treated with cyclophosphamide indicated that C-0-1 improves the secretion of serum-related cytokines (IFN-γ, TNF-α, IL-2, IL-4, and IL-10) and affects the balance of T helper cells Th1/Th2. Given the structural and bioactivity similarity between Cordyceps cicadae and Cordyceps sinensis, we can conclude that Cordyceps cicadae could be used as an important medicinal fungus like Cordyceps sinensis.

Toward Protein-Repellent Surface Coatings from Catechol-Containing Cationic Poly(2-ethyl-2-oxazoline)

Inspired by mussel proteins that enable surface binding in harsh marine environments, we envisioned a platform of protein-repellent macromolecules based on poly(2-ethyl-2-oxazoline) carrying catechol and cationic functional groups. To facilitate surface attachment, catechol units were installed by copolymerizing a functional comonomer, i.e., 2-(3,4-dimethoxyphenyl)-2-oxazoline, in a gradient fashion. Cationic units were introduced by partial acidic hydrolysis. The surface affinity of these polymers was probed using a quartz crystal microbalance with dissipation monitoring (QCM-D), and it was found that polymers with catechol units had a strong tendency to form surface-bound layers on different substrates, i.e., gold, iron, borosilicate, and polystyrene. While the neutral catechol-containing polymers showed strong, but uncontrolled binding, the ones with additional cationic units were able to form defined and durable polymer films. These coatings were able to prevent the attachment of different model proteins, i.e., bovine serum albumin (BSA), fibrinogen (FI), or lysozyme (LYZ). The herein-introduced platform offers straightforward access to nonfouling surface coatings using a biomimetic approach.

Structure of a highly branched galacturonoglucan from fruits of Schisandra chinensis (Turcz.) Baill.

A novel galacturonoglucan, named SCP-1, is isolated and purified from Schisandra chinensis fruits. The structure of SCP-1 is systematically investigated by a combination of monosaccharide compositions, absolute Mw, methylation analysis, partial acid hydrolysis, isoamylase degradations, and nuclear magnetic resonance spectroscopy. The structure of SCP-1 is theoretically described as follows: (i) Glc and GalA in a molar ratio of 17:3; (ii) → 4)-α-Glcp-(1→, →4,6)-α-Glcp-(1→, →3,4,6)-α-Glcp-(1→, α-Glcp-(1→, →4)-α-GalAp-6-OMe-(1→, α-GalAp-6-OMe-(1→, β-Glcp-(1→, →6-)-β-Glcp-(1 → and →3,4)-β-Glcp-(1 → in a molar ratio of 48:5:3:3:10:5:12:5:9; (iii) a repeating unit of →4)-α-Glcp-(1 → as a backbone with branched points at C-3 and C-6, substituted by different types of acidic and neutral side chains to form multiple branches; and (iv) a rigid rod configuration deduced from α value of 1.26 in Mark-Houwink equation ([η] = kMα). Anti-tumor assay investigated the effects of SCP-1 on human HepG2 cancer cell lines in vitro. This is for the first time to report a galacturonoglucan in S. chinensis fruits.

In Vitro Neurotrophic Properties and Structural Characterization of a New Polysaccharide LTC-1 from Pyrola corbieri Levl (Luticao).

Pyrola corbieri Levl has been used to strengthen bones and nourish the kidney (the kidney governs the bone and is beneficial to the brain) by the local Miao people in China. However, the functional components and neurotrophic activity have not been reported. A new acidic homogeneous heteropolysaccharide named LTC-1 was obtained and characterized by periodate oxidation, Smith degradation, partial acid hydrolysis, GC-MS spectrometry, methylation analysis, and Fourier transform infrared spectroscopy, and its molecular weight was 3239 Da. The content of mannuronic acid (Man A) in LTC-1 was 46%, and the neutral sugar was composed of L-rhamnose (L-Rha), L-arabinose (L-Ara), D-xylose (D-Xyl), D-mannose (D-Man), D-glucose (D-Glc) and D-galactose (D-Gal) with a molar ratio of 1.00:3.63:0.86:1.30:6.97:1.30. The main chain of LTC-1 was composed of Glc, Gal, Man, Man A and the branched chain Ara, Glc, Gal. The terminal residues were composed of Glc and Gal. The main chain and branched chains were linked by (1→5)-linked-Ara, (1→3)-linked-Glc, (1→4)-linked-Glc, (1→6)-linked-Glc, (1→3)-linked-Gal, (1→6)-linked-Gal, (1→3, 6)-linked-Man and ManA. Meanwhile, neurotrophic activity was evaluated through PC12 and primary hippocampal neuronal cell models. LTC-1 exhibited neurotrophic activity in a concentration-dependent manner, which significantly induced the differentiation of PC12 cells, promoted the neurite outgrowth of PC12 cells, enhanced the formation of the web architecture of dendrites, and increased the density of dendritic spines in hippocampal neurons and the expression of PSD-95. These results displayed significant neurotrophic factor-like activity of LTC-1, which suggests that LTC-1 is a potential treatment option for neurodegenerative diseases.

A novel Stauntonia leucantha fruits arabinogalactan: isolation and structural characterization

Polysaccharides were the key ingredients of many herbal medicines, and were responsible for multiple pharmacological activities. In this study, a novel polysaccharide fraction, named SLP-2, was isolated from Stauntonia leucantha fruits, and purified by DEAE-52 and Sephadex G-100 column chromatography. Furthermore, SLP-2 was identified by congo red, methylation, partial acid hydrolysis and NMR. The results indicated that the backbone of SLP-2 was composed of →4)-β-D-Galp-(1 → 4)-β-D-Galp-(1→ substituted at C-6 with 1,5-linked arabinan. SLP-2 had good anti-oxidation ability in vitro. Surprisingly, we found that reduction of carboxyl groups and methylation of hydroxyl groups enhanced the ability to scavenge 2,2′-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) radicals and inhibit lipid peroxidation, and weakened the activity to scavenge 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals and reduce ferric iron.

Preparation of miniaturized hydrophilic affinity monoliths: Towards a reduction of non-specific interactions and an increased target protein density

In affinity chromatography, non-specific interactions between the ligands and the affinity column may affect the results, leading to misinterpretations during the investigation of protein-ligand interactions (detection of false positives in ligand screening, lack of specificity in purification). Such non-specific interactions may arise both from the underlying support or from the target protein itself. If the second ones are protein-dependent (and cannot be studied in a general framework), the first ones occur in the same way regardless of the immobilized target. We propose a methodology to identify the origin of such non-specific interactions with the underlying material of the affinity column. This methodology relies on the systematic investigation of the retention behavior of a set of 41 low-molecular weight compounds covering a wide chemical space (net charge, log D, functionality). We first demonstrate that the main source of non-specific interactions on the most commonly used GMA-co-EDMA monolith comes from hydrophobic effects. To reduce such non-specific interactions, we developed a new hydrophilic glycidyl methacrylate-based monolith by replacing the EDMA crosslinker by the more hydrophilic NN’ Methylenebisacrylamide (MBA). Optimization of the synthesis parameters (monomer content, initiation type, temperature) has focused on the reduction of non-specific interaction with the monolithic support while maximizing the amount of protein that can be grafted onto the monolith at the issue of its synthesis. The retention data of the 41 test solutes on the new poly(GMA-co-MBA) monolith shows a drastic reduction of non-specific interactions except for cationic compounds. The particular behavior of cationic compounds is due to their electrostatic interactions with carboxylic groups resulting from the partial acidic hydrolysis of amide groups of MBA during the epoxide ring opening step. So, the ring opening step in acidic media was replaced by a hot water treatment to avoid side reaction on MBA. The new monolith poly(GMA-co-MBA) not only has improved hydrophilic surface properties but also a higher protein density (16 ± 0.8 pmol cm−1 instead of 8 ± 0.3 pmol cm−1). To highlight the benefits of this new hydrophilic monolith for affinity chromatographic studies, frontal affinity chromatography experiments were conducted on these monoliths grafted with con A.