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Two rare types of 4,6-dimethyl-3,4-dihydrochromen-2-one derivatives, named cralactones A and B (1and2), were isolated from the culture broth ofCraterellus odoratus. The structures of the new ones were established on the basis of extensive spectroscopic analysis, and it was found that the new compounds did not show pancreatic lipase inhibitory activity. Compounds1and2are the first examples of 4,6-dimethyl-3,4-dihydrochromen-2-one. [ABSTRACT FROM PUBLISHER]

The mechanical behavior of commercial purity Ti (CP-Ti)/Ti–6Al–2Zr–1Mo–1V structurally graded materials (SGMs) fabricated by laser additive manufacturing was investigated via uniaxial tensile experiments. Although the strength of all SGM specimens is higher than that of the monolithic CP-Ti specimens, only the SGM specimen of Ø10mm gauge diameter with bulky α-grains exhibits excellent plasticity comparable to the CP-Ti specimen under the same conditions. The SGM presents a potential for use as load-bearing components due to its good strength–ductility balance. [ABSTRACT FROM AUTHOR]

A new Co(II) cluster, {[CoL(DMF)]2(OAc)2Co}·2DMF (H2L = 4,4'-dichloro-2,2'-[(1,3-propylene)dioxybis (nitrilomethylidyne)]diphenol), has been synthesized and characterized by elemental analysis, IR spectrum, UV-Vis spectrum, and X-ray diffraction method. The results indicate that the Co(II) cluster consists of three Co(II) ions, two tetradentate (μ-L)2- units, two coordinated μ-acetate ions, two coordinated DMF, and two crystallizing DMF molecules. All the hexa-coordinated Co(II) ions of the Co(II) cluster have a slightly distorted octahedral geometry. The crystal packing of the Co(II) cluster shows that a notable feature of this structure resides in the formation of a novel 2D supramolecular structure through intermolecular C-H···O interaction and weak intramolecular C-H···(Ph) interaction along the b-axes. [ABSTRACT FROM AUTHOR]

Phosphorylation is a key route to achieve varieties of biological activities for polysaccharides. Currently, conventional phosphorylation reagents are characterized by long processing times and high reaction temperatures. Here, we reported phosphorylation of Artemisia sphaerocephala polysaccharides (PASP) with the degrees of substitution (DS) of 0.34-0.54 in mild reaction conditions (3–4 h and 25 °C) by employing POCl 3 /pyridine technique. FT-IR spectroscopy and X-ray photoelectron spectroscopy (XPS) analysis confirmed the appearance of phosphate ester (P 5+ ) groups in PASP. Size exclusion chromatography combined with multi-angle laser light scattering (SEC-MALLS) result clearly showed temperature-dependent increment of weight average molecular mass ( M W ). High temperature facilitated the reaction of phosphoryl chloride with primary and secondary hydroxyl groups, favoring the crosslinking of polysaccharide chains by phosphate di-esters as further confirmed in 13 C NMR determination. Our results provide insight into the relationship between the structure and reaction conditions of phosphorylated polysaccharide, which is important for understanding and exploiting these derivatives in a wide range of applications. [ABSTRACT FROM AUTHOR]

In this work, selenylation of Artemisia sphaerocephala polysaccharide (SeASP MW ) was studied by using H 2 SeO 3 /HNO 3 /BaCl 2 reaction system in microwave field. SeASP MW exhibited the Se content range of 111–264 μg/g with high yields (72.1–94.9%). 13 C NMR results indicated that the weak C-6 substitution was occurred. The decrease (from 7.348 × 10 4 g/mol to 1.736–4.667 × 10 4 g/mol) in weight average molecular mass ( M W ) of SeASP MW was observed in size exclusion chromatography combined with multi angle laser light scattering (SEC-MALLS) analysis. SeASP MW exhibited a more rigid solution conformation which might be due to the degradation of polysaccharide chains in acidic reaction reagent. This was also supported by atomic force microscopy (AFM) result that SeASP MW showed short chains and island-like topography. In anti-tumor activity assays, SeASP MW6 exhibited the inhibition rates of 32.381% and 39.776% against human non-small cell lung cancer cell line (H1650) at the concentration of 100 and 200 μg/mL, respectively. The relatively weak inhibition effect of SeASP MW was not related to cell apoptosis and cell cycle arrest, suggesting Se content might be a key factor to influence the anti-tumor activities of selenized polysaccharides in vitro . [ABSTRACT FROM AUTHOR]

Sulfated derivatives of galactomannan from locust bean gum (LBG) with the degree of substitution (DS) of 0.34–1.07 were synthesized using chlorosulfonic acid/pyridine (CSA/Py) method. Box–Behnken design (BBD) of response surface methodology (RSM) was employed to optimize the reaction conditions. Results of FT-IR and X-ray photoelectron spectroscopy (XPS) indicated that SO 3 H groups were widely present in sulfated LBG (SLBG). 13 C NMR result revealed that sulfation had occurred and C-6 substitution was predominant in SLBG. All sulfated samples showed a decrease in M w and more broad molar mass distribution in size exclusion chromatography combined with laser light scattering (SEC-LLS) analysis. Results of M W – 〈 S 2 〉 z 1 / 2 showed a decrease in fractal dimension ( d f ) value. Laser light scattering results also showed a conformation transition from a compact chain conformation of branched clusters to a random coil conformation of SLBG. Compared to LBG and SLBG with low DS and molecular weight, SLBG 2 exhibited an internal structure of random coil with a DS of 1.07. DS and molecular weight had great influence on its conformation in aqueous solution. Our results confirmed that the degradation of polysaccharide and SO 3 H groups improved significantly the stiffness of the chains due to the electrostatic effect. [ABSTRACT FROM AUTHOR]

Highlight: [•] A neutral glucan LJW0F2 was isolated and purified from flowers of Lonicera japonica Thunb. [•] The structure of LJW0F2 was elucidated as to an α-d-(1→4)-glucan with an α-(1→4) linked branch attached to C-6 position. [•] The polysaccharide LJW0F2 could block Aβ 42 aggregation directly and attenuated its cytotoxicity in SH-SY5Y cells. [Copyright &y& Elsevier]

Abstract: We reported here a new synthesis of C-2 and C-3 sulfated guar gum (SRSGG) with low degree of substitution (DSS) of 0.58, employing triphenylchloromethane (TrCl) as a protected precursor. The yield and DSTr (calculated from the weight of triphenylmethanol) of triphenylmethylated GG (GGTr) was 165.6% and 0.71, respectively. In addition, low ratio (1:4) of chlorosulfuric acid to pyridine (1:4) was chosen in sulfation reaction since the protecting group was slightly sensitive to acid. Results of FT-IR and 13C NMR spectroscopy indicated that C-2 and C-3 substitution was predominant but not fully sulfated in SRSGG. Size-exclusion chromatograph combined with multi-angle laser photometer (SEC-LLS) showed a decrease in molecular weight in the reaction. This might be due to the degradation in sulfation and deprotection process. Finally, we investigated the effect of structure features on the antioxidant activities in vitro. Vitro antioxidant experiments revealed that the regioselective sulfation at C-2 and C-3 and low molecular weight afforded strong antioxidant activities showing a much higher scavenging abilities of 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydroxyl radical than that by the known C-6-sulfated derivative. The antioxidant activities of sulfated polysaccharides were not a function of a single factor but a combination of molecular weight, DSS and substitution positions. [Copyright &y& Elsevier]

Abstract: The seed of Cassia obtusifolia is a food or herbal medicine used for improving eyesight, treating constipation and other disorders, and polysaccharides have been implicated in these pharmacological activities. The endosperm of the seeds, Cassia gum, is a commercial thickening or gelling agent, composed mainly of galactomannans. However, the whole seeds of C. obtusifolia, rather than the endosperm, are used in folk medicine or food, which might contain more complex constituents of polysaccharides. In this study, the whole seeds of C. obtusifolia were extracted with boiling water, and from the water extract, three homogeneous fractions were isolated, designated CFAA-1, CFAA-3, and CFBB2, respectively, after treatment with Fehling solution followed by anion-exchange and gel permeation chromatography. Using chemical and spectroscopic methods, CFAA-1, and CFAA-3 were elucidated to be both branched galactomannans with different molecular weights, consisting of 1,4-linked β-d-mannopyranosyl backbone with single-unit α-d-galactopyranosyl branches attached to O-6 of mannose, while CFBB2 was shown to be a linear (1→4)-α-polygalacturonic acid. [Copyright &y& Elsevier]

Abstract: It was essential to understand the chemical structure of polysaccharides for further research and biochemical or medical application of this natural biopolymer. In the present study, sulfated derivatives of guar gum with high degree of sulfation (DS) were synthesized using 4-dimethylaminopyridine (DMAP)/dimethylcyclohexylcarbodiimide (DCC) as catalyst in homogeneous conditions. The effects of the ratio of chlorosulfuric acid to pyridine, the content of catalyst and reaction temperature were investigated. Results of FT-IR, 1H and 13C NMR indicated that C-6 substitution was predominant in sulfated polysaccharide. In the sulfation reaction, a sharp decrease in M W was observed. The enhanced antioxidant activities of sulfated polysaccharides were not a function of a single factor but a combination of high DS and low molecule weight. [Copyright &y& Elsevier]

Abstract: To discover anti-pancreatic cancer cells growth inhibitor, a new water-soluble glucan, WTMA, was isolated from the rhizome of Gastrodia elata Bl. The mean molecular weight of the polysaccharide was estimated to be 7.0×105 Da by high performance gel permeation chromatography (HPGPC). The structure of WTMA was characterized by GC, GC–MS, NMR and MALDI-TOF. WTMA was deduced as an α-(1→4)-glucan with α-(1→4) linked branches attached to O-6 at branch points. Bioactivity tests in vitro indicated that WTMA and its partial acid hydrolysis-derived mixture product, WTMA-AD-O, could significantly inhibit the proliferation of pancreatic cancer cells. However, WTMA-DE, the degraded polysaccharide without branch chain by isoamylase, did not inhibit the proliferation of pancreatic cancer cells. Thus side chain on WTMA was deduced to be required for the anti-cancer cell activity. Further study demonstrated that WTMA and all of its hydrolysis products had no inhibition effect on liver LO2 cells. [Copyright &y& Elsevier]

Abstract: Sulfated polysaccharides exerted potent biological property which was relative to degree of sulfation (DS), M w, substitution position and chain conformation. In the present study, sulfated derivatives of Artemisia sphaerocephala polysaccharide (ASP) with different DS were synthesized by chlorosulfuric acid/pyridine method. FT-IR and 13C NMR analysis indicated that C-6 substitution was predominant in sulfated ASP (SASP) compared with other positions at C-2. In the sulfation reaction, a sharp decrease in M w was observed in SASP. The d f values from 1.96 to 2.77 indicated that the –SO3H groups leading to the relatively expanded conformation of SASP. Antioxidant assays showed that SASP had better antioxidant activities. The data obtained in vitro models indicated that high DS and moderate M w showed the best antioxidant capacities. [Copyright &y& Elsevier]

Abstract: Sulfated polysaccharides exerted potential biological property which was relative to degree of sulfation (DS), M w, substitution position and chain conformation. In the present study, commercial guar gum was purified and its sulfated derivates with different DS and M w were synthesized. FT-IR and 13C NMR analysis indicated that C-6 substitution was predominant in sulfated samples compared with other positions. In the sulfation reaction, a sharp decrease in M w was observed. The d f values from 1.92 to 2.85 indicated that the –SO3H groups led to the relatively expanded conformation of sulfated polysaccharides. Antioxidant assays showed that sulfated polysaccharides had better antioxidant activities. The data obtained in in vitro models indicated that high DS and low M w showed the best antioxidant capacities. [Copyright &y& Elsevier]

Abstract: The conventional extraction methods for polysaccharides were time-consuming, laborious and energy-consuming. Microwave-assisted extraction (MAE) technique was employed for the extraction of Artemisia sphaerocephala polysaccharides (ASP), which is a traditional Chinese food. The extracting parameters were optimized by Box-Behnken design. In microwave heating process, a decrease in molecular weight (M w) was detected in SEC-LLS measurement. A d f value of 2.85 indicated ASP using MAE exhibited as a sphere conformation of branched clusters in aqueous solution. Furthermore, it showed stronger antioxidant activities compared with hot water extraction. The data obtained showed that the molecular weights played a more important role in antioxidant activities. [Copyright &y& Elsevier]