Removal of methylene blue by porous biochar obtained by KOH activation from bamboo biochar.

A series of activated biochar (KBBC-700, KBBC-800 and KBBC-900) which were modified by KOH and pyrolysis at various temperatures from ball-milling bamboo powder were obtained. The physicochemical properties and pore structures of activated biochar were investigated by scanning electron microscopy (SEM), fourier transform infrared spectoscopy (FT-IR), X-ray diffraction (XRD) and N2 adsorption/desorption. The adsorption performance for the removal of methylene blue (MB) was deeply studied. The results showed that KBBC-900 obtained at activation temperature of 900 °C exhibited a great surface area which reached 562 m2/g with 0.460 cm3/g of total pore volume. The enhancement of adsorption capacity could be ascribed to the increase of surface oxygen-containing functional groups, aromatization and mesoporous channels. The adsorption capacity was up to 67.46 mg/g under the optimum adsorption parameters with 2 g/L of adsorbent dose, 11 of initial solution pH and 298 K of the reactive temperature. The adsorption capacity was 70.63% of the first time after the material was recycled for three cycles. The kinetics indicated that the adsorption equilibrium time for MB on KBBC-900 was of about 20 min with the data fitted better to the pseudo-second-order kinetics model. The adsorption process was mainly dominated by chemical adsorption. Meanwhile, the adsorption isotherm showed that the Langmuir model fitted the best, and thermodynamic parameters revealed that the adsorption reaction was the endothermic nature and the spontaneous process. Adsorption of MB mainly attributed to electrostatic interactions, cation-π electron interaction and redox reaction. This study suggested that the activated biochar obtained by KOH activation from bamboo biochar has great potentials in the practical application to remove MB from wastewater.

In vitro fecal fermentation characteristics of bamboo insoluble dietary fiber and its impacts on human gut microbiota.

Bamboo contains abundant hemicellulose, cellulose, and lignin, which are a high-quality insoluble dietary fiber (IDF) raw material. To investigate IDF- induced changes in the production of short-chain fatty acids (SCFAs) and the composition of human gut microbiota, IDF was extracted by alkaline hydrogen peroxide (named BIDF), complex enzymatic hydrolysis method (named OIDF) from bamboo, and commercial bamboo fiber BF90. The in vitro fecal fermentation characteristics of BIDF, OIDF, BF90 and its impacts on human gut microbiota were studied for the first time. Results showed that BIDF, OIDF, and BF90 could promote the production of total SCFAs after 24 h fermentation. Additionally, BIDF could alter the composition and microbial diversity of gut microbiota, especially increase the relative abundance of Bacteroides and decrease the ratio of Firmicutes to Bacteroidetes (F/B) value. These results revealed that the IDF from bamboo could be partially utilized by specific bacteria in human intestines and provide a reference for the study of the effects of IDF fermentation on SCFAs production and microbial composition.

Enrichment and separation of steroidal saponins from the fibrous roots of Ophiopogon japonicus using macroporous adsorption resins.

In this study, a simple and effective strategy for the enrichment of total steroidal saponins (TSS) from the fibrous roots of Ophiopogon japonicus (L. f.) Ker-Gawl. (FROJ) using macroporous adsorption resin was systematically developed. XAD-7HP resin was selected from six macroporous resins for further study because of the highest static adsorption and desorption capacities. The static adsorption of TSS on XAD-7HP resin fitted well to the Langmuir isotherm model and pseudo second-order kinetic model; the thermodynamics test showed that the adsorption process was spontaneous and exothermic. The dynamic tests on XAD-7HP resin columns demonstrated that the breakthrough volume was 16 bed volume (BV), and 6 BV of 80% ethanol was suitable for dynamic desorption. In a lab scale-up separation under optimal dynamic conditions, the content of TSS in the resin-enrichment fraction increased from 1.83% in the crude extracts to 13.86% by 7.59-fold with a recovery yield of 82.68%. Three steroidal saponins were obtained from the resin-enrichment fraction, and showed protective effects against oxidized low-density lipoprotein (ox-LDL) induced human umbilical vein endothelial cell (HUVEC) injury. Overall, these results suggested that XAD-7HP resin chromatography was an effective strategy for the large scale enrichment of TSS from FROJ, which showed the potential for functional food and pharmaceutical application.

Effect of quaternization degree on physiochemical and biological activities of chitosan from squid pens.

Chitosan was prepared by alkaline N-deacetylation of ß-chitin from squid pens, and N-(2-hydroxy) propyl-3-trimethyl ammonium chitosan chloride (HTCC) derivatives, with different degrees of quaternization (DQ) ranging from 0.77 to 1.06, were synthesized. It was identified by FT-IR, 1H NMR and XRD analysis. All of the HTCC showed good water solubility in a wide pH range. The moisture absorption and retention abilities of all the HTCC were much better than that of the chitosan. The moisture absorption and retention values of all the HTCC at 43% RH for 24 h were above 49% and 92%, respectively. The scavenging ability of HTCC against hydroxyl and ABTS radicals improved with increasing concentration. The effectiveness of HTCC against hydroxyl radicals was lower than that of chitosan. These results indicated that HTCC, which has a much better moisture absorption and retention capacity, may act as a potential moisturizer in vitro.

Optimization of total polysaccharide extraction from Herba Lophatheri using RSM and antioxidant activities.

Effects of extraction temperature, extraction time and ratio of water to material as well as their interactions on the yield of total polysaccharide from Herba lophatheri were studied by response surface methodology (RSM). The optimal conditions for the extraction of polysaccharides were determined to be the ratio of liquid to solid of 39.01, extraction time of 2.11h and extraction temperature of 97.09°C. Under these optimal conditions, the yield of polysaccharides obtained was 5.73±0.10%, which was well matched with the value predicted by the model. In vitro antioxidant assays showed that the polysaccharides HLP possessed significant inhibitory effects on superoxide radical. It also exhibited strong 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activities, hydroxyl radical scavenging activities and its reducing power, ferrous ions chelating effect was also strong. These results suggested that H. lophatheri polysaccharides could be a suitable natural antioxidant and may be the functional foods for humans.

Effects of hydroxypropyl degree on physiochemical activities of chitosan from squid pens.

Chitosan was prepared by alkaline N-deacetylation of ß-chitin and hydroxypropyl derivatives with different degrees of substitution (DS) were synthesized. It was characterized by Fourier transform infrared (FT-IR) and elemental analysis. The DS of hydroxypropyl chitosan (HPCS) calculated by an element analyzer were 0.42, 0.75, 1.20, 1.82 and 2.25. HPCS showed better foam capacity and stability than that of chitosan, and the effectiveness correlated well with the DS of HPCS. The highest bile acid-binding capacity of all five HPCS reached 56.02 mg/g, which was 4.0-fold higher than that of chitosan. The scavenging ability of HPCS against hydroxyl and ABTS radicals improved with increasing concentration. The correlation between the hydroxypropyl content (DS) of HPCS and scavenging ABTS radical ability was positive. The hydroxyl radicals scavenging activity of HPCS correlated well with its increasing concentration, and EC50 values were below 12.5 mg/mL. These results indicated that hydroxypropylation is a possible approach to obtain chitosan derivatives with desirable physiochemical properties.

2-Acetyl-amino-1,3,4,6-tetra-O-(tri-methyl-silyl)-2-de-oxy-α-d-gluco-pyran-ose.

The title compound, C20H47NO6Si4, was synthesized by per-O-tri-methyl-silylation of N-acetyl-d-glucosa-mine using chloro-tri-methyl-silane in the presence of hexa-methyl-disiloxane. The tri-methyl-silyl group and acetamido group are located on the same side of the pyran ring, showing an α-configuration glycoside. One of the tri-methyl-silyl groups is disordered over two orientations, with site-occupancy factors of 0.625 (9) and 0.375 (9). In the crystal, N-H⋯O hydrogen bonds link the mol-ecules into supra-molecular chains along the a-axis direction.

Composition and antioxidant activities of four polysaccharides extracted from Herba Lophatheri.

Four polysaccharides (BLF80-A, BLF80-B, BLF80-C and BLF80-D) were isolated by hot-water extraction and purified from the leaves of Herba Lophatheri by DEAE-Sepharose fast flow. Their chemical and physical characteristics were determined and antioxidant activities were investigated on the basis of DPPH radical assay, hydroxyl radical assay and superoxide radical assay. The results showed that four polysaccharides exhibited antioxidant activities in a concentration-dependent manner, and the higher molecular weight, the stronger antioxidant activities of polysaccharides. Besides, the monosaccharide compositions of polysaccharides also influence their antioxidant activities. BLP80-D showed the strongest scavenging ability, followed by BLP80-C, BLP80-B and BLP80-A.

In vitro antioxidant activities of polysaccharides extracted from Moso Bamboo-Leaf.

The objective of this study was to evaluate in vitro antioxidant capacities of polysaccharides extracted from Moso Bamboo-Leaf (BLP). The molecular weight of the polysaccharides were obtained by SEC-LLS and their molecular masses were 13.4×10(4)Da, 2.8×10(4)Da and 1.9×10(4)Da, respectively. Available data obtained with in vitro models suggested WB1 (precipitated by 30% ethanol) showed significant inhibitory effects on superoxide radical, hydroxyl radical, DPPH radical and ferrous metal-chelating capacities. These results clearly establish the possibility that polysaccharides extracted from Moso Bamboo-Leaf could be effectively employed as ingredient in health or functional food, to alleviate oxidative stress.

Biochemical activities of 6-carboxy ß-chitin derived from squid pens.

TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl radical)-mediated 6-carboxy ß-chitin derivatives (T-chitin) with different carboxylate content were successfully synthesized by controlling the addition level of NaClO as the primary oxidant. The structural and biochemical properties of the derivatives were investigated. The carboxylate contents of the derivatives calculated by electrical conductivity titration were 1.33, 1.68, 1.80, and 2.08 mmol/g, respectively. The yield of T-chitin with carboxylate content of 2.08 mmol/g reached 74.55%. T-chitin exhibited stronger bile acid binding capacities than that of ß-chitin. The scavenging ability of T-chitin against hydroxyl radicals improved with increasing concentration, and EC(50) values were below 1.2 mg/mL. All T-chitin exhibited a strong ferrous ion chelating effect. At 8 mg/mL, the chelating effects of T-chitin with carboxylate content of 0.81 mmol/g reached 80.15%. These results showed that T-chitin had good bile acid binding capacity and antioxidant activities and it may be a potential antioxidant in vitro.

2,3,4,6-Tetra-O-acetyl-ß-d-galacto-pyrano-syl butyrate.

The title compound, C(18)H(26)O(11), was synthesized by a condensation reaction of 2,3,4,6-tetra-O-acetyl-α-d-galactopyranosyl bromide and butyric acid. The acet-oxy-methyl and butyrate groups are located on the same side of the pyran ring, showing the ß configuration for the d-glycosyl ester; the butyl group adopts an extend conformation, the C-C-C-C torsion angle being 179.1 (7)°. In the crystal, the mol-ecules are linked by weak C-H⋯O hydrogen bonds.

Cloud point extraction and determination of trace trichlorfon by high performance liquid chromatography with ultraviolet-detection based on its catalytic effect on benzidine oxidizing.

4-Amino-4'-nitrobiphenyl, which is formed by catalytic effect of trichlorfon on sodium perborate oxidizing benzidine, is extracted with a cloud point extraction method and then detected using a high performance liquid chromatography with ultraviolet detection (HPLC-UV). Under the optimum experimental conditions, there was a linear relationship between trichlorfon in the concentration range of 0.01-0.2 mgL(-1) and the peak areas of 4-amino-4'-nitrobiphenyl (r=0.996). Limit of detection was 2.0 microgL(-1), recoveries of spiked water and cabbage samples ranged between 95.4-103 and 85.2-91.2%, respectively. It was proved that the cloud point extraction (CPE) method was simple, cheap, and environment friendly than extraction with organic solvents and had more effective extraction yield.