Phenolic Constituents, Antioxidant and Cytoprotective Activities, Enzyme Inhibition Abilities of Five Fractions from Vaccinium dunalianum Wight.

The bud of Vaccinium dunalianum Wight has been traditionally consumed as health herbal tea by "Yi" people in Yunnan Province, China, which was locally named "Que Zui tea". This paper studied the chemical constituents of five fractions from Vaccinium dunalianum, and their enzyme inhibitory effects of α-glucosidase and pancreatic lipase, antioxidant activity, and cytoprotective effects on H2O2-induced oxidative damage in HepG2 cells. The methanol extract of V. dunalianum was successively partitioned with petroleum ether (PF), chloroform (CF), ethyl acetate (EF), n-butanol (BF), and aqueous (WF) to obtain five fractions. The chemical profiling of the five fractions was analyzed by ultra-high-performance liquid chromatography coupled with a tandem mass spectrometry (UHPLC-MS/MS), and 18 compounds were tentatively identified. Compared to PF, CF, BF and WF, the EF revealed the highest total phenols (TPC) and total flavonoids (TFC), and displayed the strongest enzyme inhibition ability (α-glucosidase and pancreatic lipase) and antioxidant capacity (DPPH, ABTS and FRAP). Furthermore, these five fractions, especially EF, could effectively inhibit reactive oxygen species (ROS) production and cell apoptosis on H2O2-induced oxidative damage protection in HepG2 cells. This inhibitory effect might be caused by the up-regulation of intracellular antioxidant enzyme activity (CAT, SOD, and GSH). The flavonoids and phenolic acids of V. dunalianum might be the bioactive substances responsible for enzyme inhibitory, antioxidant, and cytoprotective activities.

Ethanolic Extract from Pteris wallichiana Alleviates DSS-Induced Intestinal Inflammation and Intestinal Barrier Dysfunction by Inhibiting the TLR4/NF-κB Pathway and Regulating Tight Junction Proteins.

The aim of the research was to determine the protective effect and mechanism of Pteris wallichiana J. Agardh extract (PWE) on DSS-induced ulcerative colitis (UC) in mice. In this research, PWE is rich in flavonoids and diterpenoids by UPLC-MS/MS analysis. In LPS-induced RAW264.7 cells, PWE reduced the productions of inflammatory factors (i.e., NO, TNF-α, IL-6, and IL-1ß). In DSS-induced UC in mice, PWE improved disease activity index (DAI) score, attenuated oxidative stress by decreasing MPO and MDA activities and activating GSH and SOD levels, and inhibited TNF-α, IL-6, and IL-1ß expressions in the colonic tissues. PWE also improved the intestinal barrier by upregulating the expressions of tight junction proteins, including occludin and ZO-1. Moreover, PWE extract alleviated intestinal inflammation by suppressing the TLR4/MyD88/NF-κB signaling pathway. Conclusion: PWE can alleviate DSS-induced UC in mice by increasing the expressions of intestinal tight junction proteins and inhibiting the TLR4/NF-κB inflammatory pathway.

Cellulose nanocrystals/graphene oxide composite for the adsorption and removal of levofloxacin hydrochloride antibiotic from aqueous solution.

Residual antibiotics in water are often persistent organic pollutants. The purpose of this study was to prepare a cellulose nanocrystals/graphene oxide composite (CNCs-GO) with a three-dimensional structure for the removal of the antibiotic levofloxacin hydrochloride (Levo-HCl) in water by adsorption. The scanning electron microscope, Fourier transform infrared (FT-IR), energy-dispersive spectroscopy, X-ray photoelectron spectroscopy and other characterization methods were used to study the physical structure and chemical properties of the CNCs-GO. The three-dimensional structure of the composite material rendered a high surface area and electrostatic attraction, resulting in increased adsorption capacity of the CNCs-GO for Levo-HCl. Based on the Box-Behnken design, the effects of different factors on the removal of Levo-HCl by the CNCs-GO were explored. The composite material exhibited good antibiotic adsorption capacity, with a removal percentage exceeding 80.1% at an optimal pH of 4, the adsorbent dosage of 1.0 g l-1, initial pollutant concentration of 10.0 mg l-1 and contact time of 4 h. The adsorption isotherm was well fitted by the Sips model, and kinetics studies demonstrated that the adsorption process conformed to a quasi-second-order kinetics model. Consequently, the as-synthesized CNCs-GO demonstrates good potential for the effective removal of antibiotics such as levofloxacin hydrochloride from aqueous media.

Optimization of polyvinylamine-modified nanocellulose for chlorpyrifos adsorption by central composite design.

Developing an efficient adsorption material is of great significance for application in wastewater contaminated with pesticides. The present study investigated a promising nanomaterial (PhaCNCs) prepared with nanocellulose by grafting polyvinylamine for adsorption chlorpyrifos (CP). Structures and characteristics of PhaCNCs were analyzed using scanning electron microscopy (SEM), Fourier transform infrared (FT-IR), X-ray photoelectron spectroscopy (XPS), and Brunauer-Emmett-Teller (BET). Central composite design based on response surface methodology was used to optimize adsorption process of CP by PhaCNCs. The optimum chemometric showed that 0.57 g L-1 PhaCNCs adsorbed 36.81 mg L-1 CP to yield an efficiency of 92.72 %. The results indicated that the adsorption process was well-described by the pseudo-second-order model. Langmuir isotherm calculated the maximum adsorption capacity for CP of 98.116 mg g-1, implied that the adsorption capacity of PhaCNCs was significantly higher than other adsorbents. This study will contribute to the development of adsorption processes for CP removal from aqueous environments.

Cloning and characterization of a novel amylopullulanase from Bacillus megaterium Y103 with transglycosylation activity.

OBJECTIVE: To obtain a novel pullulanase with synthetic ability from a microorganism and characterize its substrates specificity. RESULTS: A novel pullulanase, PulY103A, from Bacillus megaterium Y103 was purified, characterized and expressed in Escherichia coli. PulY103A contained the signature sequences of type I pullulanases and showed 94.7% identity with a type I pullulanase (BmPul) from B. megaterium WW1210, showing similar molecular weight (110.8 kDa) and optimal pH (6.5). However, PulY103A had an optimal temperature of of 45 °C and exhibited relatively higher activity toward amylose (48.3%) compared with pullulan (100%), soluble starch (67.5%), and amylopectin (23.1%). The thin-layer chromatography results showed that the major pullulan hydrolysis products were maltotriose and maltohexaose, which differed from those reported in other pullulanases. On the basis of enzyme specificity, PulY103A was an amylopullulanase, which presented transglycosylation activity by forming α-1,4-glucosidic linkages. CONCLUSIONS: A novel amylopullulanase with transglycosylation activity was characterized. The features of this enzyme suggested its potential to produce maltohexaose.

Nanocellulose-organic montmorillonite nanocomposite adsorbent for diuron removal from aqueous solution: optimization using response surface methodology.

Herbicides have been ubiquitous in water environments in recent years, and so it is an appealing proposition to develop an efficient adsorbent for the adsorption of diuron. Therefore, the present study investigated a cellulose nanocrystal/organic montmorillonite nanocomposite adsorbent (CNC/CTM) and its adsorption properties towards diuron present in water. The structure and characteristics of the adsorbent used in this study were characterized by various characterization methods. The optimal diuron adsorption conditions for the CNC/CTM nanocomposite were analyzed based on the response surface methodology (RSM). The adsorption isotherms and kinetics of diuron adsorption were investigated. The results indicated that the adsorption process is the result of hydrogen bonding and the hydrophobicity of the alkyl chain. Under the optimal adsorption conditions, 0.07 g L-1 CNC/CTM adsorbed 5.86 mg L-1 diuron in less than 318.68 min and an efficiency of 82.32% could be achieved. The simulation results showed that the adsorption capacity of CNC/CTM for diuron removal followed the Sips model most closely. The maximum adsorption capacity was approximately 69.04 mg g-1 at 288 K. The experimental data was described best by a pseudo-second-order kinetic equation, signifying a chemical adsorption process. The adsorbent can be reused at least five times after simple solvent washing. This study provides a theoretical basis for understanding the adsorption process of diuron present in water.

Carboxylated cellulose nanofiber/montmorillonite nanocomposite for the removal of levofloxacin hydrochloride antibiotic from aqueous solutions.

Herein, we report the facile two-step synthesis of an effective carboxylated cellulose nanofiber/montmorillonite nanocomposite (CMNFs-MMT) adsorbent for levofloxacin hydrochloride (Levo-HCl). CMNFs-MMT was characterized using scanning electron microscopy, energy dispersive X-ray spectrometry, Brunauer-Emmett-Teller measurements, X-ray photoelectron spectroscopy, X-ray diffraction, and Fourier transform infrared spectroscopy. Based on the central composite design, the effects of various factors on the removal of Levo-HCl by the CMNFs-MMT were explored, wherein the effect of pH was the most significant. To gain a clearer perspective on the adsorption process of Levo-HCl onto CMNFs-MMT, the adsorption kinetics and isotherms were also measured, revealing that the reaction is pseudo-second-order and the Sips models provide the best fit with experimental data. Comparing the adsorption in pure water with the removal in river water, the rate of river water removal (90.37%) was slightly lower than that of pure water (93.97%) when adsorption equilibrium was reached, confirming that CMNFs-MMT is not easily influenced by environmental conditions. Reusability experiments indicate that CMNFs-MMT can maintain a certain adsorption capacity for Levo-HCl after six uses. Overall, this work indicates that CMNFs-MMT is an effective adsorbent for eliminating Levo-HCl from aqueous media in future engineering applications.