Engineered mesenchymal stem cell-derived extracellular vesicles constitute a versatile platform for targeted drug delivery.

Extracellular vesicles (EVs) are promising therapeutic carriers owing to their ideal size range and intrinsic biocompatibility. However, limited targeting ability has caused major setbacks in the clinical application of EV therapeutics. To overcome this, we genetically engineered natural free streptavidin (SA) on the cellular surface of bone marrow mesenchymal stem cells (BMSCs) and obtained typical EVs from these cells (BMSC-EVs). Biotin-coated gold nanoparticles confirmed the expression of SA on the membrane of EVs, which has a high affinity for biotinylated molecules. Using a squamous cell carcinoma model, we demonstrated that a pH-sensitive fusogenic peptide -modification of BMSC-EVs achieved targetability in the microenvironment of a hypoxic tumor to deliver anti-tumor drugs. Using EGFR+HER2- and EGFR-HER2+ breast cancer models, we demonstrated that anti-EGFR and anti-HER2 modifications of BMSC-EVs were able to specifically deliver drugs to EGFR+ and HER2+ tumors, respectively. Using a collagen-induced arthritis model, we confirmed that anti-IL12/IL23-modified BMSC-EVs specifically accumulated in the arthritic joint and alleviated inflammation. Administration of SA-overexpressing BMSC-EVs has limited immunogenicity and high safety in vivo, suggesting that BMSC-derived EVs are ideal drug delivery vehicle. These representative scenarios of targeting modification suggest that, using different biotinylated molecules, the SA-overexpressing BMSC-EVs could be endowed with different targetabilities, which allows BMSC-EVs to serve as a versatile platform for targeted drug delivery under various situations.

Antioxidant and ultraviolet shielding performance of lignin-polysaccharide complex isolated from spent coffee ground.

Spent coffee ground (SCG) is a representative type of biomass waste with huge annual output. To better develop high value applications of SCG, in this study, the lignin-polysaccharide complex (LPC) was isolated from SCG by applying effective ball milling and the subsequent solvent extraction of 96 % 1, 4-dioxane aqueous solution. In addition to the comprehensive analyses of the obtained LPC regarding its chemical composition, surface morphology, molecular weight distribution, characteristic functional groups, surface chemical linkages, and thermal stability, its potentials in radical scavenging and UV shielding had been emphatically investigated. As revealed from the results, a proper duration (e.g., 4 h) of UV irradiation could evidently enhance the radical-scavenging capacity of LPC, ascribed to the increasing number of antioxidant groups. Moreover, the LPC-containing composite sunscreens also exhibited strengthened UV resistance after UV irradiation, which may benefit from the UV-induced conjugated structures and the π-π stacking of aromatic rings from both LPC and the active ingredients in commercial sunscreen. Therefore, LPC is highly promising to be exploited for the development of novel antioxidants and UV-shielding products, by virtue of its characteristic chemical structure and potential synergistic effect with other active ingredients from the composite.

Tunning active oxygen species for boosting Hg0 removal and SO2-resistance of Mn-Fe oxides supported on (NH4)2S2O8 doping activated coke.

Active oxygen species (AOS) play an essential role in modulating the activity of activated coke (AC) based samples. In this paper, AC was endowed with abundant AOS by modifying with (NH4)2S2O8 and MnOx-FeOx for Hg0 removal. (NH4)2S2O8 treatment induced abundant micropores and oxygen-containing functional groups, and thus provided more anchoring sites for the dispersion of MnOx-FeOx. The synergy of MnOx-FeOx and interaction between MnOx-FeOx and NAC support contributed to a larger surface area, highly-dispersed active components, stronger reducibility, and more metal ions with high valence of MnFe/NAC. The optimal MnFe/NAC exhibited superior Hg0 removal efficiency above 90% at 120∼180 â„ƒ, as well as excellent performance for simultaneous removal of Hg0 and NO, and 600 ppm SO2 and 8 vol.% H2O addition led to a slight deterioration. XPS and Hg-TPD revealed that mercury adsorbed on MnFe/NAC included phy-Hg, C=O-Hg, COO-Hg, and OL-HgO. Besides, the priority of AOS for Hg0 chemisorption was C=O > COO- > OL, and Hg2+ was also detected in the outlet. Moreover, the SO2-poisoning effect was ascribed to the sulfation of MnOx and the occupation of COO- and C=O, and FeOx incorporation enhanced the SO2-resistance through weakening SO2 adsorption on C=O and COO-. The motivation of O2 mainly contributed to the regeneration of AOS, especially OL. The excellent regeneration performance and stability further affirmed the application potential of MnFe/NAC for Hg0 capture from coal-fired flue gas.

Recent Progress of Carbon Dots for Air Pollutants Detection and Photocatalytic Removal: Synthesis, Modifications, and Applications.

Rapid industrialization has inevitably led to serious air pollution problems, thus it is urgent to develop detection and treatment technologies for qualitative and quantitative analysis and efficient removal of harmful pollutants. Notably, the employment of functional nanomaterials, in sensing and photocatalytic technologies, is promising to achieve efficient in situ detection and removal of gaseous pollutants. Among them, carbon dots (CDs) have shown significant potential due to their superior properties, such as controllable structures, easy surface modification, adjustable energy band, and excellent electron-transfer capacities. Moreover, their environmentally friendly preparation and efficient capture of solar energy provide a green option for sustainably addressing environmental problems. Here, recent advances in the rational design of CDs-based sensors and photocatalysts are highlighted. An overview of their applications in air pollutants detection and photocatalytic removal is presented, especially the diverse sensing and photocatalytic mechanisms of CDs are discussed. Finally, the challenges and perspectives are also provided, emphasizing the importance of synthetic mechanism investigation and rational design of structures.

High-Performance and Water Resistant PVA-Based Films Modified by Air Plasma Treatment.

Plasma treatment is considered a straightforward, cost-effective, and environmental-friendly technique for surface modification of film materials. In this study, air plasma treatment was applied for performance improvement of pure PVA, cellulose nanocrystal (CNC)/PVA, and CNC/oxalic acid (OA)/PVA films. Compared with the original performance of pure PVA, the mechanical properties and water resistance of air plasma treated films were greatly improved. Among them, the CNC/OA/PVA film treated by three minutes of air plasma irradiation exhibits the most remarkable performance in mechanical properties (tensile strength: 132.7 MPa; Young's modulus: 5379.9 MPa) and water resistance (degree of swelling: 47.5%; solubility: 6.0%). By means of various modern characterization methods, the wettability, surface chemical structure, surface roughness, and thermal stability of different films before and after air plasma treatment were further revealed. Based on the results obtained, the air plasma treatment only changed the surface chemical structure, surface roughness, and hydrophobicity, while keeping the inner structure of films intact.

Cassava Starch-Based Thermo-Responsive Pb(II)-Imprinted Material: Preparation and Adsorption Performance on Pb(II).

Heavy metal pollution is currently an increasing threat to the ecological environment, and the development of novel absorbents with remarkable adsorption performance and cost-effectiveness are highly desired. In this study, a cassava starch-based Pb(II)-imprinted thermo-responsive hydrogel (CPIT) had been prepared by using cassava starch as the bio-substrate, N-isopropyl acrylamide (NIPAM) as the thermo-responsive monomer, and Pb(II) as the template ions. Later, a variety of modern techniques including FTIR, DSC, SEM, and TGA were employed to comprehensively analyze the characteristic functional groups, thermo-responsibility, morphology, and thermal stability of CPIT. The obtained material exhibited superior performance in adsorption of Pb(II) and its maximum adsorption capacity was high-up to 114.6 mg/g under optimized conditions. Notably, the subsequent desorption (regeneration) process was fairly convenient by simply rinsing with cold deionized water and the highest desorption efficiency could be achieved as 93.8%. More importantly, the adsorption capacity of regenerated CPIT still maintained 88.2% of the value of starting material even after 10 recyclings. In addition, the excellence of CPIT in selective adsorption of Pb(II) should also be highlighted as its superior adsorption ability (97.9 mg/g) over the other seven interfering metal ions.

LOXL2-enriched small extracellular vesicles mediate hypoxia-induced premetastatic niche and indicates poor outcome of head and neck cancer.

Small extracellular vesicles (sEVs) operate as a signaling platform due to their ability to carry functional molecular cargos. However, the role of sEVs in hypoxic tumor microenvironment-mediated premetastatic niche formation remains poorly understood. Methods: Protein expression profile of sEVs derived from normoxic and hypoxic head and neck squamous cell carcinoma (HNSCC) cells were determined by Isobaric Tagging Technology for Relative Quantitation. In vitro invasion assay and in vivo colonization were performed to evaluate the role of sEV-delivering proteins. Results: We identified lysyl oxidase like 2 (LOXL2) which had the highest fold increase in hypoxic sEVs compared with normoxic sEVs. Hypoxic cell-derived sEVs delivered high amounts of LOXL2 to non-hypoxic HNSCC cells to elicit epithelial-to-mesenchymal transition (EMT) and induce the invasion of the recipient cancer cells. Moreover, LOXL2-enriched sEVs were incorporated by distant fibroblasts and activate FAK/Src signaling in recipient fibroblasts. Increased production of fibronectin mediated by FAK/Src signaling recruited myeloid-derived suppressor cells to form a premetastatic niche. Serum sEV LOXL2 can reflect a hypoxic and aggressive tumor type and can serve as an alternative to tissue LOXL2 as an independent prognostic factor of overall survival for patients with HNSCC. Conclusion: sEVs derived from the hypoxic tumor microenvironment of HNSCC can drive local invasion of non-hypoxic HNSCC cells and stimulate premetastatic niche formation by delivering LOXL2 to non-hypoxic HNSCC cells and fibroblasts to induce EMT and fibronectin production, respectively.

Cellulose Isolated From Waste Rubber Wood and Its Application in PLA Based Composite Films.

Waste rubber wood (RW) is the castoff of rubber plantation with abundant reservation but without high-value utilization. In this study, cellulose with high purity has been efficiently isolated from waste RW and further processed into cellulose nanocrystals. By means of acetylation, more hydrophobic cellulose-based products, namely acetylated rubber wood cellulose (Ac-RWC) and acetylated rubber wood cellulose nanocrystals (Ac-RW-CNC) had been attempted as reinforcing fillers for fabricating two series of PLA-based composite films via spin coating instead of currently prevailing melt compounding technique. To ensure a uniformed dispersion of fillers in PLA matrix, the addition of reinforcing filler should be equal to or less than 5% based on the film dry weight. Compared with pure PLA film, the Ac-RWC reinforced PLA composite films are more thermally stable, while the Ac-RW-CNC reinforced PLA composite films on the other hand exhibit more enhanced performance in mechanical properties and the degree of crystallinity. The highest tensile strength (55.0 MPa) and Young's modulus (3.9 GPa) were achieved for 5%Ac-RW-CNC/PLA composite film.

Highly efficient simultaneous removal of HCHO and elemental mercury over Mn-Co oxides promoted Zr-AC samples.

MnxCoy/Zrz-AC prepared by impregnation method was investigated on the simultaneous removal of HCHO and Hg0. The samples were characterized by BET, SEM, XRD, H2 pulse chemisorption, H2-TPR, XPS, Hg-TPD and in-situ DRIFTS. Thereinto, the optimal Mn2/3Co8/Zr10-AC achieved 99.87% HCHO removal efficiency and 82.41% Hg0 removal efficiency at 240 °C, respectively. With increased surface area and pore volume, Zr-AC support facilitated higher dispersion of MnOx-CoOx. Moreover, the co-doping of MnOx-CoOx endowed the sample with more active oxygen species and higher reducibility, which further facilitated the removal of HCHO and Hg0. Chemisorption was proved to predominate in Hg0 removal, and oxidation also worked as Hg2+ was detected in outlet gas. Besides, HCHO predominated in the competition of active oxygen species, especially for lattice oxygen, thus suppressed the Hg0 removal. According to in-situ DRIFTS, HCHO removal proceeded as HCHOads → DOM → formate species → CO2 + H2O, and was boosted by active oxygen species. Furthermore, Mn2/3Co8/Zr10-AC was proved with excellent regeneration performance, indicating its potential in practical application.

Insight into the effect of SO2 on the Hg0 removal performance over a 1V-8Ce/AC sorbent at low temperatures.

The influences of SO2 on Hg° removal over the 1V-8Ce/AC sorbent were systematically investigated at low temperatures. The experimental results showed that SO2 has a dual effect on Hg° removal, that is, SO2 has both a promoting effect and an inhibiting effect on Hg° removal. The SO2 transient response experiment indicated that SO2 could not only react with Hg° to promote the removal of Hg° but also react with the active components and poison the sorbent. O2 is indispensable for the removal of Hg°, which can offset the adverse effects caused by SO2 and H2O. HCl exhibited an obvious promoting effect on Hg° removal in the presence of SO2. The 1V-8Ce/AC sorbent exhibited good sulfur resistance and excellent stability (EHg = 90.04 %) after a 24 h reaction performed under the 1000 ppm SO2 condition at 150 °C. In addition, the Hg-TPD and XPS methods were used to assist in studying the effect of SO2 on Hg° removal over the 1V-8Ce/AC sorbent. Finally, the mechanism of Hg° removal in an SO2 atmosphere was also explored, which showed that Hg° was removed by two possible pathways over the 1V-8Ce/AC sorbent.

Promotional removal of gas-phase Hg0 over activated coke modified by CuCl2.

Impregnating CuCl2 on AC (activated coke) support to synthesize xCuCl2/AC showed superior activity with higher 90% Hg0 removal efficiency at 80-140 °C, as well as a lower oxygen demand of 2% O2 for Hg0 removal. The acceleration on Hg0 removal was observed for NO and SO2. The BET, SEM, XRD, XPS, TPD, and FT-IR characterizations revealed that the larger surface area, sufficient active oxygen species and co-existence of Cu+ and Cu2+ may account for the efficient Hg0 removal. In addition, the low demand of gaseous O2 was contributed to higher content of active oxygen and formed active Cl. After adsorbing on Cu sites, Cl sites, and surface functional groups, the Hg0(ads) removal on xCuCl2/AC was proceeded through two ways. Part of Hg0(ads) was oxidized by active O and formed Hg0, and the other part of Hg0 combined with the active Cl, which was formed by the activation of lattice Cl with the aid of active O, and formed HgCl2. Besides, the Hg2+ detected in outlet gas through mercury speciation conversion and desorption peak of HgCl2 and Hg0 further proved it. As displayed in stability test and simulated industrial application test, CuCl2/AC has a promising industrial application prospect.

Catalytic removal of toluene over manganese oxide-based catalysts: a review.

It is necessary to control the emissions of toluene, which is hazardous to both human health and the atmosphere environment and has been classified as a priority pollutant. Manganese oxide-based (Mn-based) catalysts have received increased attention due to their high catalytic performance, good physicochemical characteristic, availability in various crystal structures and morphologies, and being environmentally friendly and low cost. These catalysts can be classified into five categories, namely single manganese oxide, Mn-based composite oxides, Mn-based special oxides, supported Mn-based oxides, and Mn-based monoliths. This review focused on the recent progress on the five types of Mn-based catalysts for catalytic removal of toluene at low temperature and further systematically summarized the strategies improving catalysts, including improving synthetic methods, incorporating MnOx with other metal oxides, depositing Mn-based oxides on proper supports, and tuning the supports. Moreover, the effect of coexisting components, the reaction kinetics, and the oxidation mechanisms toward the removal of toluene were also discussed. Finally, the future research direction of this field was presented.

Adsorption and oxidation of elemental mercury from coal-fired flue gas over activated coke loaded with Mn-Ni oxides.

A series of Mn-Ni/AC (AC, activated coke) catalysts were synthesized by the impregnation method for the removal of elemental mercury (Hg0) from simulated flue gas. The samples were characterized by BET, ICP-OES, SEM, XRD, XPS, H2-TPR, FT-IR, and TGA. Mn6Ni0.75/AC exhibited optimal removal efficiency of 96.6% in the condition of 6% O2 and balanced in N2 at 150 °C. The experimental results showed that both O2 and NO facilitated Hg0 removal. SO2 could restrain the Hg0 removal in the absence of O2, while the inhibitory effect of SO2 was weakened with the aid of 6% O2. In addition, H2O exhibited a slightly negative influence on Hg0 removal. The characterization of the samples indicated that Mn6Ni0.75/AC possessed larger specific surface area, higher dispersion of metal oxides, and stronger redox ability. In the meantime, the results of XPS and FT-IR demonstrated that the lattice oxygen and chemisorbed oxygen made contributions to Hg0 removal and the consumed oxygen could be compensated by the redox cycle of metal oxides and gas-phase O2. Meanwhile, the mechanisms of Hg0 removal were proposed based on the above studies.

Preparation and characterization of cellulose nanofibrils from coconut coir fibers and their reinforcements in biodegradable composite films.

Coconut waste husks were effectively utilized in this study as a promising cellulose source for production of purified coir cellulose (PCC) after multiple treatments, e.g., ultrasonic-assisted solvent immersion, alkaline treatment, bleaching, etc. As to upgrade the self-value of coir cellulose based products and further broaden their applications in light of biorefinery, coir cellulose nanofibrils (CCNF) with an average diameter of 5.6 ± 1.5 nm were prepared by selection of a milder TEMPO-mediated oxidation system (TEMPO/NaClO/NaClO2, pH = 4.8) accompanied by subsequent ultrasonic treatment. The cellulose nanofibrils were comprehensively characterized in terms of their functional groups, crystallinity, morphology, and thermal stability. The potential reinforcement of CCNFs as a filler for biodegradable PVA based films was investigated and the main properties including tensile strength, elongation at break, and thermal stability of CCNF/PVA composite films were significantly enhanced especially when 3% of CCNF (based on dry film weight) was applied.

The synthetic evaluation of CuO-MnOx-modified pinecone biochar for simultaneous removal formaldehyde and elemental mercury from simulated flue gas.

A series of low-cost Cu-Mn-mixed oxides supported on biochar (CuMn/HBC) synthesized by an impregnation method were applied to study the simultaneous removal of formaldehyde (HCHO) and elemental mercury (Hg0) at 100-300° C from simulated flue gas. The metal loading value, Cu/Mn molar ratio, flue gas components, reaction mechanism, and interrelationship between HCHO removal and Hg0 removal were also investigated. Results suggested that 12%CuMn/HBC showed the highest removal efficiency of HCHO and Hg0 at 175° C corresponding to 89%and 83%, respectively. The addition of NO and SO2 exhibited inhibitive influence on HCHO removal. For the removal of Hg0, NO showed slightly positive influence and SO2 had an inhibitive effect. Meanwhile, O2 had positive impact on the removal of HCHO and Hg0. The samples were characterized by SEM, XRD, BET, XPS, ICP-AES, FTIR, and H2-TPR. The sample characterization illustrated that CuMn/HBC possessed the high pore volume and specific surface area. The chemisorbed oxygen (Oß) and the lattice oxygen (Oα) which took part in the removal reaction largely existed in CuMn/HBC. What is more, MnO2 and CuO (or Cu2O) were highly dispersed on the CuMn/HBC surface. The strong synergistic effect between Cu-Mn mixed oxides was critical to the removal reaction of HCHO and Hg0 via the redox equilibrium of Mn4+ + Cu+ ↔ Mn3+ + Cu2+.

Analysis of lignin-carbohydrate and lignin-lignin linkages after hydrolase treatment of xylan-lignin, glucomannan-lignin and glucan-lignin complexes from spruce wood.

Xylan-lignin (XL), glucomannan-lignin (GML) and glucan-lignin (GL) complexes were isolated from spruce wood, hydrolyzed with xylanase or endoglucanase/ß-glucosidase, and analyzed by analytical pyrolysis and 2D-NMR. The enzymatic hydrolysis removed most of the polysaccharide moieties in the complexes, and the lignin content and relative abundance of lignin-carbohydrate linkages increased. Analytical pyrolysis confirmed the action of the enzymatic hydrolysis, with strong decreases of levoglucosane and other carbohydrate-derived products. Unexpectedly it also revealed that the hydrolase treatment alters the pattern of lignin breakdown products, resulting in higher amounts of coniferyl alcohol. From the anomeric carbohydrate signals in the 2D-NMR spectra, phenyl glycoside linkages (undetectable in the original complexes) could be identified in the hydrolyzed GML complex. Lower amounts of glucuronosyl and benzyl ether linkages were also observed after the hydrolysis. From the 2D-NMR spectra of the hydrolyzed complexes, it was concluded that the lignin in GML is less condensed than in XL due to its higher content in ß-O-4' ether substructures (62 % of side chains in GML vs 53 % in XL) accompanied by more coniferyl alcohol end units (16 vs 13 %). In contrast, the XL lignin has more pinoresinols (11 vs 6 %) and dibenzodioxocins (9 vs 2 %) than the GML (and both have ~13 % phenylcoumarans and 1 % spirodienones). Direct 2D-NMR analysis of the hydrolyzed GL complex was not possible due to its low solubility. However, after sample acetylation, an even less condensed lignin than in the GML complex was found (with up to 72 % ß-O-4' substructures and only 1 % pinoresinols). The study provides evidence for the existence of structurally different lignins associated to hemicelluloses (xylan and glucomannan) and cellulose in spruce wood and, at the same time, offers information on some of the chemical linkages between the above polymers.

Understanding pulp delignification by laccase-mediator systems through isolation and characterization of lignin-carbohydrate complexes.

The effects and mechanism of pulp delignification by laccases in the presence of redox mediators have been investigated on unbleached eucalyptus kraft pulp treated with laccases from Pycnoporus cinnabarinus (PcL) and Myceliophthora thermophila (MtL) and 1-hydroxybenzotriazole (HBT) and methyl syringate (MeS) as mediators, respectively. Determination of the corrected κ number in eucalyptus pulps after the enzymatic treatments revealed that the PcL-HBT system exhibited a more remarkable delignification effect than the MtL-MeS system. To obtain further insight, lignin-carbohydrate complexes were fractionated and subsequently characterized by nuclear magnetic resonance, thioacidolysis (followed by gas chromatography and size exclusion chromatography), and pyrolysis-gas chromatography-mass spectrometry (pyrolysis-GC-MS) analyses before and after the enzymatic treatments and their controls. We can conclude that the laccase-mediator treatments altered the lignin structures in such a way that more lignin was recovered in the xylan-lignin fractions, as shown by Klason lignin estimation, with smaller amounts of both syringyl (S) and guaiacyl (G) uncondensed units, as shown by thioacidolysis and gas chromatography, especially after the PcL-HBT treatment. The laccase-mediator treatment produced oxidation at Cα and cleavage of Cα and Cß bonds in pulp lignin, as shown by pyrolysis-GC-MS. The general mechanism of residual lignin degradation in the pulp by laccase-mediator treatments is discussed in light of the results obtained.

Universal fractionation of lignin-carbohydrate complexes (LCCs) from lignocellulosic biomass: an example using spruce wood.

It is of both theoretical and practical importance to develop a universally applicable approach for the fractionation and sensitive lignin characterization of lignin-carbohydrate complexes (LCCs) from all types of lignocellulosic biomass, both natively and after various types of processing. In the present study, a previously reported fractionation approach that is applicable for eucalyptus (hardwood) and flax (non-wood) was further improved by introducing an additional step of barium hydroxide precipitation to isolate the mannan-enriched LCC (glucomannan-lignin, GML), in order to suit softwood species as well. Spruce wood was used as the softwood sample. As indicated by the recovery yield and composition analysis, all of the lignin was recovered in three LCC fractions: a glucan-enriched fraction (glucan-lignin, GL), a mannan-enriched fraction (GML) and a xylan-enriched fraction (xylan-lignin, XL). All of the LCCs had high molecular masses and were insoluble or barely soluble in a dioxane/water solution. Carbohydrate and lignin signals were observed in (1) H NMR, (13) C CP-MAS NMR and normal- or high-sensitivity 2D HSQC NMR analyses. The carbohydrate and lignin constituents in each LCC fraction are therefore believed to be chemically bonded rather than physically mixed with one another. The three LCC fractions were found to be distinctly different from each other in terms of their lignin structures, as revealed by highly sensitive analyses by thioacidolysis-GC, thioacidolysis-SEC and pyrolysis-GC.

On hexenuronic acid (HexA) removal and mediator coupling to pulp fiber in the laccase/mediator treatment.

Flax soda/AQ pulps were treated with different fungal laccase-mediator combinations followed by physical and chemical characterization of the pulps to obtain a thorough understanding of the laccase/mediator effects on hexenuronic acid (HexA) removal and the coupling of mediator onto pulps for fiber functionalization. Large differences were found and the presence of lauryl gallate (LG) during Trametes villosa laccase (TvL) treatment (TvL+LG) resulted in a much larger reduction of pulp-linked HexA than the combination of p-coumaric acid (PCA) and Pycnoporus cinnabarinus laccase (PcL). A major portion of LG became attached to the pulp as revealed by an increase in the kappa number and further confirmed by thioacidolysis and (1)H NMR analysis of solubilized pulp fractions. Additional experiments with other chemical pulps and isolated pulp xylan and lignin revealed that HexA seems to be the sole pulp component attacked by TvL+LG. As a substrate for TvL, the reaction preference order is PCA>HexA>LG.

Biological activities of procyanidins from the bark of Pinus caribaea Morelet.

The extraction and biological activities of procyanidins from the bark of Pinus caribaea Morelet (P. caribaea) have been studied for the first time in our research. The main factors influencing the extraction, including solvent, temperature and liquid-to-solid (L/S) ratio, were discussed. The results illustrate that the suitable conditions for the extraction of procyanidins from the bark of P. caribaea are as follows: extraction temperature at 50 degrees C, L/S ratio at 11 : 1 and ethanol volume fraction at 70%. The focus of this study is to investigate the biological activities of the procyanidins from the bark of P. caribaea. Free-radical scavenging activity of the procyanidins was measured by means of 2,2-diphenyl-1-picrylhydrazyl (DPPH) method, and it was clear that the procyanidins product had a strong radical scavenging ability. Furthermore, the inhibition effect of the procyanidins from the bark of P. caribaea on different human cancer cells cultured in vitro was investigated. The results indicated that the procyanidins extracted with water had a stronger inhibition on promycelocytic cells HL-60, an effective inhibition on human stomach adenocarcinoma cells BGC-823 and human hepatocellular carcinoma cells BEL-7402, but no effect on human lung carcinoma cells A549, whereas the procyanidins extracted with ethanol had an effective inhibition on HL-60 and BGC-823, but no effect on A549 or BEL-7402.