Monomeric Compounds Research Articles

Identification of lignans and quality assessment in Dendrobium officinale under different cultivation modes.

Lignans have attracted much attention from researchers because of their wide distribution and industrial applications in plants, as well as the remarkable diversity of their biological activities. As the literature has mainly focused on the extraction and identification of monomeric compounds of lignans, most lignans in Dendrobium officinale, a traditional Chinese medicine with a long cultivation history and rich sources, have not been detected using quality control methods. The aim of this study was to identify the lignans in Dactilon officinale. High-performance liquid chromatography (HPLC) coupled with diode array detection and HPLC multiple-stage tandem mass spectrometry was used to identify the chemical constituents of D. officinale. Simultaneously, the characteristic chromatograms of D. officinale were established. Additionally, a method was established to determine the content of syringaresinol-4,4'-di-O-β-D-glucoside, syringaresinol-4-O-β-D-glucoside and syringaresinol. Thirty-three lignans, including 17 tetrahydrofuran lignans, two dibenzylbutane lignans, three aryl tetrahydronaphthalene lignans and 11 8-O-4'-neolignans, were tentatively identified from the methanol extract of the stems of D. officinale. This is the first report of 8-O-4'-neolignans from D. officinale. In addition, a total of eight characteristic peaks were marked in characteristic chromatograms, which were identified as lyoniresinol-9'-O-β-D-glucoside, syringaresinol-4,4'-di-O-β-D-glucoside, 8-hydroxy-syringaresinol-4-O-β-D-glucoside, 5,5'-dimethoxy-lariciresinol-4-O-β-D-glucoside, syringaresinol-4-O-β-D-glucoside, 4-hydroxy-3,3',5,5'-tetramethoxy-8,4'-oxyneoligna-7'-ene-9,9'-diol-9-O-β-D-glucoside, 4-hydroxy-3,3',5,5'-tetramethoxy-8,4'-oxyneoligna-7'-ene-9,9'-diol-4-O-β-D-glucoside and syringaresinol. Our results showed that no significant difference occurred in lignan composition among the 99 batches of D. officinale from different sources. However, the peak areas of the lignans of D. officinale planted under simulated wild culture were generally higher than those in greenhouses, and showed an upward trend with the increase in growth years. The average contents of syringaresinol-4,4'-di-O-β-D-glucoside, syringaresinol-4-O-β-D-glucoside and syringaresinol were 10.112-179.873, 51.227-222.294 and 6.368-120.341 μg/g, respectively. This study provided a basis for improving the quality control of D. officinale and could provide references for the identification of lignans in other Dendrobium species.

Extraction of phenolic compounds from hydrothermal processing of black liquor: Effect of reactor type and pH of recovered liquid phase

The goal of this work was to study the effect of pH on the extraction yield of phenolic compounds from liquid phases recovered after the hydrothermal treatment of black liquor in the batch and continuous reactors at 280 and 350 °C. The pH values of the recovered liquid phases under investigation were adjusted to 9, 8, and 7. The liquid-liquid extraction was subsequently performed using ethyl acetate for 4 h at room temperature. The identification and quantification of phenolic products were conducted using GC-Mass analysis. The main monomeric compounds identified in the aqueous phase were phenol, guaiacol, and syringol. The results indicated that reducing the pH slightly improved the phenol and guaiacol extraction from the various recovered liquid phases after hydrothermal treatment. However, reducing the pH of liquid phases greatly increased the extraction yield of syringol. This was very noticeable in the recovered liquid phases after treatment at 280 °C, where the quantity of syringol was initially high. Additionally, a lower pH hindered the ethyl acetate hydrolysis during liquid-liquid extraction. The extraction experiments with various pH also confirmed the superior performance of the continuous reactor over the batch reactor to obtain the phenolic compounds. In addition, the phenolic products degraded as the treatment temperature increased from 280 to 350 °C.

Comparative studies of DFT and experimental Raman spectra of pure 5O.14 liquid crystalline compound

ABSTRACT This article studies the density functional theory (DFT) and experimentally measured Raman spectrum of 5O.14 monomeric liquid crystalline compound. Raman spectroscopy in liquid crystal (LC) is very sensitive to temperature and with the variation of temperature every bond in the molecule shows different Raman peaks. Some important changes in the peaks were also noticed in different phases with the change in temperature. These changes occurred basically due to the changes in the molecular orientation with varying temperature. The structural and dynamics changes of the LC undergoing phase transitions have been analysed from the investigations of peak positions and linewidths. Finally, the results obtained from experimental and DFT generated Raman spectra confirm some interesting features to understand the behaviours of 5O.14 LC.

Saccharification of sugarcane bagasse using cellulases and oxidoreductases enzymes

Lignin is the major polymer responsible for limiting the rates of lignocellulose degradation. Enzymatic hydrolysis of lignin (using oxidorreductases enzymes) open the way to action of cellulose and hemicellulose -degrading enzymes systems to obtain a fermentable hydrolysate rich in monomeric compounds from the carbohydrate polymers present in the biomass. Trichoderma reesei is an important fungus that is widely used as a source of cellulases for the hydrolysis of plant cell wall polysaccharides. In this study, was identified the filamentous fungi Pestalotiopsis sp BBF245, as a promising strain for production of oxidoreductases enzymes. Enzyme cocktails were composed, using cellulases from T. reesei and oxidoreductases enzymes from Pestalotiopsis sp BBF245 for hydrolysis of sugarcane bagasse (SCB) in natura. The amounts of reducing sugars released from the saccharification of bagasse was of 15,52 g/L after 24 hours of incubation. The results show that the combination of lignocellulose-degrading enzymes significantly increased the degradation of sugarcane bagasse and suggest that the use of enzyme cocktails oxidoreductases and cellulases may significantly improve the hydrolysis of biomass.

The Anion Impact on Dimensionality of Cadmium(II) Complexes with Nicotinamide

Three novel cadmium(II) coordination compounds, the dimeric [Cd(CH3COO)2(nia)2]2 (1), the polymeric {[Cd(nia)4](ClO4)2}n (2), and the monomeric [Cd(H2O)3(nia)3](ClO4)2·nia (3), were prepared in the reactions of the nicotinamide (pyridine-3-carboxamide, nia) with the corresponding cadmium(II) salts. All prepared compounds were characterized by elemental analyses, FT-IR spectroscopy, TGA/DTA, and single crystal X-ray analysis. The impact of anions (acetate, perchlorate) and solvent used on the dimensionality of cadmium(II) complexes and the cadmium(II) coordination environment was investigated. The bridging capabilities of acetate ions enabled the formation of dimers in the crystal structure of 1. It was shown that the dimensionality of perchlorate complexes depends on the solvent used. The coordination polymer 2 is isolated from an ethanol solution, while monomeric compound 3 was obtained by using a water/ethanol mixture as a solvent. The pentagonal-bipyramidal coordination of cadmium(II) was found in the presence of chelating and bridging acetate ions in 1. In the presence of non-coordinating perchlorate anions in 2 and 3, the coordination geometry of cadmium(II) is found to be octahedral. The supramolecular amide-amide homosynthon R22(8) was preserved in the hydrogen-bonded frameworks of all three compounds.

Formulation and Evaluation on Synergetic Anti-Hepatoma Effect of a Chemically Stable and Release-Controlled Nanoself-Assembly with Natural Monomers.

Hepatoma is the leading cause of death among liver diseases worldwide. Modern pharmacological studies suggest that some natural monomeric compounds have a significant effect on inhibiting tumor growth. However, poor stability and solubility, and side effects are the main factors limiting the clinical application of natural monomeric compounds. In this paper, drug-co-loaded nanoself-assemblies were selected as a delivery system to improve the chemical stability and solubility of Tanshinone II A and Glycyrrhetinic acid, and to produce a synergetic anti-hepatoma effect. The study suggested that the drug co-loaded nanoself-assemblies showed high drug loading capacity, good physical and chemical stability, and controlled release. In vitro cell experiments verified that the drug-co-loaded nanoself-assemblies could increase the cellular uptake and cell inhibitory activity. In vivo studies verified that the drug co-loaded nanoself-assemblies could prolong the MRT0-∞, increase accumulation in tumor and liver tissues, and show strong synergistic anti-tumor effect and good bio-safety in H22 tumor-bearing mice. This work indicates that natural monomeric compounds co-loaded nanoself-assemblies would be a potential strategy for the treatment of hepatoma.

PFI-3 induces vasorelaxation with potency to reduce extracellular calcium influx in rat mesenteric artery.

PFI-3 is a small-molecule inhibitor that targets the bromodomains (BRDs) of Brahma-related gene 1 (BRG1). This monomeric compound, which has high selectivity and potent cellular effects, has recently been developed. Although PFI-3 has been reported as a potential therapeutic agent targeting thrombomodulin, its role in the regulation of vascular function remains unknown. Therefore, we aimed to investigate the impact of PFI-3 on arterial vessel tone. A microvascular tension measurement device (DMT) was utilized to identify alterations in vascular tension within the mesenteric artery. To detect variations in cytosolic [Ca2+]i, a Fluo-3/AM fluorescent probe and fluorescence microscope were employed. Additionally, whole-cell patch clamp techniques were utilized to evaluate the activity of L-type voltage-dependent calcium channels (VDCCs) in cultured arterial smooth muscle cells (A10 cells). PFI-3 exerted a dose-dependent relaxation effect on rat mesenteric arteries with both intact and denuded endothelium after phenylephrine (PE)- and high-K+-induced constriction. PFI-3-induced vasorelaxation was not affected by the presence of L-NAME/ODQ or K+ channel blockers (Gli/TEA). PFI-3 abolished Ca2+-induced contraction on endothelium-denuded mesenteric arteries preincubated by PE in Ca2+-free solution. Incubation with TG had no impact on PFI-3-induced vasorelaxation pre-contracted by PE. PFI-3 reduced Ca2+-induced contraction on endothelium-denuded mesenteric arteries pre-incubated by KCl (60mM) in Ca2+-free solution. PFI-3 declined extracellular calcium influx in A10 cells detected by Fluo-3/AM fluorescent probe and fluorescence microscope. Furthermore, we observed that PFI-3 decreased the current densities of L-type VDCC by whole-cell patch clamp techniques. PFI-3 blunted PE and high K+-induced vasoconstriction independent of endothelium on rat mesenteric artery. The vasodilatory effect of PFI-3 may be attributed to its inhibition of VDCCs and receptor-operated calcium channels (ROCCs) on vascular smooth muscle cells (VSMCs).

Isolation and identification of a polyester-polyurethane degrading bacterium Bacillus altitudinis YX8-1

Although polyurethane (PUR) plastics play important roles in daily life, its wastes bring serious environmental pollutions. Biological (enzymatic) degradation is considered as an environmentally friendly and low-cost method for PUR waste recycling, in which the efficient PUR-degrading strains or enzymes are crucial. In this work, a polyester PUR-degrading strain YX8-1 was isolated from the surface of PUR waste collected from a landfill. Based on colony morphology and micromorphology observation, phylogenetic analysis of 16S rDNA and gyrA gene, as well as genome sequence comparison, strain YX8-1 was identified as Bacillus altitudinis. The results of high performance liquid chromatography (HPLC) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) showed that strain YX8-1 was able to depolymerize self-synthesized polyester PUR oligomer (PBA-PU) to produce a monomeric compound 4, 4'-methylene diphenylamine. Furthermore, strain YX8-1 was able to degrade 32% of the commercialized polyester PUR sponges within 30 days. This study thus provides a strain capable of biodegradation of PUR waste, which may facilitate the mining of related degrading enzymes.

Bromobenzene Transforms Lanthanoid Pseudo-Grignard Chemistry.

Divalent lanthanoid pseudo-Grignard reagents PhLnBr (Ln=Sm, Eu and Yb) can be easily prepared by the oxidative addition of bromobenzene (PhBr) to lanthanoid metals in tetrahydrofuran (THF). PhLnBr reacts with bulky N,N'-bis(2,6-di-isopropylphenyl)formamidine (DippFormH) to generate LnII complexes, namely [Ln(DippForm)Br(thf)3 ]2 ⋅6thf (1; Sm, 2; Eu), and [Yb(DippForm)Br(thf)2 ]2 ⋅2thf (3; Yb). Samarium and europium (in 1 and 2) are seven coordinate, whereas ytterbium (in 3) is six coordinate, and all are bromine-bridged dimers. When PhLnBr reacts with 3,5-diphenylpyrazole (Ph2 pzH), both divalent (5; [Eu(Ph2 pz)2 (thf)4 ]) and trivalent (4 a; [Sm(Ph2 pz)3 (thf)3 ]⋅3thf, 4 b; [Sm(Ph2 pz)3 (dme)2 ]⋅dme) complexes are obtained. In the monomeric compounds 4(a,b), samarium is nine coordinate but europium is eight coordinate in 5. The use of PhLnBr in this work transforms the outcomes from earlier reactions of PhLnI.

Lignin Valorization for Added-Value Chemicals: Kraft Lignin versus Lignin Fractions

Lignin is a raw material that can potentially be converted into valuable compounds through depolymerization reactions in addition to its use as a polymer or material. However, the chemical recalcitrance and the heterogeneous composition and structure of lignin make it challenging to establish processes that add value to this complex aromatic biopolymer. In this work, solvent fractionation was applied to obtain lignin fractions with a narrowed molecular weight and specific structural characteristics, improving its homogeneity and purity. A kraft lignin was submitted to fractionation using different ratios of acetone, ranging from 60 to 15% v/v, in aqueous mixtures. The composition, structure, and molecular weight of each fraction were studied and their potential applications were evaluated. The most water-soluble fraction has more phenolic OH, less aliphatic OH groups, and shows the lowest content of aryl-ether linkages, which is in accordance with its highest degree of condensation. On the other hand, the insoluble fraction from the mixture with 60% of acetone has the lowest molecular weight and the highest content of inorganic material. Radar plots were applied for lignin fractions evaluation and the fraction with the highest potential (IF 30:70) was submitted to alkaline oxidation with O2. The results were compared with the products yielded from kraft lignin. An increase of about 13 and 19% was found for vanillin and syringaldehyde, respectively, when the fraction IF 30:70 was submitted to oxidation. In conclusion, the proposed fractionation process showed to be an effective method to obtain lignin fractions with specific composition and structural characteristics that could improve its potential as a source of high added-value monomeric phenolic compounds.

Fresh and Browned Lotus Root Extracts Promote Cholesterol Metabolism in FFA-Induced HepG2 Cells through Different Pathways.

Browning of fresh-cut plants is mainly attributed to the enzymatic browning of phenolic compounds induced by polyphenol oxidase (PPO), producing browning products such as anthraquinones, flavanol oxides, and glycosides, which are usually considered to be non-toxic. Could browning bring any benefits on behalf of their bioactivity? Our previous study found that browned lotus root extracts (BLREs) could reduce the cholesterol level in obese mice as fresh lotus root extracts (FLREs) did. This study aimed to compare the mechanisms of FLRE and BLRE on cholesterol metabolism and verify whether the main component's monomer regulates cholesterol metabolism like the extracts do through in vitro experiments. Extracts and monomeric compounds are applied to HepG2 cells induced by free fatty acids (FFA). Extracellular total cholesterol (TC) and triglyceride (TG) levels were also detected. In addition, RT-PCR and Western blot were used to observe cholesterol metabolism-related gene and protein expression. The in vitro results showed that BLRE and FLRE could reduce TC and TG levels in HepG2 cells. In addition, BLRE suppressed the synthesis of cholesterol. Meanwhile, FLRE promoted the synthesis of bile acid (BA) as well as the clearance and efflux of cholesterol. Furthermore, the main monomers of BLRE also decreased cholesterol synthesis, which is the same as BLRE. In addition, the main monomers of FLRE promoted the synthesis of BAs, similar to FLRE. BLRE and FLRE promote cholesterol metabolism by different pathways.

Phenolic compounds, methylxanthines, and preference drivers of dark chocolate made with hybrid cocoa beans

The distinct properties of cocoa beans may be due to their different geographical and genetic origins which lead to chocolates with different characteristics. This study aimed to evaluate dark chocolate samples made with hybrid cocoa cultivated in the Bahia State, Brazil, regarding the composition of bioactive compounds (spectrophotometry, High Performance Liquid Chromatography) and the sensory characteristics (Quantitative Descriptive Analysis-QDA®), and acceptance test). External preference mapping was conducted by first using principal components analysis (PCA) on the QDA data, and then relating consumer preference (overall liking) to this PCA space by regression analysis. Significant differences among the cocoa varieties were found. Chocolate samples that showed lower acceptability also presented higher content of theobromine, caffeine, anthocyanins, and gallic acid which conferred greater intensities of bitterness, astringency, and intense cocoa flavor. Lower levels of methylxanthines, monomeric phenolic compounds, and anthocyanins allowed the highlight of fruity, sweet and caramelized notes, which contributed to greater acceptance of the chocolate samples. Therefore, these characteristics can be recognized as consumer preference drivers (negative and positive, respectively) for the high cocoa chocolates. It seems that higher values of ephicatechin and catechin had no negative contribution to the flavor of the chocolate samples. The findings of this study can be used in agriculture and in the cocoa/chocolate industry, suggesting the potential and applicability of promising hybrid cocoa, with important characteristics, representing a genetic material of great quality, that may be classified as fine flavor cocoa, associating greater value to the product, and contributing to meet consumer needs.

Isolation and characterization of uric acid-lowering functional components from Polygonum cuspidatum

Polygonum cuspidatum (P. cuspidatum) is an herbaceous perennial plant known as Asian knotweed that is used in Chinese medicine due to its active components. Recent studies of the uric acid-lowering activity of P. cuspidatum extracts have mainly focused on analysis of its crude extract or specific chemical components, with limited research about its uric acid-lowering activity in vivo. In present study, monomeric compounds with higher uric acid-lowering ability were isolated from P. cuspidatum extract by column chromatography and thin-layer chromatography (TLC) and tested in a hyperuricemia mouse model and xanthine oxidase (XOD) inhibition assay in vitro. Structural characterization of the isolated components was performed by nuclear magnetic resonance (NMR) spectroscopy and the potential mechanism of decreasing uric acid was analyzed using untargeted metabolomics. Two main novel compounds were isolated and identified, 1-(4-hydroxy-2-methoxyphenyl)-2-(4-hydroxy-3,5-dimethylphenyl)butane-1,2,3-triol (compound 1) and 1-(4-hydroxy-2-methoxyphenyl)-2-(4-hydroxy-3,5-dimethylphenyl)-3-methylbutane-1,2-diol (compound 2), and compounds 1 was proved more significant inhibitory effect on the activity of XOD (p < 0.01) with inhibition of 49.80%. Metabolomics analysis indicated that the fractions (compound 1 and compound 2) affected hyperuricemic mice mainly through changes in galactose metabolism (p = 5.74E-4) and the effects were closely related to metabolic pathways of organic acid, carbohydrate, and lipid metabolism. These results contribute to providing theoretical support for the utilization of P. cuspidatum as a food and medicinal material, which can increase its use as an alternative treatment for hyperuricemia.

Rhaponticin suppresses the hypoxia-induced factor-1 alpha-mediated aggressive phenotype of tongue squamous cell carcinoma

BackgroundEmerging evidence suggests that rhaponticin, a stilbene monomeric compound isolated from North China rhubarb, has been shown to exhibit significant biological activity against tumors. However, the anticancer effects and mechanisms of rhaponticin in tongue squamous cell carcinoma (TSCC) remain elusive.ObjectiveWe investigated the changes of migration and invasion abilities and EMT progression of TSCC cells treated with different concentrations of rhaponticin under hypoxia, as well as the possible mechanisms, in order to initially explore the effects of rhaponticin on the biological characteristics of TSCC cells under hypoxia.ResultsThe number of cell migration and invasion was prominently increased, E-cadherin protein was down-regulated, and N-cadherin and HIF-1α protein expression was elevated under hypoxia. Rhaponticin intervention strikingly prevented the increased abilities of migration and invasion and EMT of TSCC cells under hypoxia. This was followed by further validation finding that rhaponticin indeed leads to reduced HIF-1α post-transcriptional activity. Mechanistically, rhaponticin may bind to aryl-hydrocarbon nuclear translocator (ARNT) domain of HIF-1α.ConclusionsRhaponticin repressed the invasion and migration abilities and EMT process of TSCC cells under a hypoxic environment in vitro by targeted suppression of HIF-1α.

Role of traditional Chinese medicine in ameliorating mitochondrial dysfunction via non-coding RNA signaling: Implication in the treatment of neurodegenerative diseases.

Neurodegenerative diseases (NDs) are common chronic disorders associated with progressive nervous system damage, including Alzheimer's disease, Parkinson's disease, and Huntington's disease, among others. Mitochondria are abundant in various nervous system cells and provide a bulk supply of the adenosine triphosphate necessary for brain function, considered the center of the free-radical theory of aging. One common feature of NDs is mitochondrial dysfunction, which is involved in many physiopathological processes, including apoptosis, inflammation, oxidative stress, and calcium homeostasis. Recently, genetic studies revealed extensive links between mitochondrion impairment and dysregulation of non-coding RNAs (ncRNAs) in the pathology of NDs. Traditional Chinese medicines (TCMs) have been used for thousands of years in treating NDs. Numerous modern pharmacological studies have demonstrated the therapeutic effects of prescription, herbal medicine, bioactive ingredients, and monomer compounds of TCMs, which are important for managing the symptoms of NDs. Some highly effective TCMs exert protective effects on various key pathological features regulated by mitochondria and play a pivotal role in recovering disrupted signaling pathways. These disrupted signaling pathways are induced by abnormally-expressed ncRNAs associated with mitochondrial dysfunction, including microRNAs, long ncRNAs, and circular RNAs. In this review, we first explored the underlying ncRNA mechanisms linking mitochondrial dysfunction and neurodegeneration, demonstrating the implication of ncRNA-induced mitochondrial dysfunction in the pathogenesis of NDs. The ncRNA-induced mitochondrial dysfunctions affect mitochondrial biogenesis, dynamics, autophagy, Ca2+ homeostasis, oxidative stress, and downstream apoptosis. The review also discussed the targeting of the disease-related mitochondrial proteins in NDs and the protective effects of TCM formulas with definite composition, standardized extracts from individual TCMs, and monomeric compounds isolated from TCM. Additionally, we explored the ncRNA regulation of mitochondrial dysfunction in NDs and the effects and potential mechanisms of representative TCMs in alleviating mitochondrial pathogenesis and conferring anti-inflammatory, antioxidant, and anti-apoptotic pathways against NDs. Therefore, this review presents an overview of the role of mitochondrion-related ncRNAs and the target genes for TCM-based therapeutic interventions in NDs, providing insight into understanding the "multi-level compound-target-pathway regulatory" treatment mechanism of TCMs.

Comparative characteristics of the chemical structure of ormokers and traditional composites

This article presents a review of the advantages of using ormokers rather than composite filling material from a chemical point of view. Ormokers are a modified type of hybrid organo-inorganic dental material. They were developed to reduce the shrinkage of filling material from polymerization, improve edge adaptation and abrasion resistance, and increase biocompatibility (compared to composites). The new matrix is based on inorganic polymers, which are polycondensed siloxanes (triblock copolymers). The formation of an inorganic chain of molecules occurs by hydrolysis and polycondensation of Si(OR) groups. Unstable organosilanols are formed from chlorine-containing silanes, as at least two hydroxyl groups are associated with one carbon atom. Such compounds do not exist, as they are rapidly isomerized to form carbonyl compounds (aldehydes and ketones). The resulting organosilanols are then oligomerized to form polysiloxanes with polymerized groups. The basis for the production of ormokers is the sol-gel process. The classical approach involves the formation of an inorganic grid by hydrolysis and condensation of a monomeric organic alkoxy compound followed by crosslinking of the introduced reactive groups (e.g., ultraviolet polymerization). The traditional synthesis of ormokers begins with the finding that alkoxysilanes are functionalized by metal alkoxides to form Si-O-Si nanostructures. One of the metals that functionalizes alkoxysilanes is titanium. In addition to titanium alkoxide, zirconium- or aluminum-alkoxides can be used. These oligomers replace traditional methacrylic monomers in composites. Composite filling materials available today based on the ormoker technology are not pure ormoker systems. Traditional methacrylate monomers-diluents are used to regulate the viscosity of the condensate, which does not improve biocompatibility. The presence of an amide group in the structure of the ormoker increases their biocompatibility with protein compounds in dental tissues.

Antibacterial sensitizers from natural plants: A powerful weapon against methicillin-resistant Staphylococcus aureus.

Methicillin-resistant Staphylococcus aureus (MRSA) is a drug-resistant bacterium that can cause a range of infections with high morbidity and mortality, including pneumonia, etc. Therefore, development of new drugs or therapeutic strategies against MRSA is urgently needed. Increasing evidence has shown that combining antibiotics with "antibacterial sensitizers" which itself has no effect on MRSA, is highly effective against MRSA. Many studies showed the development of antibacterial sensitizers from natural plants may be a promising strategy against MRSA because of their low side effects, low toxicity and multi-acting target. In our paper, we first reviewed the resistance mechanisms of MRSA including "Resistance to Beta-Lactams", "Resistance to Glycopeptide antibiotics", "Resistance to Macrolides, Aminoglycosides, and Oxazolidinones" etc. Moreover, we summarized the possible targets for antibacterial sensitizers against MRSA. Furthermore, we reviewed the synergy effects of active monomeric compounds from natural plants combined with antibiotics against MRSA and their corresponding mechanisms over the last two decades. This review provides a novel approach to overcome antibiotic resistance in MRSA.

Extraction, Identification and Antioxidant Activity of 3-Deoxyanthocyanidins from Sorghum bicolor L. Moench Cultivated in China.

3-deoxyanthocyanidins (3-DAs) are typical flavonoids found in sorghum bran, and they have received much attention in recent years owing to their bioactivities. To further enhance the resource utilization of sorghums cultivated in China, three brewing sorghum cultivars (Liaoza-48, Liaonuo-11, and Liaonian-3) commonly used in China were selected as raw materials for the construction of an extraction technology system for 3-DAs and the clarification of their structures and bioactivities. Based on single-factor experiments and response surface analysis, the optimized system for the extraction of 3-DAs from sorghum grains was as follows: a hydrochloric acid-methanol solution (1:100, v/v) was the extraction solvent, the solid-liquid ratio was 1:20 (g/mL), the extraction time was 130 min, and the temperature was 40 °C. This extraction system was simple and feasible. High performance liquid chromatography analysis suggested that the main monomeric compounds of the extracted 3-DAs were Apigeninidin (AE) and Luteolinidin (LE). Among the three selected sorghum grains, Liaoza-48 had the highest amount of AE (329.64 μg/g) and LE (97.18 μg/g). Antioxidant experiments indicated that the 3-DAs extracted from Liaoza-48 showed higher free-radical scavenging activities for DPPH, ABTS+, and hydroxyl radicals than those extracted from Liaonuo-11 and Liaonian-3. These results provide basic data and technical support for the high-value and comprehensive utilization of sorghums in China.

Hydrophobic effects enhance xylooligosaccharides production from mulberry branch using xylanase-methacrylate conjugate-catalyzed hydrolysis

Xylooligosaccharides have received widespread attention as a high-quality non-renewable resource due to the global shortage of resources. However, it remains challenging to address both the stability and catalytic activity of biocatalysts throughout the preparation process. Herein, three XYL-polymer conjugates were synthesized by grafting monomeric compounds containing C2-C4 alkyl chains onto the surface of xylanase using an atom transfer radical polymerization (ATRP) “grafting from” strategy. Besides, the results show that the stability and catalytic efficiency of the conjugates were improved, and the degree of lifting was found to be related to the hydrophobicity of the monomer. Among them, XYL-pBMA could remain at 67.61% relative activity after treatment at 90 °C for 1 h which was 12.3 times of free xylanase. And the catalytic efficiency of XYL-pBMA was 1609.40 mL/s/mg which was 1.3 times that of free xylanase. Furthermore, XYL-pBMA still retains more than 60% of residual activity after 7 reuses. In addition, the mulberry branch was hydrolyzed via the synergistic action of XYL-polymer conjugates and cellulase. The reducing sugar concentration reached 8.72 mg/mL, and more than 99% of the oligosaccharide riched in xylose, xylobiose, and xylotriose. Accordingly, xylanase-methacrylate conjugates to produce oligosaccharides from mulberry branch are an efficient and sustainable method.

Enhancement of the wettability of a coal seam during water injection: effect and mechanism of surfactant concentrations above the CMC.

This paper determines the optimal surfactant concentration for enhancing coal's wettability and explores the wetting mechanism at surfactant concentrations above the critical micelle concentration (CMC) during coal seam water injection. In this study, laboratory experiments and field tests were used to investigate the influence of monomeric surfactants and compound surfactants at various concentrations on coal's wettability. The results showed that when the surfactant solution concentration was greater than the CMC, the coal's wettability was significantly enhanced as the surfactant concentration increased. However, the coal's wettability did not monotonically increase with the concentration, and the maximum value was reached in the range of 0.5-3 wt.%. Increasing the surfactant adsorption density and changing the adsorption state on the coal surface were the essential reasons surfactants continued improving the coal's wettability at concentrations above the CMC. The Marangoni flow effect and changes in the viscosity of the surfactant solution with concentration were also important factors that affected the coal's wettability.