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Abstract Screening for new bioactive microbial metabolites, we found a novel okaramine derivative, for which we propose the trivial name lemmokaramine, as well as two already known okaramine congeners – okaramine H and okaramine J - responsible for antimicrobial activity of the recently described microscopic filamentous fungus, Keratinophyton lemmensii BiMM-F76 (= CCF 6359). In addition, two novel substances, a new cyclohexyl denominated lemmensihexol and a new tetrahydroxypyrane denominated lemmensipyrane, were purified and characterized. The compounds were isolated from the culture extract of the fungus grown on modified yeast extract sucrose medium by means of flash chromatography followed by preparative HPLC. The chemical structures were elucidated by NMR and LC-MS. The new okaramine (lemmokaramine) exerted antimicrobial activity against Gram-positive and Gram-negative bacteria, yeasts and fungi and anticancer activity against different mammalian cell lines (Caco-2, HCT116, HT29, SW480, MCM G1, and MCM DLN). Furthermore, we found a significant antioxidant effect of lemmokaramine following H2O2 treatment indicated by activation of the Nrf2 pathway. This is the first report describing analysis and structural elucidation of bioactive metabolites for the onygenalean genus Keratinophyton.

Linkage analysis after permethylation allows the determination of the linkage patterns between monomers in complex polysaccharides. Fucoidan is a heteropolysaccharide found in algae that is derivatised with sulphate groups. We recently improved the methodology for the linkage analysis in fucoidan with a focus on fucose. Critical improvements were done in reaction conditions, reagents, isolation of the polymer, and the optimisation of the chromatographic separation. In this study, we employ this enhanced method to the fucoidans of Fucus serratus (FSR), Fucus evanescens (FE), Fucus vesiculosus (FV) and Laminaria hyperborea (LH). This shed new light on the diversity found in fucoidans and the capabilities of the method. The fucoidans were found to be very varied, with a degree of sulphation from 0.26 to 0.73. The sulphate content as determined by the linkage analysis agreed well with the barium sulphate method, which tended to underestimate higher sulphate contents. Sulphate groups were present in positions 3 and 4, 2 and 4, and exclusively 2, but never in all three possible positions. Glycosidic linkages were found in all possible positions, with 3 as the more common one. Branching occurs in all linkage-combinations, and only F. vesiculosus featured a sulphate substituent at a branching point.

The genus Maerua (Capparaceae) comprises 85 woody species distributed across the paleotropics, with some species used in traditional medicine. This study investigated the phylogenetic placement, genetic diversity, and phytochemical composition of Maerua siamensis, a species native to Indochina. Phylogenetic analyses using matK and rbcL markers confirmed the monophyly of the M. siamensis specimens collected from Thailand. Population genetic analyses revealed low genetic diversity across the sampled populations, suggesting purifying selection or recent demographic events. Phytochemical investigations of the leaf extracts led to the isolation and identification of 12 compounds, including two novel structures: maeruamide and maeruaoside. The isolated compounds encompass simple phenolics, l-proline-derived betaines, and flavonoid glycosides. Bioactivity assays revealed moderate antioxidant activity of the crude extract (EC50 = 106 μg mL−1), but no significant insecticidal or nematocidal effects were observed. This study provides new insights into the genetic diversity, phytochemistry, and potential bioactivities of M. siamensis, contributing to our understanding of this understudied species and its ethnomedicinal applications.

Pyrolytic lignin (PL) has emerged as a promising renewable material for the production of polyurethanes (PU) due to the high concentration of hydroxyl groups in its structure, being a potential substitute for petroleum-based polyols. On one hand, the high functionality and liquid form of PL favor its application as a polyol in PU formulations. On the other hand, the inherent heterogeneity of PL still imposes a challenge for the development of new materials with reproducible properties. In this work, aiming to overcome these limitations, an acetone-water fractionation process was successfully used to fractionate PL. The resulting fractions were analytically characterized by HSQC NMR, 31P NMR and rheological analysis, revealing significant structural and compositional differences. Afterwards, these fractions partially replaced an industrial polyether polyol in the formulation of rigid PU foams. Finally, microstructure and mechanical properties of these foams were evaluated by SEM and uniaxial compressive tests. The lignin-based foams exhibited reduced cell size and improved mechanical properties compared to the reference foam (based on a polyether polyol). Thus, the mechanical properties of PU foams can be enhanced through the selection of specific PL fractions. These results highlight the potential of PL fractions as a sustainable and viable alternative to industrial polyols for PU foams with improved properties.

Abstract Background Spermacoce princeae (K. Schum) has been used in the treatment of bacterial skin infections in Uganda. Pharmacological studies revealed that extracts of S. princeae exhibited antibacterial, antioxidant, and sun protection potential. This study aimed at isolating and identifying pure compounds from the extracts based on comprehensive analytical characterization by multiple analytical techniques. Methods The plant samples were extracted by sequential maceration using n-hexane, ethyl acetate, methanol, and distilled water. The compounds were isolated using a combination of chromatographic techniques and their structures were elucidated by multiple spectroscopic techniques. The antibacterial and antifungal activity determination of the isolated compounds was carried out using an agar well diffusion and potato dextrose assay against Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Candida albicans, and Aspergillus flavus while the antioxidant activity was screened with the 2,2-diphenyl-2-picryl-hydrazyl (DPPH) radical scavenging assay. The sun protection factor was determined using a Shimadzu Ultra Violet-visible (UV–VIS) double beam spectrophotometer between 290 to 320 nm. Results Eleven compounds; quercetin (1), kaempferol-3-O-rutinoside (2), rutin (3, 12), myo-inositol (4), asperulosidic acid (5), hexadecanoic acid (6), β-sitosterol (7), stigmasterol (8), campesterol (9), ursolic acid (10), and β-sitosterol glucoside (11) were identified in the S. princeae extracts. Compound 2 had good antifungal activity against C. albicans (zone of inhibition, 23.0 ± 0.1 mm). Compound 10 showed antibacterial and antifungal activity against S. aureus, P. aeruginosa, C. albicans, and A. flavus. Compound 2 had a good percentage radical scavenging effect (IC50 = 64.81 µg/ml) and a good sun protection factor (SPF = 26.83). Conclusion This study reports the first-time isolation and identification of compounds 1 to 11 from S. princeae, which contribute to its antimicrobial, antioxidant, and sun protection potential.

Advected cyanobacteria, algal blooms and cyanotoxins have been increasingly detected in freshwater ecosystems. This review gives an insight into the present state of knowledge on the taxonomy, dynamics, toxic effects, human and ecological health implications of cyanobacteria, algal blooms and cyanotoxins in the East African Community lakes. The major toxigenic microalgae in East African lakes include Microcystis, Arthrospira, Dolichospermum, Planktolyngbya and Anabaenopsis species. Anatoxin-a, homoanatoxin-a, microcystins (MCs), cylindrospermopsin and nodularin have been quantified in water from below method detection limits to 81 µg L−1, with peak concentrations characteristically reported for the wet season. In whole fish, gut, liver and muscles, MCs have been found at concentrations of 2.4 to 1479.24 μg kg−1, which can pose human health risks to a daily consumer. While there have been no reported cases of cyanotoxin-related poisoning in humans, MCs and anatoxin-a (up to 0.0514 μg kg−1) have been identified as the proximal cause of indiscriminate fish kills and epornitic mortality of algivorous Phoeniconaias minor (lesser flamingos). With the unequivocal increase in climate change and variability, algal blooms and cyanotoxins will increase in frequency and severity, and this will necessitate swift action towards the mitigation of nutrient-rich pollutants loading into lakes in the region.

Abstract The aging behavior of ancient papyri is not entirely understood, although such understanding is crucial for tailored conservation concepts to preserve these precious historical documents for the millennia to come. In a study on accelerated aging, the effect of light on papyrus sheets was studied, and the consequences were monitored by a combination of non-invasive and invasive techniques. Papyrus sheets were aged for two months at 90 °C and 50% relative humidity, with and without the influence of light. Changes at the optical, mechanical, and molecular levels were monitored using CIELAB color measurements, tensile tests, Fourier transform-infrared spectroscopy (FTIR), and size exclusion chromatography—multi angle light scattering (SEC-MALS). Light exposure has severe consequences for the optical and mechanical properties of papyri, reflected by a strong decrease in cellulose chain length and tensile strength. SEC-MALS proved to be the best method to assess the conservation status of papyri due to its clear results and low sample demand. This publication seeks to highlight the effects of light-induced degradation of papyri and to facilitate an understanding of the underlying aging mechanisms, to support in future conservation measures. Graphical Abstract

Cellulose is an appealing material for tissue engineering. In an attempt to overcome some obstacles with cellulose II cell scaffolding materials related to insufficient biomineralization, lack of micron-size porosity, and deficiency in surface charge, respective solutions have been proposed. These included covalent phosphorylation of different cellulose materials targeting relatively low degrees of substitution (DS 0.18–0.23) and processing these cellulose derivatives into scaffolding materials by a dissolution/coagulation approach employing the hitherto rarely used TBAF/DMSO/H2O system for cellulose dissolution. Here, we report bioactivity and preliminary hemocompatibility testing of dual-porous cellulose phosphate aerogels (contrasted with the phosphate-free reference) obtained via coagulation (water/ethanol), solvent exchange and scCO2 drying. Deposition of hydroxyapatite from simulated body fluid (7 days of immersion) revealed good bioactivity (1.5–2.2 mg Ca2+ per mg scaffold). Incubation of the scCO2-dried and rehydrated scaffolding materials in heparin anticoagulated human whole blood was conducted to study selected parameters of hemostasis (prothrombin F1+2 fragment, PF4, count of thrombocyte-leukocyte conjugates) and inflammatory response (C5a fragment, leukocyte activation marker CD11b). Adhesion of leukocytes on the surface of the incubated substrates was assessed by scanning electron and fluorescence microscopy (DAPI staining). The results suggest that phosphorylation at low DS does not increase platelet activation. However, a significant increase in platelet activation and thrombin formation was observed after a certain fraction of the negative surface charges had been compensated by Ca2+ ions. The combination of both phosphorylation and calcification turned out to be a potent means for controlling the inflammatory response, which was close to baseline level for some of the studied samples.

Papyrus (Cyperus papyrus L.) is a sedge plant with a high rate of biomass productivity that represents an interesting raw material to produce chemicals, materials and fuels, which are currently still obtained from fossil resources, in the context of a lignocellulosic biorefinery. In this work, the content and chemical composition of the lipids present in papyrus stems were thoroughly studied. For this, the papyrus stems were separated into the rind and the pith. The lipid content accounted for 4.1% in the rind and 4.9% in the pith (based on dry matter). The main compounds identified in both parts of the papyrus stem were hydrocarbons, n-fatty acids, 2-hydroxyfatty acids, alcohols, alkylamides, mono- and diglycerides, steroids (sterols, ketones, hydrocarbons, esters and glycosides), tocopherols, tocopherol esters, phytol, phytol esters, alkyl ferulates, ω-carboxyalkyl ferulates (and their monoglycerides), and acylglycerol glycosides. The rind presented a predominance of n-fatty acids (6790 mg/kg; that represented 28.6% of all identified compounds), steroid compounds (6255 mg/kg; 26.3%), phytol and phytol esters (4985 mg/kg; 21.0%), and isoprenoid hydrocarbons, namely phytadiene and squalene (2660 mg/kg; 11.2%), while the most abundant lipids in the pith were steroids (8600 mg/kg; 44.4% of all identified compounds) and fatty acids (6245 mg/kg; 32.2%). Due to the great diversity and significant abundance of the compounds identified in papyrus, it can be considered as a potential raw material for biorefineries to obtain valuable phytochemicals of interest to various industrial sectors.

The efficiency of chemical reactions in biological systems is often connected to the properties of confined water, but the developments and applications of artificial mimicking systems are impeded by the complexity of the biological systems. Here, the authors show how surface bound water in nanoporous cellulosic fibers can increase the reaction rate of surface acetylation reactions and enable regioselectivity of the reaction

This dataset is related to the research article entitled ``A fast method to measure the degree of oxidation of dialdehyde celluloses using multivariate calibration and infrared spectroscopy''. In this article, 74 dialdehyde cellulose samples with different degrees of oxidation were prepared by periodate oxidation and analysed by Fourier-transform infrared (FTIR) and near-infrared spectroscopy (NIR). The corresponding degrees of oxidation were determined indirectly by periodate consumption using UV spectroscopy at 222 nm and by the quantitative reaction with hydroxylamine hydrochloride followed by potentiometric titration. Partial least squares regression (PLSR) was used to correlate the infrared data with the corresponding degree of oxidation (DO). The developed NIR/PLSR and FTIR/PLSR models can easily be implemented in other laboratories to quickly and reliably predict the degree of oxidation of dialdehyde celluloses.

The work consists of primary and analysed data from rheological measurements of carbohydrate-hydroxymethylfurfural-amine adhesives. The studied adhesives are a bio-based alternative to conventional wood adhesives. The rheological properties were studied at different temperatures in isothermal (80, 90, 95 °C) and non-isothermal (20–120 °C) oscillatory measurements. Non-isothermal rheological measurements were used for the determination of the activation energy based on Vyazovskin's isoconversional method. The viscosity profile of the adhesives, determined from isothermal measurements, was fitted by an empirical model. The viscosity kinetic constant can be obtained from this empirical model and used in further rheokinetic analysis.Data from density and swelling experiments was measured for the characterization of the adhesive network. The determined polymer-solvent interaction parameter is included in the collected data.The provided datasets were used in the investigation of the reactivity and curing reaction of the studied adhesives. A discussion and interpretation of the data can be found in the previous publication [1].

A new triterpene glycoside, silviridoside, was isolated from the aerial parts of Silene viridiflora (Caryophyllaceae) using different chromatographic techniques. The structure of silviridoside was comprehensively elucidated as 3-O-β-D-galacturonopyranosyl-quillaic acid 28-O-β-D-glucopyranosyl-(1→2)-[α-L-rhamnopyranosyl-(1→3)]-β-D-fucopyranosyl ester by one- and two-dimensional nuclear magnetic resonance (NMR) spectroscopy and high-resolution mass spectrometry (HR-MS). Silviridoside showed promising antioxidant activity in different antioxidant assays such as 2,2-diphenyl-1-picrylhydrazyl (DPPH) (2.32 mg TE/g), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) (1.24 mg TE/g), cupric-reducing antioxidant capacity (CUPRAC) (9.59 mg TE/g), ferric-reducing antioxidant power (FRAP) (5.13 mg TE/g), phosphomolybdenum (PHD) (0.28 mmol TE/g), and metal-chelating (MCA) (6.62 mg EDTA/g) assays. It exhibited a good inhibitory potential on acetylcholinesterase (AChE) (2.52 mg GALAE/g), butyrylcholinesterase (BChE) (7.16 mg GALAE/g), α-amylase (0.19 mmol ACAE/g), α-glucosidase (1.21 mmol ACAE/g), and tyrosinase (38.83 mg KAE/g). An in silico evaluation of the pharmacodynamic, pharmacokinetic, and toxicity properties of silviridoside showed that the new compound exhibited reasonable pharmacodynamic and pharmacokinetic properties without any mutagenic effect, but slight toxicity. Thus, it could be concluded that silviridoside could act as a promising lead drug for pharmaceutical and nutraceutical developments to combat oxidative stress and various disorders, but a future optimization is necessary.

Spinning of cellulosic fibers requires the prior dissolution of cellulose. 3-Alkyl-1-methylimidazolium ionic liquids have proven to be suitable solvents for that purpose, but the degradation of cellulose in the spinning dope can be severe. Suitable stabilizers are therefore required that prevent cellulose degradation, but do not adversely affect spinnability or the long-term yellowing behavior of the fibers. A group of twelve renewables-based antioxidants was selected for stabilizing 5% cellulose solutions in the ionic liquids and their effects on cellulose integrity, dope discoloration, and aging behavior were tested by gel permeation chromatography (GPC) and ISO brightness measurements. Propyl gallate (a gallic acid derivative), hydroxytyrosol (from olives), and tocopheramines (a vitamin E derivative) performed best in the three test categories, minimizing both cellulose degradation, chromophore formation in the spinning dope, and yellowing upon accelerating aging of the spun fibers. The use of these stabilizers for cellulose solutions in the imidazolium-based solvent system can therefore be recommended from the point of view of both performance and sustainability.

Nanoporous silica gels feature extremely large specific surface areas and high porosities and are ideal candidates for adsorption-related processes, although they are commonly rather fragile. To overcome this obstacle, we developed a novel, completely solvent-free process to prepare mechanically robust CNF-reinforced silica nanocomposites via the incorporation of methylcellulose and starch. Significantly, the addition of starch was very promising and substantially increased the compressive strength while preserving the specific surface area of the gels. Moreover, different silanes were added to the sol/gel process to introduce in situ functionality to the CNF/silica hydrogels. Thereby, CNF/silica hydrogels bearing carboxyl groups and thiol groups were produced and tested as adsorber materials for heavy metals and dyes. The developed solvent-free sol/gel process yielded shapable 3D CNF/silica hydrogels with high mechanical strength; moreover, the introduction of chemical functionalities further widens the application scope of such materials.

Abstract Background Anthocyanins are abundant secondary metabolites responsible for most blue to blue-black, and red to purple colors of various plant organs. In wheat grains, anthocyanins are accumulated in the pericarp and/or aleurone layer. Anthocyanin pigmented wheat grains can be processed into functional foods with potential health benefits due to the antioxidant properties of the anthocyanins. The grain anthocyanin content can be increased by pyramidizing the different genes responsible for the accumulation of anthocyanins in the different grain layers. Our objective was to develop a high-performance thin-layer chromatography (HPTLC) method that allows the determination of both the anthocyanin profile and the total pigment concentration. Thereby, selection of breeding lines with significantly higher grain anthocyanin content from purple pericarp × blue aleurone wheat crosses should become more efficient than selection based on only visual scoring of grain color and the unspecific determination of anthocyanin concentration by UV/Vis spectroscopy. Results A wide variability in the grain anthocyanin content was observed in breeding lines and check varieties. The highest concentration of anthocyanins was observed in deep purple (i.e. combination of the purple pericarp and blue aleurone genetics) grained breeding lines, followed by blue aleurone and purple pericarp genotypes. Determination of the total anthocyanin content was included into the chromatographic analysis, rendering an additional photometric analysis unnecessary. Ten target zones were identified in anthocyanin pigmented wheat grains; four of these zones were typically for blue aleurone types, five for purple pericarp types, and one (i.e. kuromanin glucoside) was characteristic for both. Chemometrics applied to the anthocyanin profile recorded by scanning densitometry revealed that peak heights and peak areas are highly correlated and that seven out of the ten target zones were responsible for about 90% of the total variation in the germplasm. Multivariate analysis of these seven target zones allowed not only a separation of the genetic material into purple, blue and deep purple grained genotypes, but also the identification of genotypes with a specific anthocyanin pattern. Thereby, the original classification by visual scoring was overruled in about one-third of the breeding lines. Conclusions The presented HPTLC method with à côté calibration allowed the profiling of the pigments and quantification of wheat grain anthocyanin content in a single analysis, replacing UV/Vis spectroscopy with subsequent HPLC analysis. Moreover, no sample preparation apart from extraction and filtration is required, and more than 15 samples can be evaluated in one analysis run, corresponding to several dozens of samples per day. Hence, the method fulfills the requirements for screening methods in early generations of a plant breeding program such as high-throughput, small sample size, high repeatability, fast determination, and reasonable costs per sample. Combined with multivariate statistical analysis, the anthocyanin pattern allowed the validation of the genetic background in the offspring of purple × blue wheat crosses and, therefore, the efficient selection of genotypes exhibiting both the cyanidin and delphinidin aglycon.

Polyanionic cellulose carbamates were synthesized by rapid and efficient homogeneous aminolysis of cellulose carbonate half-esters in an ionic liquid/DMF medium. Cellulose bis-2,3-O-(3,5-dimethylphenyl carbamate), as a model compound, reacted with different chloroformates to cellulose carbonates. These intermediates were subjected to aminolysis, for which both the reactivity of different chloroformates towards C6-OH and the reactivity/suitability of the respective carbonate half-ester in the aminolysis were comprehensively studied. Phenyl chloroformate and 4-chlorophenyl chloroformate readily reacted with C6-OH of the model cellulose derivative, while 4-nitrophenyl chloroformate did not. The intermediate 4-chlorophenyl carbonate derivative with the highest DS (1.05) was then used to evaluate different aminolysis pathways, applying three different amines (propargyl amine, β-alanine, and taurine) as reactants. The latter two zwitterionic compounds are only sparingly soluble in pure DMF as the typical reaction medium for aminolysis; therefore, several alternative procedures were suggested, carefully evaluated, and critically compared. Solubility problems with β-alanine and taurine were overcome by the binary solvent system DMF/[EMIM]OAc (1:1, v/v), which was shown to be a promising medium for rapid and efficient homogeneous aminolysis and for the preparation of the corresponding cellulose carbamate derivatives or other compounds that are not accessible by conventional isocyanate chemistry. The zwitterionic cellulose carbamate derivatives presented in this work could be promising chiral cation exchangers for HPLC enantiomer separations.

In this study, a cellulose membrane (CM) was chemically treated with phenolic (PF) resin to improve its performance as a polymeric insulator. The CM was prepared from kenaf pulp, and the PF was synthesized from oil palm empty fruit (EFB) fibre. Four different concentrations of synthesized PF resin (5, 10, 15, and 20 wt.%) were impregnated under wet or dry conditions. Thermal analysis of the phenolic cellulose membrane (PCM) showed that the samples had good chemical interaction and compatibility. The PF uptake in the wet phenolic cellulose membrane (PCMW) was higher than in the dry phenolic cellulose membrane (PCMD). During the PF uptake, the CM underwent solvent exchange and absorption in wet and dry membranes, respectively. This difference also affected the crosslinking of PCM samples via the formation of methylene bridges. Due to the PF treatment, the PCM showed lower water absorption than CM. The PF concentrations also affect the surface roughness and electrical properties of PCM samples. These findings prove that PCM can be used as a renewable and green polymer electrical insulator.

In the process of screening for new bioactive microbial metabolites we found a novel ƴ-pyrone derivative for which we propose the trivial name luteapyrone, in a recently described microscopic filamentous fungus, Metapochonia lutea BiMM-F96/DF4. The compound was isolated from the culture extract of the fungus grown on modified yeast extract sucrose medium by means of flash chromatography followed by preparative HPLC. The chemical structure was elucidated by NMR and LC-MS. The new compound was found to be non-cytotoxic against three mammalian cell lines (HEK 263, KB-3.1 and Caco-2). Similarly, no antimicrobial activity was observed in tested microorganisms (gram positive and negative bacteria, yeast and fungi).

Two new species, Penicillium krskae (isolated from the air as a lab contaminant in Tulln (Austria, EU)) and Penicillium silybi (isolated as an endophyte from asymptomatic milk thistle (Silybum marianum) stems from Josephine County (Oregon, USA)) are described. The new taxa are well supported by phenotypic (especially conidial ornamentation under SEM, production of red exudate and red pigments), physiological (growth at 37 °C, response to cycloheximide and CREA), chemotaxonomic (production of specific extrolites), and multilocus phylogenetic analysis using RNA-polymerase II second largest subunit (RPB2), partial tubulin (benA), and calmodulin (CaM). Both new taxa are resolved within the section Exilicaulis in series Restricta and show phylogenetic affiliation to P. restrictum sensu stricto. They produce a large spectrum of toxic anthraquinoid pigments, namely, monomeric anthraquinones related to emodic and chloremodic acids and other interesting bioactive extrolites (i.e., endocrocin, paxilline, pestalotin, and 7-hydroxypestalotin). Of note, two bianthraquinones (i.e., skyrin and oxyskyrin) were detected in a culture extract of P. silybi. Two new chloroemodic acid derivatives (2-chloro-isorhodoptilometrin and 2-chloro-desmethyldermoquinone) isolated from the exudate of P. krskae ex-type culture were analyzed by nuclear magnetic resonance (NMR) and liquid chromatography–mass spectrometry (LC–MS).

Polysaccharides, oligosaccharides, and their derivatives, particularly of amylose, cellulose, chitosan, and β-cyclodextrin, are well-known chiral selectors (CSs) of chiral stationary phases (CSPs) in chromatography, because they can separate a wide range of enantiomers. Typically, such CSPs are prepared by physically coating, or chemically immobilizing the polysaccharide and β-cyclodextrin derivatives onto inert silica gel carriers as chromatographic support. Over the past few years, new chiral selectors have been introduced, and progressive methods to prepare CSPs have been exploited. Also, chiral recognition mechanisms, which play a crucial role in the investigation of chiral separations, have been better elucidated. Further insights into the broad functional performance of commercially available chiral column materials and/or the respective newly developed chiral phase materials on enantiomeric separation (ES) have been gained. This review summarizes the recent developments in CSs, CSP preparation, chiral recognition mechanisms, and enantiomeric separation methods, based on polysaccharides and β-cyclodextrins as CSs, with a focus on the years 2019–2020 of this rapidly developing field.

Papyri belong to the oldest writing grounds in history. Their conservation is of the highest importance in preserving our cultural heritage, which is best achieved based on an extensive knowledge of the materials’ constituents to choose a tailored conservation approach. Thermogravimetric Analysis (TGA) has been widely employed to quantify cellulose and lignin in papyrus sheets, yielding reported lignin contents of 25% to 40%. In this work, the TGA method conventionally used for papyrus samples was repeated and compared to other lignin determination approaches (Klason-lignin and acetyl bromide-soluble lignin). TGA can lead to a large overestimation of the lignin content of commercial papyrus sheets (~27%) compared to the other methods (~5%). A similar overestimation of the lignin content was found for the pith and rind of the native papyrus plant. We concluded that the TGA method should, therefore, not be used for lignin quantification.

Surface modification of cellulose, as the world’s most abundant polymer, plays an important role in sustainable chemistry. Microcrystalline cellulose, Avicel, was modified by an alkoxysilane under mild conditions in water, at room temperature and with a catalytic amount of sodium hydroxide. (3-Mercaptopropyl)-trimethoxysilane in three concentrations 535, 1074, 1614 µmol/mL (100, 200, 300 µL of silane, respectively) was grafted onto cellulose, then the modified cellulose was characterized by FTIR spectroscopy as well as solid state 13C NMR and 29Si NMR spectroscopy. Increasing the concentration of the alkoxysilane from 353 to 1074 µmol/mL increased the ratio of siloxane bridges with the cellulose backbone, while by increasing the silane concentration from 1074 to 1614 µmol/mL, has inhanced the ratio of polysiloxane bridges relative to covalent links with the cellulose backbone from 34% to 66%.

The compositions of volatile components in the aerial parts of six Astragalus species, namely A. campylotrichus (Aca), A. chiwensis (Ach), A. lehmannianus (Ale), A. macronyx (Ama), A. mucidus (Amu) and A. sieversianus (Asi), were investigated using gas chromatograph-mass spectrometry (GC-MS) analysis. Ninety-seven metabolites were identified, accounting for 73.28, 87.03, 74.38, 87.93, 85.83, and 91.39% of Aca, Ach, Ale, Ama, Amu and Asi whole oils, respectively. Sylvestrene was the most predominant component in Asi, Amu and Ama, with highest concentration in Asi (64.64%). In addition, (E)-2-hexenal was present in a high percentage in both Ale and Ach (9.97 and 10.1%, respectively). GC-MS based metabolites were subjected to principal component analysis (PCA) and hierarchal cluster analysis (HCA) to explore the correlations between the six species. The PCA score plot displayed clear differentiation of all Astragalus species and a high correlation between the Amu and Ama species. The antioxidant activity was evaluated in vitro using various assays, phosphomolybdenum (PM), 2,2 diphenyl-1-picryl-hydrazyl-hydrate (DPPH), 2,2-azino bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), cupric reducing antioxidant capacity (CUPRAC), ferric reducing power (FRAP) and ferrous ion chelation (FIC) assays. In addition, the potential for the volatile samples to inhibit both acetyl/butyrylcholinesterases (AChE, BChE), α- amylase, α-glucosidase and tyrosinase was assessed. Most of the species showed considerable antioxidant potential in the performed assays. In the DPPH assay, Ama exhibited the maximum activity (24.12 ± 2.24 mg TE/g sample), and the volatiles from Amu exhibited the highest activity (91.54 mgTE/g oil) in the ABTS radical scavenging assay. The effect was more evident in both CUPRAC and FRAP assays, where both Ale and Ama showed the strongest activity in comparison with the other tested species (84.06, 80.28 mgTE/g oil for CUPRAC and 49.47, 49.02 mgTE/g oil for FRAP, respectively). Asi demonstrated the strongest AChE (4.55 mg GALAE/g oil) and BChE (3.61 mg GALAE/g oil) inhibitory effect. Furthermore, the best tyrosinase inhibitory potential was observed for Ale (138.42 mg KAE/g). Accordingly, Astragalus species can be utilized as promising natural sources for many medicinally important components that could be tested as drug candidates for treating illnesses such as Alzheimer’s disease, diabetes mellitus and oxidative stress-related diseases.

Scaffolds used for bone tissue engineering need to have a variety of features to accommodate bone cells. The scaffold should mimic natural bone, it should have appropriate mechanical strength, support cell differentiation to the osteogenic lineage, and offer adequate porosity to allow vascularization and bone in-growth. In this work, we aim at developing a new process to fabricate such materials by creating a porous composite material made of silk fibroin and cellulose as a suitable scaffold of bone tissue engineering. Silk fibroin and cellulose are both dissolved together in N,N-dimethylacetamide/LiCl and molded to a porous structure using NaCl powder. The hydrogels are prepared by a sequential regeneration process: cellulose is solidified by water vapor treatment, while the remaining silk fibroin in the hydrogel is insolubilized by methanol, which leads to a cellulose framework structure embedded in a silk fibroin matrix. Finally, the hydrogels are soaked in water to dissolve the NaCl for making a porous structure. The cellulose composition results in improving the mechanical properties for the hydrogels in comparison to the silk fibroin control material. The pore size and porosity are estimated at around 350 µm and 70%, respectively. The hydrogels support the differentiation of MC3T3 cells to osteoblasts and are expected to be a good scaffold for bone tissue engineering.

Cellulose derivatives have many potential applications in the field of biomaterials and composites, in addition to several ways of modification leading to them. Silanization in aqueous media is one of the most promising routes to create multipurpose and organic–inorganic hybrid materials. Silanization has been widely used for cellulosic and nano-structured celluloses, but was a problem so far if to be applied to the common cellulose derivative “dialdehyde cellulose” (DAC), i.e., highly periodate-oxidized celluloses. In this work, a straightforward silanization protocol for dialdehyde cellulose is proposed, which can be readily modified with (3-aminopropyl)triethoxysilane. After thermal treatment and freeze-drying, the resulting product showed condensation and cross-linking, which was studied with infrared spectroscopy and 13C and 29Si solid-state nuclear magnetic resonance (NMR) spectroscopy. The cross-linking involves both links of the hydroxyl group of the oxidized cellulose with the silanol groups (Si-O-C) and imine-type bonds between the amino group and keto functions of the DAC (-HC=N-). The modification was achieved in aqueous medium under mild reaction conditions. Different treatments cause different levels of hydrolysis of the organosilane compound, which resulted in diverse condensed silica networks in the modified dialdehyde cellulose structure.

In the past two decades, research on electrospinning has boomed due to its advantages of simple process, small fiber diameter, and special physical and chemical properties. The electrospun fibers are collected in a non-woven state in most cases (electrospun non-woven fabrics, ESNWs), which renders the electrospinning method an optimum approach for non-woven fabric manufacturing on the nano-scale. The present study establishes a convenient preparation procedure for converting water-soluble dialdehyde cellulose (DAC) into DAC-based electrospun non-woven fabrics (ESNWs) reinforced with poly(vinyl alcohol) (PVA). The aldehyde content, which was quantified by colorimetry using Schiff’s reagent, was 11.1 mmol per gram of DAC, which corresponds to a conversion yield of ca. 90%. DAC is fully water-soluble at room temperature between 10 and 30 wt%, and aqueous solutions turn into hydrogels within 24 h. To overcome gelation, NaHSO3, which forms bisulfite adducts with aldehyde functions, was added to the DAC and its concentration was optimized at 1 wt%. The electrospun (ES) dope containing 5 wt% DAC, 5 wt% PVA, and 1 wt% NaHSO3 in an aqueous solution was successfully transformed into ESNW, with an average fiber diameter of 345 ± 43 nm. Post-spinning treatment with excess hexamethylene diisocyanate was performed to insolubilize the ESNW materials. The occurrence of this chemical conversion was confirmed by energy-dispersive X-ray elemental analysis and vibrational spectra. The cross-linked DAC/PVA ESNW retained its thin fiber network upon soaking in distilled water, increasing the average fiber diameter to 424 ± 95 nm. This suggests that DAC/PVA-ESNWs will be applicable for incorporation or immobilization of biologically active substances.

Biopolymer aerogels of appropriate open-porous morphology, nanotopology, surface chemistry, and mechanical properties can be promising cell scaffolding materials. Here, we report a facile approach towards the preparation of cellulose phosphate aerogels from two types of cellulosic source materials. Since high degrees of phosphorylation would afford water-soluble products inappropriate for cell scaffolding, products of low DSP (ca. 0.2) were prepared by a heterogeneous approach. Aiming at both i) full preservation of chemical integrity of cellulose during dissolution and ii) utilization of specific phase separation mechanisms upon coagulation of cellulose, TBAF·H2O/DMSO was employed as a non-derivatizing solvent. Sequential dissolution of cellulose phosphates, casting, coagulation, solvent exchange, and scCO2 drying afforded lightweight, nano-porous aerogels. Compared to their non-derivatized counterparts, cellulose phosphate aerogels are less sensitive towards shrinking during solvent exchange. This is presumably due to electrostatic repulsion and translates into faster scCO2 drying. The low DSP values have no negative impact on pore size distribution, specific surface (SBET ≤ 310 m2 g−1), porosity (Π 95.5–97 vol.%), or stiffness (Eρ ≤ 211 MPa cm3 g−1). Considering the sterilization capabilities of scCO2, existing templating opportunities to afford dual-porous scaffolds and the good hemocompatibility of phosphorylated cellulose, TBAF·H2O/DMSO can be regarded a promising solvent system for the manufacture of cell scaffolding materials.

The purpose of this article is to provide the reader with an overview of the methods used to determine the molecular weights of cellulose. Methods that employ direct dissolution of the cellulose polymer are described; hence methods for investigating the molecular weight of cellulose in derivatized states, such as ethers or esters, only form a minor part of this review. Many of the methods described are primarily of historical interest since they have no use in modern cellulose chemistry. However, older methods, such as osmometry or ultracentrifuge experiments, were the first analytical methods used in polymer chemistry and continue to serve as sources of fundamental information (such as the cellulose structure in solution). The first part of the paper reviews methods, either absolute or relative, for the estimation of average molecular weights. Regardless of an absolute or relative approach, the outcome is a molecular weight average (MWA). In the final section, coupling methods are described. The primary benefit of performing a pre-separation step on the molecules is the discovery of the molecular weight distribution (MWD). Here, size exclusion chromatography (SEC) is unquestionably the most powerful and most commonly-applied method in modern laboratories and industrial settings.

The effect of ball milling expressed as the yield of milled wood lignin (MWL) on the structure and molar mass of crude milled wood lignin (MWLc) preparation is studied to better understand the process’ fundamentals and find optimal conditions for MWL isolation (i.e., to obtain the most representative sample with minimal degradation). Softwood (loblolly pine) MWLc preparations with yields of 20–75% have been isolated and characterized based on their molar mass distribution (by Size Exclusion Chromatography (SEC)), hydroxyl groups of different types (31P NMR), methoxyl groups (HS-ID GC-MS), and sugar composition (based on methanolysis). Classical MWL purification is not used to access the whole extracted lignin. The results indicate that lignin degradation during ball milling occurs predominantly in the high molar mass fraction and is less pronounced in the low molar mass fraction. This results in a significant decrease in the Mz and Mw of the extracted MWLc with an increase in the yield of MWLc, but has only a very subtle effect on the lignin structure if the yield of MWLc is kept below about 55%. Therefore, no tedious optimization of process variables is necessary to achieve the required MWLc yield in this range for structural studies of softwood MWL. The sugar composition shows higher amounts of pectin components in MWLs of low yields and higher amounts of glucan and mannan in high-yield MWLs, confirming that lignin extraction starts from the middle lamella in the earlier stages of MWL isolation, followed by lignin extraction from the secondary wall region.

The effective and straight-forward modification of nanostructured celluloses under aqueous conditions or as “never-dried” materials is challenging. We report a silanization protocol in water using catalytic amounts of hydrogen chloride and then sodium hydroxide in a two-step protocol. The acidic step hydrolyzes the alkoxysilane to obtain water-soluble silanols and the subsequent addition of catalytic amounts of NaOH induces a covalent reaction between cellulose surficial hydroxyl groups and the respective silanols. The developed protocol enables the incorporation of vinyl, thiol, and azido groups onto cellulose fibers and cellulose nanofibrils. In contrast to conventional methods, no curing or solvent-exchange is necessary, thereby the functionalized celluloses remain never-dried, and no agglomeration or hornification occurs in the process. The successful modification was proven by solid state NMR, ATR-IR, and EDX spectroscopy. In addition, the covalent nature of this bonding was shown by gel permeation chromatography of polyethylene glycol grafted nanofibrils. By varying the amount of silane agents or the reaction time, the silane loading could be tuned up to an amount of 1.2 mmol/g. Multifunctional materials were obtained either by prior carboxymethylation and subsequent silanization; or by simultaneously incorporating both vinyl and azido groups. The protocol reported here is an easy, general, and straight-forward avenue for introduction of anchor groups onto the surface of never-dried celluloses, ready for click chemistry post-modification, to obtain multifunctional cellulose substrates for high-value applications.