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Maskwio'mi (Mi'kmaw language for "oil made from birch bark") is a traditional topical skin medicine of the Mi'kmaq people of Atlantic Canada and is produced in a torrefaction process by heating birch bark (Betula papyrifera, paper birch) inside a metal container in a fire. The resulting viscous, oily mixture is traditionally mixed with goose fat or bear grease to create a topical salve that is subsequently applied to affected skin areas. When birch bark is exposed to high temperatures, pyrolytic chemical processes produce a complex mixture of pharmacologically active compounds, including potentially harmful side products such as ortho-, meta-, and para-cresol. This study discusses the qualitative and quantitative GC-MS analysis of cresols found in maskwio'mi and the challenges of the complex organic matrix. Using caffeine as an internal standard, ortho-, meta-, and para-cresol in birch bark extract were determined to be in the approximate order of 50–1500 ppm range with 3.24 ± 0.09 × 102 ng mg−1 (324 ppm), 8.7 ± 1.0 × 102 ng mg−1 (87 ppm), and 12.4 ± 1.6 × 102 ng mg−1 (1240 ppm), respectively, and thus suitable by Health Canada and FDA cosmetics regulation standards when the extract is co-formulated in creams to concentrations of 0.1–5 wt.% for topical use. [ABSTRACT FROM AUTHOR]

Research was carried out on the isolation of betulin and suberin from the debarking waste of the Arkhangelsk Pulp and Paper Mill pulpwood, ground on an abrasive crusher. Betulin was extracted from various fractions of technical bark with 86% ethanol under exposure to microwave electromagnetic field (EMF) (microwave extraction). Suberin was isolated from the extracted bark by hydrolysis with an aqueous KOH solution under microwave heating conditions as well. The maximum yields of betulin and suberin were achieved when using coarse bark fractions (3–4.5 mm), which were essentially crushed birch bark. The resulting products were identified by IR and NMR spectroscopy and by gas chromatography combined with mass spectrometry (GC/MS). The contents of the components in the bark extracts were determined by HPLC analysis. The extractives were dominated by triterpenoid betulinol (70–72%), with betulinic acid, lupeol, and erythrodiol being present less abundantly. Fatty, dibasic carboxylic acids, and hydroxy acids, dominated by 2-hydroxydecanedioic (2-hydroxysebacic) acid, were identified among the suberin monomers. The content of ferulic acid, a natural antioxidant, was determined in the product from different fractions of the bark (from 2.65 to 11.27 g/kg). The suberin obtained from fine bark fractions differs in the composition from that obtained from coarse fractions. Ribofuranose and xylose were detected in the product obtained from the 1–2 mm bark fraction but were absent in that from the 2–3 mm fraction; lanosterol was present in the suberin from fine fraction of the bark, and cycloartenol, in that from coarse fraction. [ABSTRACT FROM AUTHOR]

The aim of this research was to obtain new polymer composites with a silicone rubber matrix, having favorable mechanical and functional properties. They contained admixtures in the amount of 10% by weight of expanded graphite (EG) or birch bark (BB). Additionally, some composites contained magnetic particles in the form of carbonyl iron in the amount of 20% by weight. The tensile strength, water absorption, frost resistance, surface contact angle, and free surface energy were examined. Microscopic images were taken using the SEM method and the content of some elements in selected microareas was determined using the EDXS method. In the study, a constant magnetic field with magnetic induction B was used, by means of which the properties and structure of polymer composites were modified. Scientific research in the field of polymers is the driving force behind the progress of civilization. Smart materials are able to respond to external stimuli, such as magnetic fields, with significant changes in their properties. The magnetic field affects not only chemical reactions, but also the crystallographic structure and physicochemical properties of the final products. Owing to their unique properties, such materials can be used in the space industry, automotive industry, or electrical engineering. [ABSTRACT FROM AUTHOR]

Suberin is a complex polyester biopolymer, and it is practically impossible to estimate the real content of suberin in suberised plant tissues. This indicates the importance of the development of instrumental analytical methods for the comprehensive characterisation of suberin derived from plant biomass for the successful integration of suberinic products into biorefinery production chains. In this study, we optimised two GC-MS methods—one with direct sylilation, and the second with additional depolymerisation, using GPC methods with RI detector and polystyrene calibration and with a three-angle light scattering detector and an eighteen-angle light scattering detector. We also performed MALDI-Tof analysis for non-degraded suberin structure determination. We characterised suberinic acid (SA) samples obtained from birch outer bark after alkaline depolymerisation. The samples were particularly rich in diols, fatty acids and their esters, hydroxyacids and their corresponding esters, diacids and their corresponding esters, as well as extracts (mainly betulin and lupeol) and carbohydrates. To remove phenolic-type admixtures, treatment with ferric chloride (FeCl3) was used. The SA treatment with FeCl3 allows the possibility to obtain a sample that has a lower content of phenolic-type compounds and a lower molecular weight than an untreated sample. It was possible to identify the main free monomeric units of SA samples by GC-MS system using direct silylation. By performing an additional depolymerisation step before silylation, it was possible to characterise the complete potential monomeric unit composition in the suberin sample. For the molar mass distribution determination, it is important to perform GPC analysis. Even though chromatographic results can be obtained using a three- laser MALS detector, they are not fully correct because of the fluorescence of the SA samples. Therefore an 18-angle MALS detector with filters was more suitable for SA analysis. MALDI-Tof analysis is a great tool for the polymeric compound structural identification, which cannot be done using GC-MS. Using the MALDI data, we discovered that the main monomeric units that makes up the SA macromolecular structure are octadecanedioic acid and 2-(1,3-dihydroxyprop-2-oxy)decanedioic acid. This corresponds with GC-MS results, showing that after depolymerisation hydroxyacids and diacids were the dominant type of compounds found in the sample. [ABSTRACT FROM AUTHOR]

The aim of this review was to gather general data about the Betula pendula, but also its properties and toxicity. This is a genus that includes over 140 species distributed on several continents, but is native to Europe and central Siberia. However, birch's ability to colonize empty areas is very strong along with its tolerance to nutrient-poor soils. Furthermore, common birches are rich in resources with important bioactive components, some of which being used even in the pharmaceutical industry. The content of biologically active substances found in birch shows its dependence on the season, weather, and its biological variability. Due to the properties of the substances extracted from the birch, they can modify some proteins. It contains reactive oxygen species, substances which are also mediators of cell damage and play a key role in triggering many diseases by altering the oxidative balance. Birch medicines can also cause side effects such as nausea, diarrhea, allergic reactions such as skin blisters, itching. These medicines are not recommended for people with allergies to pollen or leaves or for people who are hypersensitive. Although, in healthy conditions, it is known that that birch juice along with other components from which teas can be made are very good for certain diseases such as kidneys and heart diseases, rheumatism. Isolated from birch, they are good for treating and caring for the surface, hair loss, cellulite, and scars. [ABSTRACT FROM AUTHOR]

In this study, novel blends of mycelium biocomposites (MB) were developed. Various combinations of birch sawdust and hemp shives with birch bark (BB) and wheat bran (WB) additives were inoculated with basidiomycete Trametes versicolor to produce self-growing biomaterials. MB were characterized according to mycelial biomass increment in final samples, changes in chemical composition, elemental (C, H, N) analyses, granulometry of substrates, water-related and mechanical properties, as well as mold resistance and biodegradability. The mycelial biomass in manufactured MB increased by ~100% and ~50% in hemp and sawdust substrates, respectively. The lignocellulose ingredients during fungal growth were degraded as follows: cellulose up to 7% and 28% in sawdust and hemp substrates, respectively, and lignin in the range of 13% in both substrates. A larger granulometric fraction in hemp MB ensured higher strength property but weakened water absorption (600–880%) performance. Perspective MB combinations regarding strength performance were hemp/BB and pure hemp MB (σ10 0.19–0.20 MPa; E 2.9 MPa), as well as sawdust/WB combination (σ10 0.23 MPa; E 2.9 MPa). WB positively affected fungal biomass yield, but elevated water absorption ability. WB improved compressive strength in the sawdust samples but decreased it in the hemp samples. BB supplement reduced water absorption by more than 100% and increased the density of sawdust and hemp samples. All MB samples were susceptible to mold contamination after full water immersion, with identified fungal genera Rhizopus, Trichoderma and Achremonium. The MB exhibited high biodegradability after 12 weeks' exposure in compost, and are therefore competitive with non-biodegradable synthetic foam materials. [ABSTRACT FROM AUTHOR]

Interactions between pentacyclic triterpenes isolated from white birch (Betula pendula Roth.) bark samples from Northeast Bulgaria and bovine serum albumin or human serum albumin were investigated using fluorescence techniques. The experimental results show the formation of complexes between the isolated triterpenes with serum albumins. Quenching of the intrinsic fluorescence of human serum albumins was monitored by emission spectra of varied quencher concentration solutions. By analysing the fluorescence spectra and fluorescence intensity, some parameters of the serum albumins - quencher interaction were determined to evaluate the type of quenching. An extract containing the isolated triterpenes formed complexes with both bovine serum albumin and human serum albumin, leading to quenching the fluorescence of both albumins by a combined quenching mechanism. [ABSTRACT FROM AUTHOR]

Betulin is the most popular of the known triterpenoids of the lupan series. It has valuable pharmacological properties. It exhibits antibacterial, antiviral, antitumor, hypolipidemic and other types of activity. The prospects of using betulin in medicine, pharmacology, and veterinary medicine require the development of effective methods for obtaining it from waste from the woodworking industry. Therefore, the question arises of the need to develop a technology for isolating and purifying triterpenoids from birch bark in large quantities. This review contains a variety of methods for the isolation of betulin. The advantages and disadvantages of the proposed methods are described. The following methods are considered: vacuum sublimation after preliminary alkaline; vacuum pyrolysis; supercritical extraction with carbon dioxide or mixtures of carbon dioxide with various solvents; extraction with organic solvents. Also, the method of microwave is described, it is activation on the example of the Kyrgyz birch (Betula kirghisorum), this is an endemic species that has not been studied before, growing on the territory of the Republic of Kazakhstan. [ABSTRACT FROM AUTHOR]

The aim of this study is to gain specific information on the water vapour interaction with archaeological and ethnographic birch bark. Water is involved in a number of curative and preventive conservation measurements e.g. when re-shaping or drying objects and when defining climate directives for long-term storage. We measured the sorption isotherm of archaeological, ethnographic and contemporary birch bark at different temperatures and analysed the moisture-induced size and shape changes (swelling, shrinkage, deformation) during humidification and drying. The analysis revealed that, compared to other organic materials like wood, the moisture uptake of outer birch bark is modest. This can be attributed to the cell structure and composition: outer birch bark is composed of closed cells made to a large extent of hydrophobic components (suberin, lignin). The equilibrium moisture content is higher if lenticels or inner bark are present. The extent of brittleness and delamination of the sample influences the sorption behaviour: the less brittle and delaminated archaeological birch bark is, the lower the equilibrium moisture content (EMC). Since the moisture uptake is modest, the related swelling of the outer bark is also modest, but anisotropic due to the cellular arrangement. Swelling is largest in the radial direction, smaller in longitudinal and negligible in tangential direction. Water vapour can plasticize birch bark and as birch bark becomes flexible, it bends towards the outside of the bark. This deformation takes place at high moisture contents and the adsorption process is slow. Based on these results recommendations on how best to perform treatments involving moisture and on relative humidity ranges for birch bark objects are provided. [ABSTRACT FROM AUTHOR]

Extract obtained from the bark of Betula Pendula was treated with sodium hydroxide solution to obtain 4‐(4‐hydroxyphenyl)butan‐2‐one. New (meth)acrylates were synthesized on the basis of 4‐(4‐hydroxyphenyl)butan‐2‐one. Free radical polymerization of the new (meth)acrylates was compared with that of commercial monomers (e. g. phenyl(meth)acrylate, 2‐phenoxyethyl methacrylate, and benzyl methacrylate) in solution resulting in soluble polymers as expected in all examples. In contrast to this, free radical polymerization of 4‐(4‐acryloyloxyphenyl)butan‐2‐one in bulk resulted in a crosslinked material although an extremely high molecular weight soluble polymer was received in case of bulk polymerization of 4‐(4‐methacryloyloxyphenyl)butan‐2‐one. The 3‐oxobutyl substituent at the phenyl ring of these monomers may influence their radical polymerization. Furthermore, enzyme mediated radical polymerization and photoinitiated polymerization were applied for the polymer synthesis using 4‐(4‐methacryloyloxyphenyl)butan‐2‐one. [ABSTRACT FROM AUTHOR]

Background: Epidermolysis bullosa (EB) is a group of rare, genetic diseases that affect the integrity of epithelial tissues, most notably the skin. Patients experience recurrent skin wounding, with severity depending on type, sub-type, and mutation. Oleogel-S10, a formulation of birch bark extract, has demonstrated efficacy in a Phase 2 trial assessing re-epithelialization of wounds in EB. EASE (NCT03068780, EudraCT 2016-002066-32) is a randomized, Phase 3, placebo-controlled study designed to determine the efficacy of Oleogel-S10 versus placebo in patients with EB.Methods: EASE is a Phase 3, two-phase study comprising a 90-day, double-blind, randomized, placebo-controlled phase, followed by 24 months of open-label, single-arm follow-up. Patients with junctional EB, dystrophic EB, or Kindler syndrome and target wounds (10 - 50cm2) present for > 21 days and < 9 months, are randomized in a 1:1 ratio to receive wound dressings according to local standard of care with or without Oleogel-S10. Placebo is based on the Oleogel-S10 vehicle, which is sunflower oil formulated to have a consistency indistinguishable from that of the active product. The primary endpoint of the trial, directed by the US health authority according to the required study endpoints for chronic cutaneous ulcer and burn wounds, is to compare the efficacy of Oleogel-S10 versus placebo according to the proportion of patients with complete closure of the target wound within 45 ± 7 days of treatment. Additional EB-focused endpoints include wound burden, patient-reported outcomes, and safety.Results: Results of the primary endpoint are anticipated to be available by H2 2019.Trial Registration: ClinicalTrials.gov, NCT03068780 . EudraCT, 2016-002066-32. Registered on 3 March 2017. [ABSTRACT FROM AUTHOR]

Birch bark tar, the oldest adhesive known in Europe, was widely used during Prehistory. This material, produced by the dry distillation of birch bark, has been identified in various spheres of activities and provides valuable information on the know-how and technical and territorial systems of past societies. This biomaterial can also provide evidence on socio-economic networks and mobility. However, very little is known about the production systems of birch bark tar during Prehistory, including the Neolithic period. The lack of findings in the archaeological record necessitates the development of an approach that combines experimental archaeology and biomolecular chemistry. We present here (1) the results of experiments in which different birch bark tar production systems were tested and (2) the molecular signatures of the birch bark tars produced according to different processes based on the use of ceramic vessels. The key role of bark quality is highlighted for the first time. This study also details direct archaeological inference of the experimental results obtained: a total of 23 samples from the site of Nice-Giribaldi (France, second part of the fifth century BCE) was investigated. Different categories of birch bark tars were identified during Neolithic in the south of France, providing evidence for the existence of complex manufacturing systems and procurement networks. [ABSTRACT FROM AUTHOR]

A new method for preparation of organic aerogels by sol-gel polymerization of formaldehyde with polyphenols (PPs), isolated from larch bark and birch bark, was developed. The functional composition and properties of the original polyphenols were studied by thermogravimetric methods and FTIR spectroscopy. It was found that larch polyphenol material had higher thermal stability in the temperature range 25−700°C, while the process of thermal decomposition of birch bark polyphenols completes at 600°C. It has been established that polyphenol larch compounds contain more aromatic structures and hydroxyl groups. The effect of the pH of gelation solutions in the range from 4 to 12 on the porous structure of organic gels synthesized from polyphenols was studied. The porous structures and adsorption properties of polyphenol-formaldehyde organic gels were studied using the BET method, scanning electron microscopy and sorption (methylene blue and gelatin). It was shown that an increase in pH contributes to the formation of a product with a more compacted texture. The electron microscopic images of polymer gels demonstrate a uniform granular texture with visible microglobules with an average particle size of ≈50−70 nm. [ABSTRACT FROM AUTHOR]

Abstract: Archaeological excavations carried out in Early Iron Age Vetulonia (northern Tuscany, Italy) brought to light a funerary urn particularly noteworthy for the presence of an unusual decoration obtained by plastering the vase surface with an organic dark grey substance, on which metal strips were originally fixed. In order to reveal the origin of such coating, it was chemically studied by gas chromatography coupled with mass spectrometry (GC/MS). Chemical analysis not only revealed that birch bark tar was used as coating/adhesive material for the manufacture of the urn, but also allowed us to discuss the significance of the vessel in terms of eco‐technological knowledge and possible cultural connections on a large geographical scale. [ABSTRACT FROM AUTHOR]

Birch bark is commonly found in indigenous collections in Canadian museums. It is empirically known that light can cause the cambium side of birch bark to change colour. The purpose of this research is to better assess the light sensitivities of various colours of birch barks, and the manner, degree, and rate of colour change during light exposure. Six barks with different colours were used: beige, yellow, orange, orange-brown, red, and brown. Samples were exposed to daylight through a north-facing window (window), LED light from an enclosed chamber (LED), and the Newport-Oriel microfade tester (MFT). Window and MFT samples received a total light dose of approximately 25 Mlux-hours, and LED samples, 182 Mlux-hours. Colour monitoring of the samples showed that almost all barks initially darkened and then faded. Daylight through window caused the most rapid and extensive darkening and fading. Bluewool (BW) ratings for window samples were the lowest (most light sensitive). The MFT and LED samples showed a similar degree of colour change, with the same dose, despite the difference in intensity. Ratings of MFT samples are within one BW step difference compared to LED samples. The rate and extent of initial darkening depended on the colour of the bark; the middle range orange-toned barks showed the most rapid and extensive darkening followed by fading. [ABSTRACT FROM AUTHOR]

The effect of the conditions of the acetylation process of raw and activated birch bark on the yield and composition of the products is investigated. The structure of biologically active betulin diacetate (BDA) is confirmed with physicochemical methods. The optimal regimes of the one-step original method for the production of BDA from raw and activated birch bark are established using the experimental and computational techniques. [ABSTRACT FROM AUTHOR]

Abstract: We propose a novel method for automatically estimating the age of birch bark manuscripts based solely on the appearance of graphemes (paleographic dating). Our method achieves mean absolute accuracy of 18.9 years which is comparable to or surpasses the performance of human experts and of other computational paleography studies. [ABSTRACT FROM AUTHOR]

The development of thermal insulation materials from sustainable, natural fibrous materials is desirable. In the present study, cellulose fiber based insulation foams made of bleached chemi thermo mechanical pulp (CTMP) have been investigated. To improve water resistance, the foams were impregnated with hydrophobic extractives from the outer bark of birch (Betula verrucosa) and dried. The surface morphology of the foams and the distribution of the deposited particles from the extractives were observed by scanning electron microscopy (SEM). The modified foams showed improved water resistance, as they did not disintegrate after immersion in water for 7 days, whereas the unmodified foam did. Compared to the unmodified foam, the modified foams absorbed 50% less moisture within 24 h. The modification had no negative effects on the thermal insulation properties, fungal resistance or compressive strength of the foams. The proposed approach is simple and can be easily integrated into plants working based on the biorefinery concept. [ABSTRACT FROM AUTHOR]

Natural pentacyclic triterpenes were extracted from birch bark with subcritical solvents. The influence of the solvent nature, temperature, and the number of extraction cycles on the efficiency of the process was studied. Using methanol at 100 °С provides the highest tri-terpene extraction rate. Bark extracts prepared using various solvents were analyzed for chemical composition and antioxidant activity. [ABSTRACT FROM AUTHOR]

Objective: The present study investigated the comparative analysis of fatty acid and antioxidant activity from the bark of Betula utilis, collected from Kashmir and Sikkim coded as BUK and BUS respectively. Methods: Fatty acid constituents were analyzed by GCMS (gas chromatography mass spectroscopy) in BUK and BUS bark. B. utilis bark extracts of both the locations were phytochemically investigated and radical scavenging activity was evaluated by DPPH in all solvent fractions. Results: Phenolic content were found to be higher in methanolic extracts of BUK bark, 5.8 ± 0.1 mg/gm and flavonoid content were higher in the water extract of BUK bark, 6.16 ± 0.2 mg/gm. The radical scavenging activity was found to be higher methanolic, alcoholic and water extracts of BUK bark. The lowest IC50 value for radical scavenging activity of methanolic and water extracts of B. utilis bark collected from Kashmir were found 18.7 ± 1.1 and 18.2 ± 0.3 µg/mL, respectively. Thirteen fatty acids were identified in the sample BUK as well as BUS in which the major fatty acids were found-Palmitic acid, linoleic acid and oleic acid. BUK possess the highest amount of Palmitic acid (18.07%) in oily portion of the bark. Conclusion: The present study concluded that BUK and BUS extracts have shown significant antioxidant activity in comparison to standard but BUK possess potent radical scavenging activity over BUS, and higher amounts palmitic acid, linoleic acid and oleic acid was present in the extract, and may a play an important role in nutritional and pharmaceutical applications. [ABSTRACT FROM AUTHOR]

Even if up to date, betulonic acid (BA) was not investigated for biological activities as much as other triterpenic derivatives like betulinic acid, and there are several papers describing the synthesis, isolation and investigations-both instrumental and biological-of this compound. In this paper, the kinetic behavior associated with thermal decomposition of BA in oxidative conditions is presented. The kinetic study was realized on the main decomposition process which occurs in the 200-300 °C temperature range, according to the ICTAC 2000 protocol, namely employing three isoconversional methods, one differential (Friedman) and two integral (Kissinger-Akahira-Sunose and Flynn-Wall-Ozawa). In order to separate the multistep contributions to the degradation process of BA, the NPK method was employed. This method suggested that the degradation occurs by two parallel processes, with different energetic contributions, with a mean value of 162.1 ± 5.5 kJ mol. [ABSTRACT FROM AUTHOR]

A new and relatively simple method for purification of betulin from birch bark extract was developed in this study. Its five purification steps are based on the differential solubility of extract components in various solvents and their crystallization and/or precipitation, on their affinity for Ca(OH)2 in ethanol, and on the affinity of some impurities for silica gel in chloroform. In addition, all used solvents can be simply recycled. Betulin of more than 99% purity can be prepared by this method with minimal costs. Various observations including crystallization of betulin, changes in crystals during heating, and attempt of localization of betulin in outer birch bark are also described in this work. The original extract, fraction without betulinic acid and lupeol, amorphous fraction of pure betulin, final crystalline fraction of pure betulin and commercial betulin as a standard were employed to determine the antiproliferative/cytotoxic effect. We used WST-1 tetrazolium-based assays with triple negative breast cancer cell line BT-549. The decrease in cell survival showed clear relationship with the purity of the samples, being most pronounced using our final product of pure crystalline betulin. WST-1 proliferation/cytotoxicity test using triple negative breast cancer cell line BT-549 clearly showed the importance of purity of betulin for biological experiments and, apparently, for its medicinal use. [ABSTRACT FROM AUTHOR]

A comparative study among different pretreatment methods used for the fractionation of the birch outer bark components, including steam explosion, hydrothermal and organosolv treatments based on the use of ethanol/water media, is reported. The residual solid fractions have been characterized by ATR-FTIR, 13C-solid-state NMR and morphological alterations after pretreatment were detected by scanning electron microscopy. The general chemical composition of the untreated and treated bark including determination of extractives, suberin, lignin and monosaccharides was also studied. Composition of the residual solid fraction and relative proportions of different components, as a function of the processing conditions, could be established. Organosolv treatment produces a suberin-rich solid fraction, while during hydrothermal and steam explosion treatment cleavage of polysaccharide bonds occurs. This work will provide a deeper fundamental knowledge of the bark chemical composition, thus increasing the utilization efficiency of birch outer bark and may create possibilities to up-scale the fractionation processes. [ABSTRACT FROM AUTHOR]

Betulin from birch bark was extracted using two principally different extraction methodologies – classical Reflux Boiling (RB) and Pressurized Liquid Extraction (PLE). The extraction methods were analyzed based on both recovery and purity as well as for RB industrial feasibility. The purity and recovery for the different extraction methods were analyzed using High Performance Liquid Chromatography (HPLC) coupled with three different detection principles: Diode Array Detection (DAD), Mass Spectrometry (MS) and Charged Aerosol Detection (CAD). The chromatographic purity was determined by all detections whereas the DAD was used also for complementary gravimetric calculations of the purity of the extracts. The MS detection (in MS and MS/MS modes) was mainly used to characterize the impurities. Two steps to increase the purity of RB extracts were evaluated – pre-boiling the bark in water and precipitation by adding water to the extract. Finally, the methods were compared in terms of amounts of betulin produced and solvent consumed. The RB method including a precipitation step produced the highest purity of betulin. However, results indicate that PLE using three cycles with the precipitation step gives similar purities as for RB. The PLE method produced up to 1.6 times higher amount of extract compared to the RB method. However, the solvent consumption (liter solvent per gram product) for PLE was around 4.5 times higher as compared to the classical RB. PLE performed with only one extraction cycle gave results more similar to RB with 1.2 times higher yield and 1.4 times higher solvent consumption. The RB process was investigated on an industrial scale using a model approach and several important key-factors could be identified. The most energy demanding step was the recycling of extraction solvent which motivates that solvent consumption should be kept low and calculations show a great putative energy reduction by decreasing the ethanol concentration used in the RB process to lower than 90%. [ABSTRACT FROM AUTHOR]

Birch bark, left over as residue fuel in the pulp and plywood industry, is rich in pentacyclic lupane-type triterpenes – primarily betulin and lupeol – promising starting materials for the synthesis of biologically active compounds with a broad spectrum of medical applications. A comparative study on the main triterpenes of the outer bark of two birch species – silver birch ( Betula pendula Roth.) and downy birch ( Betula pubescens Ehrh.) – is reported. The total yield of extractives decreased with crop age. For the first time, pre-treatment with hot water and Na 2 CO 3 water solution of birch outer bark was carried out before extraction. Pre-treatment with Na 2 CO 3 water solution substantially improved the ethanol extracts’ triterpene content (from 67.7 to 99.0%). The effect of different solvents on the yield and composition of extracts was studied. Nonpolar solvents behave more selectively toward triterpenes and admixtures. It is possible to improve the extracts’ triterpene content by modifying the extraction technology employed and choosing the appropriate solvents. [ABSTRACT FROM AUTHOR]

An alternative and green method for extraction of betulinic acid (BA) from birch bark is here proposed as Subcritical Water Extraction (SWE). Using response surface methodology (RSM), optimization was conducted on reaction parameters for maximum extraction yield of BA. Optimal modifying conditions are as follows: extraction time of 27.37 min, extraction temperature at 184.52 °C and a solvent/solid ratio of 59.60 mL/g. Under optimal conditions, the maximum BA yield was 28.03 mg/10 g birch bark. Extracts by different methods (leaching extraction, reflux extraction, ultrasonic extraction, and SWE) were comparatively and quantitatively analyzed, using High Performance Liquid Chromatography (HPLC). Results show BA yields by SWE are higher than those obtained using ethanol, a traditional extraction method, plus the extract contained fewer impurities. Furthermore, the extraction processes for all four of the above methods were modeled and reviewed individually. [ABSTRACT FROM AUTHOR]

We showed that the addition of suberin fatty acids (SFAs) even at small concentrations significantly improves the water vapor barrier properties of hydroxypropyl methylcellulose (HPMC) films. SFAs were isolated from the outer birch bark using extractive hydrolysis. The effects of SFAs on the film formation of aqueous HPMC were investigated with free films plasticized with polyethylene glycol (PEG 400). Special attention was paid on the physical solid-state, moisture barrier and mechanical stress-strain properties of films intended for tablet film coatings. Topography and surface morphology, glass transition temperature ( T g ), tensile strength, Young’s modulus, and water vapor permeation (WVP) of films were studied. The addition of SFAs lowered the T g of films suggesting partial enhancement in film plasticization. The WVP of films decreased with increasing SFAs concentration up to 15% (calculated as a % w/w from a polymer weight). The WVP value for a non-suberized reference film and suberized film plasticized with PEG 400 was 2.13 × 10 −6 and 0.69[ × 10 −6 g/(mm 2 × h) × mm/Pa], respectively. The addition of SFAs impaired the mechanical stress-strain properties of HPMC films by reducing the deformation capacity of film. In conclusion, the film properties and performance of aqueous HPMC can be modified by including SFAs in the films. [ABSTRACT FROM AUTHOR]

The acceleration of wound healing is a major surgical concern. A triterpene extract from birch bark (Betulae cortex) experimentally enhances keratinocyte differentiation in vitro and accelerates wound healing ex vivo. We conducted an open, blind-evaluated, controlled, prospective, randomized (1:1) phase II clinical trial in patients requiring split-thickness skin graft transplantation at two university hospitals in Germany. Donor sites on the upper legs were covered with a moist silicone-coated dressing. Oleogel-S10 ointment containing 10% birch bark extract was randomly applied to the distal or proximal half of the wound, with the other half serving as an intraindividual control, for 14 days after the skin graft surgery. The primary efficacy variable was faster reepithelialization as determined from macrophotographs by independent, blinded experts. Twenty-four patients were randomized and completed the trial. After the 14-day test period, the planned interim analysis revealed a highly significant (p < 0.0001) superiority of Oleogel-S10 in the primary efficacy variable and the trial was terminated early due to ethical concerns. The treatment side was also better reepithelialized and more similar to normal skin after 3 months. In conclusion, Oleogel-S10 significantly accelerated reepithelialization at split-thickness skin graft donor sites. Treatment with Oleogel-S10 was safe and well tolerated. © 2014 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Pentacyclic triterpenoids from birch bark are of great interest as biologically active substances and raw materials for producing a wide range of drugs. In this work, a method for the highly sensitive determination of betulin, betulinic acid, lupeol, and erythrodiol in plant extracts based on a combination of high-performance liquid chromatography with tandem mass spectrometric detection is proposed. Mass spectra under the conditions of atmospheric pressure chemical ionization and collision-induced dissociation spectra of analytes are obtained. The conditions for mass spectrometric detection in the multiple reaction monitoring mode are optimized. The calculated detection limits are in the range 0.7-1.8 μg/L. [ABSTRACT FROM AUTHOR]

Betulin-containing products were obtained in a yield of about 40% from absolutely dry birch bark. The content of betulin in the products was 74-75% or 85-89% depending on the presence of sodium or potassium hydroxide, respectively. The one-step method of extraction of high-purity betulin (97.7%) is presented. Betulin was identified by physic-chemical methods, i.e., elemental analysis, IR and NMR spectroscopy, and electron scanning microscopy. The thermal characteristics of betulin were also studied. It was shown that betulin exhibits gastroprotective, hepatoprotective, and capillary-strengthening properties. [ABSTRACT FROM AUTHOR]

The process of isolation of the extractives and betulin from birch bark exposed to a microwave field was investigated. It was shown that under the use of microwave treatment in a microwave field the duration of the extraction process was reduced 10-15 times, as compared with the extraction by infusion. The influence of the main parameters on the process of microwave extraction of extractives from birch bark was studied. Using high performance liquid chromatography we established quantitatively the content of betulin in the birch bark extracts. [ABSTRACT FROM AUTHOR]

Bark extracts are sustainable sources of biopolymers and have great potential to replace fossil-based polymers in wood coating applications. The present study investigated the applicability of suberin fatty acids hydrolysate (SFA) extracted from the outer bark of silver birch (Betula pendula Roth.) for coating of aspen wood (Populus tremula L.). The SFA combined with maleic anhydride (MA) and octadecyltrichlorosilane (OTS) as a curing agent was prepared in ethanol and used in surface coating. The water contact angle, surface reflectance spectra, FTIR, and SEM-EDS were used to characterize the physical and chemical properties of the coated wood samples. Further, the long-term stability of the SFA coating was analyzed via artificial aging. The wood surface became hydrophobic, as the contact angle for the water droplet (WCA) was over ~120°, and was stable for all of the prepared combinations of SFA, MA, and OTS. [ABSTRACT FROM AUTHOR]

Elizabeth Simcoe (1762–1850) travelled from England to Canada in 1791 and returned to her home, Wolford Lodge, in Honiton, Devon, in 1796. She was accompanying her husband, John Graves Simcoe (1752–1806), who had just been appointed Lieutenant Governor of the newly formed province of Upper Canada. Throughout their travels, Elizabeth recorded her Canadian experiences in her diaries and sketchbooks. She drew, corrected and copied maps for her husband. Upon their return to England they offered to the king an album of 32 works and a map, all drawn on birch bark. The map and the album acted as a report to the king of her husband’s political achievements in Canada and her engagement as a cartographer. [ABSTRACT FROM PUBLISHER]

Highlights: [•] Autothermal operation is possible with oxygen addition into the pyrolysis reactor. [•] Under autothermal conditions, 22% of the dry bio-oil chemicals are lost at 500°C. [•] Under autothermal conditions, 25% of total bio-oil energy is lost at 500°C. [•] Partial oxidation helps reduce the content of heavy compounds in the bio-oil. [ABSTRACT FROM AUTHOR]

Highlights: [•] Fractional condensation proves successful in recovering nearly water free bio-oil (less than 1wt%). [•] The heating value of water free bio-oil is higher than ethanol. [•] Nearly 90% of energy present in the original bio-oil is recovered in water free bio-oil. [•] The fractional condensation system uses electrostatic precipitator-cum-condenser (C–ESP). [ABSTRACT FROM AUTHOR]

An introduction is presented which discusses articles within the issue on topics including the labrets of British Columbia's (BC's) indigenous coastal people, birch bark artifacts created by BC First Nations people and the Vancouver, BC politicians' reactions to hippies in the 1960s.

The article discusses the First Nations women's birch bark artifacts in the Canadian Plateau of British Columbia (BC), through referencing archaeology in the region. An overview of First Nations' culture, including the role that birch bark technologies played in First Nation basketry, harvesting, transportation and cooking of food, is provided. Several archaeological charts and diagrams, including in regard to the design of First Nations' birch bark containers, are presented.

A major problem within forest industry is unwanted browsing on seedlings from mammalian herbivores. The aim of this study was to evaluate the effects of birch bark extracts as repellents towards fallow deer. Birch bark was extracted in a conventional way with ethanol as solvent at ambient temperature and with a new method, liquid CO 2 extraction. An analysis of the ethanol-extracted birch bark showed that it contained large amounts of terpenoids, of which the most abundant was betulin. In seven different treatment trials, we used 15 individually handled fallow deer. To investigate the binary taste preferences, birch bark extract was added to food and presented in two bowls in typical two-choice tests. We found that the amount of a food type consumed during a trial and the number of shifts between food bowls were dependent on the amount of the birch extract the food contained. Concentrations of above 1 % by dry weight of birch extract acted as a repellent. In addition, such concentrations produced shorter feeding bouts by a greater willingness to change bowls. Therefore, our conclusion is that birch bark extract acts as a repellent towards fallow deer and is therefore likely to act as a repellent against other deer species. In addition, we show that birch bark extract produced by the new and more environmentally sustainable method employing liquid CO 2 mixed with ethanol has the same repellent effect as the traditional ethanol extraction. [ABSTRACT FROM AUTHOR]

[Display omitted] • Use of a green and sustainable synthetic strategy to CHA-based polyesters. • Low temperature (35–55 °C) polycondensation in scCO 2 achieved. • The valuable epoxy groups of the monomers were preserved. • Our process led to reasonably high molecular weight polyesters. There is significant potential for industrial use of renewables for a wide range of materials demanded by society. Plants, trees and algae are increasingly attracting attention as sustainable sources for functionalised and polymerizable building blocks. In particular, the outer bark of the birch tree (Betula pendula) is a side stream of the forestry industry with so far very little utilisation besides energy recovery. It is composed of a macromolecular network, suberin, that could provide a renewable, low cost and competitive resource. Within raw suberin is the potentially very useful multifunctional extract cis -9,10-epoxy-18-hydroxyoctadecanoic acid (CHA). Our drive has been to develop a green and sustainable synthetic strategy to CHA-based polyesters, by exploiting supercritical carbon dioxide (scCO 2) as a reaction medium and leveraging the regio- and chemo-selective properties of the biocatalyst Novozym 435 (Lipase B). Low temperature (35–55 °C) polycondensation in scCO 2 shows significant advantages compared to traditional polymerisation methods leading to reasonably high molecular weight polyesters. The mild synthetic conditions also preserve the valuable epoxy groups of the CHA which we show can be exploited by post-polymerisation functionalisation to create sustainable resins for bio-renewable coatings. [ABSTRACT FROM AUTHOR]

A simple, rapid, and nondestructive method for the determination of betulin in the outer birch bark was developed using near infrared spectroscopy (NIRS). NIRS data of the outer birch bark collected throughout the year was preprocessed and analyzed by principal component analysis, which led to clear discrimination of the samples according to their harvest times. The reference content of betulin, a major constituent of the outer birch bark, was determined using ultra performance liquid chromatography with a diode array detector (UPLC-DAD). The optimized and validated analytical conditions of UPLC-DAD provided better separation and faster analysis time compared to a conventional HPLC method. Betulin content also showed seasonal variation and was higher in the samples collected during the summer season. Partial least squares calibration techniques were employed to estimate the relationship between the NIRS data and betulin contents. The spectral data showed high correlation coefficients (over 0.700) with betulin content. These results indicate that NIRS combined with UPLC can be used to determine the quality and to quantify the betulin content of the outer birch bark. [ABSTRACT FROM AUTHOR]

Abstract: The construction and application of a novel electrochemical detection system with an in situ plated lead film electrode for high-performance liquid chromatography (HPLC) is described. The working electrode of interest was tested as a potential sensor for the adsorptive stripping voltammetric determination of betulinic acid (BA). The high sensitivity of the proposed electrochemical detection results from the accumulation by adsorption of BA on the lead film surface before the proper electrode process. In a solution of sodium hydroxide, used as a supporting electrolyte for the proposed voltammetric method, the oxidation signal for BA was found to be proportional to the BA concentration in the range from 0.02 to 0.5μgL−1 with a limit of detection equal to 0.009μgL−1 (with preconcentration for 15s). The voltammetric detection was successfully applied to the determination of BA in the birch bark (Betula verrucosa) extracts after HPLC separation. The content of BA obtained by the proposed method was in close agreement with that obtained by HPLC coupled with photodiode array detector (HPLC–PAD). This appears to be the first application of electrochemical detection to the determination of pentacyclic triterpene. [Copyright &y& Elsevier]

Abstract: The effect of mineral addition on biomass thermal decomposition was investigated in slow pyrolysis conditions (10°Cmin−1). The tests were carried out on the biomass components, their mixtures and real wood (birch wood), using thermogravimetric analyses (TGA) and pyrolysis coupled to mass spectrometry technique (Py-MS). The main criteria chosen to study the additivity of thermal behaviour were: the mass loss of the samples (C.R %), the temperature of the maximum mass loss (T m ) and the initial degradation temperature (T i ). Furthermore, to highlight the primary reactions of thermal behaviour of the studied samples, the chemical composition of emitted vapours was analysed and the influence of some mineral salts (MgCl2, NiCl2) on pyrolysis primary mechanisms was also investigated. Considering the large data sets collected (integrated MS intensities of 19 selected ions), principal component analysis (PCA) was used to provide a tool to simplify pyrolysis data interpretation. Considering mineral effects, it is possible to favour some primary mechanisms: dehydration (inducing to char formation); ring opening (with gas and light vapours formation) and depolymerisation (with sugars, pyrans and furans formation). MgCl 2 catalyses inter (or intra) molecular dehydration. However, NiCl2 does not catalyse the mentioned primary reactions but appreciably modifies the emitted gas and vapours composition. With the help of the PCA calculations, the effect of metallic salts on xylan and ternary mixtures was evidenced. [Copyright &y& Elsevier]

Inspired by the birch bark, which has multilayered structures, we fabricated layer-by-layer (LbL) assembled montmorillonite (MMT) and poly( p-aminostyrene) (PPAS) nanocomposites on cotton fiber curved surfaces to provide protection from atomic oxygen (AO) erosion. The multilayer coated fibers had high flexibility, uniformity, defect free, ease of preparation and low cost. The AO erosion durability has been dramatically enhanced which was evidenced by testing in the ground-based AO effects simulation facility. And the dimension and surface morphologies of the fibers observed by SEM had few changes, indicating excellent AO erosion resistant ability of the coatings. These results provide us a new method to design fibrous materials exposed directly in low earth orbit environment. [ABSTRACT FROM AUTHOR]

A one-step synthesis of the betulin dipropionate directly from the birch bark without a separate stage of the betulin preparation is described in this paper. Extracts with different content of the betulin dipropionate were shown to form depending on the conditions of acylation of the upper birch bark with propionic acid. The product with the maximum content of the betulin dipropionate was prepared from the starting fraction of 2-5 mm of the upper birch bark and the fraction of 10-20 mm that was preliminarily activated with superheated water vapor. The upper bark extract was analyzed by gas chromatography. The structure of betulin dipropionate was confirmed by element analysis, H NMR, C NMR, and FTIR spectroscopy. [ABSTRACT FROM AUTHOR]

In order to evaluate the content of betulin and betulinic acids in Birch barks originating from Western Carpathians, Transylvania (Romania) forests, in relation with the location of birch trees, it was recorded the geographic and vegetation conditions at the specific locations of each type of sample. Two groups of birch tree bark (totally 10 samples) were collected, from two regions, pasture surfaces where birch trees appeared spontaneously (samples 1 to 5) and another group from forests of combined trees, including mainly pine trees (samples 6 to 10). The identification and quantitation of betulin and betulinic acid were made by High Performance Liquid Chromatography with UV detection. In the first region it has been found mean concentrations of 126.85 ± 12.56 mg/g betulin bark while acid betulinic had average values of 12.78 ± 1.26 mg/g bark. In the second region we found mean concentrations of 89.84 ± 8.43 mg/g betulin of bark while acid betulinic had average values of 10.60 ± 0.97 mg/g bark. Statistically, significant differences were noticed between the two regions, the first region being richer in these molecules. Generally, the percentage of betulinic acid was around 11.23% against betulin, higher in the second region, even the absolute concentrations were lower for both molecules. These data are useful indicators of the potential offered by birch bark sources found in Transylvania region, to obtain extracts enriched in betulin and betulinic acid. [ABSTRACT FROM AUTHOR]

Abstract: Experiments with birch bark samples have been carried to enable a distinction between extraction and degradation effects during pressurised hot water extraction. Two samples, E80 and E180, contained birch bark extracts obtained after extraction at 80 and 180°C for up to 45min, respectively. Two other samples, P80 and P180, were only extracted for 5min at the two temperatures and were thereafter filtered and hydrothermally treated at 80 and 180°C, respectively. During the latter treatment, samples were collected at different times to assess the stability of the extracted compounds. An offline DPPH (2,2-diphenyl-1-picrylhydrazyl) assay, as well as a high performance liquid chromatographic separation coupled to an electrochemical detector, were used to determine the antioxidant capacity of the processed samples. The results obtained with the different techniques were compared to assess the yield of the extraction and degradation processes. In addition, an online hyphenated system comprising high performance liquid chromatography coupled to diode-array; electrochemical; and tandem mass spectrometric detection (HPLC-DAD-ECD-MS/MS) was used to study the compositions of the extracts in more detail. The results for the samples processed at 80°C showed that the extraction reached a steady-state already after 5min, and that the extracted compounds were stable throughout the entire extraction process. Processing at 180°C, on the other hand, gave rise to partly degraded extracts with a multitude of peaks in both the diode array and electrochemical detectors, and a higher antioxidant capacity compared to for the extracts obtained at 80°C. It is concluded that HPLC-DAD-ECD is a more appropriate technique for the determination of antioxidants than the DPPH assay. The mass spectrometric results indicate that one of the extracted antioxidants, catechin, was isomerised to its diastereoisomers; (+)-catechin, (−)-catechin, (+)-epicatechin, and (−)-epicatechin. [Copyright &y& Elsevier]