Russian Journal of Bioorganic Chemistry

Various types of plant raw material are widely used in the pulp and paper, textile, food, and agricultural industries and pharmacology. One of the problems of utilizing the complex plant biomass is poor knowledge of its hemicellulose content and the lack of effective enzymes for hydrolysis of hemicelluloses. Xyloglucan is the major structural and storage polysaccharide in all dicots and a great number of monocots. It has a branched architecture with a backbone constructed of β-1,4-connected cellotetraose units decorated with short sidechains composed of xylose, galactose, arabinose, fucose and some other residues. Sidechain composition and alternation order are specie-specific and can change during cell growth resulting in variety of xyloglucan structural types. In general, xyloglucan structure depends on the taxonomic position of the plant. Structural features of xyloglucans belonging to different taxonomic groups are discussed in the evolutionary aspect. Xyloglucan hydrolysis is a necessary condition during conversion of plant biomass into high added-value products. Variety of xyloglucan structural types complicates the selection of enzymes for its hydrolysis. Xyloglucanase-containing multienzyme complexes can be used for efficient decomposition of plant biomass polysaccharides into fermentable sugars for biotechnology, and for the improvement of feed quality. Investigation of xyloglucanases is necessary for the development of methods for protecting plants from pathogenic microorganisms, which use these enzymes in the invasion of plant tissue. The article discusses structural features of xyloglucans from different taxonomic groups in the evolutionary aspect and reviews selection of xyloglucanases for efficient hydrolysis of complex plant biomass.

To raise the efficacy and the selectivity of known medicinal substances (MS), methods have recently been developed to create systems for their directed transport in the body using various carriers. The problem of decreasing the toxicity and increasing the selectivity of antitumor MSs is particularly relevant. In recent years, studies are underway for the development of conjugates of MSs and the natural polymers, in particular, the non-starch polysaccharides, many of which manifest antitumor and immunomodulatory properties. Owing to the unique combination of physicochemical and biological properties, arabinogalactan from larch wood (AG) is one of the most promising tools for the development of complex preparations with elevated bioavailability and reduced toxicity. The aim of the present work is to obtain mechanocomposites of cyclophosphamide (CPA) with the initial arabinogalactan (molecular mass 16 645 Da) and its fragments (molecular mass 8380 Da) and to study their physicochemical properties. According to IR and ¹³С, ¹⁵N and ³¹Р NMR spectroscopy, long-term mechanochemical treatment does not lead to a change in chemical composition of CPA molecules, only the formation of hydrogen bonds NH···OH is observed. The data on X-ray analysis, IR and multinuclear NMR spectroscopy show that, with a weight ratio of 1 : 5 and 1 : 10, disordering of CPA crystallographic structure and its molecular dispersion without chemical interaction of the components occur in the matrix of the polysaccharide with mechanical treatment of mixtures of CPA–AG over 4–12 hours.

Utilization of paper wastes as renewable resource of lignocellulosic constituents has the opportunity to promote a cleaner environment and to prepare valuable materials. This paper describes our study on an isolation of low-fiber powder cellulose from two grades of wastes as feedstocks: waste newsprint paper and cardboard wrapper through recycling including a thermal defibration, an alkali treatment with a solution of NaOH with a concentration from 0.03 to 1.00 М, bleaching with a solution of Н₂О₂ with a concentration from 0.8 to 2.6 М followed with an acid hydrolysis of the pretreated species with a solution of HNO₃ of 1.5 and 3.0 M. The impact of the pretreatment on sizes of fibers was evaluated with stereoscopic microscopy. The powder celluloses obtained as a result of the acid hydrolysis exhibited the structure of cellulose I revealed with a WAXS method and were of a high-grade purity, according to EDXA. Sorption capacities of the powder celluloses from the waste cardboard and newsprint towards a dye methylene blue were 6.67 and 8.75 mg g^–1, respectively.

The anthocyanin composition of five purple leaves cultivars of Ocimum basilicum L. was investigated by reversed-phase HPLC with mass-spectrometric detection by ESI mode with ion partial fragmentation as well as preparation of dried differently colored forms of anthocyanins encapsulated into maltodextrin matrix. Analysis of the mass spectra revealed that according to the chromatographic profile the set of basil cultivar anthocyanins under investigation may be divided into two groups with the common feature being a high level of acylation with (mainly) p-coumaric, ferulic and malonic acids of the same base: cyanidin-3-dihexoside-5-hexoside. The presence of acylation with substituted cinnamic acids permits us to obtain solutions not only with a red color (the property of the flavylium form) but also with blue shades of coloration due to quinonoid and negatively charged quinonoid forms. All forms except that of flavylium are not stable in solution but stable enough to prepare dried encapsulated forms by lyophilization. Although the loss of anthocyanins with drying is not negligible, the final product is characterized with high stability for storage in a refrigerator.

Metabolic analysis of methanol extracts of leaves of Prunella vulgaris L. (Lamiaceae) grown in a climate chamber has been carried out using gas chromatography—mass spectrometry (GC-MS). Up to 102 components (including the 41 identified components) have been detected in each metabolic profile. A comparative analysis of metabolomic changes in P. vulgaris ontogenesis has shown that the metabolic profile at the vegetative stage is significantly different from the ones at other stages (due to the absence of such groups of metabolites as amino acids, terpenes, and lipids in vegetative plants). Comparison of the results of statistical processing of the data on all detected metabolites shows that the metabolomes of blooming and fruiting plants often coincide, and only a small number of metabolites are specific to these stages, i.e., that are the quantitative characteristics of the P. vulgaris metabolome at the stages of blooming and fruiting that make it specific. Studies on the spatial structure of the metabolic network have shown heterogeneity of the metabolite distribution at the leaf base, and its middle and apical regions. The comparison of the total metabolite profiles using principal component analysis (PCA) has revealed that the difference between metabolomes of individual leaves in a single plant is much larger than local differences within parts of one leaf blade. Spatial inhomogeneities in metabolite distribution in a lamina have been illustrated on the example of threonic acid.

Hairy roots cultures are being considered as a promising system for producing valuable second metabolites. These genetically transformed root cultures are characterized by high growth rate, genetic stability and growth in hormone free media. Using A. rhizogenes-mediated transformation method (strain А4), we have obtained hairy roots cultures of the ecdysteroid-containing species of Silene linicola. HPLC analysis of the sample studied revealed that 20-hydroxyecdysone (20E), turkesterone and polypodin B were synthesized under the specified experimental conditions. Application of methyl jasmonate at a concentration of 100 μM resulted in stimulation of 20E biosynthesis (up 74%) after three days of cultivation and turkesterone up to 35% at six days. It was noted that total ecdysteroid content in sample tested varied: turkesterone from 25 to 60%, and 20E from 8 to 30%. At the same time, the level of 20E biosynthesis decreased from 0.023 to 0.014% in the samples without methyl jasmonate treatment. Hairy roots lines of S. linicola with different responses to the presence of elicitors in the culture medium can be used to study the pathways of ecdysteroid biosynthesis.

The new isocaryophyllene derivatives: 6-hydroxyisocaryophyllene [(1R,4Z,6R,9S)-8-methylene-11,11-dimethylbicyclo[7.2.0]undec-4-ene-6-ol], epoxide of 6-hydroxyisocaryophyllene [(6R)-hydroxy-(4R,5S)-epoxyisocaryophyllene [(1R,4R,5S,6R,9S)-4.5-epoxy-8-methylene-11,11-dimethylbicyclo[7.2.0]undeco-6-ol], (6R)-acetoxyisocaryophyllene [(6R)-acetoxy-(1R,4Z,9S)-8-methylene-11,11-dimethylbicyclo[7.2.0]undec-4-ene], isocaryphyllenic acid [(1R,4E,9S)4-carboxy-8-methylene-11,11-dimethylbicyclo[7.2.0]undec-4-ene] were first detected in the birch vegetative buds. 6-Hydroxyisocaryophyllene and epoxide of 6-hydroxyisocaryophyllene are isolated by from the Betula pendula Roth. birch buds etheric extract by chromatography on silica gel. (6R)-Acetoxyisocaryophyllene was synthesized. The structure of 6-hydroxyisocaryophyllene and epoxide of 6-hydroxyisocaryophyllene isolated from the buds were determined by NMR spectroscopy. Caryophyllenic acids are isolated from the ether extract with an aqueous solution of alkali. Caryophyllenic acids are separated by chromatography on silica gel. The structures of caryophyllenic acid and isocaryphyllenic acid isolated from the Betula grandifolia Litv., B. albo-sinensis Burk., B. fusca Pall.ex Georg, B. obscura A. Kotula, B. litwinowii Doluch., B. hallii Howell, B. grandifolia Litv. birch buds were determined by X-ray diffraction analysis. The physico-chemical characteristics and NMR data of 6-hydroxyisocaryophyllene, epoxide of 6-hydroxyisocaryophyllene and all the isolated acids are given. The obtained mixtures of compounds were analyzed by gas chromatography–mass spectrometry (GC-MS). The gas chromatographic retention indices of all identified compounds were determined.

The genus Potentilla (Potentilla L.) is a member of the family Rosaceae, widespread in temperate, arctic, and alpine zones of the northern hemisphere. This genus has been known since ancient times for its curative properties. Recent pharmacological studies have confirmed the traditional use of extracts of the Potentilla species against different diseases. The phytochemistry of the members of Potentilla L. remains poorly studied. A biotechnological technique for the production of renewable raw materials has been developed only for Potentilla alba L. The goal of this work is to conduct the phytochemical analysis of biotechnological raw materials of Potentilla alba L. and Potentilla fragarioides L. and to identify the features of the elemental composition and accumulation of biologically active substances in regenerants, compared to the intact plants. The research has led to the development of a biotechnological technique for the production of P. fragarioides phytomass. The intensity and the specificity of accumulation of chemical elements by organs of regenerated plants of P. alba from the nutrient media in tissue culture have been evaluated. The elements of vigorous accumulation (Ca, Mg, Fe, Mn, Zn, Mo, and Cu), as well as the element of strong accumulation, Co, are noted. The features of the elemental composition of P. alba raw materials, depending on the production method, are noted. The quality, the content of water- and alcohol-soluble extractives and of some groups of biologically active substances have been estimated. It is revealed that P. alba and P. fragarioides are concentrators of flavonoids and tannins. At the same time, the indicators of accumulation of biologically active substances in P. fragarioides are higher than those for P. alba, in both conventional and biotechnological plant raw materials.