Valery A. Isidorov

Volatile organic compounds from leaves litter

Qualitative composition of volatile emissions of litter of five species of deciduous trees was investigated by GC-MS. The list of identified substances contains more than 70 organic compounds of various classes. It was established that the composition of components emitted by the litter into the gas phase greatly differs from that of essential oils extracted by hydrodistillation from turned leaves collected from trees during fall. It is suggested that most compounds found in litter emissions are products of vital activity of microorganisms decomposing it. The reported data indicate that after the vegetative period is over the decomposition processes of litter are important seasonal sources of reactive organic compounds under the forest canopy.

GC-MS analysis of compounds extracted from buds of Populus balsamifera and Populus nigra.

Abstract The composition of hexane and ether extracts from buds of two poplar species (Populus balsamifera and P. nigra) was investigated by GC-MS method. In hexane extracts, 54 “neutral” compounds were recorded. The greatest amounts of them are sesquiterpenes and nalkanes. Among 56 components of ether extracts, many aliphatic acids and hydroxyacids were detected. However, the main fraction consists of phenolcarboxylic acids, substituted cinnamic acids, and their esters. It was established that chemotaxonomic differences between Populus balsamifera and P. nigra are observed in the case of both hexane and ether bud extracts.

Gas chromatographic retention indices of biologically and environmentally important organic compounds on capillary columns with low-polar stationary phases.

This work presents linear temperature programmed retention indices on the columns with stationary phases of 5% phenylpolydimethyl silicone of 389 organic compounds, including extractive substances of plant tissues and environmentally important compounds. Certain factors which influence the values and reproducibility of retention indices during gas chromatographic analysis of multicomponent mixtures are discussed.

Rapid GC/MS determination of botanical precursors of Eurasian propolis.

In this work, ether extracts of propolises from 11 countries of Europe and Asia together with extracts of the buds of their principal plant precursors were prepared and investigated by gas chromatography-mass spectrometry. For the first time, chemical compositions of the exudates of aspen, white birch and silver birch buds were determined. Basing on the data on the content of individual components and their groups, the method of rapid examination of plant precursors of propolis was developed. This new method is based on the use of a chromatogram for one extracted ion m/z=219, characteristic for a group of similar substances: phenylpropenoids. The I(T) retention indices of silylated derivatives of 449 substances registered in the buds of 6 species of trees and 37 samples of propolis extracts were calculated. These useful analytical parameters (majority of which are absent in the available databases) are attached in Supplementary information.

HS-SPME/GC–MS analysis of volatile and semi-volatile organic compounds emitted from municipal sewage sludge

The aim of the research involved identification and semi-quantitative determination of unknown volatile and semi-volatile organic compounds emitted to air by sewage sludge formed in the process of municipal wastewater treatment in a sewage treatment plant. Samples taken directly after completion of the technological process as well as the sludge stored on the premise of the sewage treatment plant were analyzed. A simple method using off-line headspace solid-phase microextraction combined with gas chromatography–mass spectrometry has been proposed for extraction and detection of organic pollutants. For reliable identification of compounds, combination of two independent parameters: mass spectra and linear temperature programmed retention indices were employed. Over 170 compounds of different structure were identified including aliphatic and aromatic hydrocarbons, alcohols, esters, carbonyls, as well as sulfur, nitrogen, and chlorine containing compounds. The prevailing substances included: ethyl ether, n-hexane, p-xylene, o-xylene, mesitylene, m-ethylbenzene, limonene, n-decane, n-undecane, and n-dodecane. A few compounds such as methanetiol, dimethyl polisulfide, octaatomic sulfur, phthalic anhydride, and indoles were identified in the sludge for the first time.

Gas chromatographic analysis of essential oil from buds of different birch species with preliminary partition of components

Abstract The results of gas chromatographic analysis of essential oils from the buds of four birch forms growing in Karelia are reported. This includes 61 compounds, some of which have been identified for the first time in these oils. Differences in the composition of sesquiterpenes in the essential oils from B. pubescens and B. pendula were recorded. In the case of B. pendula, compounds of the cadinane and selinane groups are prevalent. In the essential oils from the buds of B. pubescens, compounds of the caryophyllane and humulane groups and the methanoazulene C10H16 hydrocarbon cedrane are the major components. A new algorithm is proposed to increase the reliability of the identification of individual compounds. It is based on the simultaneous use of retention indices and partition coefficients of components in the n-hexane–acetonitrile heterogenic system. In the first stage, the components of the mixture are assigned to certain homologous series and in the second stage they are identified within these series. The advantages and limitations of this algorithm are discussed.

Chemical composition and antimicrobial activity of Polish herbhoneys

The present study focuses on samples of Polish herbhoneys (HHs), their chemical composition and antimicrobial activity. A gas chromatography-mass spectrometry (GC-MS) method was used to analyse eight samples of herbal honeys and three samples of nectar honeys. Their antimicrobial activities were tested on selected Gram-positive (Bacillus cereus, Staphylococcus aureus, Staphylococcus schleiferi) and Gram-negative (Escherichia coli) bacteria, as well as on pathogenic fungi Candida albicans. Ether extracts of HHs showed significant differences in composition but the principal groups found in the extracts were phenolics and aliphatic hydroxy acids typical of royal jelly and unsaturated dicarboxylic acids. In spite of the differences in chemical composition, antimicrobial activity of the extracts of HHs against all the tested microorganisms except E. coli was observed.

Gas chromatographic retention indices of trimethylsilyl derivatives of terpene alcohols

This paper presents the experimentally determined retention indices (RI(TMS)) for a set of 75 silylated terpenols (33 monoterpenols and 42 sesquiterpenols). The attempt was made to assess the dependence of RI(TMS) on RI (for non-silylated terpenols) and on RI(Ac) (for acetylated terpenols). Satisfactory linear regression parameters (RI(TMS)=b(0)+b(1)RI) were observed for tertiary substituted monoterpenols and primary or secondary substituted sesquiterpenols. The mass spectra of silylated terpenols that were not found in the available literature are in Supplementary information.

Chemical profile and antimicrobial activity of extractable compounds of Betula litwinowii (Betulaceae) buds

Abstract In spite of the long history of therapeutic use of buds from different birch species in folk medicine the existing information on their chemical composition is insufficient. The main goal was to develop a method for GC-MS determination of the chemical profile of birch buds as well as their antimicrobial activity. 150 substances of different classes were identified in Betula litwinowii buds. The volatile elements of the buds were mainly represented by sesquiterpene compounds. Ether extracts also contained other biologically active components such as flavonoids and triterpenoids. However, a particular feature of this fraction was the high content of sesquiterpene phenylpropenoids, including esters of ferulic and caffeic acids with caryophyllene-type alcohols that had not been previously found in any biological samples. Apart from carbohydrates, a series of free amino acids were detected in methanol extracts. The antimicrobial activity of the ether extracts of the buds was observed against all of the microorganisms tested, with MIC values from 0.04 to 0.08 mg mL-1 for Gram-positive bacteria and Candida albicans. However, their inhibitory activities against tested Gram-negative bacteria were rather occasional. Graphical Abstract

Gas chromatographic–mass spectrometric investigation of metabolites from the needles and roots of pine seedlings at early stages of pathogenic fungi Armillaria ostoyae attack

An investigation was carried out of the composition of metabolites in pine seedlings tissues at the initial stages of the infectious process caused by pathogenic fungi Armillaria ostoyae, which causes a root rot of trees and degradation of forest resources. With the help of successive extraction with organic solvents of different polarity, more than 190 metabolites were extracted from the needles and roots of the seedlings and then identified by GC–MS method. The composition of the extracts from control plants and those inoculated with Armillaria ostoyae were compared. It was established that part of secondary metabolites (glucosamines and free amino acids, carbohydrates raffinose and trehalose) were present only in the tissues of inoculated plants. Possible roles of some of these compounds appearing in the roots of seedlings infected with the fungus are also discussed in the paper.