Characteristics of Escherichia coli Lipopolysaccharide Isolated from Hypericum perforatum

Abstract

Wild herbaceous plants are a valuable natural resource, which are a source of plant food and medicinal raw materials and play an important role in the functioning of natural ecosystems. They produce a variety of biologically active compounds of various orientations. The growth conditions of medicinal plants affect their microbiological purity, the activity of biological compounds that they synthesize, as well as the suitability of these plants for further use. In particular, dry medicinal herbs may contain various microorganisms. The aim of this work was to investigate the composition of the microbiota of these plants and to investigate the properties of lipopolysaccharide (LPS) isolated from one of the strains of Escherichia coli isolated from Hypericum. Methods. For the research, the plants of hypericum (Hypericum perforatum L.), meadow clover (Trifolium pratense L.), plantain (Plantago major L.), dandelion (Taraxacum officinale Wigg.), and wild chicory (Cichorium intybus L.), which are used in official medicine to obtain herbal medicines, were taken. The analysis of plant contamination with microorganisms was carried out by inoculating them on commonly used MPA and selective nutrient media: Scharlau CETRIMIDE AGAR (A), (Solid medium for the isolation of Pseudomonas aeruginosa), Scharlau MacCONKEY AGAR (B), and Scharlau XLD Agar (C) (for the isolation of E. coli). LPS from one of the Escherichia coli strains isolated from hypericum was obtained by the water-phenol method; the monosaccharide and fatty acid composition was identified on an Agilent 6890N/5973 chromatographic-mass spectrometric system, and heterogeneity was determined by SDS-PAAG electrophoresis. Results. As a result of analysis of the microbiota that grew on selective nutrient media after inoculation of plant material on them, 35 isolates of microorganisms, representatives of Pseudomonas aeruginosa and Escherichia coli, were isolated. They were isolated from plant material, regardless of where the plants were collected -- near the Zhuliany airfield, Nizhyn, or from the pharmacy network. In the LPS of E. coli 43, isolated from hypericum, which grew near the Zhuliany airfield, the dominant monosaccharides were galactose (36.64%), mannose (30.62%), and glucose (24.13%). Only three fatty acids, 3-hydroxytetradecanoic (44.8%), tetradecanoic (32.6%), and dodecanoic (22.6%), were identified in its composition. The studied LPS turned out to be toxic, like the LPS of previously studied representatives of E. coli, but apyrogenic. This distinguishes it from the LPS of other E. coli representatives, which exhibit high pyrogenicity. It can be assumed that this is due to the fact that it is isolated from plants, in particular, hypericum. LPS is heterogeneous, which is manifested in its formation of a classic profile in the form of a ladder on electrophoresis. Conclusions. Medicinal herbs collected from different ecological niches: the pharmacy network, near the Zhulyany or Nizhyn airfields, are contaminated to varying degrees with representatives of P. aeruginosa and E. coli. E. coli LPS isolated from hypericum differed in biochemical characteristics and biological activity from LPS isolated from other sources. Most likely, these differences are due to the peculiarities of each strain studied.