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The volume-sensitive outwardly rectifying anion channel (VSOR) is a key component of volume regulation system critical for cell survival in non-isosmotic conditions. The aim of the present study was to test the effects of four tannin extracts with defined compositions on cell volume regulation and VSOR. Preparation I (98% of hydrolysable tannins isolated from leaves of sumac Rhus typhina L.) and Preparation II (100% of hydrolysable tannins isolated from leaves of broadleaf plantain Plantago major L) completely and irreversibly abolished swelling-activated VSOR currents in HCT116 cells. Both preparations profoundly suppressed the volume regulation in thymocytes with half-maximal effects of 40.9 μg/ml and 12.3 μg/ml, respectively. The inhibition was more efficient at lower concentrations but reverted at higher doses due to possible non-specific membrane-permeabilizing activity. Preparations III and IV (54,7% and 54.3% of hydrolysable tannins isolated, respectively, from roots and aboveground parts of Fergana spurge Euphorbia ferganensis B.Fedtch) inhibited VSOR activity in a partially reversible manner and suppressed the volume regulation with substantially higher half-maximal doses of 270 and 278 μg/ml, respectively, with no secondary reversion at higher doses. Hydrolysable tannins represent a novel class of VSOR channel inhibitors with the capacity to suppress the cell volume regulation machinery.

Among the natural compounds representing medicinal benefits significant place belong to plant phenolics. A wide range of biological action and low toxicity allows include them in a number of promising medicinal formulations in this regard. Therefore, the search for plants containing phenolics, the development of methods for their isolation, the determination of their chemical structure, and the study of biological activity is an actual problem in bioorganic chemistry. In this regard, the aimof our study is study the chemical composition of the polyphenols of the Rhus glabra(Smooth sumac) plant, in order to search for new sources of raw materials rich in biological active compounds growing on the territory of the Republic of Uzbekistan. The leaves of R.glabra were collected at the end of the vegetative period, air dried in the shade. 70% aqueous acetone used for full extraction of phenolics, afterevaporation of acetone under vacuum, the aqueous residue sequentially partitioned with chloroform and ethyl acetate. Ethyl acetate fraction, containing main amount of phenolics (controlled by Folin-Ciocalteu's reagent) vacuum concentrated as far as possible and pool of phenol compounds precipitated by adding of chloroform. The yield of total phenolics was 12% of the air-dry weight of the raw material. Qualitative reactions and TLC methods revealed the presence of flavonols, phenolic acids and tannins in the composition of the total polyphenols. RP-HPLC with corresponding standards and LCMS/MS shown, that the main constituent of prepared phenolic fraction there was a group of the hydrolysable tannins - poly galloyl glucose. In Table below listed the identified compounds. [ABSTRACT FROM AUTHOR]

Nitraria sibirica Pall is a traditional Chinese medicine (TCM) and rich in polysaccharides. The Xinjiang district of China is rich in Nitraria sibirica resources. Numerous preparations containing Nitraria sibirica have been used to treat various diseases in TCM. However, the relevant studies lack systematicness in both chemistryand pharmacodynamics, and the effective substances are still not clear. They are facing the crisis of "insufficient scientific interpretation of drug theory" and "unclear sourceof medicinal materials", which leads to the lack of scientific methods and indicators for the quality control of Nitraria sibirica or its preparations. Therefore, it is essential to systematically study genuine medicinal materials to solve the problems such as the confusion of medicinal materials, the lack of related literature, andtheoretical basis. In this paper, the isolation and bioactivity evaluation of polysaccharides from the Nitraria sibirica medicinal material was systematically discussed, which laid an important basis for elucidating the theoretical basis of its medicinal substances. The main findings are as follows: The ultrasonic-assisted extraction of Nitraria sibirica polysaccharides (NSP) was optimized by response surface methodology. The results showed that the optimum conditions were liquidsolid ratio 33 mL/g, ultrasonic power 430 W, ultrasonic temperature 60 ℃ and ultrasonic time 70 min. At this condition, the yield of NSP wasup to 14.63 ± 0.21%. Four homogenous polysaccharides, namely NSP-a, NSP-b1, NSPb2, and NSP-c, were obtained through purifying by AB-8 macroporous resin, dialysis, DEAE-650M anion exchange, and Sephadex G-150 gel permeation chromatography. Among them, NSP-a was a neutral polysaccharide, and acidic polysaccharides for the others, with the purity 91.12 ± 1.15%, 94.02 ± 2.18%, 95.71 ± 2.56%, 94.30 ± 0.87%, respectively. [ABSTRACT FROM AUTHOR]

The non-polar compounds are very important organic molecules that play a key role in the manufacture of various drugs, membranes, mechanical oils, dyes, and some important fine chemicals. The production of non-polar compounds by microbial fermentation is convenient and fast. This paper presents the obtained experimental data on the study of the non-polar components isolated from the culture filtrate of the endophytic fungus Ovatospora senegalensis isolated from the flowers of the plant Vernonia anthelmintica, used in traditional Chinese and Uyghur medicine. The supernatant of the endophytic fungus O. senegalensis was extracted with petroleum ether, dichloromethane and ethyl acetate, successively. The non-polar components of these extracts were analyzed by GC-MS. The GC-MS analysis of the petroleum ether, dichloromethane and ethyl acetate extracts detected 36 compounds in comparison with the NIST library based on the peak area (%), molecular weight, retention time, and CAS number. The identified compounds appeared to belong to different chemical classes including tert-butyl phenol compounds, fatty acid methyl esters, hydrocarbons, aldehydes, benzoquinones, pyrroles, and terpenes. The highest number of compounds were identified from the ethyl acetate extract (15 compounds). In the petroleum ether extract, 13 compounds were identified, whereas the dichloromethane extract showed 8 compounds. Major components of these extracts are 9-octadecenoic acid (Z)-methyl ester (8.0%), 1,4-benzenedicarboxylic acid, dimethyl ester (72.9%), cholesterol (30.7%), phenylethyl alcohol (16.6%), dibutyl phthalate (26.3%), diisooctyl phthalate (27.9%), benzenepropanoic acid, 3,5-bis (1.1-dimethylethyl)-4-hydroxy-, octadecyl ester (5.2%), 1 2-bis(trimethylsilyl)benzene (13.3%). It should be noted that 1,4-benzenedicarboxylic acid, dimethyl ester was the main compound in almost all extracts. ACKNOWLEDGMENT This work was supported by the West Light Foundation of the Chinese Academy of Science (2021-XBQNXZ-026), the Central Aisan Drug Discovery and Development Center of Chinese Academy of Sciences (CAM202101), Xinjiang Uygur Autonomous Region Tianshan Yingcai-Leading Talents in Scientific and Technological Innovation (2022TSYCLJ0008), Xinjiang Uygur Autonomous Region Tianshan Cedar Plan - Science and Technology Innovation Leaders Reserve Candidate Program (2020XS08), and the Chinese Academy of Sciences president's international fellowship initiative (2022VBA0015). [ABSTRACT FROM AUTHOR]

Dental caries (DC) is the most common oral pathology. The main bacteria responsible for DC is Streptococcus mutans . One of the strategies that can decrease or eliminate the risk of DC development is using compounds that will inhibit both the growth and virulence factors of S. mutans . Tannins are plant polyphenols that have strong antibacterial activity. The purpose of this study was to assess the antibacterial activity of three tannins against S. mutans. In this investigation, microbiological tests (MIC and MBC) and physicochemical techniques like the fluorescence measurements of tannins' interaction with S. mutans cell membrane and membrane proteins, zeta potential, and thermodynamic analyses were used to obtain knowledge about the antibacterial potential of the investigated compounds against S. mutans as well as about the mechanisms associated with antibacterial activity. The obtained results demonstrate that the used compounds exhibit high antibacterial activity against S. mutans . The mechanisms of their antibacterial activity are linked to the strong change in the S. mutans membrane fluidity and potential, and to their interaction with membrane proteins that can result in great disturbance of bacterial physiology and ultimately the inhibition of bacterial growth, triggering their death. Therefore, it can be concluded that the investigated compounds can be potentially used as natural factors in the prevention of dental caries.

Tannins are natural plant origin polyphenols that are promising compounds for pharmacological applications due to their strong and different biological activities, including antibacterial activity. Our previous studies demonstrated that sumac tannin, i.e., 3,6-bis-O-di-O-galloyl-1,2,4-tri-O-galloyl-β-D-glucose (isolated from Rhus typhina L.), possesses strong antibacterial activity against different bacterial strains. One of the crucial factors of the pharmacological activity of tannins is their ability to interact with biomembranes, which may result in the penetration of these compounds into cells or the realization of their activity on the surface. The aim of the current work was to study the interactions of sumac tannin with liposomes as a simple model of the cellular membrane, which is widely used in studies focused on the explanation of the physicochemical nature of molecule-membrane interactions. Additionally, these lipid nanovesicles are very often investigated as nanocarriers for different types of biologically active molecules, such as antibiotics. In the frame of our study, using differential scanning calorimetry, zeta-potential, and fluorescence analysis, we have shown that 3,6-bis-O-di-O-galloyl-1,2,4-tri-O-galloyl-β-D-glucose interacts strongly with liposomes and can be encapsulated inside them. A formulated sumac-liposome hybrid nanocomplex demonstrated much stronger antibacterial activity in comparison with pure tannin. Overall, by using the high affinity of sumac tannin to liposomes, new, functional nanobiomaterials with strong antibacterial activity against Gram-positive strains, such as S. aureus , S. epidermitis, and B. cereus , can be formulated.

In this study, using bilayer lipid membrane technique, we report a novel facet of antihemolytic activity of two tannins (1,2,3,4,5-penta-O-galloyl-β-D-glucose (PGG) and 1,2-di-O-galloyl-4,6-valoneoyl-β-D-glucose (dGVG)), which consists in inhibiting the formation of α-hemolysin channels and blocking the conductivity of already formed channels. These effects were observed at tannin concentrations well below minimal inhibitory concentration values for S. aureus growth. Using spectroscopic methods, we show that these two tannins differing in molecular structure but having the same number of -OH groups and aromatic rings form firm complexes with hemolysin in aqueous solutions, which may underlie the disruption of its subsequent interaction with the membrane, thus preventing hemolysis of erythrocytes. In all experimental settings, PGG was the more active compound compared to dGVG, that indicates the important role of the flexibility of the tannin molecule in interaction with the toxin. In addition, we found that PGG, but not dGVG, was able to block the release of the toxin by bacterial cells. This toxin is a strong pathogenic factor causing a number of diseases and therefore is considered as a virulence target for treatment of S. aureus infection, so the data obtained suggest that PGG and possibly other tannins of similar structure have therapeutic potential in fighting the virulence of S. aureus., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

It is well known that accumulation of advanced glycation ends products (AGEs) lead to various diseases such as diabetes and diabetic complications. In this study we showed that hydrolysable tannin from Sumac (Rhus typhina L.)-3,6-bis-O-di-O-galloyl-1,2,4-tri-O-galloyl-β-D-glucose (C 55 H 40 O 34 ) inhibited generation of glycation markers in bovine serum albumin such as AGEs, dityrosine, N'-formylkynurenine and kynurenine under high glucose treatment. This effect was accompanied by stabilization of the protein structure, as was shown using ATR-FT-IR spectroscopy and fluorescence methods. C 55 H 40 O 34 exhibited also a neuroprotective effect in high glucose-exposed Neuro2A cells suppressing ROS formation and expression of phospho NF-κβ and iNOS. At the same time C 55 H 40 O 34 increased expression of heme oxygenase-1 and NAD(P)H: quinone oxidoreductase and mitochondrial complex I and V activities. Results from this study demonstrates a potent antiglycation activity of C 55 H 40 O 34 in vitro and indicates its possible therapeutic application in glycation related diseases., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Polyphenols, including tannins, are phytochemicals with pronounced antimicrobial properties. We studied the activity of two hydrolysable tannins, (i) gallotannin-1,2,3,4,5-penta-O-galloyl-β-D-glucose (PGG) and (ii) ellagitannin-1,2-di-O-galloyl-4,6-valoneoyl-β-D-glucose (dGVG), applied alone and in combination with antibiotics against Staphylococcus aureus strain 8324-4. We also evaluated the effect of these tannins on bacterial membrane integrity and fluidity and studied their interaction with membrane proteins and lipids. A correlation between the antimicrobial activity of the tannins and their membranotropic action depending on the tannin molecular structure has been demonstrated. We found that the antibacterial activity of PGG was stronger than dGVG, which can be associated with its larger flexibility, dipole moment, and hydrophobicity. In addition, we also noted the membrane effects of the tannins observed as an increase in the size of released bacterial membrane vesicles.

Tannins belong to plant secondary metabolites exhibiting a wide range of biological activity. One of the important aspects of the realization of the biological effects of tannins is the interaction with lipids of cell membranes. In this work we studied the interaction of two hydrolysable tannins: 1,2,3,4,6-penta-O-galloyl-β-d-glucose (PGG) and 1,2-di-O-galloyl-4,6-valoneoyl-β-d-glucose (T1) which had the same number of both aromatic rings (5) and hydroxyl groups (15) but differing in flexibility due to the presence of valoneoyl group in the T1 molecule with DMPC (dimyristoylphosphatidylcholine) lipid nano-vesicles (liposomes). Tannins-liposomes interactions were investigated using fluorescence spectroscopy, differential scanning calorimetry, laser Doppler velocimetry, dynamic light scattering and Fourier Transform Infra-Red spectroscopy. It was shown that more flexible PGG molecules stronger decreased the microviscosity of the liposomal membranes and increased the values of negative zeta potential in comparison with the more rigid T1. Both compounds diminished the phase transition temperature of DMPC membranes, interacted with liposomes via PO groups of head of phospholipids and their hydrophobic regions. These tannins neutralized DPPH free radicals with the stoichiometry of the reaction equal 1:1. The effects of the studied compounds on liposomes were discussed in relation to tannin quantum chemical parameters calculated by molecular modeling., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Tannins belong to secondary metabolites of plants that exhibit a variety of biological activities, including antiviral one. In this research, we studied the interaction of human serum albumin (HSA) with two ellagitannins: 2,4-valoneoyl-3,6-hexahydroxydiphenoyl-β-d-glucose (T1) and 1,2-di-O-galloyl-3,6-valoneoyl-β-d-glucose (T2) from Euphorbia species having antiviral potential against HIV and differing in molecular flexibility due to the presence of valoneoyl- and hexahydroxydiphenoyl groups. A fluorescence analysis demonstrated that the tannins studied strongly interacted with HSA and quenched tryptophan (Trp) fluorescence in the range of 0.25-4 μM. The quenching occurred by a static mechanism. The logK b for more flexible T2 was generally higher in comparison with stiffer T1 (4.94 ± 0.82 vs. 4.12 ± 0.31 and 4.94 ± 0.53 vs. 4.07 ± 0.45 for 296 K and 303 K respectively). The difference was also in the nature of the forces participating in the interaction with HSA. The stiff T1 reacted with HSA via hydrophobic forces, whereas the flexible T2 interacted with the protein by van der Waals forces and hydrogen bonds. The nature of the bonds was also confirmed by a study of the hydrophobicity of the compounds. Zeta-potential measurements showed slightly modifications of albumin electric charge but without significant changes in the surface structure of protein. Surface Plasmon Resonance imaging (SPRi) revealed that the used tannins fully saturated a 3 ng/mL solution of albumin at the concentrations of above 15 ng/mL. Our experiments clearly showed that the tannins used formed complexes with HSA and that the flexibility of the tannins was an important factor determining their interaction with the protein., Competing Interests: Declaration of Competing Interest Authors declare no ethical, financial or other conflict of interests., (Copyright © 2020 Elsevier B.V. All rights reserved.)

The objective of the study was a comparative analysis of the antihemolytic activity against two Staphylococcus aureus strains (8325-4 and NCTC 5655) as well as α-hemolysin and of the membrane modifying action of four hydrolysable tannins with different molecular mass and flexibility: 3,6-bis-O-di-O-galloyl-1,2,4-tri-O-galloyl-β-D-glucose (T1), 1,2,3,4,5-penta-O-galloyl-β-D-glucose (T2), 3-O-galloyl-1,2-valoneoyl-β-D-glucose (T3) and 1,2-di-O-galloyl-4,6-valoneoyl-β-D-glucose (T4). We showed that all the compounds studied manifested antihemolytic effects in the range of 5-50 µM concentrations. However, the degree of the reduction of hemolysis by the investigated tannins was not uniform. A valoneoyl group-containing compounds (T3 and T4) were less active. Inhibition of the hemolysis induced by α-hemolysin was also noticed on preincubated with the tannins and subsequently washed erythrocytes. In this case the efficiency again depended on the tannin structure and could be represented by the following order: T1 > T2 > T4 > T3. We also found a relationship between the degree of antihemolytic activity of the tannins studied and their capacity to increase the ordering parameter of the erythrocyte membrane outer layer and to change zeta potential. Overall, our study showed a potential of the T1 and T2 tannins as anti-virulence agents. The results of this study using tannins with different combinations of molecular mass and flexibility shed additional light on the role of tannin structure in activity manifestation.

The etiology of Parkinson's disease (PD) relates to α-synuclein, a small protein with the ability to aggregate and form Lewy bodies. One of its prevention strategies is inhibition of α-synuclein oligomerization. We have investigated the interaction of α-synuclein and human serum albumin with 3,6-bis-О-di-О-galloyl-1,2,4-tri-О-galloyl-β-d-glucose (a tannin isolated from the plant Rhus typhina). Using fluorescence spectroscopy method we found that this tannin interacts strongly with α-synuclein forming complexes. Circular dichroism analysis showed a time-dependent inhibition of α-synuclein aggregation in the presence of the tannin. On the other hand, 3,6-bis-О-di-О-galloyl-1,2,4-tri-О-galloyl-β-d-glucose had a much stronger interaction with human serum albumin than α-synuclein. The calculated binding constant for tannin-protein interaction was considerably higher for albumin than α-synuclein. This tannin interacted with albumin through a "sphere of action" mechanism. The results lead to the conclusion that 3,6-bis-О-di-О-galloyl-1,2,4-tri-О-galloyl-β-d-glucose is a potent preventive compound against Parkinson's disease. However, this tannin interacts very strongly with human serum albumin, significantly reducing the bioavailability of this compound., (Copyright © 2017 Elsevier B.V. All rights reserved.)