Cancer cells perform their malicious activities through own cell membranes that screen and transmit inhibitory and stimulatory signals out of the cells and into them. This work is focused on changes of phospholipids content (PI-phosphatidylinositol, PS-phosphatidylserine, PE-phosphatidylethanolamine, PC-phosphatidylcholine) and electric charge that occur in cell membranes of colorectal cancer of pT 3 stage, various grades (G2, G3) and without/with metastasis. Qualitative and quantitative composition of phospholipids in the membrane was determined by HPLC (high-performance liquid chromatography). The surface charge density of colorectal cancer cell membranes was measured using electrophoresis. The measurements were carried out at various pH of solution. It was shown that the process of cancer transformation was accompanied by an increase in total amount of phospholipids as well as an increase in total positive charge at low pH and total negative charge at high pH. A malignant neoplasm cells with metastases are characterized by a higher PC/PE ratio than malignant neoplasm cells without metastases.

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Chronic exposure of the skin to solar UV radiation induces a number of biological alterations, including a redox imbalance; therefore, there is an urgent need for skin cells protective compounds. The aim of this study was to determine the effects of natural, previously extensively examined, polyphenol with antioxidant properties – rutin, on UV-induced skin fibroblasts membrane disruption. Accordingly, fibroblasts exposed to UVA and UVB irradiation were incubated with rutin (12 h before and/or up to 24 h after irradiation), and the structural and metabolic changes were examined. Rutin penetration through the fibroblast phospholipid bilayer was aided by UVA-induced bilitranslocase activity 2–4 h after irradiation, while UVB irradiation led to enhanced phospholipid peroxidation and higher membrane permeability to facilitate the interaction of rutin with phospholipids. Lipidomic analysis revealed that 4 h of rutin treatment also partially prevented UVA/B-induced increase in phosphatidylethanolamine and phosphatidylcholine level, as well as their membrane localization, which resulted in an enhanced zeta potential in the cells and liposomes. Moreover, rutin 2 h following irradiation, in a various degree, prevented the increased in phospholipase A2 activity and ROS generation, and partially protected against the reduction of arachidonic and linoleic acids level and the lipid peroxidation product 4-hydroxynonenal level increase. Rutin effectively prevented against decrease in glutathione peroxidase, glutathione and vitamins E and C activities/levels, particularly 2 h following UVA irradiation.In conclusion, highest skin fibroblasts membrane level of rutin occurred in 2–4 h following UVA/B-radiation results in its strongest effect on biomembrane structure and functions and cellular antioxidant system irrespective of the radiation type.

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-triO -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. Over the past few years, a significant increase in bacterial resistance to antibiotics and transference of resistance genes from animal to human strains has become a global medical problem. Therefore, constant search for new antimicrobial agents among them being compounds of plant origin, including polyphenols, is ongoing 1,2. In addition to the antibiotic approaches of combating bacteria, anti-virulence strategies have also been considered recently. An anti-virulent strategy assumes a direct effect of compounds on virulent factors by reducing