Novel network polymers possessing cation-exchange properties have been synthesized by the catalytic resol polycondensation of calix[4]resorcinarene derivatives with formaldehyde or with furfural and formaldehyde. The ion-exchange capacities of the polymers with respect to Na+, Me4N+, Et4N+, Bu4N+cations have been determined. It is shown that the potentiometric titration curves of the polymers are similar to the titration curve of the resorcinol-formaldehyde resin, but they are shifted toward lower pH values and have inflections. The formation enthalpies of calix[4]resorcinarene derivatives and their salts with Na+, Me4N+have been calculated by the MNDO/PM3 method. The heat of the reaction simulating the interaction of the polymers with NaOH and Me4NOH has been determined. It is found out that the inflections of the potentiometric titration curves of the cationites appear when appreciable differences in the changes of the enthalpies of modeling reaction stages are observed.

Polyphenols are potential neuroprotectors that increase lifespan and slow down aging. Red clover (Trifolium pratense L.) is a promising source of biologically active substances. Its extracts contain biochanin A and chlorogenic acid. This research used Caenorhabditis elegans to study the effect of polyphenols extracted from red clover callus cultures on SOD-3 and HSP-16.2 genes, as well as their anti-amyloid potential. The chlorogenic acid and biochanin A (200, 100, 50, and 10 µM) with a purity of 95% were isolated from callus extracts of T. pratense L. The effect of polyphenols on SOD-3 and HSP-16.2 was assessed after 5 and 2 h of heat stress (35°C), respectively, using C. elegans N2 Bristol as model organism. The neuroprotective potential was measured by counting paralyzed nematodes after 18, 40, and 62 h of incubation. The research established a dose-dependent effect between the concentration of biologically active substances and the percentage of paralyzed nematodes after 18 h of cultivation. The lowest paralysis phenotype count occurred at a concentration of 200 μM. The activity of 200 μM biochnin A was 1.18 times as high as that of a 200 μM chlorogenic acid solution. Biochanin A solutions increased SOD-3 expression by 3.7 times, compared to the control. The biologically active substances exhibited relative neuroprotective activity and affected the expression of antioxidant defense gene in C. elegans.

The sorption of 2-pyridinecarboxylic, 3-pyridinecarboxylic, and 4-pyridinecarboxylic acids by polystyrene sulfonic acid type cation exchange resin Dowex 50W-X8 and Dowex 50W-X4 from aqueous solutions was studied. Based on the analysis of the FT-IR spectra of acids, sulfates of their protonated forms, and an acid-saturated cation exchange resin, it was shown that pyridinecarboxylic acid is in the protonated form in the cation exchange phase. The equilibrium constants of sorption proceeding with participation of pyridinecarboxylic acid, sulfonic cation exchange resin, and proton were calculated according to experimental data on the equilibrium distribution of acids in the aqueous solution–cation exchange resin system. The values of the equilibrium constant of the cation exchange of the sulfonic ion-exchange resin proton by the pyridinecarboxylic acid cation from solution lie in the range 3.2–4.4. The equilibrium constants of sorption of 2-pyridinecarboxylic acid molecules are 25 dm³ mol^–1, they increase to 195–220 dm³ mol^–1 for 4-pyridinecarboxylic acid, and reach 320–330 dm³ mol^–1 for 3-pyridinecarboxylic acid. Changing the amount of the cross-linking agent (from 4 to 8% divinylbenzene) in the polystyrene sulfonic acid type cation exchange resin does not significantly affect its sorption activity toward pyridinecarboxylic acids.