H. Ya. Hachkova’s research while affiliated with Lviv University and other places

Background. Diabetes mellitus intensifies non-enzymatic glycosylation (glycation) of biomolecules under conditions of chronic hyperglycemia and facilitates accumulation of advanced glycation end products. Disorders of the cells of various tissues are caused by binding of advanced glycation end products to the corresponding receptors, the level of receptors for advanced glycation end products increases under conditions of hyperglycemia. The interaction between receptors for advanced glycation end products and advanced glycation end products leads to the formation of excessive reactive oxygen species, changes in intracellular signaling, gene expression, increased secretion of pro-inflammatory cytokines and contributes to the development of diabetic complications. The search for factors of natural origin that will slow down the development of specific complications of diabetes, determines the feasibility of studies of the corrective ability of biologically active substances isolated from medicinal plants for the process of glycation of proteins in diabetes. Materials and methods. Experimental diabetes mellitus was induced by intraperitoneal administration of streptozotocin. Separation of blood leukocytes was performed in Ficoll density gradient. To determine the extent of advanced glycation end products and receptor for advanced glycation end products in leukocyte immunoperoxidase labeling was performed. Results. A decrease in the content of advanced glycation end products in leukocy­tes under conditions of experimental diabetes mellitus was found. The obtained data indicate a possible contravention of glucose uptake by leukocytes in the studied pathology. At the same time, an increase in exposure to the receptor for advanced glycation end products leukocyte membranes in response to chronic hyperglycemia has been demonstrated. The ability of alkaloid free fraction of Galega officinalis extract to reduce the content of receptors for end products of glycation on the membranes of immunocompetent cells in diabetic animals has been confirmed, which may be due to the presence of biologically active substances with hypoglycemic action in its composition. Conclusion. Corrective effect of alkaloid free fraction of Galega officinalis L. extract on the content of receptor for advanced glycation end products in diabetes mellitus is mediated by its normalizing effect on carbohydrate metabolism.

The article describes the effect of alkaloid-free fraction of the Galega officinalis extract (AFFGE) on the aggregation ability of immunocompetent blood cells, as well as on the process of actin polymerization and structural rearrangements among sialylated glycoconjugates of the peripheral blood leukocyte membranes of rats in the norm and under experimental diabetes mellitus (EDM) conditions. The flow cytometry method (using phalloidin labelled with fluorescent tetramethyl rhodamine-5-isothiocyanate (TRITC)) and the western blot analysis have allowed us to detect an increase in the rat leukocyte F-actin content in the event of diabetes mellitus, which indicated changes in the structural and functional properties of the leukocytes and their preactivation phase. A quantitative analysis of the total polymerized actin pool redistribution between its constituent fraction (represented by cytoskeletal filaments) and short actin filaments has shown that, against an increase in the total F-actin level, the number of actin filaments of the cytoskeleton decreased and the content of short actin filaments increased in leukocytes of animals with EDM. The use of sialylated lectins has allowed a conclusion to be made on the study of the pathology that the number of exposed oligosaccharide determinants on leukocyte membrane, the structure of which contained N-acetyl-β-D-glucosamine and sialic acid residues, increased, whereas the number of sialic acid-containing surface glycoconjugates bound to subterminal galactose residues by α2→3 and α2→6-glycoside bonds decreased. The administration of AFFGE to diabetic animals led to an increase in the content of F-actin and short filaments of the leukocyte cytoskeleton and a reduction in the lectin-induced leukocyte aggregation. The correction effect of the studied extract on the functional state of leukocytes can be realized through the action on the processes underlying the formation of the actin cytoskeletal elements and due to the quantitative redistribution of leukocyte membrane glycoconjugates with different structures of carbohydrate determinants, such as, due to a decrease in the exposure of N-acetyl-β-D-glucosamine residues and an increase in the exposure of sialic acids bound to subterminal galactose residues by α2→3 and α2→6-glycoside bonds.

Methods of obtaining a stable substance for functional foods with antioxidant and hypoglycemic action based on powder root tubers of yacon’ are proposed. The aim of the study was to develop a substance stabilizing method which can be the basis for functional food, using yacons root tubers and investigate the changes of hypoglycemic effect of yacons’ root tubers water suspensions after stabilization with PS biocomplex under experimental model of diabetes. Stabilized basis for functional food product were received in several ways: by adding to control suspension a surface-active PS biocomplex in concentrations of 0.00001 g/ml, 0.00002 g/ml, 0.00003 g/ml per 1 ml suspension and by using yacons root tubers powder that were pre-mixed with PS biocomplex in the concentration of 0.00001 g/ml of water. It was shown that both methods of obtaining stable substances for functional foods ensure getting the aggregation stable suspensions. Application method of PS biocomplex do not particularly affect a stability of the studied substances, but preliminary addition of PS biocomplex to the powder is convenient for development of biological preparations encapsulated forms manufacturing technology. Addition of PS biocomplex to the suspension of yacons’ root tubers allows increasing the accuracy of substance dosing and increasing bioavailability of bioactive substances, that was indicated by more severe hypoglycemic effect of a suspension stabilized form.

Article contain the results of the yacons leaves and root tubers water extracts and suspensions of yacons root tubers effect on glucose tolerance in animals with experimental diabetes mellitus (EDM). It was shown that the studied yacons extracts and suspensions at a 500 mg / kg dose has significant hypoglycemic effect under the experimental diabetes mellitus. Glucose tolerance test and analysis of the area under the glycemic curves revealed that the best hypoglycemic effect possess yacons root tubers in the form of a stabilized suspension.