Synthesis and immunomodulating activity of new glycopeptides of glycyrrhizic acid containing residues of L-glutamic acid

New glycopeptides of glycyrrhizic acid (GA) containing Glu residues and their alpha-methyl esters, gamma-methyl esters, and alpha,gamma-dimethyl esters were synthesized using N,N'-dicyclohexylcarbodiimide in the presence of N-hydroxybenzotriazole or N-hydroxysuccinimide. Formation of amide bonds was observed on all the three COOH groups of GA, or selectively on the COOH groups of the GA carbohydrate part in dependence on the ratio of reagents and the reaction conditions. The GA glycopeptide with three residues of Glu(OH)-OMe at a dose of 2 mg/kg stimulated the production of antibody-forming cells in mouse spleen in comparison with the control. The GA glycopeptide containing Glu residues only in the GA carbohydrate part turned out to be an immunosuppressor. The glycopeptide of the 30-methyl ester of GA with residues of free Glu in its carbohydrate part increased the hemagglutinine titer at oral doses of 2 and 10 mg/kg. All the studied compounds had practically no effect on the delayed-type hypersensitivity in mice.     

Animal in vivo model of arrhythmia for genes target identification for 5-amino-exo-3-azatricyclo[5.2.1.0(2,6)]decan-4-one

The goal of the current work is to study the molecular mechanisms underlay the action of 5- amino-exo-3-azatricyclo[5.2.1.0(2,6)]decan-4-one (P-11) with combined antiarrhythmic, nootropic, anti-inflammatory and anaesthetic activities. The aconitine-induced experimental rat model of cardiac arrhythmia has been used in our study. Aconitine was administered once intravenously in a dose 50 microg/kg whereas experimental animal group received P-11 in a dose 0.3 mg/kg (the compound was injected intravenously 2 min before acute aconitine treatment). Expression macroarray (Atlas Rat cDNA Expression Array, #7738-1; BD Biosciences) was used to identify the target genes for P-11 compound. Comparative analysis of changes in the status of expression of genes in the heart of rats induced by P-11 against the simulated in vivo arrhythmia identified 16 genes that reproducibly alter the level of expression.These genes encode the extracellular matrix proteins (glypican 1, Gpc1; tissue inhibitor of metalloproteinase 2, 3, Timp2, Timp 3); intracellular signaling molecules (rho GTPase activating protein 7, Dlc1; protein tyrosine phosphatase 4a1, Ptp4a1; phosphodiesterase 4D, PDE4D; PI3-kinase regulatory subunit alpha, PIK3R1; guanine nucleotide binding protein alpha 12, Gna12) and protein of intermediate junctions (junction plakoglobin, Jup), proteins involved in glycolysis (phosphofructokinase I, Pfk1) and hemostasis (tissue plasminogen activator, Plat), plasma membrane transporters (Solute carrier family 16, member 1, Slc16a1; ATPase, Na+/K+ transporting, Atp1a), and ets. (c-fos protooncogene, c-fos; telomerase protein component 1, tlp; Annexin 1, anxa 1). Thus, the data about the selective effect of P-11 on genes whose products are involved in the aritmogenesys mechanisms, allow us to consider this compound as a promising means of pathogenetically oriented pharmacotherapy of cardiac arrhythmias.     

Transformation of glycyrrhizic acid. Synthesis of glycopeptides of glycyrrhizic acid monomethyl ether, having anti-inflammatory and immunostimulating action

Three triterpene glycopeptides, glycyrrhizic acid monomethly ester derivatives containing peptide fragment of N-acetylmuramoyldipeptide and its analogues, are synthesized. They possess high prednizolone-like antiinflammatory activity and display pronounced stimulative effect on humoral factors of immunity.     

Genes targets identification of 5-amino-<Emphasis Type="Italic">exo</Emphasis>-3-azatricyclo[5.2.1.0<Superscript>2,6</Superscript>]decane-4-one in an in vivo model of arrhythmia

The molecular mechanisms of action of 5-amino-exo-3-azatricyclo[5.2.1.0^2,6]decane-4-one (P11), a compound possessing strong antiarrhythmic, nootropic, anti-inflammatory and analgesic activity, have been studied. Cardiac rhythm disturbances were modeled by administering the arrhythmogenic compound aconitin in a dose of 50 μg/kg to the animals from the control group. P-11 in a dose of 0.3 mg/kg was injected intravenously in the experimental group of animals 2 min before aconitin administration. P-11 target genes were identified using the Atlas™ Rat cDNA Expression macroarray (#7738-1, BD Biosciences, United States). Reproducible changes in the expression levels of 16 genes in the heart of rats treated with P-11 concommitantly to arrhythmia modeling in vivo were detected. The genes regulated by the substance coded for proteins of the extracellular matrix are (glypican 1, Gpc1; tissue inhibitor of metalloproteinase 2, 3, Timp2, Timp3), intracellular signaling proteins (rho GTPase activating protein 7, Dlc1; protein tyrosine phosphatase 4a1, Ptp4a1; phosphodiesterase 4D, PDE4D; PI3-kinase regulatory subunit alpha, PIK3R1; guanine nucleotide binding protein alpha 12, Gna12), proteins involved in glycolysis (phosphofructokinase 1, Pfk1), intercellular interactions (junction plakoglobin, Jup), and hemostasis (tissue plasminogen activator, Plat), membranebound pumps and transporters (solute carrier family 16, member 1, Slc16a1; ATPase, Na⁺/K⁺ transporting, Atp1a), and others (c-fos proto-oncogene, c-fos; telomerase protein component 1, tlp; Annexin 1, anxa1). Therefore, the data concerning the selective effect of P-11 on genes coding for proteins involved in arrhythmogenesis allow for considering this compound as a promising medication for pathogenetically oriented therapy of arrhythmias.     

Synthesis and immunomodulating activity of new diglycopeptides of of glycyrrhizinic acid and it's 30-methyl ester

New amino acid derivatives of glycyrrhizic acid and its methyl ester were selectively synthesized using active N-succinimide esters. The compounds with residues of glycine ethyl ester and alanine methyl and butyl esters increased the level of agglutinins and hemolysins in blood serum of mice two- to threefold in comparison with the control upon parenteral administration at a dose of 2 mg/kg for 14 days. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2004, vol. 30, no. 2; see also http://www.maik.ru.     

Synthesis and Immunomodulating Activity of New Amino Acid Derivatives of Glycyrrhizic Acid and Its Methyl Ester

New amino acid derivatives of glycyrrhizic acid and its methyl ester were selectively synthesized using active N-succinimide esters. The compounds with residues of glycine ethyl ester and alanine methyl and butyl esters increased the level of agglutinins and hemolysins in blood serum of mice two- to threefold in comparison with the control upon parenteral administration at a dose of 2 mg/kg for 14 days.     

Synthesis and immunomodulating activity of new glycopeptides of glycyrrhizic acid containing residues of L-glutamic acid

New glycopeptides of glycyrrhizic acid (GA) containing Glu residues and their α-methyl esters, γ-methyl esters, and α,γ-dimethyl esters were synthesized using N,N′-dicyclohexylcarbodiimide in the presence of N-hydroxybenzotriazole or N-hydroxysuccinimide. Formation of amide bonds was observed on all the three COOH groups of GA, or selectively on the COOH groups of the GA carbohydrate part in dependence on the ratio of reagents and the reaction conditions. The GA glycopeptide with three residues of Glu(OH)-OMe at a dose of 2 mg/kg stimulated the production of antibody-forming cells in mouse spleen in comparison with the control. The GA glycopeptide containing Glu residues only in the GA carbohydrate part turned out to be an immunosuppressor. The glycopeptide of the 30-methyl ester of GA with residues of free Glu in its carbohydrate part increased the hemagglutinine titer at oral doses of 2 and 10 mg/kg. All the studied compounds had practically no effect on the delayed-type hypersensitivity in mice.     

Synthesis and biological activity of new glycyrrhizic acid conjugates with amino acids and dipeptides

New glycyrrhizic acid (GA) conjugates were synthesized with the use of tert-butyl esters of amino acids or benzyl esters of dipeptides; they contained two residues of L-amino acids (Met, Phe, Pro, and Ile or dipeptides Gly-Leu and Gly-Phe). Activation of GA carboxy groups was carried out with the help of N-hydroxysuccinimide, N,N′-dicyclohexylcarbodiimide, or N-hydroxybenzotriazole with dicyclohexylcarbodiimide. A proline-containing GA derivative is a low-toxic substance; it raises the level of agglutinins by 3.7 times in the blood of mice and 3 times that of hemolysins compared with the control. Dipeptide GA derivatives possess an expressed anti-HIV-1 activity in cultures of MT-4 cells and are 90-70 times less cytotoxic than azidothymidine. The selectivity index of the compounds exceeds those of GA by 110 and 34 times, respectively.     

Biological properties of immunochemically pure tetanus antitoxin

Immunochemically pure tetanus antitoxin obtained from enzyme-treated horse serum is less reactogenic and anaphylactogenic and possesses higher therapeutic properties than antitoxin purified by nonspecific physico-chemical methods and containing ballast antigens. Due to its increased persistence in the recipient's body, the immunochemically pure antitoxin induces passive immunity in considerably lower doses than the preparations purified by the method "Diaferm-3".     

Synthesis and immunostimulating activity of cysteine-containing glycopeptide derivatives of glycyrrhizic acid

New cysteine-containing derivatives of glycyrrhizic acid were synthesized by its coupling with Cys(Bzl) esters or the Cys(Bzl)-Val-OBu(t) dipeptide by the active ester method (DCC/HOSu) or by Woodward's reagent K. The derivatives with Cys(Bzl) and Cys(Bzl)-Val residues attached to the carbohydrate part of the molecule stimulated the primary immune response and the reaction of delayed-type hypersensitivity in mice at a dose of 2 mg/kg. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2004, vol. 30, no. 1; see also http://www.maik.ru.