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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.

The reduction of glycyrrhizic acid by NaBH 4 and LiAIH 4 was studied. The conditions for the selective reduction of the COOH groups of the carbohydrate chain and the C(I 1)=O group of aglycon were found.

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Glycyrrhizic acid and its 30-methyl ester were conjugated with 2-amino-1,3,4,6-tetra-O-acetyl-2-deoxy-alpha-D-glucopyranose, 2,3,4,6-tetra-O-acetyl-beta-D-glucopyranosyl amine, 2,3,4-tri-O-acetyl-apha-L-arabinopyranosyl amine, 2-acetamido-2-deoxy-beta-D-glucopyranosyl amine, and beta-D-galactopyranosyl amine using N,N'-dicyclohexylcarbodiimide and its mixtures with N-hydroxybenzotriazole. Structures of the conjugates were confirmed by IR, UV, 1H, and 13C NMR spectroscopy. The glycoconjugate with the residues of 2-acetamido-2-deoxy-beta-D-glucopyranosyl amine in the carbohydrate part of its molecule exhibited antiviral activity (ID50 4 microg/ml) toward the herpes simplex type 1 virus (HSV-1) in the VERO cell culture. Two compounds demonstrated anti-HIV-1 activity (50-70% inhibition of p24) in a culture of MT-4 cells at concentrations of 0.5-20 microg/ml. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2004, vol. 30, no. 3; see also http://www.maik.ru.

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