3-Hydroxyimino derivatives of minor licorice triterpenoids possessed pronounced antiulcer activity and protected rat gastric mucosa from ulceration in indomethacin and orthophen ulcer models at a dose of 50 mg/kg. 3-Hydroxyimino-11-deoxoglycyrrhetic acid was the most active antiulcerogenic substance and was superior in activity to carbenoxolone.

3-Оксиимино-производные минорных тритерпеноидов солодки обладают выраженной противоязвенной активностью и предохраняют слизистую оболочку желудка крыс от изъязвления на модели индометациновых и ортофеновых язв в дозе 50 мг/кг. 3-Окси-имин 11-дезоксо-глицирретовой кислоты является наиболее активным антиульцерогенным веществом, превосходящим по активности карбеноксолон.

Methyl esters of 3β-O-acetoxy-18βH-olean-12-en-30-oic, 3β-hydroxy-9(11),12(13)-dien-30-oic, and 3β-O-acetoxy-18βH-olean-12-en-30-oic acids were oxidized by meta-chloroperbenzoic acid (m-CPBA) to produce methyl esters of 3β-O-acetoxy-12α,13α-epoxy-18β-oleanan-30-oic and 3β-O-acetoxy-18β-oleanan-12-on-30-oic acids in addition to 3β-hydroxy-12-oxo-18βH-olean-9(11)-en-30-oic and 3β-O-acetoxy-18β-oleanan-12-on-30-oic acids in 70–75% yields. The structures of the synthesized compounds were confirmed by PMR and 13C NMR spectra.

Ozonolysis of methyl 3β-hydroxyolean-9(11),12(13)-dien-30-oate at –60°C in CH 2 Cl 2 –MeOH followed by reduction of the ozonolysis products by dimethylsulfide formed methyl esters of 3β-hydroxy-18βH-olean-9(11),14(15)-dien-12β-methoxy-30-oic and -olean-9(11)-en-12-oxo-30-oic acids and stereoisomeric 12α, β-hydroxy derivatives of olean-9(11),14(15)-dien-12β-methoxy-30-oic acid. The structures of the oxidation products were established using CH-correlation NMR spectra.

New 2-hydroxy-1-en-3-ones were prepared by oxidation of 11-deoxoglycyrrhetic acid 3-oxo-derivatives and its 30-methyl ester by atmospheric oxygen in the presence of t -BuOK. 2-Hydroxy-3-oxo-18 β H-olean-1,12-dien-30-oic acid at a dose of 50 mg/kg reduced the blood glucose concentration in the alloxan-induced rat diabetes mellitus model by 34% compared with the control after 120 min.

New 1-hydroxy-1-en-3-one derivatives of 18β- and 18α-glycyrrhetic acids were synthesized via oxidation of the 3-ketotriterpenoids by atmospheric oxygen in the presence of an excess of t-BuOK. 2-Hydroxy-3,11-dioxo-18αH-olean-1,12-dien-30-oic acid exhibited pronounced hypoglycemic activity and decreased the blood glucose concentration by 42.7% compared with a control after 120 min at a dose of 50 mg/kg in a rat alloxan-induced diabetes model.

Conjugates of glycyrrhetic acid (GLA) with amino acids (L-isoleucine, -leucine, -valine, and -phenylalanine) were synthesized by the acid-chloride method using methyl or tert-butyl esters of the acids. Tests in MDCK cell culture showed that the GLA conjugate with phenylalanine exhibited high antiviral activity against influenza A/H1N1/pdm09 virus (ED50 = 4.4 μg/mL, SI = 161).

New oxidative and skeletal transformations of olean-9(11),12(13)-dien-30-oic acid that were based on ozonolysis and UV irradiation produced the 9α,11α-epoxide and opened ring C.

new A-noroleanane triterpenoid with an altered pentacyclic skeleton of 2,11-dioxo-norolean A(1)-12,18(19)dien-30-oic acid based on 18,19-dehydroglycyrrhetic acid was synthesized.

A-Homo-4-aza-3-oxo- and 3-cyano-3,4-seco-olean-4,12-diene derivatives of 11-deoxo-glycyrrhetic acid were synthesized by first- and second-order Beckmann rearrangement of 3-hydroxyiminoolean-12-en-30-oic acid methyl ester.

Ring A was transformed and new A-homo-4-aza- and 3-cyano-3,4-seco-olean-4-ene derivatives of 3β-hydroxy18βH-olean-9,12-dien-30-oic acid were synthesized.

A simplified method of synthesis of triterpene 1,2- trans -glycosides was developed using the glycosylation of glycyrrhetic acid (GLA) and 18,19-dehydro-GLA by β-pyranose peracetates in the presence of SnCl 4 and molecular sieves 4 Å. The synthesized glycosides exhibited hepatoprotective activity toward the human hepatoma HepG2 cell line on the model of alcohol hepatitis and decreased the level of TNF-[alpha] protein.

A method was optimized for obtaining monoammonium salt of glycyrrhizic acid (glycyram) from roots of Ural licorice (Glycyrrhiza uralensis Fisher) of Siberian populations, including the following stages: the extraction treatment of roots with 0.5 % NH 4OH solution, the sedimentation of the sum of acids using concentrated H2SO4 , the subsequent re-extraction with 1 % H2SO4 solution in acetone, the precipitation of triammonium salt of glycyrrhizic acid with 25 % NH4OH solution and its conversion into monoammonium salt (glyciram) via crystallization from glacial NI3NIII. With the use of this method one could obtain the samples of glycyram with the purity of 85.2–87.5 % (according to HPLC data). The content of of glycyrrhizic acid in the samples of the Ural licorice roots under investigation ranges within 2–4 %.

12-Oxo derivatives of 11-desoxolycyrrhetic acid and its derivatives were produced by oxidative transformation using ozone. Olean-3,12-dion-30-oic acid was produced for the first time by exhaustive ozonolysis of 11-desoxoglycyrrhetic acid at −60°C.

Several skeletal and oxidative transformations of 11-deoxyglycyrrhetic acid were carried out to produce A- nor -derivatives. Signals for protons and C atoms in the PMR and 13 C NMR spectra of the A- nor -derivatives were assigned using high-resolution 1 H (400 MHz) and 13 C (125 MHz) NMR spectroscopy.

We describe an optimized method for obtaining glycyrrhizic acid (GA, 90.5 ± 1.5%), which is the main triterpene glycoside of licorice root (Glycyrrhiza glabra L., Gl. uralensis Fisher) extract, and its trisodium and monoammonium salts from a commercial licorice root extract containing 20.0 ± 1.5% GA.

The optimized method of preparation of Glycyrrhizic Acid (GA) (90.5 ± 1.5%), the main triterpene glycoside of licorice roots ( Glycyrrhiza glabra L., Gl. uralensis Fisher) extract, and its trisodium and monoammonium salts has been developed based on the commercial licorice extract containing 20.0 ± 1.5% GA.