Alkaloids ofAconitum kirinense. Structure of akiramidine

A new alkaloid called akiramidine is isolated from the aerial part ofAconitum kirinense. The structure 6β,14α,16β-trimethoxy-1α,4β,8β-trihydroxy-N-ethylaconitane is proposed based on spectral data and confirmed by chemical transformation from akiramine. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 774–776, November–December, 1999.     

Cardenolide glycosides ofCheiranthus allioni. XV. Glucocheiranthoside

Another new cardenolide glycoside has been isolated from the plantCheiranthus allioni Hort., and has been named glucocheiranthoside. Its chemical structure has been established as 3β-(4′-O-β-D-glucopyranosyl-β-D-gulmoethylpyranosyloxy)-14-hydroxy-19-oxo-5β,14β-card-20(22)-enolide. State Scientific Center for Drugs, Ukraine, 310085, Kharkov, USSR. ul. Astronomicheskaya, 33. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 269–271, March–April, 1994.     

Phytoecdysteroids of Rhaponticum carthamoides. II. Rhapisterone B

A new ecdysteroid (rhapisterone B) has been isolated from the seeds ofRhaponticum cathamoides (Willd.) Iljin. (familyCompositae). It has been shown that it is 2β, 3β, 11α, 14α, 20R, 24ξ-hexahydroxy-5β-cholest-7-en-6-one. Institute of the Chemistry of Plant Substances, Uzbek Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 806–808, November–December, 1991.     

Withasteroids of Physalis. IX. Physangulide — The first natural 22S-withasteroid

A new withasteroid — physangulide — has been isolated from the leaves ofPhysalis angulata L. It has been shown that physangulide is the first natural 22S-withanolide. Its structure has been determined as 3β,4β,20,24,25-pentahydroxy-1-oxo-5β,6β-epoxy-20R,22S,24S,25R-withanolide. Its¹H and¹³C NMR spectra, confirming this interpretation, are given. Institute of the Chemistry of Plant Substances, Uzbek SSR Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 366–371, May–June, 1990.     

Triterpene glycosides from <Emphasis Type="Italic">Astragalus</Emphasis> and their genins. LXXXI. Chemical transformation of cycloartanes. VII. Synthesis of cyclosiversigenin lactone

The lactone 20R-25-norcycloartan-3β,6α,16β-triol-20,24-olide was synthesized from cyclosiversigenin. Presented at the 1st International Symposium on Edible Plant Resources and the Bioactive Ingredients, Xinjiang, China, July 25–27, 2008. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 324–327, May–June, 2009.     

Triterpene glycosides ofTragacantha and their genins. Cyclostipulosides A and B fromTragacantha stipulosa

Two new triterpene glycosides of the cycloartane series, which have been called cyclostipulosides A and B, have been isolated in the individual form from the roots ofTragacantha stipulosa Boviss. Their structures have been established by physicochemical methods. Cyclostipuloside A is 24R-cycloartane-3β,6α,16β,24,25-pentaol 16-O-β-D-glucopyranoside 3-O-β-D-xylopyranoside, and cyclostipuloside B is 24R-cycloartane-3β,6α,16β,24,25-pentaol 6-O-α-L-arabinopyranoside 16-O-β-D-glucopyranoside 3-O-β-D-xylopyranoside. By the acid hydrolysis of cyclostipulosides A and B we have obtained the new glycoside 24R-cycloartane-3β,6α,16β,24,25-pentaol 16-O-β-D-glucopyranoside. Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent, fax (371) 120 64 75. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 670–674, September–October, 1998.     

Triterpene glucosides of <Emphasis Type="Italic">Astragalus</Emphasis> and their genins. LXXIV. Cyclotrisectoside,the first trisdesmoside of cyclocephalogenin

The two trisdesmoside cycloartane glycosides astragaloside VII and cyclotrisectoside were isolated from Astragalus dissectus (Leguminosae) and identified. The latter was 20R,25-epoxy-24S-cycloartan-3β,6α,16β,24-tetraol 3-O-β-D-xylopyranoside-6,24-di-O-β-D-glucopyranoside and was a new natural compound. Presented at the Sixth International Symposium on the Chemistry of Natural Compounds (SCNC, Turkey, Ankara, 28–29 June 2005). __________ Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 132–134, March–April, 2007.     

Modified Coumarins. 17. Synthesis and Anticoagulant Activity of 3,4-Cycloannelated Coumarin D-Glycopyranosides

3,4-Cyclocondensed coumarin O-glycopyranosides containing glucose, galactose, xylose, and arabinose were synthesized by condensation of potassium salts of hydroxycoumarins and acetobromosugars. 7-(β-D-Galactopyranosyloxy)-2,3-dihydrocyclopenta[c]chromen-4-one, 3-(β-D-xylopyranosyloxy)-7,8,9,10-tetrahydrobenzo[c]chromen-6-one, and 3-(α-D-arabinopyranosyloxy)benzo[c]chromen-6-one exhibited distinct anticoagulant activity. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 416–419, September–October, 2005.     

An enzyme-linked immunosorbent assay to compare the affinity of chemical compounds for β-amyloid peptide as a monomer

Aβ_1–42 is the proteolytic cleavage product of cleavage of the amyloid precursor protein by β- and γ-secretases. The aggregation of Aβ_1–42 plays a causative role in the development of Alzheimer’s disease. To lock Aβ_1–42 in a homogenous state, we embedded the Aβ_1–42 sequence in an unstructured region of Bcl-x_L. Both the N-terminus and the C-terminus of Aβ_1–42 were constrained in the disordered region, whereas the conjunction did not introduce any folding to Aβ_1–42 but maintained the sequence as a monomer in solution. With Bcl-x_L-Aβ₄₂, we developed an enzyme-linked immunosorbent assay to compare the affinity of compounds for monomeric Aβ_1–42. Bcl-x_L-Aβ₄₂ was coated on a microplate and this was followed by incubation with different concentrations of compounds. Compounds binding to Leu17-Val24 of Aβ_1–42 inhibited the interaction between Bcl-x_L-Aβ₄₂ and antibody 4G8. The method can not only reproduce the activities of the reported Aβ_1–42 inhibitors such as dopamine, tannin, and morin but can also differentiate decoy compounds that do not bind to Aβ_1–42. Remarkably, using this method, we discovered a new inhibitor that binds to monomeric Aβ_1–42 and inhibits Aβ_1–42 fibril formation. As the structure of Bcl-x_L-Aβ₄₂ monomer is stable in solution, the assay could be adapted for high-throughput screening with a series of antibodies that bind the different epitopes of Aβ_1–42. In addition, the monomeric form of the Aβ_1–42 sequence in Bcl-x_L-Aβ₄₂ would also facilitate the identification of Aβ_1–42 binding partners by coimmunoprecipitation, cocrystallization, surface plasmon resonance technology, or the assay as described here.     

Triterpene Glycosides from <Emphasis Type="Italic">Astragalus</Emphasis> and Their Genins. LXXI. Cycloorbicoside D,a New Glycoside from <Emphasis Type="Italic">Astragalus orbiculatus</Emphasis>

The new cycloartane glycoside cycloorbicoside D, which has the structure 23ξ,24ξ-cycloartan-3β6α,16β,23,24,25-hexaol 3-O-β-D-xylopyranoside, was isolated from the aerial part of Astragalus orbiculatus Ledeb. (Leguminosae). __________ Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 345–346, July–August, 2005.     

Triterpene glycosides ofHedera taurica. XI. Structures of taurosides St-G1, St-H1, and St-H2 from the stems of Crimean ivy

The previously known glycosides 3-O-α-L-arabinopyranosyl-28-O-[α-L-rhamnopyranosyl-(1→4)-O-β-D-glucopyranosyl-(1→6)-O-β-D-glucopyranosyl]hederagenin and 3-O-[α-L-rhamnopyranosyl-(1→2)-O-α-L-arabinopyranosyl]-28-O-[α-L-rhamnopyranosyl-(1→4)-O-β-D-glucopyranosyl-(1→6)-O-β-D-glucopyranosyl]hederagenin and the new triterpene glycoside tauroside St-H₁ — 3-O-β-D-glucopyransyl-28-O-[α-L-rhamnopyranosyl-(1→4)-O-β-D-glucopyranosyl-(1→6)-O-β-D-glucopyranosyl]hederagenin — have been isolated from the stems ofHedera taurica Carr. M. V. Frunze Simferopol' State University. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 571–579, July–August, 1993.     

Triterpene glycosides from <Emphasis Type="Italic">Astragalus</Emphasis> and their genins. LXXX. Cyclomacroside D,a new bisdesmoside

The structure of the new cycloartane glycoside cyclomacroside D, which was isolated from Astragalus macropus Bunge (Leguminosae) and is 24R-cycloartan-1α,3β,7β,24,25-pentaol 3-O-α-L-rhamnopyranoside–24-O-β-D-xylopyranoside, was proved. Presented at the 7th International Symposium on the Chemistry of Natural Compounds (SCNC, Tashkent, Uzbekistan, October 16–18, 2007). Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 48–50, January–February, 2009.     

Phytoecdysteroids of the plants of the genusSilene XV. Silenoside F — Brahuisterone 3-O-β-D-glucopyranoside fromSilene brahuica

A new brahuisterone glycoside — silenoside F — has been isolated from the epigeal part ofSilene brahuica Bois. (fam. Caryophyllaceae). Its structure has been established by an analysis of spectral characteristics: 3β,5,14α,22R,25-pentahydroxy-5β-cholest-6-one 3-O-β-D-glucopyranoside. Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent, fax (3712) 89 14 75. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 734–737, November–December, 1994.     

Steroids of the spirostan and furostan series from nolina microcarpa III. Structure of nolinofurosides G and H

Two new glycosides which have been called nolinofurosides G(I) and H(III), have been isolated from the leaves ofNolina microcarpa. Nolinofuroside G is the sodium salt of 26-β-D-glucofuranosyloxy-(25S)-furost-5,20(22)-diene-1β, 3β-diol 1-sulfate, and nolinofuroside H is the sodium salt of 1-β-D-fucopyranosyloxy-26-β-D-glucopyranosyloxy-(25S)-furost-5,20(22)-dinen-1β-3β-ol 3-sulfate. M. V. Frunze Simferopol' State University. Institute of the Chemistry of Plant Substances, Uzbek. Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 801–806, November–December, 1991.     

Triterpene glycosides from <Emphasis Type="Italic">Astragalus</Emphasis> and their genins. LXXVI. Glycosides from <Emphasis Type="Italic">A. sieversianus</Emphasis>

Nine compounds including six cycloartane glycosides cyclosieversiosides A, B, F, G, and H and astrasieversianin IX; β-sitosterol, β-sitosterol β-D-glucopyranoside, and D-3-O-methyl-chiro-inositol were isolated and identified from roots of Astragalus sieversianus Pall. (Leguminosae) growing in the Republic of Kyrgyzstan. Presented at the 6th International Symposium on the Chemistry of Natural Compounds (SCNC, Ankara, Turkey, June 28–29, 2005. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 253–256, May–June, 2008.     

Triterpene glycosides of alfalfa. V. Medicoside H

A new triterpene glycoside — medicoside H — has been isolated from the roots ofMedicago sativa L. (Fabaceae), and on the basis of chemical transformations and spectral characteristics its structure has been established as medicagenic acid 3-O-β-D-glucopyranoside 28-O-[O-α-L-rhamnopyronosyl-(1 → 2)-β-L-arabino-pyranoside]. Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 673–677, September–October, 1989.     

Steroids of the furostan and spirostan series from Nolina microcarpa II. structures of nolinospiroside D and nolinofurosides D,E, and F

In addition to the know steroid sapogenin (25S)-ruscogenin (I), three new glycosides have been isolated from the leaves ofNolina microcarpa S. Wats. (family Dracaenacea), and the following structures are suggested for them: (25S)-spirost-5-ene-1β,3β-diol 1-O-β-D-fucopyranoside (nolinospiroside C, II), (25S)-furost-5-ene-1β,3β,22α,26-tetraol 1-O-β-D-fucopyranoside (nolinofuroside A, III), and (25S)-furost-5-ene-1β, 3β, 22α, 26-tetraol 1-O-β-D-fucopyranoside 26-O-β-D-glucopyranoside (nolinofuroside C, V). M. V. Frunze Simferopol' State University. Institute of Chemistry of Plant Substances, Uzbek Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 672–678, September–October, 1991.     

Glycosylation of triterpenoids of the dammarane series. X. Regio- and stereoselective synthesis of 20(S)-protopanaxadiol 3-O-β-D-glucopyranoside (ginsenoside Rh2)

The regio- and stereoselective synthesis of ginsenoside R_h2, which possesses antitumoral activity, has been effected by the glycosylation of 12β-acetoxydammar-24-ene-3β,20(S)-diol. Condensation with α-acetobromoglucose was carried out in the presence of silver oxide in dichloroethane at room temperature, and the yield of the desired glycoside amounted to 50%. A method for the selective protection of the C-12-OH group of dammar-24-ene-3β,12β,20(S)-triol [20(S)-protopanaxadiol] has been proposed. Pacific Ocean Institute of Bioorganic Chemistry, Far Eastern Branch, USSR Academy of Sciences, Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, Vol. 6, pp. 813–816, November–December, 1989.     

Carbohydrates of Allium. XIII. Glucofructans ofAllium suvorovii

The structures of the glucofructans GFAS-B3 and GFAS-I have been established on the basis of the results of periodate oxidation, methylation, and IR and¹³C NMR spectroscopies. It has been shown that the glucofructans studied are compounds containing both inulin, (2→1)β, and levan, (2→6)β, glycosidic bonds. Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent, FAX (3712) 62 73 48. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 179–183, March–April, 1994.     

Effect of amyloid beta peptides Aβ<Subscript>1–28</Subscript> and Aβ<Subscript>25–40</Subscript> on model lipid membranes

To investigate the molecular interaction of amyloid beta peptides Aβ_1–28 or Aβ_25–40 with model lipid membranes differential scanning calorimetry (DSC) and DPH and TMA DPH fluorescence anisotropy approaches were used. The main transition temperature (T _m) and enthalpy change (ΔH) of model lipid membranes composed of DMPC/DPPG on addition of Aβ_25–40 or Aβ_25–40 at 10:1 (w/w) phospholipid/peptide ratio either non-aggregated or previously aggregated were examined. The effect of Aβ_1–28 and Aβ_25–40 on the membrane fluidity of liposomes made of DMPC/DPPG (98:2 w/w) was determined by fluorescence anisotropy of incorporated DPH and TMA DPH. The results of this study provide information that Aβ_1–28 preferentially interacts with the hydrophilic part of the model membranes, while Aβ_25–40 rather locates itself in the hydrophobic core of the bilayer where it reduces the order of the phospholipids packing.