Alexandr S. Antonov

Triterpene Glycosides from Antarctic Sea Cucumbers. 1. Structure of Liouvillosides A1, A2, A3, B1, and B2 from the Sea Cucumber Staurocucumis liouvillei: New Procedure for Separation of Highly Polar Glycoside Fractions and Taxonomic Revision

Five new triterpene glycosides, liouvillosides A1 (1), A2 (2), A3 (3), B1 (4), and B2 (5), have been isolated from the Antarctic sea cucumber Staurocucumis liouviellei along with the known liouvilloside A(6), isolated earlier from the same species, and hemoiedemosides A (7) and B (8), isolated earlier from the Patagonian sea cucumber Hemioedema spectabilis. The isolation was carried out using a new chromatographic procedure including application of ion-pair reversed-phase chromatography followed by chiral chromatography on a cyclodextrin ChiraDex column. The structures of the new glycosides were elucidated using extensive NMR spectroscopy (1H and 13C NMR spectrometry, DEPT, 1H-(1)H COSY, HMBC, HMQC, and NOESY), ESI-FTMS, and CID MS/MS, and chemical transformations. Glycosides 1-3 are disulfated tetraosides and glycosides 4 and 5 are trisulfated tetraosides. Glycosides 2 and 3 contain 3-O-methylquinovose, found for the first time as a natural monosaccharide in sea cucumber glycosides. On the basis of analyses of glycoside structures a taxonomic revision is proposed.

Triterpene Glycosides from Antarctic Sea Cucumbers. 2. Structure of Achlioniceosides A1, A2, and A3 from the Sea Cucumber Achlionice violaecuspidata (=Rhipidothuria racowitzai)

Three new triterpene glycosides, achlioniceosides A(1) (1), A(2) (2), and A(3) (3), have been isolated from the Antarctic sea cucumber Achlionice violaecuspidata. The glycoside structures were elucidated using extensive NMR spectroscopic analysis including one-dimensional (1)H and (13)C spectra, (1)H-(1)H-COSY, HMBC, HMQC, and NOESY and mass spectrometry. Gycosides 1-3 are disulfated pentaosides that are branched at the first xylose residue. The sulfates are attached to C-6 of the glucose residues. Glycosides 1-3 are the first triterpene glycosides isolated from a sea cucumber belonging to the order Elasipodida.

Mycaloside A, a new steroid oligoglycoside with an unprecedented structure from the Caribbean sponge Mycale laxissima

Abstract The structure of mycaloside A ( 1 ) isolated from the Caribbean sponge Mycale laxissima has been established as (22 E ,20 R ,24 S )-3- O -{α- d -Galp(1→2)-β- d -Arap(1→3)-[β- d -Galp(1→4)]-β- d -Glcp}-3β,4β,15α,21-tetrahydroxy-24-methylcholesta-5,22-diene by interpretation of spectral data and chemical transformations.

Triterpene glycosides from Antarctic sea cucumbers III. Structures of liouvillosides A4 and A5, two minor disulphated tetraosides containing 3-O-methylquinovose as terminal monosaccharide units from the sea cucumber Staurocucumis liouvillei (Vaney)

Two new minor triterpene glycosides, liouvillosides A4 (1) and A5 (2) have been isolated from the sea cucumber Staurocucumis liouvillei living in Antarctic and Sub-Antarctic waters. The structures of the new glycosides were elucidated using extensive nuclear magnetic resonance (NMR) spectroscopy (1H- and 13C-NMR spectroscopy, 1H–1H COSY, 1D-TOCSY, HMBC, HSQC and NOESY), ESI-MS and MALDI TOF MS. The glycosides 1 and 2 are disulphated tetraosides having very rare 3-O-methylquinovose as terminal monosaccharide.

New triterpene oligoglycosides from the Caribbean sponge Erylus formosus.

Seven new triterpene glycosides, erylosides R(1) (1), T(1) (3), T(2) (4), T(3) (5), T(4) (6), T(5) (7), and T(6) (8) along with the known formoside (2) were isolated from the sponge Erylus formosus collected along the Caribbean coast of Mexico. Glycoside 1 was determined as a trisaccharide, glycoside 2 as a tetrasaccharide while glycosides 3-8 were hexasaccharide. Their carbohydrate chains were unprecedented and have never been found in oligosaccharides from other biological sources, except Erylus spp. Three carbohydrate chains in the glycosides 3 and 6, 4 and 7, 5 and 8 correspondingly are new. The glycosides 1-5 have penasterol as aglycone while glycosides 6-8 proved to be glycoconjugates of 24-methylene-14-carboxy-lanost-8(9)-en-3β-ol.

Structure of ulososide A, a new triterpenoid glycoside from theUlosa sp. sponge

A new triterpenoid glycoside, (20S,22S,23R,24S)-3β,22,23-trihydroxy-3-O-[O-(β-D-glucuronopyranosyl)-(1→6)-(β-D-glucopyranosyl)]-14-nor-24-methyllanost-8(9)-en-31-oic acid (ulososide A), has been isolated from the sponge Ulosa sp. and characterized.

Pallidopenillines: Polyketides from the Alga-Derived Fungus Penicillium thomii Maire KMM 4675

Eleven new polyketides, pallidopenillines 1-11, were isolated from the alga-derived fungus Penicillium thomii. The structures of these compounds were established based on spectroscopic methods. The absolute configuration of pallidopenilline A (1) as 4R, 5S, 8S, 9R, 10R, 13R was established using a combination of the modified Moshers method, X-ray analysis, and NOESY data. The absolute configurations of 2-5 were determined by time-dependent density functional theory calculations of the ECD spectra and ECD and NOESY data. It was shown that 1-acetylpallidopenilline A (2) and pallidopenilline G (10) inhibit the growth of colonies of 22Rv1 cells by 40% at 2 and 1 μM, respectively.

New Triterpene Glycosides from an Ulosa sp. Sponge

New triterpene glycosides, ulososides C, (20S,22S,23R,24S)-3 beta,22, 23-trihydroxy-3-O-(beta-D-glucopyranosyl)-32-nor-24-methyllanost- 8(9)-ene-30-oic acid, D, (20S,22S,23R,24S)-3 beta,22, 23-trihydroxy-3-O-(beta-D-N-acetyl-glucosaminopyranosyl)-32-nor- 24-methyllanost-8(9)-ene-30-oic acid, and E, (20S,22S,23R,24S)-3 beta,22, 23-trihydroxy-3-O-(beta-D-glucuronopyranosyl-(1-->2)-alpha-D- arabinopyranosyl-32-nor-24-methyllanost-8(9)-ene-30-oic acid, were isolated from an Ulosa sp. sponge. Their structures were determined by spectral methods and chemical transformations. Specific features of their structures are discussed.New triterpene glycosides, ulososides C, (20S,22S,23R,24S)-3β,22,23-trihydroxy-3-O-(β-D-glucopyranosyl)-32-nor-24-methyllanost-8(9)-ene-30-oic acid, D, (20S,22S,23R,24S)-3β,22,23-trihydroxy-3-O-(β-D-N-acetylglucosaminopyranosyl)-32-nor-24-methyllanost-8(9)-ene-30-oic acid, and E, (20S,22S,23R,24S)-3β,22,23-trihydroxy-3-O-(β-D-glucuronopyranosyl-(1 → 2)-α-D-arabinopyranosyl-32-nor-24-methyllanost-8(9)-ene-30-oic acid, were isolated from an Ulosa sp. sponge. Their structures were determined by spectral methods and chemical transformations. Specific features of their structures are discussed.

Zosteropenillines: Polyketides from the MarineDerived Fungus Penicillium thomii

Twelve new polyketides, zosteropenillines A–L (1–12), together with known polyketide pallidopenilline A (13), were isolated from the ethylacetate extract of the fungus Penicillium thomii associated with the seagrass Zostera marina. Their structures were established based on spectroscopic methods. The absolute configuration of zosteropenilline A (1) as 4R, 5S, 8S, 9R, 10R, and 13S was determined by a combination of the modified Mosher’s method, X-ray analysis, and NOESY data. Absolute configurations of zosteropenillines B–D (2–4) were determined by time-dependent density functional theory (TD-DFT) calculations of ECD spectra. The effect of compounds 1–3, 7, 8, 10, and 11 on the viability of human drug-resistant prostate cancer cells PC3 as well as on autophagy in these cancer cells and inhibitory effects of compounds 1, 2, and 8–10 on NO production in LPS-induced RAW 264.7 murine macrophages were examined.

Erylosides F8, V1–V3, and W–W2 – New triterpene oligoglycosides from the Carribean sponge Erylus goffrilleri

Seven new triterpene glycosides, erylosides F8 (1), V1 (2), V2 (3), V3 (4), W (5), W1 (6) and W2 (7), were isolated from a Carribean sponge Erylus goffrilleri collected from the Carribean Sea near the Arrecife-Seco reef (Cuba). Structures of the glycosides were determined using 1H and 13C NMR spectroscopy, including 2D NMR procedures (1H-1H COSY, 1H-13С HMBC, 1H-13С HSQC and NOESY) and HR ESI mass spectrometry. Erylosides 1 and 4 have 14-carboxy-24,25-dimethyllanost-8(9)-en-3β,25-diol as aglycone whereas glycosides 2, 3, 5, 6 and 7 are 14-carboxy-24-acetoxy-24-methyllanost-8(9)-en-3β-ol glycoconjugates. Cytotoxic activities of the isolated compounds against Ehrlich carcinoma cells and hemolysis were examined and their dependence on eryloside structure was evaluated.