Sequence analysis of the sulfated rhamno-oligosaccharides derived from a sulfated rhamnan

Three sulfated rhamno-oligosaccharides, designated O1, O2 and O3, were obtained by mild acid hydrolysis of the sulfated rhamnan and purified by gel-permeation chromatography. On the basis of one- and two-dimensional nuclear magnetic resonance (1D, 2D NMR) spectroscopic analyses, the oligosaccharide O1 was characterized to be α-l-Rhap-(2SO4)-(1→3)-α-l-Rhap. The fragmentation pattern of the homogeneous disaccharide in the product ion spectra was recognized by negative-ion electrospray tandem mass spectrometry with collision-induced dissociation (ES-CID MS/MS). With the principles established, the sequences of the oligosaccharides O2 and O3 were deduced to be α-l-Rhap-(2SO4)-(1→3)-α-l-Rhap-(1→3)-α-l-Rhap, and α-l-Rhap-(2SO4)-(1→3)-α-l-Rhap-(1→3)-α-l-Rhap-(1→3)-α-l-Rhap (2SO(4)), respectively. The investigation demonstrated that the sulfated rhamnan-derived oligosaccharides were novel sulfated oligosaccharides different from those of other polysaccharides-degraded from algae, and it could be possible to determine the sequence of the sulfated rhamno-oligosaccharides directly from the glycosidic cleavage fragmentation in the product ion spectra.     

黄花远志的新齐墩果烷型三萜皂甙

从云南产远志科药用植物黄花远志(PolygalaarillataBuchHamexDDon)茎皮的乙醇提取物中分离得到4个新的齐墩果烷型三萜皂甙,命名为黄花远志皂甙(arillatanoside)A～D。同时还分离得到1个已知的三萜皂甙远志甙(polygalasaponin)XXXV。它们的结构通过波谱方法推定。     

Oleanane-type glycosides from Weigela x Styriaca and two cultivars of W. florida: “Minor black” and “Brigela”

Sixteen oleanane-type glycosides were extracted from three Weigela hybrids and cultivars: W. x Styriaca, W. florida “Minor black” and W. florida “Brigela”, and four of them were previously undescribed ones: 3-O-β-D-xylopyranosyl-(1→4)-β-D-xylopyranosyl-(1→3)-α-L-rhamnopyranosyl-(1→2)-β-D-xylopyranosyloleanolic acid, 3-O-β-D-xylopyranosyl-(1→4)-β-D-xylopyranosyl-(1→3)-α-L-rhamnopyranosyl-(1→2)-α-L-arabinopyranosyloleanolic acid, 3-O-β-D-xylopyranosyl-(1→4)-β-D-xylopyranosyl-(1→4)-β-D-xylopyranosyl-(1→3)-α-L-rhamnopyranosyl-(1→2)-α-L-arabinopyranosyloleanolic acid, and 3-O-β-D-xylopyranosyl-(1→4)-β-D-xylopyranosyl-(1→4)-β-D-xylopyranosyl-(1→4)-β-D-xylopyranosyl-(1→3)-α-L-rhamnopyranosyl-(1→2)-α-L-arabinopyranosyloleanolic acid. Their full structural elucidation required extensive 1D and 2D NMR experiments, as well as mass spectrometry analysis. Six compounds among the known ones were in sufficient amount to be tested for their antifungal activity against Candida albicans, and their antibacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa.     

Structure of the O-polysaccharide of Pragia fontium 27480 containing 2,3-diacetamido-2,3-dideoxy-d-mannuronic acid

The following structure of the O-polysaccharide of Pragia fontium 27480 was elucidated by sugar analysis, including determination of the absolute configurations of the monosaccharides, and Smith degradation along with 1D and 2D ¹H and ¹³C NMR spectroscopy:→4)-β-d-ManpNAc3NAcA-(1→2)-α-l-Rhap-(1→3)-β-l-Rhap-(1→4)-α-d-GlcpNAc-(1→where ManNAc3NAcA stands for 2,3-diacetamido-2,3-dideoxymannuronic acid.     

Effects of backbone substitutions on the conformational behavior of Shigella flexneri O-antigens: implications for vaccine strategy

The O-antigen (O-Ag), the polysaccharide part of the lipopolysaccharide, is the major target of the serotype-specific protective humoral response elicited upon host infection by Shigella flexneri, the main causal agent of the endemic form of bacillary dysentery. The O-Ag repeat units (RUs) of 12 S. flexneri serotypes share the tetrasaccharide backbone →2)-α-l-Rhap-(1?→?2)-α-l-Rhap-(1?→?3)-α-l-Rhap-(1?→?3)-β-d-GlcpNAc-(1→, with site-selective glucosylation(s) and/or O-acetylation defining the serotypes. To investigate the conformational basis of serotype specificity, we sampled conformational behaviors during 60?ns of molecular dynamic simulations for oligosaccharides representing three RUs of each one of the O-Ags corresponding to serotypes 1a, 1b, 2a, 2b, 3a, 3b, 4a, 4b, 5a, 5b, X and Y, respectively. The calculated trajectories were checked by nuclear magnetic resonance (NMR) for 1a, 2a, 3a and 5a O-Ags. The simulations predict that in all O-Ags, but 1a and 1b, serotype-specific substitutions of the backbone do not induce any new backbone conformations compared with the linear type O-Ag Y, although they restrain locally the accessible conformational space. Moreover, the influence of any given substituent on the backbone is independent of the eventual presence of other substituents. Finally, only slight differences in conformational behavior between terminal and inner RUs were observed. These results suggest that the reported serotype-specificity of the protective immune response is not due to recognition of distinct backbone conformations, but to binding of the serotype-defining substituents in the O-Ag context. The gained knowledge is discussed in terms of impact on the development of a broad-serotype coverage vaccine.     

Spirostanol saponins from Paris polyphylla,structures of polyphyllin C,D, E and F

The structures of four new saponins, polyphyllin C, D, E and F, isolated from the tubers of Paris polyphylla have been elucidated as diosgenin-3-O-α-l-rhamnopyranosyl(1→3)-β-d-glucopyranoside, diosgenin-3-O-α-l-rhamnopyranosyl(1→3)- [α-l-arabinofuranosyl(1→4)]-β-d-glucopyranoside, diosgenin-3-O-α-l-rhamnopyranosyl(1→2)-α-l-rhamnopyranosyl (1→4)[α-l-rhamnopyranosyl(1→3)]-β-d-glucopyranoside and diosgenin-3-O-α-l-rhamnopyranosyl(1→4)[α-l- rhamnopyranosyl(1→3)][β-d-glucopyranosyl(1→2)]-α-l-rhamnopyranoside, respectively, on the basis of chemical and spectral data.     

Different asparagine-linked sugar chains on the two polypeptide chains of human chorionic gonadotropin

Human chorionic gonadotropin (hCG) purified from placenta, like urinary hCG, is shown to have the sialylated forms of three neutral oligosaccharides: Galβ1→4GlcNAcβ1→2Manα1→6(Galβ1→4GlcNAcβ1→2Manα1→3)Manβ1→4GlcNAcβ1→4(Fucα1→6)GlcNAc (N-1), Galβ1→4GlcNAcβ1→2Manα1→6(Galβ1→4GlcNAcβ1→2Manα1→3)Manβ1→4GlcNAcβ1→4GlcNAc (N-2) and Manα1→6(Galβ1→4GlcNAcβ1→2Manα1→3)Manβ1→4GlcNAcβ1→4GlcNAc (N-3). Gel permeation chromatographic analysis of oligosaccharides released from α- and β-subunits of placental hCG has revealed that the α-subunit has one each of sialylated N-2 and N-3, while the β-subunit has one each of sialylated N-1 and N-2.     

New steroidal saponins of Agave americana

Two new saponins, agavasaponin E and agavasaponin H have been isolated from the methanolic extract of Agave americana leaves and their structures elucidated. Agavasaponin E is 3-O-[β-d-xylopyranosyl-(1→2glc1)-α-l-rhamnopyranosyl-(1→4)-α-l-rhamnopyranosyl-(1→3glc 1)-β-d-glucopyranosyl-(1→4)-β-d-glucopyranosyl-(1→4)-α-d-galactopyranosyl]-(25R)-5α-spirostan-12-on-3β-ol, whereas agavasaponin H is 3-O-[β-d-xylopyranosyl-(1→2 glc 1)-α-l-rhamnopyranosyl-(1→4)-α-l-rhamnopyranosyl-(1→3 glc 1)-β-d-glucopyranosyl-(1→4)-β-d-glucopyranosyl-(1→4)-β-d-galactopyranosyl]-26-O-[β-d-glucopyranosyl]-(25R)-5α-furostan-12-on-3β,22α,26-triol.     

Flavonol triglycosides from Magnolia utilis

Three undescribed flavonol triglycosides, rhamnetin-3-O-α-L-rhamnopyranosyl-(1→2)-[α-L-rhamnopyranosyl-(1→6)]-β-d-glucopyranoside (champaluangoside A), rhamnetin-3-O-α-l-rhamnopyranosyl-(1→2)-[α-l-rhamnopyranosyl-(1→6)]-β-d-galactopyranoside (champaluangoside B) and rhamnocitrin-3-O-α-l-rhamnopyranosyl-(1→2)-[α-l-rhamnopyranosyl-(1→6)]-β-d-glucopyranoside (champaluangoside C), were isolated from Magnolia utilis in addition to eleven known compounds; quercetrin-3-O-α-l-rhamnopyranosyl-(1→2)-[α-l-rhamnopyranosyl-(1→6)]-β-d-glucopyranoside, oxytroflavoside G, magnoloside A, magnoloside M, magnoloside D, manglieside A, manglieside B, 1,2-di-O-β-d-glucopyranosyl-4-allylbebzene, syringrin, benzyl β-d-allopyranoside and (+)-syringaresinol-O-β-d-glucopyranoside. The structure elucidation of these compounds was based on analyses of physical and spectroscopic data.     

Beshornin and beshornoside,steroidal saponins of Beshorneria yuccoides

Two new saponins beshornin and beshornoside have been isolated from the methanolic extract of Beshorneria yuccoides leaves and their structures elucidated. Beshornin is 3-O-[α-l-rhamnopyranosyl-(1 → 4)-β-d-glucopyranosyl- (1 → 2)-[α-l-rhamnopyranosyl-(1 -+ 4)-P-D-glucopyranosyl-(1 → 3)]-β-d-glucopyranosyl-(1 → 4)-β-d- galactopyranosyl-(25R)-5α-spirostan-3β-ol, whereas beshornoside is 3-O-[α-l-rhamnopyranosyl-(1 → 4)- β-d)-glycopyranosyl-(1 → 2)]-[α-l-rhamnopyranosyl-(1 → 4)-β-d-glucopyranosyl-(1 → 3)]-β-d-glucopyranosyl- (1 → 4)-β-d-galactopyranosyl 26-O-[β-d]-glucopyranosyl-(25R)-5α-furostan-3β,22α,26-triol.     

Triterpene saponins from Cyclamen hederifolium

Five triterpene saponins never reported before, hederifoliosides A-E, and four known triterpene saponins were isolated from the tubers of Cyclamen hederifolium. The structures of hederifoliosides A-E were determined as 3β,16α-dihydroxy-13β,28-epoxyolean-30-oic acid 3-O-{[β-D-glucopyranosyl-(1 → 2)-O]-β-D-xylopyranosyl-(1 → 2)-O-β-D-glucopyranosyl-(1 → 4)-O-α-L-arabinopyranoside}, 3β,16α-dihydroxy-13β,28-epoxyolean-30-oic acid 3-O-{[β-D-glucopyranosyl-(1 → 2)-O]-β-D-xylopyranosyl-(1 → 2)-O-[β-D-glucopyranosyl-(1 → 3)]-O-β-D-glucopyranosyl-(1 → 4)-O-α-L-arabinopyranoside}, 3β,16α-dihydroxy-13β,28-epoxyolean-30-al 3-O-{[β-D-glucopyranosyl-(1 → 2)-O]-β-D-xylopyranosyl-(1 → 2)-O-[β-D-glucopyranosyl-(1 → 3)]-O-[β-D-glucopyranosyl-(1 → 6)]-O-β-D-glucopyranosyl-(1 → 4)-O-α-L-arabinopyranoside}, 30-O-β-D-glucopyranosyl-(1 → 2)-O-β-D-glucopyranosyl-3β,16α,30-trihydroxyolean-12-en-28-al 3-O-{[β-D-glucopyranosyl-(1 → 2)-O]-β-D-xylopyranosyl-(1 → 2)-O-β-D-glucopyranosyl-(1 → 4)-O-α-L-arabinopyranoside}, 30-O-β-D-glucopyranosyl-(1 → 2)-O-β-D-glucopyranosyl-3β,16α,28,30-tetrahydroxyolean-12-en 3-O-{[β-D-glucopyranosyl-(1 → 2)-O]-β-D-xylopyranosyl-(1 → 2)-O-[β-D-glucopyranosyl-(1 → 3)]-O-β-D-glucopyranosyl-(1 → 4)-O-α-L-arabinopyranoside}, by a combination of one- and two-dimensional NMR techniques, and mass spectrometry. The cytotoxic activity of the isolated compounds was evaluated against a small panel of cancer cell lines including Hela, H-446, HT-29, and U937. None of the tested compounds, in a range of concentrations between 1 and 50 μM, caused a significant reduction of the cell number.     

夏至草亲水性化学成分的研究

从夏至草正丁醇萃取物中分离得到6个化合物,运用光谱技术和化学方法鉴定了其中5个化合物的结构,其中1个为无机化合物KNO3（La1)另外4个为苯丙素甙,分别为purpureaside(La2),acteoside(La3),cistanoside B(La4),jionosideA(La5),均为首次从该属植物中获得。     

Triterpenoid Saponins from Pulsatilla cernua (Thunb.)

To investigate saponins from the roots of Pulsatilla cernua (Thunb.) Bercht. et Opiz., two new compounds together with five known triterpenoid saponins were isolated. The structures of the two new triterpenoid saponins, named cernuasides A and B, were elucidated as 3-O-[β-D-xylopyranosyl(1→2)]-[α-L-rhamnopyranosyl(1→4)]-α-Larabinopyranosyl hederagenin 28-O-β-D-glucopyranosyl ester (compound 1) and 3-O-[α-L-arabinopyranosyl(1→3)]-[α-L-rhamnopyranosyl (1→2)]-α-L-arabinopyranosyl hederagenin 28-O-β-D-glucopyranosyl ester (compound 2) by 1D, 2D-NMR techniques, ESIMS analysis, as well as chemical methods.     

Structural studies of the carbohydrate moiety of human antithrombin III

Human antithrombin III contains four asparagine-linked sugar chains in one molecule. The sugar chains were quantitatively released as radioactive oligosaccharides from the polypeptide portion by hydrazinolysis followed by N-acetylation and NaB³H₄ reduction. All of the oligosaccharides, thus obtained, contain N-acetylneuraminic acid. A same neutral nonaitol was released from all acidic oligosaccharides by sialidase treatment. By combination of the sequential exoglycosidase digestion and methylation analysis, their structures were elucidated as NeuAcα2 → 6Galβ1 → 4GlcNAcβ1 → 2Manα1 → 6-(NeuAcα2 → 6Galβ1 → 4GlcNAcβ1 → 2Manα1 → 3)Manβ1 → 4GlcNAcβ1 → 4GlcNAc, Galβ1 → 4GlcNAcβ1 → 2Manα1 → 6(NeuAcα2 → 6Galβ1 → 4GlcNAcβ1 → 2Manαl → 3)Manβ1 → 4GlcNAcβ1 → 4GlcNAc, and NeuAcα2 → 6Galβ1 → 4GlcNAcβ1 → 2Manα1 → 6(Galβ1 → 4GlcNAcβ1 → 2Manα1 → 3)Manβ1 → 4GlcNAcβ1 → 4GlcNAc.     

Triterpenoid Saponins from Pulsatilla cernua (Thunb.)Bercht. et Opiz.

To investigate saponins from the roots of Pulsatilla cernua (Thunb.) Bercht. et Opiz., two new compounds together with five known triterpenoid saponins were isolated. The structures of the two new triterpenoid saponins, named cernuasides A and B, were elucidated as 3-O-[β-D-xylopyranosyl(1→2)]-[α-L-rhamnopyranosyl(1→4)]-α-Larabinopyranosyl hederagenin 28-O-β-D-glucopyranosyl ester (compound 1) and 3-O-[α-L-arabinopyranosyl(1→3)]-[α-L-rhamnopyranosyl (1→2)]-α-L-arabinopyranosyl hederagenin 28-O-β-D-glucopyranosyl ester (compound 2) by 1D, 2D-NMR techniques, ESIMS analysis, as well as chemical methods.     

Steroidal saponins of Asparagus curillus

Three spirostanol and two furostanol glycosides were isolated from a methanol extract of the roots of Asparagus curillus and characterized as 3-O-[α-l-arabinopyranosyl (1→4)- β-d-glucopyranosyl]-(25S)-5β-spirostan-3β-ol, 3-O-[{α-l-rhamnopyranosyl (1→2)} {α-l-arabinopyranosyl (1→4)}-β-d-glucopyranosyl]-(25S)-5β-spirostan- 3β-ol, 3-O-[{β-d-glucopyranosyl (1→2)} {α-l-arabinopyranosyl (1→4)}-β- d-glucopyranosyl]-(25S)-5β-spirostan-3β-ol, 3-O-[{β-d-glucopyranosyl (1→2)} {α-l-arabinopyranosyl (1→4)}-β-d-glucopyranosyl]-26-O-[β-d-glucopyranosyl]- 22α-methoxy-(25S)-5β-furostan-3β, 26-diol and 3-O-[{β-d-glucopyranosyl (1→2)} {α-l-arabinopyranosyl (1→4)}-β-d-glucopyranosyl]-26-O-[β-d-glucopyranosyl]- (25S)-5β-furostan-3β, 22α, 26-triol respectively.     

Flavan-3-ols from the rhizomes of Drynaria fortunei

One monomer flavan-3-ol, 4α-carboxymethyl-(+)-catechin methyl ester, two monomer flavan-3-ol glycosides, (+)-afzelechin-3-O-β-allopyranoside, (+)-afzelechin-6-C-β-glucopyranoside, two dimer flavan-3-ols, (-)-epiafzelechin-(4β→8)-4β-carboxymethyl-(-)-epicatechin methyl ester, and -(-)-epiafzelechin-(4β→8)-4α-carboxymethyl-(-)epiafzelechin ethyl ester, and one trimer flavan-3-ol, (-)-epiafzelechin-(4β→8)-(-)-epiafzelechin-(4β→8)-4β-carboxymethyl-(-)-epiafzelechin methyl ester, together with thirteen known flavan-3-ols were isolated from the rhizomes of Drynaria fortunei (Kunze) J.Sm (Polypodiaceae). The structures were established by analysis of their HRESIMS, 1D, 2D NMR spectroscopic, and CD data. In order to obtain improved resolution, the high-resolution NMR spectra of the dimers and trimer were measured at -40 °C.     

Tea catechins and flavonoids from the leaves of Camellia sinensis inhibit yeast alcohol dehydrogenase

Four new quercetin acylglycosides, designated camelliquercetisides A-D, quercetin 3-O-[α-L-arabinopyranosyl(1→3)][2-O″-(E)-p-coumaroyl][β-D-glucopyranosyl(1→3)-α-L-rhamnopyranosyl(1→6)]-β-D-glucoside (17), quercetin 3-O-[2-O″-(E)-p-coumaroyl][β-D-glucopyranosyl(1→3)-α-L-rhamnopyranosyl(1→6)]-β-D-glucoside (18), quercetin 3-O-[α-L-arabinopyranosyl(1→3)][2-O″-(E)-p-coumaroyl][α-L-rhamnopyranosyl(1→6)]-β-d-glucoside (19), and quercetin 3-O-[2-O″-(E)-p-coumaroyl][α-L-rhamnopyranosyl(1→6)]-β-D-glucoside (20), together with caffeine and known catechins, and flavonoids (1-16) were isolated from the leaves of Camellia sinensis. Their structures were determined by spectroscopic (1D and 2D NMR, IR, and HR-TOF-MS) and chemical methods. The catechins and flavonoidal glycosides exhibited yeast alcohol dehydrogenase (ADH) inhibitory activities in the range of IC(50) 8.0-70.3μM, and radical scavenging activities in the range of IC(50) 1.5-43.8 μM, measured by using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical.     

Narcissiflorine,narcissiflorinine and narcissifloridine,three triterpene saponins from Anemone narcissiflora

Narcissiflorine, narcissiflorinine and narcissifloridine, three new saponins, have been isolated from the ethanolic extract of Anemone narcissiflora (Ranunculaceae). The structural elucidation of narcissiflorine, narcissiflorinine and narcissifloridine has showed them to be [α-l-arabinofuranosyl-(1 → 4)-β-d-glucuronopyranosyl-(1→3)]- 3β-hydroxy-olean-12-en-28-oic acid, [α,-l-arabinofuranosyl-(1→2)-α-l-rhamnopyranosyl-(1→4)-β-d- glucuronypyranosyl(1→3)]-3-β-hydroxy-olean-12-en-28-oic acid and [α-l-arabinofuranosyl-(1→2)-α-l- rhamnopyranosyl-(1→4)-β-d-glucopyranosyl-(1→3)]-3-β-hydroxy-olean-12-en-28-oic acid, respectively.     

Triterpenoid saponins from Hydrocotyle bonariensis Lam

Phytochemical investigation of the under-ground parts of Hydrocotyle bonariensis led to the isolation of five oleanane-type triterpenoid saponins, 3-O-{β-D-glucopyranosyl-(1 → 2)-[α-L-arabinopyranosyl-(1 → 3)]-β-D-glucuronopyranosyl}-21-O-(2-methylbutyroyl)-22-O-acetyl-R(1)-barrigenol, 3-O-{β-D-glucopyranosyl-(1 → 2)-[α-L-arabinopyranosyl-(1 → 3)]-β-D-glucuronopyranosyl}-21-O-(2-methylbutyroyl)-28-O-acetyl-R(1)-barrigenol, 3-O-{β-D-glucopyranosyl-(1 → 2)-[α-L-arabinopyranosyl-(1 → 3)]-β-D-glucuronopyranosyl}-21-O-acetyl-R(1)-barrigenol, 3-O-{β-D-glucopyranosyl-(1 → 2)-[α-L-arabinopyranosyl-(1 → 3)]-β-D-glucuronopyranosyl}-R(1)-barrigenol, and 3-O-{β-D-glucopyranosyl-(1 → 2)-[α-L-arabinopyranosyl-(1 → 3)]-β-D-glucuronopyranosyl}-22-O-(2-methylbutyroyl)-A(1)-barrigenol, together with the known saniculoside-R1. Their structures were established by 2D NMR techniques and mass spectrometry. Six compounds were evaluated against two human colon cancer cell lines, HCT 116 and HT-29. Two compounds showed weak cytotoxicity with IC(50) 24.1 and 24.0, 83.0 and 83.6 μM against HT-29 and HCT 116, respectively.