Flavonol glycosides from Monnina sylvatica.

A new kaempferol triglycoside and three known kaempferol glycosides, among them two apiosides, have been isolated from the aerial parts of Monnina sylvatica. The structures were established on the basis of acid and enzymatic hydrolysis and spectral data (UV, 1H and 13CNMR, NOE difference measurements, D/CI and FAB-MS) of the isolates and of some derivatives. The triglycoside kaempferol 3-O-beta-D-glucosyl-(1----2)-O-[alpha-L-rhamnosyl(1----6)]-beta-D- galactoside is a new natural product. The configuration of the apiosyl moiety in kaempferol 3-O-beta-D-apiosyl(1----2)-beta-D-galactoside and kaempferol 3-O-beta-D-apiosyl(1----2)-O-[alpha-L-rhamnosyl(1----6)]- beta-D-galactoside was established through NOE difference measurements on the peracetate.     

Flavonol diglycosides from Blackstonia perfoliata.

Two unusual diglycosides, quercetin and kaempferol 3-rhamnosyl(1----2)galactosides and the new isorhamnetin 3-rhamnosyl(1----2)galactoside have been isolated from the aerial parts of Blackstonia perfoliata. Instead of C-glycosylflavones, the occurrence of flavonol glycosides in this species as well as in three other genera of the Gentianaceae: Centaurium, Coutoubea and Eustoma, is in agreement with the grouping of these four genera in the subtribe Chlorae of the Gentianeae.     

Two flavonol glycosides from Chenopodium quinoa.

Two new flavonol glycosides from the seeds of Chenopodium quinoa have been isolated. Their structures were established as kaempferol 3-apiofuranosyl(1"'----2")rhamnopyranosyl(1"----6")galactoside and kaempferol 3-apiofuranosyl(1"'----2")rhamnopyranosyl(1"----6")galactoside. The main flavonoid glycoside was kaempferol 3-(2,6-dirhamnopyranosyl)galactoside.     

Steroidal glycosides from the bulbs of Lilium dauricum.

The bulbs of Lilium dauricum yielded 11 compounds, including six new steroidal glycosides. The structures have been determined by spectral analysis and hydrolysis to be (25R,26R)-26-methoxyspirost-5-en-3 beta-ol 3-O-alpha-L-rhamnopyranosyl-(1----2)-O-[alpha-L-arabinopyranosyl-( 1----3)]- beta-D-glucopyranoside, (25R,26R)-26-methoxyspirost-5-en-3 beta-ol 3-O-alpha-L-rhamnopyranosyl-(1----2)-O-[beta-D-glucopyranosyl-(1----4)]- beta-D-glucopyranoside, (25R)-spirost-5-en-3 beta-ol (diosgenin) 3-O-alpha-L-rhamnopyranosyl-(1----2)-O-[alpha-L-arabinopyranosyl- (1----3)]-beta-D-glucopyranoside, (25R)-3 beta,17 alpha-dihydroxy-5 alpha-spirostan-6-one 3-O-alpha-L-rhamnopyranosyl-(1----2)-beta-D-glucopyranoside, (25R)-3 beta, 17 alpha-dihydroxy-5 alpha-spirostan-6-one 3-O-alpha-L-rhamnopyranosyl-(1----2)-O-[alpha-L- arabinopyranosyl-(1----3)]-beta-D-glucopyranoside and (20R,22R)-3 beta,20,22-trihydroxy-5 alpha-cholestan-6-one (tenuifoliol) 3-O-alpha-L-rhamnopyranosyl-(1----2)-beta-D-glucopyranoside. The absolute configurations of C-20 and C-22 of tenuifoliol were further confirmed by detailed analysis of the NOE difference spectrum of the corresponding isopropylidene derivative. Several known compounds were also isolated and identified.     

Acetylated flavonol diglucosides from Meconopsis quintuplinervia

Four acetylated flavonol diglucosides, quercetin 3-O-[2'-O-acetyl-beta-d-glucopyranosyl-(1-->6)-beta-d-glucopyranoside], quercetin 3-O-[2',6'-O-diacetyl-beta-d-glucopyranosyl-(1-->6)-beta-d-glucopyranoside], isorhamnetin 3-O-[2'-O-acetyl-beta-d-glucopyranosyl-(1-->6)-beta-d-glucopyranoside], and quercetin 3-O-[2'-O-acetyl-alpha-l-arabinopyranosyl-(1-->6)-beta-d-glucopyranoside], together with five known flavonol glycosides quercetin 3-O-beta-d-glucopyranoside, kaempferol 3-O-beta-d-glucopyranoside, quercetin 3-O-[beta-d-galactopyranosyl-(1-->6)-glucopyranoside], isorhamnetin 3-O-[beta-d-galactopyranosyl-(1-->6)-beta-d-glucopyranoside], and kaempferol 3-O-[beta-d-glucopyranosyl-(1-->2)-beta-d-glucopyranoside] have been isolated from Meconopsis quintuplinervia. Their structures were determined using chemical and spectroscopic methods including HRFABMS, (1)H-(1)H COSY, HSQC and HMBC experiments.     

Bayogenin and asterogenic acid glycosides from Bellis perennis.

Four novel triterpenoid saponins were isolated from the underground parts of Bellis perennis. The structures were elucidated as 3-O-beta-D-glucopyranosides of 2 beta,3 beta,16 alpha-trihydroxyolean-12-ene-28-oic acid-28-alpha-L- rhamnopyranosyl(1----2)-[beta-D-glucopyranosyl(1----6)]-beta-D- glucopyranoside, 2 beta,3 beta,23-trihydroxyolean-12-ene-28-oic acid-28-O-beta-D-xylopyranosyl (1----2)-[beta-D-glucopyranosyl (1----6)]- beta-D-glucopyranoside and 2 beta,3 beta,23-trihydroxyolean-12-ene-28-oic acid-28-O-alpha-L-rhamnopyranosyl(1----2)-[beta-D-glucopyranosyl(1----6) ]- beta-D-glucopyranoside and as 3-O-alpha-L-rhamnopyranosyl-2 beta,3 beta,23-trihydroxyolean-12-ene-28-oic acid-28-O-beta-D-glucopyranosyl(1----2)-[beta-D-glucopyranosyl(1----6)]- beta-D-glucopyranoside by means of high field 1D and 2D NMR spectroscopic methods without recourse to derivatization or comparison with previous data.     

The structures of oligosaccharides excreted by sheep with swainsonine toxicosis

Eleven oligosaccharides were purified form the urine of sheep with swainsonine toxicosis induced by the feeding of Astragalus lentiginosus. Oligosaccharides were extracted by charcoal adsorption, chromatographed on Bio-Gel P-2, and partially fractionated by preparative-layer chromatography. Separation into individual compounds was completed by semi-preparative high pressure liquid chromatography. Structures were determined by a combination of high pressure liquid chromatography and exo- and endo- glycosidase action, methanolysis followed by gas-liquid chromatography, methylation analysis, and high resolution nuclear magnetic resonance spectroscopy. Two homologous series of oligosaccharides were identified: (a) alpha-D-Manp-(1----6)-beta-D-Manp-(1----4)-D-GlcpNAc, alpha-D-Manp(1----3)-[alpha-D-Manp-(1----6)]-beta-D-Manp+ ++-(1----4)-D-GlcpNAc, alpha-D-Manp-(1----2)-alpha-D-Manp(1----3)-[alpha-D-Manp+ ++-(1----6)]-beta-D-Manp-(1----4)-D-GlcpNAc, and alpha-D-Manp-(1----2)-alpha-D-Manp-(1----2)-alpha-D-Manp+ ++-(1----3)-[alpha- D-Manp-(1----6)]-beta-D-Manp-(1----4)-D-GlcpNAc (minor series); (b) alpha-D-Manp-(1----6)-beta-D-Manp-(1----4)-beta-D-GlcpNAc- (1----4)-D-GlcpNAc, alpha-D-Manp-(1----3)-[alpha-D-Manp-(1----6)]-beta-D-Manp -(1----4)-beta-D-GlcpNAc-(1----4)-D-GlcpNAc, alpha-D-Manp(1----3)-alpha-D-Manp-(1----6)-beta-D-Manp -(1----4)-beta-D-GlcpNAc- (1----4)-D-GlcpNAc, alpha-D-Manp-(1----6)-alpha-D-Manp-(1----6)-beta-D-Manp++ +-(1----4)-beta-D-GlcpNAc - (1----4)-D-GlcpNAc, alpha-D-Manp-(1----3)-alpha-D-Manp-(1----6)-[alpha-D-Manp -(1----3)]-beta-D- Manp-(1----4)-beta-D-GlcpNAc-(1----4)-D-GlcpNAc, alpha-D-Manp-(1----3)-[alpha-D-Manp-(1----6)]-alpha-D-Man p-(1----6)-beta-D- Manp-(1----4)-beta-D-GlcpNAc-(1----4)-D-GlcpNAc, and alpha-D-Manp-(1----3)-[alpha-D-Manp-(1----6)]-alpha-D-Man p-(1----6)- [alpha-D-Manp-(1----3)]-beta-D-Manp-(1----4)-beta-D-GlcpNAc- (1----4)-D- GlcpNAc (major series).     

Jatropham derivatives and steroidal saponins from the bulbs of Lilium hansonii.

Two new jatropham derivatives and three new steroidal saponins were isolated from the fresh bulbs of Lilium hansonii, along with previously known compounds. The structures of the new compounds were elucidated, on the basis of spectroscopic data and chemical evidence, and by comparing them with those of known compounds, as (-)-5-hydroxy-3-methyl-3-pyrrolin-2-one (jatropham) 5-O-beta-D-glucopyranosyl-(1----3)-beta-D-glucopyranoside, (2S*,4R*)-1-(3-methyl-2-oxo-3-pyrrolinyl)-4-methyl-5-oxo-2-pyrr olidinecarboxyli c acid, 26-O-beta-D-glucopyranosyl-(25R)-5 alpha-furostan-3 beta,22 zeta-diol 3-O-alpha-L-rhamnopyranosyl-(1----2)-O-[beta-D-glucopyranosyl-(1----4)]- beta-D-glucopyranoside, (25R)-5 alpha-spirostan-3 beta,12 alpha-diol 3-O-alpha-L-rhamnopyranosyl-(1----2)-O-[beta-D-glucopyranosyl-(1----4)]- beta-D-glucopyranoside and (25R)-spirost-5-en-3 beta,12 alpha-diol 3-O-alpha-L-rhamnopyranosyl-(1----2)-O-[beta-D-glucopyranosyl-(1----4)]- beta-D-glucopyranoside, respectively. The stereostructure of jatropham dimer, the plain structure of which was presented previously, was confirmed by X-ray crystallographic analysis. The inhibitory activity on cyclic AMP phosphodiesterase of the steroidal saponins was evaluated.     

Antioxidant activity of flavonoids from Sideritis javalambrensis.

Five flavonoid glycosides, 4'-O-methylisoscutellarein 7-O-[6"'-acetylallopyranosyl(1----2)glucopyranoside], 4'-O-methylisoscutellarein 7-O-allopyranosyl(1----2)glucopyranoside, 3'-hydroxy-4'-O-methylisoscutellarein 7-O-[6"'-acetylallopyranosyl(1----2) glucopyranoside], and hypolaetin-8-glucoside have been isolated from Sideritis javalambrensis aerial parts and identified by standard methods. These glycosides have been tested for their antioxidant properties alongside other 7,8-substituted flavonoids using FeSO4/cysteine-induced microsomal lipid peroxidation. Superoxide scavenging activity was assessed in the nitroblue tetrazolium test. Among this series of flavonoids, hypolaetin-8-glucoside is the most potent inhibitor of nonenzymic lipid peroxidation. The antiperoxidative activity of these flavonoids may be related to their superoxide scavenging ability.     

Bioactive flavonoids and saponins from Climacoptera obtusifolia

Two bidesmosidic saponins were isolated from Climacoptera obtusifolia (Chenopodiaceae) and their structures were determined as gypsogenin 3-O-[beta-D-xylopyranosyl-(1-->3)-beta-D-glucopyranoside]-28-O-{beta-D-glucopyranosyl} ester (1) and hederagenin 3-O-[beta-D-xylopyranosyl-(1-->3)-beta-D-glucopyranoside]-28-O-[beta-D-glucopyranosyl} ester (2), by spectroscopic methods. Two known compounds, isorhamnetin 3-O-beta-D-glucopyranoside (3), and isorhamnetin 3-O-[alpha-L-rhamnopyranosyl-(1-->6)-beta-D-glucopyranoside (4) were also isolated for the first time from this plant. Compounds 1-4 were tested in various immunomodulatory assays. Compound 2 suppressed (92%) the reactive oxygen species (ROS) production on mononuclear cells in luminol-based chemiluminescence (CL) assay at a higher concentration (50 microg/mL). Compounds 3 and 4 demonstrated a strong inhibition on ROS production in the oxidative burst activity of whole blood, neutrophils, and mononuclear cells. Additionally compounds 3 and 4 also suppressed PHA T-cell proliferation with no cytotoxic effects.     

Triterpene saponins from Verbascum songaricum.

Songarosaponin A, B and C isolated from the aerial parts of Verbascum songaricum were shown to be 3-O-[alpha-L-rhamnopyranosyl-(1----4)-beta-D-glucopyranosyl-(1----3)]-[b eta-D-glucopyranosyl-(1----2)-beta-D-fucopyranosyl]-olea-11,13-die ne-3 beta-23,28-triol, 3-0-[alpha-L-rhamnopyranosyl-(1----4)-beta-D-glucopyranosyl-(1----3)]-[b eta-D-glucopyranosyl-(1----2)]-beta-D-fucopyranosyl]-olea-1 1-ene-3 beta-13,23,28-tetrol and 3-O-[beta-D-glucopyranosyl-(1----4)]-[beta-D-glucopyranosyl-(1----3)]-[b eta-D-glucopyranosyl-(1----2)]-beta-D-fucopyranosyl]-13 beta,28-epoxyolea-11-ene-3 beta,23-diol.     

Elongation of both branches of biantennary backbones of oligo-(N-acetyllactosamino)glycans by human serum (1----3)-N-acetyl-beta-D- glucosaminyltransferase.

Partial reactions catalyzed by a (1----3)-N-acetyl-beta-D- glucosaminyltransferase (EC2.4.1.149), known to be present in human serum, were studied by use of biantennary "backbone" saccharides of oligo-N-acetyllactosamine-type as acceptors. Incubation of the radiolabeled blood-group I-active hexasaccharide, beta-D-Galp-(1----4)-beta-D-GlcpNAc-(1----3)-[beta-D-Galp- (1----4)-beta-D-GlcpNAc-(1----6)]-beta-D-Galp-(1----4)-D-GlcNAc (1) and UDP-GlcNAc with serum gave first a transient 1:1 mixture of two isomeric heptasaccharides, beta-D-GlcpNAc-(1----3)-beta-D-Galp-(1----4)-beta-D- GlcpNAc-(1----3)-[beta-D-Galp-(1----4)-beta-D-GlcpNAc-(1----6)]-beta-D- Galp-(1----4)-D-GlcNAc (2) and beta-D-Galp-(1----4)-beta-D-GlcpNAc-(1----3)-[beta-D-GlcpNAc-(1----3)- beta-D-Galp-(1----4)-beta-D-GlcpNAc-(1----6)]-beta-D-Galp-(1----4)-D-Glc NAc (3), showing that both branches of 1 react equally well. The two heptasaccharides reacted further in the incubation mixture to form the radiolabeled octasaccharide, beta-D-GlcpNAc-(1----3)-beta-D-Galp-(1----4)-beta-D-GlcpNAc-(1----3)-[be ta-D- GlcpNAc-(1----3)-beta-D-Galp-(1----4)-beta-D-GlcpNAc-(1----6)]-beta-D-Ga lp- (1----4)-D-GlcNAc (4); during this second reaction, the composition of the heptasaccharide mixture remained unchanged, indicating that 2 and 3 reacted at approximately equal rates. The heptasaccharides 2 and 3 could not be separated from each other, but they could be detected, identified, and quantitatively determined by stepwise enzymic degradations. Partial (1----3)-N-acetyl-beta-D-glucosaminylation reactions, carried out with another acceptor, the branched pentasaccharide, beta-D-Galp-(1----4)-beta-D-GlcpNAc-(1----3)-[beta-D-Galp-(1----4)-beta- D- GlcpNAc-(1----6)]-beta-D-Gal (11), revealed that it reacted also equally well at both branches.(ABSTRACT TRUNCATED AT 400 WORDS)     

Four major saponins from Solidago canadensis.

Four new bisdesmosidic saponins each containing eight carbohydrate units were isolated from Solidago canadensis. GC, GC-MS, FABMS analysis and mainly the use of 2D NMR techniques allowed their identification as bayogeninglycosides (canadensissaponins 1-4) 3-O- [beta-D-glucopyranosyl-(1----3)-beta-D-glucopyranosyl]-28-O-[alpha-L- rhamnopyranosyl-(1----3)-beta-D-xylopyranosyl-(1----4)-[beta-D- xylopyranosyl-(1----3)]-alpha-L-rhamnopyranosyl-(1----2)-[beta-D- apio-D-furanosyl-(1----3)]-beta-D-6-deoxyglucopyranosyl- (1----]-bayogenin; -(1----2)-[beta-D-apio-D-furanosyl-(1----3)]-ara- binopyranosyl-(1----]-bayogenin; -[alpha-L-rhamnopyranosyl-(1----3)]-beta- D-6-deoxyglucopyranosyl-(1----]-bayogenin and - [alpha-L-rhamnopyranosyl- (1----3)]-arabinopyranosyl-(1----]-bayogenin.     

Primary structure of four human milk octa-, nona-, and undeca-saccharides established by 1H- and 13C-nuclear magnetic resonance spectroscopy.

The structures of two octasaccharides, one nonasaccharide, and one undecasaccharide, isolated from human milk, have been investigated by 1H- and 13C-nuclear magnetic resonance spectroscopy. The structures of these oligosaccharides are: beta-D-Galp-(1----4)-[alpha-L-Fucp- (1----3)]-beta-D-GlcpNAc-(1----3)-beta-D-Galp-(1----4)-[alpha-L-Fucp+ ++- (1----3)]-beta-D-GlcpNAc-(1----3)-beta-D-Galp-(1----4)-D-Glc; beta-D-GALp-(1----3)-[alpha-L-Fucp-(1----4)]-beta-D-GlcpNAc-(1---- 3)-beta-D - Galp-(1----4)-[alpha-L-Fucp-(1----3)]-beta-D-GlcpNAc-(1----3)-beta -D-Galp- (1----4)-D-Glc; beta-D-Galp-(1----4)-[alpha-L-Fucp-(1----3)]-beta-D-GlcpNAc-(1---- 6)-(alpha - L-Fucp-(1----2)-beta-D-Gal-(1----3)-[alpha-L-Fucp-(1----4)]- beta-D-GlcpNAc- (1----3))-beta-D-Galp-(1----4)-D-Glc; and alpha-L-Fucp-(1----2)-beta-D-Galp-(1----3)-beta-D-GlcpNAc-(1----3) -beta-D- Galp-(1----4)-[alpha-L-Fucp-(1----3)]-beta-D-GlcpNAc-(1----6)-[alp ha-L- Fucp-(1----2)-beta-D-Galp-(1----3)-beta-D-GlcpNAc-(1----3)]-beta-D -Galp- (1----4)-D-Glc. The two octasaccharides have been previously isolated from human milk as a mixture, and in a pure form from new-born feces, but the n.m.r. data were not provided. These two octasaccharides display the di-Lewis X and the composite Lewis A-Lewis X antigenic determinant, previously described as neo-antigens of adenocarcinoma cell lines.     

Primary structure determination of five sialylated oligosaccharides derived from bronchial mucus glycoproteins of patients suffering from cystic fibrosis. The occurrence of the NeuAc alpha(2----3)Gal beta(1----4)[Fuc alpha(1----3)] GlcNAc beta(1----.) structural element revealed by 500-MHz 1H NMR spectroscopy

The structure of sialylated carbohydrate units of bronchial mucins obtained from cystic fibrosis patients was investigated by 500-MHz 1H NMR spectroscopy in conjunction with sugar analysis. After subjecting the mucins to alkaline borohydride degradation, sialylated oligosaccharide-alditols were isolated by anion-exchange chromatography and fractionated by high performance liquid chromatography. Five compounds could be obtained in a rather pure state; their structures were established as the following: A-1, NeuAc alpha(2----3)Gal beta(1----4) [Fuc alpha(1----3)]GlcNAc beta(1----3)Gal-NAc-ol; A-2, NeuAc alpha(2----3)Gal beta(1----4)GlcNAc beta(1----6)-[GlcNAc beta (1----3)]GalNAc-o1; A-3, NeuAc alpha(2----3)Gal beta-(1----4)[Fuc alpha(1----3)]GlcNAc beta(1----3)Gal beta(1----3) GalNAc-o1; A-4, NeuAc alpha(2----3)Gal beta(1----4)[Fuc alpha(1----3)]Glc-NAc NAc beta(1----6)[GlcNAc beta(1----3)]GalNAc-o1; A-6,NeuAc alpha-(2----3) Gal beta(1----4)[Fuc alpha(1----3)]GlcNAc beta(1----6)[Gal beta-(1----4) GlcNAc beta(1----3)]GalNAc-o1. The simultaneous presence of sialic acid in alpha(2----3)-linkage to Gal and fucose in alpha(1----3)-linkage to GlcNAc of the same N-acetyllactosamine unit could be adequately proved by high resolution 1H NMR spectroscopy. This sequence constitutes a novel structural element for mucins.     

Conformation analysis of modified tetrasaccharide sequences of the N-glycoprotein type--problem of the alpha-(1 to 6)-glycosidic bond

The conformational analysis of the recently synthesized tetrasaccharides alpha-D-Manp (1----3)-[alpha-D-Manp-(1----6)]-4-deoxy-beta-D-lyx-hexp+ ++-(1----4)-D-GlcNAc (2) and alpha-D-Manp-(1----3)-[alpha-D-Manp-(1----6)]-beta-D-Talp -(1----4)-D-GlcNAc (3) will be described. The preferred solution conformation of 2 and 3 is a gt-conformation, which is nearly identical with the preferred conformation of the naturally occurring tetrasaccharide alpha-D-Manp-(1----3)-[alpha-D-Manp-(1----6)]-beta-D-Manp -(1----4)-D-GlcNAc (1). The main structural feature is the backfolding of the alpha-(1----6)-linked D-Man to the reducing D-GlcNAc unit. Conformational analysis of the tetrasaccharides alpha-D-Manp-(1----3)-[alpha-D-Manp-(1----6)]-beta-D-Manp -(1----4)-1,6- anhydro-beta-D-GlcNAc (4), alpha-D-Manp-(1----3)-alpha-D-Manp-(1----6)]-4-deoxy-beta-D- lyx-hexp-(1----4)- 1,6-anhydro-beta-D-GlcNAc (5), and alpha-D-Manp-(1----3)-[alpha-D-Manp-(1----6)]-beta-D-Talp -(1----4)- 1,6-anhydro-beta-D-GlcNAc (6) gave additional proof for this backfolding. The substitution of the reducing unit leads to a smaller amount of gt- and a greater amount of gg-conformers. The method used for conformational analysis of 2-6 is a combination of n.m.r.-experiments and HSEA-calculations with the program GESA. Concerning the application of new 2D-techniques, the COLOC-experiment turned out to be extremely useful in sequencing oligosaccharides.     

Coumaroyl flavonol glycosides from the leaves of Ginkgo biloba.

Two coumaroyl flavonol glycosides, isorhamnetin 3-O-alpha-L-[6"'-p-coumaroyl-(beta-D)-glucopyranosyl-(1,2)-rhamnopyranoside], and kaempferol 3-O-alpha-L-[6"'-p-coumaroyl-(beta-D)-glucopyranosyl-(1,2)-rhamnopyranoside]-7-O-beta-D-glucopyranoside, were isolated from the n-BuOH extract of Ginkgo biloba leaves. These two, together with six other flavonol glycosides, kaempferol 3-O-alpha-L-[6"'-p-coumaroyl-(beta-D)-glucopyranosyl-(1,2)-rhamnopyranoside], quercetin 3-O-alpha-L-[6"'-p-coumaroyl-(beta-D)-glucopyranosyl-(1,2)-rhamnopyranoside], quercetin 3-O-alpha-L-[6"'-p-coumaroyl-(beta-D)-glucopyranosyl-(1,2)-rhamnopyranoside]-7-O-beta-D-glucopyranoside, quercetin 3-O-beta-D-glucopyranosyl-(1-2)-alpha-L-rhamnopyranoside, quercetin 3-O-beta-rutinoside, and quercetin 3-O-beta-D-glucopyranoside, showed profound antioxidant activities in DPPH and cytochrome-c reduction assays using the HL-60 cell culture system.     

Structural elucidation of two capsular polysaccharides from one strain of Bacteroides fragilis using high-resolution NMR spectroscopy.

The capsule of Bacteroides fragilis is unusual in that it consists of two distinct capsular polysaccharides. Using a combination of high-resolution NMR spectroscopy, theoretical calculations, and as few chemical procedures as required, the structure of both polysaccharide antigens (polysaccharides A and B) was elucidated. Using the above procedures, it was possible to obtain the complete structures using minimal quantities of polysaccharides A and B (8 and 5 mg, respectively). Only small amounts of each subjected to chemical analysis were not recoverable. Polysaccharide A is composed of the following repeating unit: [----3)alpha-D-AATp(1----4)[beta-D-Galf(1----3)]alpha-D- GalpNAc(1----3)beta-D-Galp(1----], where AAT is 2-acetamido-4-amino-2,4,6-trideoxygalactose. A pyruvate substituent having the R configuration spans O-4 and O-6 of the beta-D-galactopyranosyl residue. Polysaccharide B is composed of the following repeating unit: [----4)alpha-L-QuipNAc(1----3)beta-D-QuipNAc(1----4)[alpha-L - Fucp(1----2)beta-D-GalpA(1----3)beta-D-GlcpNAc(1----3)]alpha -D-Galp(1----]. A 2-aminoethylphosphonate substituent is situated on O-4 of the N-acetyl-beta-D-glucopyranosyl residue.     

Steroidal saponins from the rhizomes of Smilax sieboldii.

Six new steroidal saponins were isolated from the rhizomes of Smilax sieboldii. Their structures were determined by spectroscopic analysis and hydrolysis to be 3 beta-hydroxy-(25R)-5 alpha-spirostan-6-one (laxogenin) 3-O-beta-D-glucopyranosyl-(1----4)-O-[alpha-L-arabinopyranosyl-(1- ---6)]-beta-D-glucopyranoside, laxogenin 3-O-alpha-L-arabinopyranosyl-(1----6)-beta-D-glucopyranoside, 3 beta,27-dihydroxy-(25S)-5 alpha-spirostan-6-one 3-O-beta-D-glucopyranosyl-(1----4)-O-[alpha-L-arabinopyranosyl-(1- ---6)]- beta-D-glucopyranoside, 26-O-beta-D-glucopyranosyl-3 beta,22 xi,26-trihydroxy-(25R)-5 alpha-furostan-6-one 3-O-alpha-L-arabinopyranosyl-(1----6)-beta-D-glucopyranoside, 26-O-beta-D-glucopyranosyl-3 beta,22 xi,26-trihydroxy-(25R)-5 alpha-furostan-6- one 3-O-beta-D-glucopyranosyl-(1----4)-O-[alpha-L-arabinopyranosyl-(1- ---6)]- beta-D-glucopyranoside and (25R)-5 alpha-spirostan-3 beta-ol (tigogenin) 3-O-beta-D-glucopyranosyl-(1----4)-O-[alpha-L-arabinopyranosyl- (1----6)]-beta-D-glucopyranoside. The inhibition of cAMP phosphodiesterase by the saponins was evaluated.     

Flavonoids of Ochradenus baccatus.

From the aerial parts of Ochradenus baccatus, the new flavonoids, quercetin 3-O-beta-glucosyl(1----2)-alpha-rhamnoside-7-O-alpha-rhamnoside and quercetin 3-O-p-coumaryl(1----6)-beta-glucosyl(1----6)-beta-glucoside-7-O-alpha rhamnoside were isolated. The known quercetin glycosides, quercetin 3-gentiobioside, isoquercitrin, quercitrin, together with the known kaempferol glycosides, astragalin and afzelin, were also characterized. The structures were established by conventional methods of analysis and confirmed by spectral analysis.