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.     

Four flavonol glycosides from Achlys triphylla.

Four new flavonol glycosides were isolated from the underground parts of Achlys triphylla in addition to eight known compounds. By means of spectroscopic analysis, the structures were characterized as isorhamnetin 3-glucosyl(1----3)galactoside, isorhamnetin 3-[6'acetylglucosyl(1----3)galactoside], isorhamnetin 3-[4'6'-di-acetylglucosyl(1----3)galactoside], and syringetin 3-[6'-acetylglucosyl(1----3)galactoside], respectively. In the aerial parts of the plant, seven known compounds were also confirmed.     

Use of 1H NMR ROESY for structural determination of O-glycosylated amino acids from a serine-containing glycopeptidolipid antigen.

A serine-containing glycopeptidolipid antigen isolated from Mycobacterium xenopi typified a new class of mycobacterial glycopeptidolipid antigens devoid of the C-mycoside core structure [Rivière, M., & Puzo, G. (1991) J. Biol. Chem. 266, 9057-9063]. The lipopeptide core assigned to C12-Ser-Ser-Phe-alloThr-OCH3 exhibits three potential sites of glycosylation. The carbohydrate parts are composed of 3-O-methyl-6-deoxy-alpha-L-talopyranosyl and 2,3,4-tri-O-methyl-L- rhamnopyranosyl(alpha 1----3)-2-O-lauroyl-L-rhamnopyranosyl(alpha 1----3)-L- rhamnopyranosyl(alpha 1----3)-2,4-di-O-(acetyl, lauroyl)-6-deoxy-alpha-L-glucopyranosyl appendages. In the present work, the carbohydrate attachment sites were successfully determined by ROESY experiments on the native glycopeptidolipid using chloroform as solvent. From the NOE contacts, we unambiguously established that the acylated serine is glycosylated by the 3-O-methyl-6-deoxy-alpha-L-talopyranosyl appendage while the 2,3,4-tri-O-methyl-L-rhamnopyranosyl(alpha 1----3)-2-O- lauroyl-L-rhamnopyranosyl(alpha 1----3)-L-rhamnopyranosyl(alpha 1----3)-2,4-di- O-(acetyl, lauroyl)-6-deoxy-alpha-L-glucopyranosyl appendage is bound to the C-terminal alloThr-OCH3. From these data, the acetyl and lauroyl residues on the C-2 and C-4 of the basal monosaccharide unit were successfully localized. Furthermore, the "L" absolute configuration for the serines and the phenylalanine residues and the "D" configuration for the allothreonine were established. The primary structure of this novel type of mycobacterial antigen, a serine-containing glycopeptidolipid, has now been fully established.     

Triterpene saponins from Cylicodiscus gabunensis.

Four new saponins were isolated from the alcoholic extract of the bark of Cylicodiscus gabunensis by means of flash chromatography. They were characterized on the basis of spectral and chemical data as 3-O-beta-[alpha-L-arabinopyranosyl (1----2),alpha-L-arabinopyranosyl(1----3),beta-D-glucopyranosyl(1- ---)] maslinic acid-28-[beta-D-glucopyranosyl(1----6),beta-D-glucopyranosyl(1----2),alp ha-L- rhamnopyranosyl(1----)] ester; 3-O-beta-[alpha-L-arabinopyranosyl(1----2),alpha-L-arabinopyran osyl (1----3),beta-D-glucopyranosyl(1----)]maslinic acid-28-[beta-D-glucopyranosyl(1----2),alpha-L-rhamnopyranosyl(1----)] ester, 3-O-beta-[alpha-L-arabinopyranosyl(1----2),alpha-L-arabinopyran osyl (1----3),beta-D-glucopyranosyl(1----)]maslinic acid and 3-O-beta(alpha-L-arabinopyranosyl(1----3),beta-D-glucopyranosyl (1----)] cylicodiscic acid.     

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.     

Two flavonol glycosides from seeds of Camellia sinensis.

Two novel flavonol triglycosides, camelliaside A and B, have been isolated from seeds of Camellia sinensis. The structures were determined to be kaempferol 3-O-[2-O-beta-D- galactopyranosyl-6-O-alpha-L-rhamnopyranosyl]-beta-D-glucopyranoside and kaempferol 3-O-[2-O-beta- D-xylopyranosyl-6-O-alpha-L-rhamnopyranosyl]-beta-D-glucopyranoside on the basis of spectroscopic, chemical and enzymatic studies. These types of interglycosidic linkages, Gal(1----2)[Rha(1----6)]Glc and Xyl(1----2)[Rha(1----6)]Glc, have not been reported previously in flavone and flavonol glycosides.     

A gamma-pyronyl-triterpenoid saponin from Pisum sativum.

A new triterpenoid saponin was isolated from Pisum sativum and characterized as 3-O-[alpha-L-rhamnopyranosyl-(1----2)-beta-D-galactopyranosyl(1----2)-be ta- D-glucuronopyranosyl(1----)]-22-O-[3'-hydroxy-2'-methyl-5',6'-dihy dro-4'- pyrone(6'----)]-3 beta, 22 beta, 24-trihydroxyolean-12-ene. The name chromosaponin I is proposed. Chromosaponin I yielded soyasaponin I, known as phytochrome inhibitor, during extraction, but the latter was not found in the free form in this plant.     

Triterpenoid saponins from Triplostegia grandiflora.

Four new oleanane triterpenoid saponins named triplosides D-G were isolated from the roots of Triplostegia grandiflora. Their structures were elucidated on the basis of chemical degradation and spectral evidence. The saponins investigated were: oleanolic acid 3-O-beta-D-xylopyranosyl(1----4)-beta-D-xylopyranosyl(1----3)-beta-D- xylopyranosyl(1----4)-alpha-L-rhamnopyranosyl(1----3)-beta-D- xylopyranosyl(1----3)-alpha-L-rhamnopyranosyl(1----2)-beta-D-xylopyranos ide, oleanolic acid 3-O-beta-D-glucopyranosyl(1----6)-[beta-D- xylopyranosyl(1----4)]-beta-D-glucopyranosyl(1----3)-beta-D- xylopyranosyl(1----4)-alpha-L-rhamnopyranosyl(1----3)-beta-D- xylopyranosyl(1----3)-alpha-L-rhamnopyranosyl(1----2)-beta-D-xylopyranos ide, oleanolic acid 3-O-beta-D-xylopyranosyl(1----3)-beta-D-xylopyranosyl(1----4)- alpha-L-rhamnopyranosyl(1----3)-beta-D-xylopyranosyl(1----3)-alpha-L- rhamnopyranosyl(1----2)-beta-D-xylopyranoside and oleanolic acid 3-O-alpha-L-rhamnopyranosyl(1----3)-beta-D-xylopyranosyl(1---3)-alpha-L- rhamnopyranosyl(1----2)-beta-D-xylopyranoside, respectively. All of them have a common aglycone and are monodesmosides.     

Further specific triglycosyl phenol phthiocerol diester from Mycobacterium tuberculosis

Mono- and two-dimensional 1H-NMR allowed the structural elucidation of a glycolipid belonging to the phenolic mycosides series: 2,3,4-tri-0-methyl fucopyranosyl (alpha 1----3) rhamnopyranosyl (alpha 1----3) rhamnopyranosyl (alpha 1----dimycocerosyl) phenol phthiocerol. It shares with the major phenolic glycolipid the two terminal sugar residues, suggesting its potential antigenicity. The glycolipid may also represent an intermediate in the biosynthesis of the major one.     

Saponins from Deutzia corymbosa.

Two new saponins were isolated from Deutzia corymbosa and characterized as: echinocystic acid-3-O-[alpha-L-arabinopyranosyl(1----4)]alpha-L- arabinopyranoside and echinocystic acid-3-O-[beta-D-galactopyranosyl(1----4)alpha-L- rhamnopyranosyl(1----4)]alpha-L-arabinopyranoside. Umbellferone and sitosterol-beta-D-glucoside were also isolated and characterized.     

Saponins from Steganotaenia araliacea.

Six saponins have been isolated and identified from the leaves of Steganotaenia araliacea. They were identified as 3-O-[beta-D-galactopyranosyl(1----2)-(beta-D-galactopyranosyl (1----3))-beta-D-glucuronopyranosyl]-21-O-tigloyl and -21-O-angeloyl-R1-barrigenol, 3-O-[beta-D-glucopyranosyl(1----2)-(beta-D-xylopyranosyl (1----3))-beta-D-glucuronopyranosyl]-21-O-tigloyl and -21-O-angeloyl-R1-barrigenol, 3-O-[beta-D-glucopyranosyl(1----2)-(beta-D-glucopyranosyl-(1----3))-(alp ha-L- rhamnopyranosyl(1----4))-beta-D-glucopyranosyl] steganogenin and 3-O-[(beta-D-galactopyranosyl(1----2)-beta-D-glucuronopyranosyl]-2 8-O- beta-D-glucopyranosyl olean-12-ene-28-oic acid. Steganogenin is a new 17,22-seco-oleanolic acid derivative. The structures of the saponins were established by analysis of their 1H and 13C NMR spectra with the help of 2D-experiments and by Californium Plasma Desorption Mass Spectrometry.     

Flavonol triglycosides containing galactose in tea.

The isolation and structural elucidation of new quercetin and kaempferol triglycosides from Camellia sinensis is described. Their structures were determined as quercetin and kaempferol 3-glucosyl(1----3) rhamnosyl(1----6)galactosides. The content of quercetin glucosylrhamnosylgalactoside ranged between 0 and 87 mg per 100 g, and that of the kaempferol homologue between 0 and 119 mg per 100 g dry wt.     

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.     

Characterisation of the phenolic profile of Boerhaavia diffusa L. by HPLC-PAD-MS/MS as a tool for quality control

Phenolic acids and flavonols of nine leaf and three root samples of Boerhaavia diffusa L., collected at different locations and subjected to several drying procedures, were characterised by reversed-phase HPLC-PAD-ESI/MS for the first time. Ten phenolic compounds were identified: 3,4-dihydroxy-5-methoxycinnamoyl-rhamnoside, quercetin 3-O-rhamnosyl(1-->6)galactoside (quercetin 3-O-robinobioside), quercetin 3-O-(2"-rhamnosyl)-robinobioside, kaempferol 3-O-(2"-rhamnosyl)-robinobioside, 3,5,4'-trihydroxy-6,7-dimethoxyflavone 3-O-galactosyl(1-->2)glucoside [eupalitin 3-O-galactosyl(1-->2)glucoside], caffeoyltartaric acid, kaempferol 3-O-robinobioside, eupalitin 3-O-galactoside, quercetin and kaempferol. Quantification was achieved by HPLC-PAD and two phenolic patterns were found for the leaves, in which quercetin 3-O-robinobioside or quercetin 3-O-(2"-rhamnosyl)-robinobioside was the major compound. Caffeoyltartaric acid was only present in the root material where it represented the main phenolic constituent. The results obtained demonstrated that the geographical origin (particularly the nature of the soil), but not the drying process, influences the phenolic composition.     

Synthesis of 6-aminohexylglycosides of a polysaccharide from Streptococcus group A and its fragments

Polycondensation of 4-O-benzoyl-1,2-O-(1-cyanoethylidene)-3-O-(3,4-di-O-benzoyl-2-O-tr ityl-alpha-L- rhamnopyranosyl)-beta-L-rhamnopyranose in the presence of 6-phthalimidohexyl-3,4-di-O-benzoyl-2-O-trityl-alpha-L- rhamnopyranoside affords, after deprotection, the polysaccharide built up of the repeating dissaccharide units----2) Rha (alpha 1----3) Rha (alpha 1----and containing 6-aminohexyl residue at the reducing end. This polysaccharide possesses the structure of the group A-variant streptococcal polysaccharide. Synthesis of 6-aminohexyl glycosides of 2- and 3-O-alpha-L-rhamnopyranosyl-alpha-L-rhamnopyranoses, which corresponds to the repeating units of the above polysaccharide, is described.     

Isoflavonoid glycosides and rotenoids from Pongamia pinnata leaves

Chromatographic separation of a 70% aqueous methanol extract (AME) of Pongamia pinnata (Linn.) Pierre (Leguminosae) leaves has led to the isolation of two new isoflavonoid diglycosides, 4'-O-methyl-genistein 7-O-beta-D-rutinoside (2) and 2',5'-dimethoxy-genistein 7-O-beta-D-apiofuranosyl-(1"'-->6")-O-beta-D-glucopyranoside (6), and a new rotenoid, 12a-hydroxy-alpha-toxicarol (5), together with nine known metabolites, vecinin-2 (1), kaempferol 3-O-beta-D-rutinoside (3), rutin (4), vitexin (7), isoquercitrin (8), kaempferol 3-O-beta-D-glucopyranoside (9), 11,12a-dihydroxy-munduserone (10), kaempferol (11), and quercetin (12). Their structures were elucidated on the basis of chemical and spectroscopic analyses.     

Synthesis of a spacer-containing repeating unit of the capsular polysaccharide of Streptococcus pneumoniae type 23F.

The synthesis is reported of 3-aminopropyl 4-O-(4-O-beta-D-glucopyranosyl-2-O-alpha-L-rhamnopyranosyl-beta-D- galactopyranosyl)-beta-L-rhamnopyranoside 3'-(glycer-2-yl sodium phosphate) (25 beta), which represents the repeating unit of the capsular polysaccharide of Streptococcus pneumoniae type 23F (American type 23) [(----4)-beta-D-Glcp-(1----4)-[Glycerol-(2-P----3)] [alpha-L- Rhap-(1----2)]-beta-D-Galp-(1----4)-beta-L-Rhap-(1----)n). 2,4,6-Tri-O-acetyl-3-O-allyl-alpha-D-galactopyranosyl trichloroacetimidate (5) was coupled with ethyl 2,3-di-O-benzyl-1-thio-alpha-L-rhamnopyranoside (6). Deacetylation of the resulting disaccharide derivative, followed by benzylidenation, and condensation with 2,3,4-trio-O-acetyl-alpha-L-rhamnopyranosyl trichloroacetimidate (10) afforded ethyl 4-O-[3-O-allyl-4,6-O-benzylidene-2-O-(2,3,4-trio-O-acetyl- alpha-L-rhamnopyranosyl)-beta-D-galactopyranosyl]-2,3-di-O-benzyl-1-thio - alpha-L-rhamnopyranoside (11). Deacetylation of 11, followed by benzylation, selective benzylidene ring-opening, and coupling with 2,3,4,6-tetra-O-acetyl-alpha-D-glucopyranosyl trichloroacetimidate (15) gave ethyl 4-O-[3-O-allyl-6-O-benzyl-4-O-(2,3,4,6- tetra-O-acetyl-beta-D-glucopyranosyl)-2-O-(2,3,4-tri-O-benzyl-alpha-L- rhamnopyranosyl)-beta-D-galactopyranosyl]-2,3-di-O-benzyl-1-thio-alpha-L - rhamnopyranoside (16). Deacetylation of 16 followed by benzylation, deallylation, and acetylation yielded ethyl 4-O-[3-O-acetyl-6-O-benzyl-4-O-(2,3,4,6-tetra-O-benzyl-beta-D-glucopy ran osyl)- 2-O-(2,3,4-tri-O-benzyl-alpha-L-rhamnopyranosyl)-beta-D-galactopyranosyl ]-2,3- di-O-benzyl-1-thio-alpha-L-rhamnopyranoside (20). The glycosyl bromide derived from 20, when coupled with 3-benzyloxycarbonylamino-1-propanol, gave the beta-glycoside (21 beta) as the major product. Deacetylation of 21 beta followed by condensation with 1,3-di-O-benzylglycerol 2-(triethylammonium phosphonate) (27), oxidation, and deprotection, afforded 25 beta.     

Syntheses of linear tetra-, hexa-, and octa-saccharide fragments of the i-blood group active poly-(N-acetyl-lactosamine) series. Blockwise methods for the synthesis of repetitive oligosaccharide sequences

N-Phthaloylation of lactosamine gave various glycosyl donors (beta-chloride, beta-trichloroacetimidate) and glycosyl acceptors (3',4'-diol). Coupling of the chloride with a methyl beta-D-glycoside led to the tetrasaccharide fragment, beta-D-Galp-(1----4)-beta-D-GlcpNac-(1----3)-beta-D-Galp-(1----4)- beta-D-GlcpNAcOMe. Acetolysis of the protected tetrasaccharide, followed by treatment with hydrogen chloride, gave a tetrasaccharide chloride which was coupled with the methyl beta-glycoside of lactosamine. A hexasaccharide fragment, [beta-D-Galp-(1----4)-beta-D-GlcpNAc-(1----3)]2-beta-D-Galp-(1----4)-bet a- D-GlcpNAcOMe, was thus obtained by this ("n + 1") method. A more efficient ("n + n") method was applied for the synthesis of an octasaccharide fragment, [beta-D-Galp-(1----4)-beta-D-GlcpNAc-(1----3)]3-beta-D-Galp- (1----4)-beta-D-GlcpNAcOMe (38), where di- and tetra-saccharide intermediates having a 3,4-O-isopropylidene-beta-D-galactopyranosyl nonreducing terminal group and a benzyl beta-D-glycoside group were precursors, either as glycosyl donors (beta-trichloroacetimidates) or glycosyl acceptors (3,4-diols as nonreducing terminal groups). Thus, doubling the length of the repetitive oligosaccharide sequence could be efficiently accomplished at each glycosylation step.     

Synthesis of phosphorylated trimannosides corresponding to end groups of the high-mannose chains of lysosomal enzymes

Glycosylation of suitably protected 8-methoxycarbonyloctyl alpha-D-manno-pyranosides with 2-O-acetyl-3,4,6-tri-O-benzyl-alpha-D-mannopyranosyl chloride provided alpha-D-Manp-(1----2)-alpha-D-Man, alpha-D-Manp-(1----3)-alpha-D-Man and alpha-D-Manp-(1----6)-alpha-D-Man derivatives from which the 2'-hydroxyl group was liberated by O-deacetylation. Addition of the terminal D-mannose 6-phosphate residues was achieved by reaction with the readily accessible 2,3,4-tri-O-acetyl-6-O-diphenoxyphosphoryl-alpha-D-mannopyranosyl bromide under standard glycosylation conditions. Conventional deprotection provided the terminal 6"-phosphate of alpha-D-Manp-(1----2)-alpha-D-Manp-(1----2)-alpha-D-Man, alpha-D-Manp-(1----2)-alpha-D-Manp-(1----3)-alpha-D-Man, and alpha-D-Manp-(1----2)-alpha-D-Manp-(1----6)-alpha-D-Man which are present as end groups on the high-mannose oligosaccharide chains of lysosomal enzymes.