Bioactive saponins from Microsechium helleri and Sicyos bulbosus

Eleven oleanane-type saponins (1-11) have been isolated from Microsechium helleri and Sicyos bulbosus roots and were evaluated for their antifeedant, nematicidal and phytotoxic activities. Saponins {3-O-β-d-glucopyranosyl (1 → 3)-β-d-glucopyranosyl-2β,3β,16α,23-tetrahydroxyolean-12-en-28-oic acid 28-O-α-l-rhamnopyranosyl-(1 → 3)-β-d-xylopyranosyl-(1 → 4)-[β-d-xylopyranosyl-(1 → 3)]-α-l-rhamnopyranosyl-(1 → 2)-α-l-arabinopyranoside} (1), and {3-O-β-d-glucopyranosyl-2β,3β,16α,23-tetrahydroxyolean-12-en-28-oic acid 28-O-α-l-rhamnopyranosyl-(1 → 3)-β-d-xylopyranosyl-(1 → 4)-[β-d-xylopyranosyl-(1 → 3)]-α-l-rhamnopyranosyl-(1 → 2)-α-l-arabinopyranoside} (2) were also isolated from M. helleri roots together with the two known compounds 3 and 4. Seven known structurally related saponins (5-11) were isolated from S. bulbosus roots. The structures of these compounds were established as bayogenin and polygalacic glycosides using one- and two-dimensional NMR spectroscopy and mass spectrometry. Compounds 7, 10, bayogenin (12) and polygalacic acid (13) showed significant (p < 0.05) postingestive effects on Spodoptera littoralis larvae, compounds 5-11 and 12 showed variable nematicidal effects on Meloydogyne javanica and all tested saponins had variable phytotoxic effects on several plant species (Lycopersicum esculentum, Lolium perenne and Lactuca sativa). These are promising results in the search for natural pesticides from the Cucurbitaceae family.     

Acylated flavonol tetraglycosides from Delphinium gracile

An ethanol extract of the aerial parts of Delphinium gracile DC. yielded five flavonol glycosides quercetin-3-O-{[β-d-xylopyranosyl (1 → 3)-4-O-(E-p-caffeoyl)-α-l-rhamnopyranosyl (1 → 6)][β-d-glucopyranosyl (1 → 2)]}-β-d-glucopyranoside (1), quercetin-3-O-{[β-d-xylopyranosyl (1 → 3)-4-O-(E-p-coumaroyl)-α-l-rhamnopyranosyl (1 → 6)][β-d-glucopyranosyl (1 → 2)]}-β-d-glucopyranoside (2), quercetin-3-O-{[β-d-xylopyranosyl (1 → 3)-4-O-(Z-p-coumaroyl)-α-l-rhamnopyranosyl (1 → 6)][β-d-glucopyranosyl (1 → 2)]}-β-d-glucopyranoside (3), kaempferol-3-O-{[β-d-glucopyranosyl (1 → 3)-4-O-(E-p-coumaroyl)-α-l-rhamnopyranosyl (1 → 6)][β-d-glucopyranoside-7-O-(4-O-acetyl)-α-l-rhamnopyranoside (4) kaempferol-3-O-{[β-d-glucopyranosyl (1 → 3)-4-O-(E-p-coumaroyl)-α-l-rhamnopyranosyl (1 → 6)][β-d-glucopyranoside-7-O-(4-O-acetyl)-α-l-rhamnopyranoside (5) in addition to 4-(β-d-glucopyranosyloxy)-6-methyl-2H-pyran-2-one (6) and rutin. Structures were elucidated by spectroscopic methods.     

Antibacterial phenolic components from Eriocaulon buergerianum

Five phenolic components, 1,3,6-trihydroxy-2,5,7-trimethoxyxanthone (1), 7,3′-dihydroxy-5,4′,5′-trimethoxyisoflavone (2), toralactone-9-O-β-d-glucopyranoside (3), patuletin-3-O-[2-O-E-feruloyl-β-d-glucopyranosyl-(1 → 6)-β-d-glucopyranoside] (4), patuletin-3-O-[β-d-glucopyranosyl-(1 → 3)-2-O-E-caffeoyl-β-d-glucopyranosyl-(1 → 6)-β-d-glucopyranoside] (5), along with 19 known compounds were isolated from Eriocaulon buergerianum (Eriocaulaceae). Their structures were determined by spectroscopic and chemical methods. All 24 isolated compounds were tested against the pathogenic bacteria Staphylococcus aureus (ATCC 25923); as a result, 10 compounds were found to exhibit antibacterial activity with MICs ranging from 32 to 256 μg/ml.     

Cycloartane glycosides from Astragalus campylosema Boiss. ssp. campylosema

Four cycloartane glycosides, 3-O-[α-l-arabinopyranosyl-(1 → 2)-β-d-xylopyranosyl]-3β,6α,16β,23α,25-pentahydroxy-20(R),24(S)-epoxycycloartane (1), 3-O-[α-l-arabinopyranosyl-(1 → 2)-β-d-xylopyranosyl]-16-O-hydroxyacetoxy-23-O-acetoxy-3β,6α,25-trihydroxy-20(R),24(S)-epoxycycloartane (2), 3-O-[α-l-arabinopyranosyl-(1 → 2)-β-d-xylopyranosyl]-3β,6α,23α,25-tetrahydroxy-20(R),24(R)-16β,24;20,24-diepoxycycloartane (3), 3-O-[α-l-arabinopyranosyl-(1 → 2)-β-d-xylopyranosyl]-25-O-β-d-glucopyranosyl-3β,6α,16β,25-tetrahydroxy-20(R),24(S)-epoxycycloartane (4), along with three known cycloartane glycosides were isolated from the MeOH extract of the roots of Astragalus campylosema ssp. campylosema. Their structures were established by the extensive use of 1D- and 2D-NMR experiments along with ESIMS and HRMS analysis. The occurrence of the hydroxyl function at position 23 (1-2) and of the ketalic function at C-24 (3) are very unusual findings in the cycloartane class.     

Phenolic compounds and rare polyhydroxylated triterpenoid saponins from Eryngium yuccifolium

Phytochemical investigation on the whole plant of Eryngium yuccifolium resulted in the isolation and identification of three phenolic compounds (1-3) and 12 polyhydroxylated triterpenoid saponins, named eryngiosides A-L (4-15), together with four known compounds kaempferol-3-O-(2,6-di-O-trans-p-coumaroyl)-β-d-glucopyranoside (16), caffeic acid (17), 21β-angeloyloxy-3β-[β-d-glucopyranosyl-(1→2)]-[β-d-xylopyranosyl-(1→3)]-β-d-glucuronopyranosyloxyolean-12-ene-15α,16α,22α,28-tetrol (18), and saniculasaponin III (19). This study reports the isolation of these compounds and their structural elucidation by extensive spectroscopic analyses and chemical degradation.     

A new ursane-type triterpenoid glycoside from Centella asiatica leaves modulates the production of nitric oxide and secretion of TNF-α in activated RAW 264.7 cells

One new ursane-type triterpenoid glycoside, asiaticoside G (1), five triterpenoids, asiaticoside (2), asiaticoside F (3), asiatic acid (4), quadranoside IV (5), and 2α,3β,6β-trihydroxyolean-12-en-28-oic acid 28-O-[α-l-rhamnopyranosyl-(1→4)-β-d-glucopyranosyl-(1→6)-β-d-glucopyranosyl] ester (6), and four flavonoids, kaempferol (7), quercetin (8), astragalin (9), and isoquercetin (10) were isolated from the leaves of Centella asiatica. Their chemical structures were elucidated by mass, 1D- and 2D-nuclear magnetic resonance (NMR) spectroscopy. The structure of new compound 1 was determined to be 2α,3β,23,30-tetrahydroxyurs-12-en-28-oic acid 28-O-[α-l-rhamnopyranosyl-(1→4)-β-d-glucopyranosyl-(1→6)-β-d-glucopyranosyl] ester. The anti-inflammatory activities of the isolated compounds were investigated on lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. Asiaticoside G (1) potently inhibited the production of nitric oxide and tumor necrosis factor-α with inhibition rates of 77.3% and 69.0%, respectively, at the concentration of 100 μM.     

Phytoconstituents from the root of Streptocaulon tomentosum and their chemotaxonomical relevance for separation from S. juventas

A new cardenolide, 17β-H-periplogenin-3-O-β-d-digitoxoside (1), and a new pregnane glycoside, Δ⁵-pregnene-3β,16α-diol-d-O-[2,4-O-diacetyl-β-digitalopyranosyl-(1 → 4)-β-d-cymaropyranoside]-16-O-[β-d-glucopyranoside] (2) were isolated from the roots of Streptocaulon tomentosum (Asclepiadaceae) together with a series of known compounds. Their chemotaxonomic significance for the separation of S. tomentosum from Streptocaulon juventas is discussed, suggesting a rather clear distinction of these species.     

Triterpenoidal saponins of Pulsatilla koreana roots

Sixteen (1-16) triterpenoidal saponins were isolated from the roots of Pulsatilla koreana, of which four were determined as the previously unknown 23-hydroxy-3β-[(O-α-L-arabinopyranosyl)oxy]lup-20(29)-en-28-oic acid 28-O-β-D-glucopyranosyl ester (1), 23-hydroxy-3β-[(O-α-L-rhamnopyranosyl-(1 → 2)-α-L-arabinopyranosyl)oxy]lup-20(29)-en-28-oic acid 28-O-β-D-glucopyranosyl ester (2), 3β-[(O-α-L-rhamnopyranosyl-(1 → 2)-α-L-arabinopyranosyl)oxy]lup-20(29)-en-28-oic acid 28-O-β-D-glucopyranosyl-(1 → 6)-β-D-glucopyranosyl ester (3), and 3β-[(O-α-L-rhamnopyranosyl-(1 → 2)-O-[β-D-glucopyranosyl-(1 → 4)]-α-L-arabinopyranosyl)oxy]lup-20(29)-en-28-oic acid 28-O-α-L-rhamnopyranosyl-(1 → 4)-O-β-D-glucopyranosyl-(1 → 6)-β-D-glucopyranosyl ester (4), respectively, based on spectroscopic analysis. The inhibition of the lipopolysaccharide-induced nitric oxide production of sixteen isolated compounds was evaluated in RAW 264.7 cells at concentrations ranging from 1 μM to 100 μM.     

Synthesis of oleanolic acid saponins mimicking components of Chinese folk medicine Di Wu

3,28-Di-O-rhamnosylated oleanolic acid saponins, mimicking components of Chinese folk medicine Di Wu, have been designed and synthesized. One-pot glycosylation and ‘inverse procedure’ technologies have been applied thus significantly simplifying the preparation of desired saponins. The cytotoxic activity of compounds 3-O-[α-l-rhamnopyranosyl-(1→2)-β-d-xylopyranosyl]oleanolic acid 28-O-[α-l-rhamnopyranosyl-(1→4)-β-d-glucopyranosyl-(1→6)-β-d-glucopyranosyl] ester (3), 3-O-[α-l-rhamnopyranosyl]oleanolic acid 28-O-[α-l-rhamnopyranosyl- (1→4)-β-d-glucopyranosyl-(1→6)-β-d-glucopyranosyl] ester (4), 3-O-[α-l-rhamnopyranosyl]oleanolic acid 28-O-[α-l-rhamnopyranosyl] ester (5), and 3-O-[α-l-rhamnopyranosyl]oleanolic acid 28-O-[6-O-(α-l-rhamnopyranosyl)hexyl] ester (6) was preliminarily evaluated against HL-60 human promyelocytic leukemia cells. The natural saponin 3 and designed saponin 4 exhibited comparable moderate cytotoxic activity under our testing conditions.     

Monoterpenoids from the aerial parts of Aruncus dioicus var. kamtschaticus and their antioxidant and cytotoxic activities

The aerial parts of Aruncus dioicus var. kamtschaticus afforded five new monoterpenoids (1-5): 4-(erythro-6,7-dihydroxy-9-methylpent-8-enyl)furan-2(5H)-one (1, aruncin A), 2-(8-ethoxy-8-methylpropylidene)-5-hydroxy-3,6-dihydro-2H-pyran-4-carboxylic acid (2, aruncin B), 4-(hydroxymethyl)-6-(8-methylprop-7-enyl)-5,6-dihydro-2H-pyran-2-one-11-O-β-d-glucopyranoside (3, aruncide A), (3S,4S,5R,10R)-3-(10-ethoxy-11-hydroxyethyl)-4-(5-hydroxy-7-methylbut-6-enyl)oxetan-2-one-11-O-β-d-glucopyranoside (4, aruncide B), and (3S,4S,5R,7R)-5-(9-methylprop-8-enyl)-1,6-dioxabicyclo[3,2,0]heptan-2-one-7-(hydroxymethyl)-12-O-β-d-glucopyranoside (5, aruncide C). Compound 2 showed potent cytotoxicity against Jurkat T cells with an IC₅₀ value of 17.15 μg/mL. In addition, compounds 7 and 10 exhibited moderate antioxidant activity with IC₅₀ values of 46.3 and 11.7 μM, respectively.     

Methylated anthocyanidin glycosides from flowers of Canna indica

Methylated anthocyanin glycosides were isolated from red Canna indica flower and identified as malvidin 3-O-(6-O-acetyl-β-d-glucopyranoside)-5-O-β-d-glucopyranoside (1), malvidin 3,5-O-β-d-diglucopyranoside (2), cyanidin-3-O-(6″-O-α-rhamnopyranosyl-β-glucopyranoside (3), cyanidin-3-O-(6″-O-α-rhamnopyranosyl)-β-galactopyranoside (4), cyanidin-3-O-β-glucopyranoside (5) and cyanidin-O-β-galactopyranoside (6) by HPLC-PDA. Their structures were subsequently determined on the basis of spectroscopic analyses, that is, ¹H NMR, ¹³C NMR, HMQC, HMBC, ESI-MS, and UV-vis. Compounds (1-4) were found to be in major quantity while compounds (5-6) were in minor quantity.     

Iridoid glycosides from Gardeniae Fructus for treatment of ankle sprain

The iridoid glycosides, genipin 1-O-β-d-isomaltoside (1) and genipin 1,10-di-O-β-d-glucopyranoside (2), together with six known iridoid glycosides, genipin 1-O-β-d-gentiobioside (3), geniposide (4), scandoside methyl ester (5), deacetylasperulosidic acid methyl ester (6), 6-O-methyldeacetylasperulosidic acid methyl ester (7), and gardenoside (8) were isolated from an EtOH extract of Gardeniae Fructus. The structures and relative stereochemistries of the metabolites were elucidated on the basis of 1D- and 2D-NMR spectroscopic techniques, high-resolution mass spectrometry, and chemical evidence. Geniposide (4), one of the main compounds of Gardeniae Fructus, was tested for treatment of ankle sprain using an ankle sprain model in rats. From the second to fifth day, the geniposide (4) (100 mg/ml) treated group exhibited significant differences (p < 0.01) with ∼21-34% reduction in swelling ratio compared with those of the vehicle treated control group. This indicated the potential effect of geniposide (4) for the treatment of disorders such as ankle sprain.     

Phenolic glycosides from Agrimonia pilosa

Phytochemical investigation of the methanolic extract from the aerial parts of Agrimonia pilosa led to the isolation of three compounds, (−)-aromadendrin 3-O-β-d-glucopyranoside (1), desmethylagrimonolide 6-O-β-d-glucopyranoside (2), and 5,7-dihydroxy-2-propylchromone 7-O-β-d-glucopyranoside (3), together with nine known compounds, agrimonolide 6-O-glucoside, takanechromone C, astragalin, afzelin, tiliroside, luteolin, quercetin, isoquercetrin, and quercitrin. Their structures were determined by various spectroscopic analysis and chemical transformations.     

Sulphated polysaccharides of the grateloupiaceae family : Part VII. Investigation of the acetolysis products of a partially desulphated sample of the polysaccharide of pachymenia carnosa

Investigation of the acetolysis products of a partially desulphated sample of the polysaccharide isolated from Pachymenia carnosa led to the isolation and characterization of the following oligosaccharides: 3-O-α-D-galactopyranosyl-D-galactose (1), 4-O-β-D-galactopyranosyl-D-galactose (2), 3-O-(2-O-methyl-α-D-galactopyranosyl)-D-galactose (3), a 4-O-galactopyranosyl-2-O-methylgalactose (4), 3-O-α-D-galactopyranosyl-6-O-methyl-D-galactose (5), 4-O-β-D-galactopyranosyl-2-O-methyl-D-galactose (6), 2-O-methyl-4-O-(6-O-methyl-β-D-galactopyranosyl)-D-galactose (14), O-β-D-galactopyranosyl-(1→4)-O-α-D-galactopyranosyl-(1→3)-D-galactose (8), O-α-D-galactopyranosyl-(1→3)-O-β-D-galactopyranosyl-(1→4)-D-galactose (9), O-β-D-galactopyranosyl-(1→4)-O-α-(2-O-methyl-D-galactopyranosyl)-(1→3)-D-galactose (11), O-α-(2-O-methyl-D-galactopyranosyl)-(1→3)-O-β-D-galactopyranosyl-(1→4)-D-galactose (12), O-α-D-galactopyranosyl-(1→3)-O-β-D-galactopyranosyl-(1→4)-2-O-methyl-D-galactose (13), O-α-(2-O-methyl-D-galactopyranosyl)-(1→3)-O-β-D-galactopyranosyl-(1→4)-2-O-methyl-D-galactose (16), and O-β-D-galactopyranosyl-(1→4)-O-α-D-galactopyranosyl-(1→3)-O-β-D-galactopyranosyl-(1→4)-D-galactose (10). In addition, evidence was obtained for the presence of 4-O-(6-O-methyl-β-D-galactopyranosyl)-D-galactose (7) and O-β-D-galactopyranosyl-(1→4)-O-α-D-galactopyranosyl-(1→3)-6-O-methyl-D-galactose (15).     

Unusual oleanane-type saponins from Arenaria montana

Three oleanane-type saponins, 3-O-β-d-glucopyranosylechinocystic acid 28-O-β-d-xylopyranosyl-(1→4)-[α-l-rhamnopyranosyl-(1→2)]-α-l-rhamnopyranosyl ester (1), 3-O-β-d-glucopyranosylechinocystic acid 28-O-α-l-arabinopyranosyl-(1→3)-β-d-xylopyranosyl-(1→4)-[α-l-rhamnopyranosyl-(1→2)]-α-l-rhamnopyranosyl ester (2), 3-O-β-d-glucopyranosylcaulophyllogenin 28-O-β-d-apiofuranosyl-(1→3)-β-d-xylopyranosyl-(1→4)-[β-d-apiofuranosyl-(1→3)]-α-l-rhamnopyranosyl-(1→2)-α-l-rhamnopyranosyl ester (3) were isolated from the whole plant of Arenaria montana. Their unusual structures for the Caryophyllaceae family were established mainly by 2D NMR techniques and mass spectrometry.     

Allelopathy is involved in the formation of pure colonies of the fern Gleichenia japonica

The fern Gleichenia japonica is one of the most widely distributed fern and occurs throughout East to South Asia. The species often dominates plant communities by forming large monospecific colonies. However, the potential mechanism for this domination has not yet been described. The objective of this study was to test the hypothesis that allelochemicals are involved in the formation of G. japonica colonies. An aqueous methanol extract of G. japonica inhibited the growth of seedlings of garden cress (Lepidium sativum), lettuce (Lactuca sativa), ryegrass (Lolium multiflorum) and timothy (Phleum pratense). Increasing extract concentration increased the inhibition. These results suggest that G. japonica contain allelopathic substances. The extract was then purified by several chromatographies with monitoring the inhibitory activity and two growth inhibitory substances causing the allelopathic effect were isolated. The chemical structures of the two substances were determined by spectral data to be a novel compound 3-O-β-allopyranosyl-13-O-β-fucopyranosyl-3β-hydroxymanool (1) and 18-O-α-l-rhamnopyranosyl-(1→2)-β-d-glucopyranosyl-13-epitorreferol (2). These compounds inhibited the shoot and root growth of garden cress, lettuce, alfalfa (Medicago sativa), timothy, ryegrass and barnyardgrass (Echinochloa crus-galli) at concentrations greater than 0.1–1.0 mM. The concentrations required for 50% growth inhibition of root and shoot growth of these test plants ranged from 0.72 to 3.49 mM and 0.79 to 3.51 mM for compounds 1 and 2, respectively. Concentration of compounds 1 and 2 in soil under the pure colony of G. japonica was 4.9 and 5.7 mM, respectively, indicating concentrations over those required for 50% growth inhibition are potentially available under monocultural stands of these ferns. Therefore, these compounds may contribute to the allelopathic effects caused by presence of G. japonica and may thus contribute to the establishment of monocultural stands by this fern.     

Regioselective synthesis of a glycomimetic trisaccharide of Sialyl Lewis (sLe)

Sialyl Lewis (sLe^x) is the smallest naturally occurring carbohydrate ligand that binds to E-Selectin on the activated endothelium. We report here the total synthesis of acetic acid-sLe^x analog (12), for testing as a therapeutic agent. Methoxyethyl 4-O-(3,4-O-isopropylidene-β-d-galactopyranosyl)-β-d-glucopyranoside (3) was prepared starting from the methoxyethyl-β-d-lactoside (2), which was selectively benzoylated to give the methoxyethyl 2,6-di-O-benzoyl-4-O-(2,6-di-O-benzoyl-3,4-O-isopropylidene-β-d-galactopyranosyl)-β-d-glucopyranoside (4). Glycosylation of acceptor 4 with methyl 2,3,4-tri-O-benzyl-1-thio-β-l-fucopyranoside (5) in the presence of cupric bromide and tetrabutylammonium bromide afforded the corresponding methoxyethyl 2,6-di-O-benzyl-3-O-(2,3,4-tri-O-benzyl-α-l-fucopyranosyl)-4-O-(2,6-di-O-benzyl-3,4-O-isopropylidene-β-d-galactopyranosyl)-β-d-glucopyranoside (6). Selective removal of the 4″,6″-O-isopropylidene group from 6 gave the deprotected trisaccharide 7. The regioselective esterification of O-3″ of trisaccharide 8 (obtained from the dibutylstannylene derivative of 7) with benzyl-2-bromoacetate and tetrabutylammonium bromide afforded the 3″-O-carbobenzyloxymethyl trisaccharide derivative 9, which on saponification and hydrogenolysis with palladium-charcoal afforded the target trisaccharide 12 glycomimetic of Sialyl Lewis (sLe^x) trisaccharide omitting the sialic acid moiety.     

Synthetic studies on the trisaccharide intermediate of resin glycoside merremoside H2

A protected trisaccharide imidate, 2,3-di-O-acetyl-4,6-O-benzylidene-β-d-glucopyranosyl-(1→3)-2-O-chloroacetyl-3-O-benzyl-4-isobutyryl-α-l-rhamnopyranosyl-(1→4)-2-O-isobutyryl-α-l-rhamnopyranosyl trichloroacetimidate (1), has been synthesized by a block synthesis approach. Compound 1 can serve as a key intermediate in the total synthesis of resin glycoside merremoside H₂.     

Isolation and structure elucidation of 5′-O-β-d-glucopyranosyl-dihydroascorbigen from Cardamine diphylla rhizome

From the methanol extract of Cardamine diphylla rhizome, 5′-O-β-d-glucopyranosyl-dihydroascorbigen (1) and 6-hydroxyindole-3-carboxylic acid 6-O-β-d-glucopyranoside (2) were isolated. The structures of the compounds were elucidated using spectroscopic methods. This is the second report on the presence of a glucosylated indole ascorbigen in plants.     

Synthetic studies on the carbohydrate moiety of the antigen from the parasite Echinococcusmultilocularis

Stereocontrolled syntheses of branched tri-, tetra-, and pentasaccharides displaying a Galβ1→3GalNAc core in the glycan portion of the glycoprotein antigen from the parasite Echinococcusmultilocularis have been accomplished. Trisaccharide Galβ1→3(GlcNAcβ1→6)GalNAcα1-OR (A), tetrasaccharide Galβ1→3(Galβ1→4GlcNAcβ1→6)GalNAcα1-OR (D), and pentasaccharides Galβ1→3(Galβ1→4Galβ1→4GlcNAcβ1→6)GalNAcα1-OR (E) and Gal β1→3(Galα1→4Galβ1→4GlcNAcβ1→6)GalNAcα1-OR (F) (R = 2-(trimethylsilyl)ethyl) were synthesized by block synthesis. The disaccharide 2-(trimethylsilyl)ethyl 2,3,4,6-tetra-O-acetyl-β-d-galactopyranosyl-(1→3)-2-azido-4-O-benzyl-2-deoxy-α-d-galactopyranoside served as a common glycosyl acceptor in the synthesis of the branched oligosaccharides. Moreover, linear trisaccharide Galβ1→4Galβ1→3GalNAcα1-OR (B) and branched tetrasaccharide Galβ1→4Galβ1→3(GlcNAcβ1→6)GalNAcα1-OR (C) were synthesized by stepwise condensation.