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.     

Oligofuro- and spiro-stanosides of Asparagus adscendens

Two oligofurostanosides and two spirostanosides, isolated from a methanol extract of Asparagus adscendens (leaves), were characterized as 3-O-[{α-l-rhamnopyranosyl (1 → 4)} {α-l-rhamnopyranosyl (1 → 6)}-β-d-glucopyranosyl]-26-O-[β-d-glucopyranosyl]-22α-methoxy-(25S)-furost-5-en-3β,26-diol (Adscendoside A), 3-O-[{α-l-rhamnopyranosyl (1 → 4)} {α-l-rhamnopyranosyl (1 → 6)}-β-d-glucopyranosyl]-26-O-[β-d-glucopyranosyl]-(25S)-furost-5-en-3β,22α,26-triol-(Adscendoside B), 3-O-[{α-l-rhamnopyranosyl (1 → 6)}-β-d-glucopyranosyl]-(25S)-spirostan-5-en-3β-ol (Adscendin A) and 3-O-[{α-l-rhamnopyranosyl (1 → 4)} {α-l-rhamnopyranosyl (1 → 6)}-β-d-glucopyr anosyl]-(25S)-spirostan-5-en-3β-ol (Adscendin B), respectively. Adscendin B and Adscendoside A are the artefacts of Adscendoside B formed through hydrolysis and methanol extraction respectively.bl]     

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.     

Steroidal saponins of Asparagus adscendens

From the methanol extract of the fruits of Asparagus adscendens sitosterol-β-d-glucoside, two spirostanol glycosides (asparanin A and B) and two furostanol glycosides (asparoside A and B) were isolated and characterized as 3-O-[β-d-glucopyranosyl (1→2)-β-d-glucopyranosyl]-(25S)-5β-spirostan-3β-ol, 3-O-{[β-d-glucopyranosyl(1→2)][α-l-rhamnopyranosyl(1→4)]-β-d-glucopyranosyl}-(25S)-5β-spirostan-3β-ol,3-O-{[β-d-glucopyranosyl(1→2)][α-l-rhamnopyranosyl(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-rhamnopyranosyl(1→4)]-β-d-glucopyranosyl}-26-O-(β-d-glucopyranosyl)- 25S)-5β-furostan-3β,22α, 26-triol, respectively.     

Steroidal saponins of Yucca filamentosa: Yuccoside C and protoyuccoside C

Two new saponins, yuccoside C and protoyuccoside C, have been isolated from the methanolic extract of Yucca filamentosa root and their structures elucidated. Yuccoside C is 3-O-[α-d-galactopyranosyl-(1 → 2)-β-d-glucopyranosyl-(1 → 4)-β-d-glucopyranosyl]-(25S)-5β-spirostan-3β-ol, whereas protoyuccoside C is 3-O-[α-d-galactopyranosyl-(1 → 2)-β-d-glucopyranosyl-(1 → 4)-β-d-glucopyranosyl]-26-O-[β-d-glucopyranosy]-(25S)-5β-furostan-3β,22α,26-triol.     

Triterpenoid saponins from Fatsia japonica

Five triterpenoid saponins isolated from the flowers, the mature fruits and the leaves of Fatsia japonica were identified as 3-O-[β-d-glucopyranosyl(1→4)-β-d-glucopyranosyl]-hederagenin (1), 3-O-[β-d-glucopyranosyl-(1→4)-α-l-arabinopyranosyl]-oleanolic acid (2), 3-O-[α-l-arabinopyranosyl]-hederagenin (3), 3-O-[β-d-glucopyranosyl]-hederagenin (4) and 3-O-[β-d-glucopyranosyl(1→4)-α-l-arabinopyranosyl]-hederagenin (5). The saponins 1 and 2 are new, naturally occurring, triterpenoid saponins. The distribution of the five saponins in three parts of the plant was investigated. Saponins 2, 3 and 5 were present in the flowers, saponins 1, 3, 4 and 5 were in the mature fruits and saponins 2, 3, 4 and 5 were in the leaves.     

N-Substituted acetamide glycosides from the stems of Ephedra sinica

Five new N-mono-/bis-substituted acetamide glycosides, N-{4-O-[3-O-(4-O-α-l-rhamnopyranosyl-β-d-glucopyranosyl)-α-l-rhamnopyranosyl]-phenethyl}-acetamide (1), N-methyl-N-{4-O-[3-O-(4-O-α-l-rhamnopyranosyl-β-d-glucopyranosyl)-α-l-rhamnopyranosyl]-phenethyl}-acetamide (2), N-methyl-N-{4-O-[3-O-(6-O-benzoyl-4-O-α-l-rhamnopyranosyl-β-d-glucopyranosyl)-α-l-rhamnopyranosyl]-phenethyl}-acetamide (3), N-methyl-N-{4-O-[3-O-(6-O-benzoyl-β-d-glucopyranosyl)-α-l-rhamnopyranosyl]-phenethyl}-acetamide (4), and N-methyl-N-{4-O-[3-O-(6-O-trans-cinnamoyl-4-O-α-l-rhamnopyranosyl-β-d-glucopyranosyl)-α-l-rhamnopyranosyl]-phenethyl}-acetamide (5), along with one known acetamide derivative, N-methyl-N-(4-hydroxyphenethyl)-acetamide, the shared aglycone of 2–5, were isolated from the ethanol extract of the stems of Ephedra sinica. The structures of these new compounds were elucidated on the basis of extensive spectroscopic examination, mainly including multiple 1D and 2D NMR and HRESIMS examinations, and qualitative chemical tests. All N,N-bissubstituted acetamide glycosides were found to show the obvious rotamerism, as in the case of the isolated known N-methyl-N-(4-hydroxyphenethyl)-acetamide, under the experimental NMR conditions, with the ratios of integrated intensities between anti- and syn-rotamers always being found to be about 4 to 3.     

Coumarins from the roots of Prangos uloptera

Three new coumarins, 6-O-[β-d-apiofuranosyl-(1 → 6)-β-d-glucopyranosyl]-prenyletin, 3″-O-[β-d-apiofuranosyl-(1 → 6)-β-d-glucopyranosyl]-oxypeucedanin hydrate and 2″-O-[β-d-apiofuranosyl-(1 → 6)-β-d-glucopyranosyl]-oxypeucedanin hydrate, together with six known coumarins, 3″-O-[β-d-apiofuranosyl-(1 → 6)-β-d-glucopyranosyl]-heraclenol, 3″-O-(β-d-glucopyranosyl)-heraclenol, tortuoside, 3″-O-(β-d-glucopyranosyl)-oxypeucedanin hydrate, heraclenol and oxypeucedanin hydrate, have been isolated from the roots of Prangos uloptera, and the structures of these coumarins were unequivocally determined by spectroscopic means, notably UV, HRESIMS, and 1D and 2D NMR spectroscopy.     

Furostanol saponins from Paris polyphylla: Structures of polyphyllin G and H

The structure of two new saponins, polyphyllins G and H, isolated from the tubers of Paris polyphylla have been elucidated as 3-O-{α-l-rhamnopyranosyl (1→3) [α-l-arabinofuranosyl (1→4)]-β-d-glucopyranosyl}-26-O-[β-d-glucopyranosyl] (25R)-22α-hydroxy-furost-5-en-3β, 26-diol and its 22-methoxy derivative respectively.     

New triterpene saponins from Phryna ortegioides

Four new and three known oleanane-type saponins have been isolated from the methanolic extract of Phryna ortegioides, a monotypic and endemic taxon of Caryophyllaceae.The structures of the new compounds were determined as gypsogenic acid 28-O-β-d-glucopyranosyl-(1→2)-O-β-d-glucopyranosyl-(1→6)-O-β-d-glucopyranosyl ester (1), 3-O-α-l-arabinofuranosyl-gypsogenic acid 28-O-β-d-glucopyranosyl-(1→3)-O-[β-d-glucopyranosyl-(1→6)]-O-β-d-glucopyranosyl ester (2), 3-O-α-l-arabinofuranosyl-gypsogenic acid 28-O-β-d-glucopyranosyl-(1→3)-O-[β-d-glucopyranosyl-(1→2)-O-β-d-glucopyranosyl-(1→6)-O-]-β-d-glucopyranosyl ester (3), 3-O-α-l-arabinofuranosyl-16α-hydroxyolean-12-en-23,28-dioic acid-28-O-β-d-glucopyranosyl-(1→3)-O-[β-d-glucopyranosyl-(1→2)-O-β-d-glucopyranosyl-(1→6)]-O-β-d-glucopyranosyl ester (4). Their structures were established by a combination of one- and two-dimensional NMR techniques, and mass spectrometry. Noteworthy, none of isolated compounds possesses as aglycone moiety gypsogenin, considered a marker of Caryophyllaceae family.The cytotoxic activity of the isolated compounds was evaluated against three cancer cell lines including A549 (human lung adenocarcinoma), A375 (human melanoma) and DeFew (human B lymphoma) cells. Only compound 6 showed a weak activity against A375 and DeFew cell lines with IC₅₀ values of 77 and 52 μM, respectively. None of the other tested compounds, in a range of concentrations between 12.5 and 100 μM, caused a significant reduction of the cell number.     

Synthese von O-(3-desoxy-α-d-manno-2-octulopyranosylonsäure)-(2→4)-O-(3-desoxy-α-d-manno-2-octulopyranosylonsäure)- (2→6)-O-(2-amino-2-desoxy-β-d-glucopyranosyl)-(1→6)-2-amino-2-desoxy-d-glucopyranose

Benzyl-3-O-benzyl-2-benzyloxycarbonylamino-6-O-[2-benzyloxycarbonyl-amino-2-deoxy-3,4-O-(tetraisopropyldisiloxane-1,3-diyl)- β-d-glucopyranosyl]-2-deoxy-α-d-glucopyranoside was coupled with methyl (4,5,7,8-tetra-O-acetyl-3-deoxy-α-d-manno-2-octulopyranosyl bromide)onate (13) to yield the α-glycosidically linked trisaccharide. After deacetylation and selective introduction of a second 7′,8′-O-tetraisopropyldisiloxane group, a further glycosidation reaction with 13 led regioselectively to the tetrasaccharide benzyl O-[methyl (4,5,7,8-tetra-O-acetyl-3-deoxy-α-d-manno-2-octulopyranosyl)onate]-(2→4)-O-{methyl [3-deoxy-7,8-O-(tetraisopropyldisiloxane-1,3-diyl)-α-d-manno-2-octulopyranosyl]-onate}-(2→6)-O- [2-benzyloxycarbonylamino-2-deoxy-3,4-O-(tetraisopropyldisiloxane-1,3-diyl)-β-d-glucopyranosyl]- (1→6)-3-O-benzyl-2-benzyloxycarbonyl-amino-2-deoxy-α-d-glucopyranoside. A series of deblocking steps gave O-(3-deoxy-α-d-manno-2-octulopyranosylonic acid)-(2→4)-O-(3-deoxy-α-d-manno-2-octulopyranosylonic acid)- (2→6)-O-(2-amino-2-deoxy-β-d-glucopyranosyl)-(1→6)-2-amino-2-deoxy-d-glucopyranose which was identical with a tetrasaccharide that had been isolated by hydrazinolysis of the lipopolysaccharide from Salmonella minnesota R 595. Hence, synthetic proof is provided for the linkages in this part of the inner core region of lipopolysaccharides.     

C-glycosylflavone with rotational isomers from Vaccaria hispanica (Miller) Rauschert seeds

Five C-glycosylflavone were isolated from Vaccaria hispanica (Miller) Rauschert seeds. Their NMR spectra showed separate signals because of the existence of rotational isomers, which is an unusual phenomenon. The spectroscopic data revealed that compounds 1–5 were identified as apigenin 6-C-[α-l-arabinopyranosyl-(1′′′→2′′)-β-d-glucopyranosyl]-7-O-β-d-glucopyranoside (1), apigenin 6-C-[α-l-arabinopyranosyl-(1′′′→2′′)-β-d-glucopyranosyl]-7-O-(6′′′′-O-dihydroferuloyl)-β-d-glucopyranoside (2), apigenin 6-C-β-d-glucopyranosyl-7-O-(6′′′-O-dihydroferuloyl)-β-d-glucopyranoside (3) and isovitexin-2′′-O-arabinoside (4) and saponarin (5), respectively. The structure of ‘vaccarin’ was revised to apigenin 6-C-[α-l-arabinopyranosyl-(1′′′→2′′)-β-d-glucopyranosyl]-7-O-β-d-glucopyranoside and consequently 1 should be named ‘vaccarin’. Among the isolated compounds, 2 and 3 are new and named vaccarin E and vaccarin F, respectively.     

Cycloartane glycosides from Astragalus gombo

Six new cycloartane-type triterpene glycosides named 3-O-[β-d-glucopyranosyl(1 → 2)-β-d-xylopyranosyl]-3β,16β,23(R),24(R),25-pentahydroxycycloartane (1), 3-O-[β-d-glucopyranosyl(1 → 2)-β-d-xylopyranosyl]-3β,16β,23(R),24(R)-tetrahydroxy-25-dehydrocycloartane (2), 3-O-[β-d-xylopyranosyl]-6α-acetoxy-23α-methoxy-16β,23(R)-epoxy-24,25,26,27-tetranorcycloartane (3), 3-O-[β-d-xylopyranosyl]-6α-acetoxy-23α-butoxy-16β,23(R)-epoxy-24,25,26,27-tetranorcycloartane (4), 3-O-[β-d-glucopyranosyl(1 → 2)]-β-d-xylopyranosyl]-6α-acetoxy-23α-methoxy-16β,23(R)-epoxy-24,25,26,27-tetranorcycloartane (5), 3-O-[β-d-glucopyranosyl(1 → 2)]-β-d-xylopyranosyl]-23α-methoxy-16β,23(R)-epoxy-4,25,26,27-tetranorcycloartane (6), in addition to three known secondary metabolites consisting of another cycloartane triterpene glycoside and two flavonol glycosides, were isolated from the aerial parts of Astragalus gombo Coss. & Dur. (Fabaceae). The structures of the isolated compounds were established by spectroscopic methods, including 1D and 2D-NMR, mass spectrometry and comparison with literature data.     

Molluscicidal saponins from Gundelia tournefortii

From the roots of Gundelia tournefortii seven saponins have been isolated mainly by DCCC. The main saponins (A and B) were characterized, mainly by ¹³C and ¹H NMR spectroscopy, as oleanolic acid 3-O-(2-[α-l-arabinopyranosyl(1 → 3) -β-d-gentiotriosyl(1 → 6) -β-d-glucopyranosyl]gb-d-xylopyranoside) (saponin A) and oleanolic acid 3-O-(2-[α-l-arabinopyranosyl] (1 → 3)-β-d-gentiobiosyl (1 → 6)-β-d-glucopyranosyl β-d-xylopyranoside) (saponin B). The other saponins are also derived from oleanolic acid and contain more sugar units. The saponin mixture and the saponins A and B possess strong molluscicidal activity against the schistosomiasis transmitting snail Biomphalaria glabrata.     

New trans- and cis-p-coumaroyl flavonol tetraglycosides from the leaves of Mitragyna rotundifolia

Two new flavonol tetraglycosides, quercetin 3-O-(4-O-trans-p-coumaroyl)-α-l-rhamnopyranosyl (1→2) [α-l-rhamnopyranosyl (1→6)]-β-d-glucopyranoside-7-O-α-l-rhamnopyranoside (krathummuoside A) and quercetin 3-O-(4-O-cis-p-coumaroyl)-α-l-rhamnopyranosyl (1→2) [α-l-rhamnopyranosyl (1→6)]-β-d-glucopyranoside-7-O-α-l-rhamnopyranoside (krathummuoside B) were isolated from the leaves of Mitragyna rotundifolia in addition to eight known compounds, quercetin 3-O-α-l-rhamnopuranosyl (1→2) [α-l-rhamnopyranosyl (1→6)]-β-d-glucopyranoside-7-O-α-l-rhamnopyranoside, rutin, (−)-epi-catechin, 3,4,5-trimethoxyphenyl β-d-glucopyranoside, (6S, 9R)-roseoside, 3-O-β-d-glucopyranosyl quinovic acid 28-O-β-d-glucopyranosyl ester, (+)-lyoniresinol 3α-O-β-d-glucopyranoside, and (+)-syringaresinol-4-O-β-d-glucopyranoside. The structure elucidation of these compounds was based on analyses of spectroscopic data including 1D- and 2D-NMR.     

Furostanol glycosides from Trigonella foenum-graecum seeds

Two new furostanol glycosides, trigofoenosides F and G, have been isolated as their methyl ethers from the methanolic extract of Trigonella foenum-graecum seeds (Leguminosae). The structures of the original glycosides have been determined as (25R)-furost-5-en-3β,22,26-triol, 3-O-α-l-rhamnopyranosyl (1 → 2)β-d-glucopyranosyl (1 → 6)β-d-glucopyranoside; 26-O-β-d-glucopyranoside and (25R)-furost-5en-3β,22,26-triol, 3-O-α-L-rhamnopyranosyl (1 → 2) [β-d-xylopyranosyl (1 → 4)]β-d-glucopyranosyl (1 → 6)β-d-glucopyranoside; 26-O-β-d-glucopyranoside, respectively.     

13C-N.M.R. characterizations of the sarsasapogenin disaccharides,the filiferins a and b: 2-O-(β-d-xylopyranosyl)- and 2-O(β-d-glucopyranosyl)-β-d-galactopyranosides

Filiferin B is identical to timosaponin A-III, which had previously been shown to be 3-O-[2-O-(β-d-glucopyranosyl)-β-d-galactopyranosyl]sarsasapogenin. A larger-scale isolation of filiferin B from the seeds of Yucca filifera led to the isolation of filiferin A, now shown to be 3-O-[2-O-β-d-xylopyranosyl)-β-d-galactopyranosyl]-sarsasapogenin. The presence of the xylose residue was established by way of hydrolysis. 8-Methoxycarbonyloctyl 2-O-(β-d-glucopyranosyl)-β-d-galactopyranoside was synthesized to serve as a model for interpretation of the ¹³C-n.m.r. spectrum of filiferin B. The information thus gained, together with the ¹³C-n.m.r. spectra of other, simple model-compounds, permitted assignment of the structure for filiferin A. 8-Methoxycarbonyloctyl 2-O-(α-d-glucopyranosyl)-β-d-galactopyranoside was also synthesized.     

Synthesis of a branched d-glucotetraose,the repeating unit of the extracellular polysaccharides of Grifola umbellate,Sclerotinia libertiana,Porodisculus pendulus,and Schizophyllum commune fries

The synthesis of d-glucotetraose, 3-O-[3-O-β-d-glucopyranosyl-β-d-glucopyranosyl]-6-O-β-d-glucopyranosyl-α (and β)-d-glucopyranose, the repeating unit of the extracellular polysaccharides of Grifora umbellata, Sclerotinia libertiana, Porodisculus pendulus, and Schizophyllum commune Fries, is described.     

A new complex triterpenoid saponin from Samanea saman with haemolytic activity and adjuvant effect

A new complex triterpenoid saponin was isolated from the stem bark of Samanea saman by using chromatographic methods. Its structure was established as 3-[(2-O-β-d-glucopyranosyl-β-d-glucopyranosyl)oxy]-2,23-dihydroxy-(2β,3β,4α)-olean-12-en-28-oic acid O-β-d-glucopyranosyl-(1 → 3)-O-[O-β-d-glucopyranosyl-(1 → 4)]-O-6-deoxy-α-l-mannopyranosyl-(1 → 2)-6-O-[4-O-[(2E,6S)-2,6-dimethyl-1-oxo-2,7-octadienyl]-6-deoxy-α-l-mannopyranosyl)oxy]-β-d-glucopyranosyl ester (1). Structural elucidation was performed using detailed analyses of ¹H and ¹³C NMR spectra including 2D NMR spectroscopic techniques and chemical conversions. The haemolytic activity of the saponin was evaluated using in vitro assays, and its adjuvant potential on the cellular immune response against ovalbumin antigen was investigated using in vivo models.     

The synthesis of P1-2-acetamido-4-O-(2-acetamido-2-deoxy-β-d-glucopyranosyl)-2-deoxy-α-d-glucopyranosyl P2-dolichyl pyrophosphate, (P1-di-N-acetyl-α-chitobiosyl P2-dolichyl pyrophosphate)

2-Acetamido-4-O-(2-acetamido-2-deoxy-β-d-glucopyranosyl)-2-deoxy-α-d-glucopyranosyl phosphate, pure according to thin-layer and gas—liquid chromatography, optical rotation, and treatment with alkaline phosphatase and 2-acetamido-2-deoxy-β-d-glucosidase, was prepared by treatment of 2-methyl-[4-O-(2-acetamido-3,4,6-tri-O-acetyl-2-deoxy-β-d-glucopyranosyl)-3,6-di-O-acetyl-1,2-dideoxy-α-d-glucopyrano]-[2,1-d]-2-oxazoline with dibenzyl phosphate, followed by the removal of the benzyl groups by catalytic hydrogenolysis, and O-deacetylation. In contrast, a sample prepared by the phosphoric acid procedure was shown to consist mainly of the β anomer. 2-Acetamido-4-O-(2-acetamido-3,4,6-tri-O-acetyl-2-deoxy-β-d-glucopyranosyl)-3,6-di-O-acetyl-2-deoxy-α-d-glucopyranosyl phosphate was treated wit P¹-diphenyl P²-dolichyl pyrophosphate to give a fully acetylated pyrophosphoric diester, which was O-deacetylated to give P¹-2-acetamido-4-O-(2-acetamido-2-deoxy-β-d-glucopyranosyl)-2-deoxy-α-d-glucopyranosyl P²-dolichyl pyrophosphate. This compound could be separated from the β anomer by t.l.c., and its behavior under dilute acid and alkaline conditions was investigated.