Synthesis of oligosaccharide derivatives related to those from sanqi, a Chinese herbal medicine from Panax notoginseng

Oligosaccharide derivatives from sanqi, a Chinese herbal medicine derived from Panax notoginseng, methyl beta-D-galactopyranosyl-(1-->3)-[alpha-L-arabinofuranosyl-(1-->6)]-alpha-D-galactopyranoside, diosgenyl beta-D-galactopyranosyl-(1-->3)-[alpha-L-arabinofuranosyl-(1-->6)]-alpha-D-galactopyranoside, and methyl beta-D-galactopyranosyl-(1-->3)-[alpha-L-arabinofuranosyl-(1-->6)]-alpha-D-galactopyranosyl-(1-->4)-beta-D-galactopyranosyl-(1-->3)-[alpha-L-arabinofuranosyl-(1-->6)]-alpha-D-galactopyranoside, were synthesized under standard glycosylation conditions. An unexpected alpha-(1-->4) linkage was formed predominantly in the presence of neighboring participation group during regioselective synthesis of hexasaccharide via 3+3 strategy.     

Glucuronide triterpene saponins from Bersama engleriana

Five 3-O-glucuronide triterpene saponins (1-5) were isolated from the stem bark of Bersama engleriana Gurke along with two known saponins, polyscias saponin C and aralia saponin 15, and one major C-glycoside xanthone, mangiferin. The structures of the saponins were established mainly by means of spectroscopic methods (one- and two-dimensional NMR spectroscopy as well as FAB-, HRESI-mass spectrometry) as 3-O-[beta-D-glucopyranosyl-(1-->2)-beta-D-glucuronopyranosyl]-28-O-[beta-D-glucopyranosyl]-betulinic acid (1), 3-O-[beta-D-glucopyranosyl-(1-->2)-[beta-D-galactopyranosyl-(1-->3)]-beta-D-glucuronopyranosyl]-oleanolic acid (2), 3-O-[beta-D-glucopyranosyl-(1-->3)-beta-D-glucuronopyranosyl]-28-O-[beta-D-xylopyranosyl-(1-->6)-beta-d-glucopyranosyl]-oleanolic acid (3), 3-O-[beta-D-galactopyranosyl-(1-->3)-beta-D-glucuronopyranosyl]-28-O-[beta-D-glucopyranosyl-(1-->4)-beta-D-glucopyranosyl]-oleanolic acid (4), and 3-O-[beta-d-glucopyranosyl-(1-->3)-beta-D-galactopyranosyl-(1-->3)-beta-D-glucuronopyranosyl]-28-O-[beta-d-xylopyranosyl-(1-->6)-beta-D-glucopyranosyl]-oleanolic acid (5).     

A major triterpenoid saponin from Gypsophila oldhamiana

A new saponin, gypoldoside A (1), was isolated from the roots of Gypsophila oldhamiana. On the basis of in-depth NMR-spectroscopic and mass-spectrometric analysis, in combination with chemical evidence, its structure was established as 3-O-{beta-D-galactopyranosyl-(1-->2)-[beta-D-xylopyranosyl-(1-->3)]-beta-D-glucuronopyranosyl}quillaic acid 28-[alpha-L-arabinopyranosyl-(1-->2)-alpha-L-arabinopyranosyl-(1-->3)-beta-D-xylopyranosyl-(1-->4)-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-fucopyranosyl] ester. Compound 1 was found to be highly active against three different human cancer cell lines, with IC50 values in the low micromolar range.     

Haemolytic acylated triterpenoid saponins from Harpullia austro-caledonica

Eight new acylated triterpenoid saponins were isolated from the stem bark of Harpullia austro-caledonica along with the known harpuloside (9). Their structures were established using 1D and 2D NMR and mass spectrometry as 3-O-beta-D-galactopyranosyl-(1-->2)-beta-D-glucuronopyranosyl-21 beta, 22 alpha-di-O-angeloylbarringtogenol C (1), 3-O-alpha-L-rhamnopyranosyl-(1-->3)-[beta-D-galactopyranosyl-(1-->2)]-beta-D-glucuronopyranosyl-21 beta, 22 alpha-di-O-angeloyl barringtogenol C (2), 3-O-alpha-L-arabinofuranosyl-(1-->3)-[beta-D-galactopyranosyl-(1-->2)]-beta-D-glucuronopyranosyl-21 beta, 22 alpha-di-O-angeloylbarringtogenol C (3), 3-O-alpha-L-arabinofuranosyl-(1-->2)-beta-D-glucuronopyranosyl-21 beta, 22 alpha-di-O-angeloylprotoaescigenin (4), 3-O-alpha-L-arabinofuranosyl-(1-->3)-[alpha-L-arabinofuranosyl-(1-->2)]-beta-D-glucuronopyranosyl-21 beta, 22 alpha-di-O-angeloyl protoaescigenin (5), 3-O-alpha-L-arabinofuranosyl-(1-->3)-[beta-D-xylopyranosyl-(1-->2)]-beta-D-glucuronopyranosyl-21 beta, 22 alpha-di-O-angeloylprotoaescigenin (6), 3-O-alpha-L-arabinofuranosyl-(1-->3)-[beta-D-glucopyranosyl-(1-->2)]-beta-D-glucuronopyranosyl-21 beta, 22 alpha-di-O-angeloylprotoaescigenin (7), 3-O-beta-D-xylopyranosyl-(1-->2)-beta-D-glucuronopyranosyl-21 beta, 22 alpha-di-O-angeloylprotoaescigenin (8). The EtOH extract of the stem bark showed in vitro cytotoxic activity against KB cells (90% at 10 microg/ml). At a concentration of 5 microg/ml, the saponin mixture showed haemolytic activity and caused 100% haemolysis of a 10% suspension of sheep erythrocytes.     

Triterpenoid saponins from Schefflera arboricola

Nine triterpenoid saponins were isolated from the leaves and stems of Schefflera arboricola. The saponins were characterised, on the basis of chemical and spectral evidence, as 3-O-[alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucuronopyranosyl] oleanolic acid, 3-O-[alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucuronopyranosyl] echinocystic acid, 3-O-[beta-D-apiofuranosyl-(1-->4)-beta-D-glucuronopyranosyl] oleanolic acid 28-O-beta-D-glucopyranosyl ester, 3-O-alpha-L-ramnopyranosyl-(1-->4)-[alpha-L-arabinopyranosyl-(1-->2)-] beta-D-glucuronopyranosyl oleanolic acid, 3-O-alpha-L-rhamnopyranosyl-(1-->4)-[alpha-L-arabinopyranosyl-(1-->2)-] beta-D-glucuronopyranosyl oleanolic acid 28-O-beta-D-glucopyranosyl ester, 3-O-alpha-L-rhamnopyranosyl-(1-->4)-[beta-D-galactopyranosyl-(1-->2)-] beta-D-glucuronopyranosyl oleanolic acid, 3-O-alpha-L-rhamnopyranosyl-(1-->4)-[beta-D-galactopyranosyl-(1-->2)-] beta-D-glucuronopyranosyl oleanolic acid 28-O-beta-D-glucopyranosyl ester, 3-O-beta-D-apiofuranosyl-(1-->4)-[alpha-L-arabinopyranosyl-(1-->2)-] beta-D-glucuronopyranosyl oleanolic acid and 3-O-beta-D-apiofuranosyl-(1-->4)-[alpha-L-arabinopyranosyl-(1-->2)-] beta-D-glucuronopyranosyl oleanolic acid 28-O-beta-D-glucopyranosyl ester.     

Synthesis of a hexasaccharide that relates to the arabinogalactan epitope.

A hexasaccharide derivative of the arabinogalactan epitope, methyl beta-D-galactopyranosyl-(1-->6)-[alpha-L-arabinofuranosyl-(1-->3)]-beta-D-galactopyranosyl-(1-->6)-beta-D-galactopyranosyl-(1-->6)-[alpha-L-arabinofuranosyl-(1-->3)]-alpha-D-galactopyranoside, was synthesized efficiently using a 3+3 strategy. The key step is the preparation of the trisaccharide donor, isopropyl 2,3,4,6-tetra-O-benzoyl-beta-D-galactopyranosyl-(1-->6)-[2,3,5-tri-O-benzoyl-alpha-L-arabinofuranosyl-(1-->3)]-2,4-di-O-benzoyl-1-thio-beta-D-galactopyranoside, from isopropyl 1-thio-beta-D-galactopyranoside using a one-pot synthesis of a 3,6-differentially protected building block.     

Two novel oligosaccharides formed by 1F-fructosyltransferase purified from roots of asparagus (Asparagus officinalis L.)

Two novel oligosaccharides, tetra-and penta-saccharides were synthesized by fructosyl transfer from 1-kestose to 4G-beta-D-galactopyranosylsucrose with a purified 1F-fructosyltransferase of asparagus roots and identified as 1F-beta-D-fructofuranosyl-4G-beta-D-galactopyranosylsucrose, O-beta-D-fructofuranosyl-(2-->1)-beta-D-fructofuranosyl-O-[beta-D-galactopyranosyl-(1-->4)]-alpha-D-glucopyranoside and 1F(1-beta-D-fructofuranosyl)2-4G-beta-D-galactopyranosylsucrose, [O-beta-D-fructofuranosyl-(2-->1)]2-beta-D-fructofuranosyl-O-[beta-D-galactopyranosyl-(1-->4)]-alpha-D-glucopyranoside, respectively. Both oligosaccharides were scarcely hydrolyzed by carbohydrase from rat small intestine. Human intestinal bacterial growth by 1F-beta-D-fructofuranosyl-4G-beta-D-galactopyranosylsucrose was compared with that by the tetrasaccharides, stachyose and nystose. Bifidobacteria utilized 1F-beta-D-fructofuranosyl-4G-beta-D-galactopyranosylsucrose to the same extent as stachyose or nystose. On the other hand, the unfavorable bacteria, Clostridium perfringens, Escherichia coli and Enterococcusfaecalis, that produce mutagenic substances did not use the synthetic oligosaccharide.     

Separation and structural analysis of some saponins from Quillaja saponaria Molina

A fraction of saponins from Quillaja saponaria Molina, QH-B, was fractionated by consecutive separations on three different reverse-phase HPLC systems. Eight compounds were isolated and the structures of these were elucidated mainly by sugar analysis and NMR spectroscopy. The structures consisted of a quillaic acid substituted with two different trisaccharides at C-3, beta-D-Galp-(1-->2)-[alpha-L-Rhap-(1-->3)]-beta-D-GlcpA and beta-D-Galp-(1-->2)-[beta-D-Xylp-(1-->3)]-beta-D-GlcpA, and a tetra- or pentasaccharide at C-28, beta-D-Xylp-(1-->4)-[beta-D-Glcp-(1-->3)]-alpha-L-Rhap-(1--> 2)-beta-D-Fucp and beta-D-Apif-(1-->3)-beta-D-Xylp-(1-->4)-[beta-D-Glcp-(1-->3) ]-alpha-L- Rhap-(1-->2)-beta-D-Fucp. These compounds were further substituted with an acyl group either at O-3 or O-4 of the fucose residue, which is the sugar linked to C-28 of the quillaic acid.     

New acylated triterpenoid saponins from Maesa lanceolata

Ten new acylated triterpenoid saponins were isolated from the leaves of Maesa lanceolata. For their structure elucidation extensive use was made of homo- and heteronuclear 2D NMR techniques such as COSY, NOESY, HSQC and HMBC. All saponins identified contained the same tetraglycosidic side chain, but the triterpenoid moiety showed a variable esterification pattern. Monoester, diester and triester derivatives were present. Maesasaponin I was a 21-monoester derivative, i.e. ?3 beta-O-[alpha-L-rhamnopyranosyl-(1-->2)-beta-D-galactopyranosyl- (1-->3)]-[beta-D-galactopyranosyl-(1-->2)]-beta-D-glucuronopyranosyl+ ++?-21 beta-angeloyloxy-13 beta, 28-oxidoolean-16 alpha, 22 alpha, 28 alpha-triol. Maesasaponins III, IV3, V3 and VI2 had an additional acetyl, propanoyl, n-butanoyl and angeloyl substituent, respectively, in position 22. Maesasaponins II, IV2, V2, VI3 and VII1 were characterised as the 16-acetyl derivatives of maesasaponins I, III, IV3, V3 and VI2, respectively. Structures of saponins previously reported in M. lanceolata had to be revised.     

Cytotoxic triterpenoid saponins from the fruits of Aesculus pavia L

Continued chemical investigation on the fruits of North American Aesculus pavia L. resulted in the isolation and identification of 13 polyhydroxyoleanene pentacyclic triterpenoid saponins, named aesculiosides IIe-IIk (1-7), and IIIa-IIIf (8-13), together with 18 known compounds: aesculiosides Ia-Ie (14-18), IIa-IId (19-22), IVa-IVc (23-25), 3-O-[beta-D-galactopyranosyl(1-->2)]-alpha-L-arabinofuranosyl(1-->3)-beta-D-glucuronopyranosyl-21,22-O-diangeloyl-3beta,15 alpha,16 alpha,21 beta,22 alpha,28-hexahydroxyolean-12-ene (26), 3-O-[beta-D-glucopyranosyl(1-->2)]-alpha-L-arabinofuranosyl(1-->3)-beta-D-glucuronopyranosyl-21,22-O-diangeloyl-3beta,16 alpha,21 beta,22 alpha,24 beta,28-hexahydroxyolean-12-ene (27), 3-O-[beta-D-galactopyranosyl(1-->2)]-alpha-L-arabinofuranosyl(1-->3)-beta-D-glucuronopyranosyl-21,22-O-diangeloyl-3beta,16 alpha,21 beta,22 alpha,28-pentahydroxyolean-12-ene (28), R(1)-barrigenol (29), scopolin (30), and 5-methoxyscopolin (31). The structures of these compounds were elucidated by spectroscopic and chemical analyses. Compounds 14-22 and 26-28 were tested in vitro for their activity against 59 cell lines from nine different human cancers including leukemia, non-small cell lung, colon, CNS, melanoma, ovarian, renal, prostate, and breast. It was found that compounds with two-acyl groups at C-21 and C-22 had cytotoxic activity for all cell lines tested with GI(50) 0.175-8.71 microM, while compounds without acyl groups at C-21 and C-22 had weak or no cytotoxic activity. These results suggest that the acyl groups at C-21 and C-22 are essential for their activity.     

Four triterpenoid saponins from dried roots of Gypsophila species.

Four new triterpenoid saponins were isolated from the roots of Gypsophila paniculata and G. arrostii. Their structures were elucidated using a combination of homo- and heteronuclear 2D NMR techniques, without having recourse to chemical degradation or modification. The saponins investigated are: 3-O-beta-D-galactopyranosyl-(1----2)-[beta-D-xylopyranosyl-(1----3)]-bet a-D- glucuronopyranosyl quillaic acid 28-O-beta-D-glucopyranosyl-(1----3)-[beta-D-xylopyranosyl-(1----4)]-alph a- L-rhamnopyranosyl-(1----2)-beta-D-fucopyranoside; 3-O-beta-D-galactopyranosyl-(1----2)-[beta-D-xylopyranosyl-(1----3)]-bet a- D-glucuronopyranosyl quillaic acid 28-O-beta-D-arabinopyranosyl-(1----4)-beta-D-arabinopyranosyl++ +-(1----3)-beta-D- xylopyranosyl-(1----4)-alpha-L-rhamnopyranosyl-(1----2)-beta-D-fucopyran oside; 3-O-beta-D-glucopyranosyl-(1----2)-beta-D-glucuronopyranosyl gypsogenin 28-O-beta-D-glucopyranosyl-(1----3)-[beta-D-xylopyranosyl-(1----4)]-alph a- L-rhamnopyranosyl-(1----2)-beta-D-fucopyranoside; 3-O-beta-D-xylopyranosyl-(1----3)-[beta-D-galactopyranosyl-(1----2)]-bet a- D-glucuronopyranosyl gypsogenin 28-O-beta-D-glucopyranosyl-(1----3)-[beta-D-xylopyranosyl-(1----4)-alpha -L- rhamnopyranosyl-(1----2)-beta-D-fucopyranoside.     

Synthesis of a tetrasaccharide representing a minimal epitope of an arabinogalactan

The hydrophobic alkyl chain-containing tetrasaccharide, dodecyl beta-D-galactopyranosyl-(1-->6)-beta-D-galactopyranosyl-(1-->6)-[alpha-L - arabinofuranosyl-(1-->2)]-beta-D-galactopyranoside, was synthesized efficiently using a convergent strategy. In coupling reactions, protected trichloroacetimidates proved to be better donors than their corresponding bromides in the preparation of the dodecyl disaccharide and trisaccharide. Zemplén deacylation provided the target tetramer in good overall yield.     

Five saponins from the root bark of Aralia elata

Five saponins, 3-O-[beta-D-glucopyranosyl (1-->2)-[beta-D-glucopyranosyl (1-->3)]-beta-D-glucopyranosyl]-oleanolic acid 28-O-beta-D-glucopyranosyl ester (aralia-saponin V), 3-O-[beta-D-glucopyranosyl (1-->2)-[beta-D-glucopyranosyl (1-->3)]-beta-D-glucopyranosyl]-echinocystic acid 28-O-beta-D-glucopyranosyl ester (aralia-saponin VI), 3-O-beta-D-glucopyranosyl (1-->2)-[beta-D-glucopyranosyl (1-->3)]-beta-D-glucopyranosyl]-hederagenin 28-O-beta-D-glucopyranosyl ester (aralia-saponin VII), 3-O-[beta-D-glucopyranosyl-(1-->3)-beta-D-glucopyranosyl-(1-->3)-[beta-D-glucopyranosyl-(1-->2)]-beta-D-glucopyranosyl]-caulophyllogenin 28-O-beta-D-glucopyranosyl ester (aralia-saponin VIII), 3-O-[beta-D-glucopyranosyl (1-->2)-[beta-D-glucopyranosyl(1-->3)]-alpha-L-arabinopyranosyl]-hederagenin 28-O-beta-D-glucopyranosyl ester (aralia-saponin IX), were isolated from the root bark of Aralia elata (Miq.) Seem., together with four known compounds. Their structures were determined on the basis of chemical and spectroscopic methods.     

Saponins and acylated saponins from Dizygotheca kerchoveana

Four new triterpenoid saponins were isolated from the leaves and stem of branches of Dizygotheca kerchoveana along with seven known ones. The new saponins were respectively characterized as 3-O-[beta-D-glucopyranosyl-(1-->3)]-[beta-D-glucopyranosyl-(1-->2)]-alpha-L-arabinopyranosyl echinocystic acid, 3-O-[beta-D-glucopyranosyl-(1-->3)]-[beta-D-glucopyranosyl-(1-->2)]-alpha-L-arabinopyranosyl echinocystic acid 28-O-[alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranosyl] ester, 3-O-[beta-D-3-O-trans-p-coumaroyl-glucopyranosyl-(1-->3)]-[beta-D-glucopyranosyl-(1-->2)]-alpha-L-arabinopyranosyl echinocystic acid 28-O-[alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranosyl] ester and 3-O-[beta-d-3-O-cis-p-coumaroyl-glucopyranosyl-(1-->3)]-[beta-D-glucopyranosyl-(1-->2)]-alpha-L-arabinopyranosyl echinocystic acid 28-O-[alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranosyl] ester. Their structures were elucidated by 1D and 2D NMR experiments, FAB-MS as well as chemical means.     

Acetylated glucuronide triterpene bidesmosidic saponins from Symplocos glomerata

Nine new bidesmosidic 3-O-glucuronide oleanane triterpenoid saponins were isolated from the stem bark of Symplocos glomerata King along with two known saponins, salsoloside C and copteroside E, and two major lignans, (-)-pinoresinol and (-)-pinoresinol-4'-O-beta-D-glucopyranoside. The structures of the new saponins were established using one- and two-dimensional NMR spectroscopy and mass spectrometry as, 3-O-[beta-D-xylopyranosyl(1-->4)-[2-O-acetyl]-beta-D-glucuronopyranosyl]-28-O-[beta-D-glucopyranosyl]-oleanolic acid, 3-O-[beta-D-xylopyranosyl(1-->4)-[3-O-acetyl]-beta-D-glucuronopyranosyl]-28-O-[beta-D-glucopyranosyl]-oleanolic acid, 3-O-[beta-D-xylopyranosyl (1-->4)-[2,3-O-diacetyl]-beta-D-glucuronopyranosyl]-28-O-[beta-D-glucopyranosyl]-oleanolic acid, 3-O-[alpha-L-arabinopyranosyl(1-->4)-beta-D-glucuronopyranosyl]-28-O-[beta-D-glucopyranosyl]-oleanolic acid, 3-O-[alpha-L-arabinopyranosyl (1-->4)-[2-O-acetyl]-beta-D-glucuronopyranosyl]-28-O-[beta-D-glucopyranosyl]-oleanolic acid, 3-O-[[beta-D-xylopyranosyl (1-->2)]-[beta-D-xylopyranosyl (1-->4)]-[3-O-acetyl]-beta-D-glucuronopyranosyl]-28-O-[beta-D-glucopyranosyl]-oleanolic acid, 3-O-[[beta-D-glucopyranosyl (1-->2)]-[beta-D-xylopyranosyl (1-->4)]-[3-O-acetyl]-beta-D-glucuronopyranosyl]-28-O-[beta-D-glucopyranosyl]-oleanolic acid, 3-O-[[beta-D-glucopyranosyl (1-->2)]-[alpha-L-arabinofuranosyl (1-->4)]-[3-O-acetyl]-beta-D-glucuronopyranosyl]-28-O-[beta-D-glucopyranosyl]-oleanolic acid, and 3beta-O-[beta-D-xylopyranosyl(1-->4)-[2-O-acetyl]-beta-D-glucuronopyranosyl]-28-O-[beta-D-glucopyranosyl]-morolic acid. The EtOH and EtOAc extracts of the stem bark showed no cytotoxic activity. At a concentration of 370 microg/ml, the saponin mixture showed haemolytic activity and caused 50% haemolysis of a 10% suspension of sheep erythrocytes.     

Triterpenoid saponins from Fagonia indica.

Two new triterpenoid saponins, 3-O-{[beta-D-glucopyranosyl-(1-->2)]-[alpha-L-arabinopyranosyl-(1- ->3)]- alpha-L-arabinopyranosyl}-ursolic acid-28-O-[beta-D-glucopyranosyl] ester (indicasaponin A), 3-O-{[beta-D-glucopyranosyl-(1-->2)]-[alpha-L-arabinopyranosyl-(1- ->3)]- alpha-L-arabinopyranosyl}-oleanolic acid-28-O-[beta-D-glucopyranosyl] ester (indicasaponin B) and two known triterpenoid saponins, 3-O-[beta-D-glucopyranosyl-(1-->3)-alpha-L-arabinopyranosyl]-ur solic acid-28-O-[beta-D-glucopyranosyl] ester, 3-O-[beta-D-glucopyranosyl-(1-->3)-alpha-L-arabinopyranosyl]-olean olic acid-28-O-[beta-D-glucopyranosyl] ester have been isolated from Fagonia indica. The structures were determined primarily by NMR spectroscopy. The assignment of NMR signals was performed by means of 1H-1H COSY, NOESY, ROESY, TOCSY, HMQC and HMBC experiments.     

Triterpenoid saponins from the stem bark of Elattostachys apetala

Six new triterpenoid saponins have been isolated from the stem bark of Elattostachys apetala together with four known triterpenoid saponins. Three of these new compounds are glycosides of a newly described genin, 29-hydroxyhederagenin (1). On the basis of spectral evidence, the structures of the new saponins were concluded to be alpha-hederin 28-O-[alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranosyl] ester (2), sapindoside B 28-O-[alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranosyl] ester (3), 3-O-beta-D-xylopyranosyl astrantiasaponin VII (4), 3-O-[alpha-L-rhamnopyranosyl-(1-->2)-alpha-L-arabinopyranosyl]-28-O-[beta-D-glucopyranosyl-(1-->2)-[beta-D-glucopyranosyl-(1-->6)]-beta-D-glucopyranosyl]-29-hydroxyhederagenin (5), 3-O-[alpha-L-arabinopyranosyl-(1-->3)-alpha-L-rhamnopyranosyl-(1-->2)-alpha-L-arabinopyranosyl]-28-O-[beta-D-glucopyranosyl(1-->2)-[beta-D-glucopyranosyl(1-->6)]-beta-D-glucopyranosyl]-29-hydroxyhederagenin (6), and 3-O-[beta-D-xylopyranosyl-(1-->3)-alpha-L-rhamnopyranosyl-(1-->2)-alpha-L-arabinopyranosyl]-28-O-[beta-D-glucopyranosyl-(1-->2)-beta-D-gluco pyranosyl-(1-->6)]-beta-D-glucopyranosyl]-29-hydroxyhederagenin (7).     

Synthesis of two bidesmosidic ursolic acid saponins bearing a 2,3-branched trisaccharide residue

The focus of this work was on the synthesis of two bidesmosidic ursolic acid saponins bearing a 2,3-branched trisaccharide residue. Therefore, 3-O-{[beta-D-glucopyranosyl-(1-->2)]-[alpha-L-arabinopyranosyl-(1-->3)]-alpha-L-arabinopyranosyl}ursolic acid-28-O-[beta-D-glucopyranosyl] ester 1 was concisely synthesized by two strategies in 22% and 41% overall yield, respectively, and another congener 3-O-{[beta-D-xylopyranosyl-(1-->2)]-[beta-D-glucopyranosyl-(1-->3)]-alpha-L-arabinopyranosyl}ursolic acid-28-O-[beta-D-glucopyranosyl] ester 2 was also efficiently prepared in 81% overall yield. The (1)H NMR and (13)C NMR signals of saponin 2 are all consistent with those reported for the natural product.     

Triterpenoid saponins from Ardisia mamillata

Two saponins were isolated from the roots of Ardisia mamillata HANCE. Their structures were established on the basis of MALDI-TOFMS, 1H, 13C NMR and 2D NMR (COSY, HOHAHA, HETCOR, HMBC and ROESY) spectra, and on chemical evidence, to be ardisimamilloside A, 3-O-[alpha-L-rhamnopyranosyl-(1 --> 2)-beta-D-glucopyranosyl-(1 --> 4)-[beta-D-glucopyranosyl-(1 --> 2)]-alpha-L-arabinopyranosyl]-3beta, 16alpha,28alpha-trihydroxy-13beta,28-epoxy-oleanan+ ++-30-al; and ardisimamilloside B, 3-O-[alpha-L-rhamnopyranosyl-(1 --> 2)-beta-D-glucopyranosyl-(1 --> 4)-[beta-D-glucopyranosyl-( 1 --> 2)]-alpha-L-arabinopyranosyl]-beta3-hydroxy-13beta,28- epoxy-oleanan-16-oxo-30-al.     

Oligosaccharide polyester and triterpenoid saponins from the roots of Polygala japonica

An oligosaccharide polyester, 1-O-(E)-p-coumaroyl-(3-O-benzoyl)-beta-D-fructofuranosyl-(2-->1)-[6-O-(E)-feruloyl-beta-D-glucopyranosyl-(1-->2)]-[6-O-acetyl-beta-D-glucopyranosyl-(1-->3)-(4-O-acetyl)-beta-D-glucopyranosyl-(1-->3)]-4-O-[4-O-alpha-L-rhamnopyranosyl-(E)-p-coumaroyl]-alpha-D-glucopyranoside (polygalajaponicose I), and four triterpenoid saponins, 3beta, 23, 27-trihydroxy-29-O-beta-D-glucopyranosyl-(1-->2)-beta-D-glucopyranosyl-olean-12-en-28-oic acid (polygalasaponin XLVII), 3-O-beta-D-glucopyranosyl presenegenin 28-O-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-fucopyranosyl ester (polygalasaponin XLVIII), 3-O-beta-D-glucopyranosyl presenegenin 28-O-beta-D-galactopyranosyl-(1-->5)-beta-D-apiofuranosyl-(1-->4)-beta-D-xylopyranosyl-(1-->4)-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranosyl ester (polygalasaponin XLIX) and 2beta, 27-dihydroxy-3-O-beta-D-glucopyranosyl 11-oxo-olean-12-en-23, 28-dioic acid 28-O-beta-D-galactopyranosyl-(1-->5)-beta-D-apiofuranosyl-(1-->4)-beta-D-xylopyranosyl-(1-->4)-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-fucopyranosyl ester (polygalasaponin L), in addition to five known compounds have been isolated from the roots of Polygala japonica.