Flavonol glycosides in leaves of Spinacia oleracea

Besides spinatoside (3,6-dimethoxy-5,7,3′,4′-tetrahydroxyflavone 4′-O-β-D-glucopyranuronide), three new flavonol glycosides have now been isolated from the polar fractions of the methanolic extract of Spinacia oleracea. They have been identified as patuletin 3-O-β-D-glucopyranosyl-(1 → 6)-[β-D-apiofuranosyl-(1 → 2)]-β-D-glucopyranoside, patuletin 3-O-β-gentiobioside and spinacetin 3-O-β-gentiobioside, respectively.     

Triterpene glycosides related to quadranguloside from Passiflora quadrangularis

Two new cyclopropane triterpene glycosides were isolated from the methanol extracts of leaves of Passiflora quadrangularis. On the basis of hydrolysis, spectral evidence and comparison with quadranguloside, these compounds were assigned the structures 9,19-cyclolanosta-22,25-epoxy-3β-21,22(R)-triol-3β-O-gentiobioside and 9,19-cyclolanosta-21,24-epoxy-3β-25,26-triol-3β-O-gentiobioside,respectively. Oleanolic acid-3-sophoroside was also isolated for the first time from a natural source.     

Flavonol glycosides from Chenopodium foliosum Asch

Three new flavonol glycosides, namely 6-methoxykaempferol-3-O-β-gentiobioside, gomphrenol-3-O-β-gentiobioside and gomphrenol-3-O-α-l-rhamnopyranosyl-(1 → 2)[β-d-glucopyranosyl-(1 → 6)]-β-d-glucopyranoside as well as the known patuletin-3-O-β-gentiobioside and spinacetin-3-O-β-gentiobioside were isolated from the aerial parts of Chenopodium foliosum Asch. The structures of the compounds were determined by means of spectroscopic methods (1D and 2D NMR, UV, IR, and HRMS). DPPH free radical scavenging activity of the new compounds was low or lacking.     

Physcion-8-O-gentiobioside from Rhamnus virgata

A new anthraquinone diglucoside isolated from Rhamnus virgata has been shown to be physcion-8-O-β-gentiobioside on the basis of spectral and other evidence.     

Biotransformation of naringin and naringenin by cultured Eucalyptus perriniana cells

The biotransformation of naringin and naringenin was investigated using cultured cells of Eucalyptus perriniana. Naringin (1) was converted into naringenin 7-O-β-d-glucopyranoside (2, 15%), naringenin (3, 1%), naringenin 5,7-O-β-d-diglucopyranoside (4, 15%), naringenin 4′,7-O-β-d-diglucopyranoside (5, 26%), naringenin 7-O-[6-O-(β-d-glucopyranosyl)]-β-d-glucopyranoside (6, β-gentiobioside, 5%), naringenin 7-O-[6-O-(α-l-rhamnopyranosyl)]-β-d-glucopyranoside (7, β-rutinoside, 3%), and 7-O-β-d-gentiobiosyl-4′-O-β-d-glucopyranosylnaringenin (8, 1%) by cultured cells of E. perriniana. On the other hand, 2 (14%), 4 (7%), 5 (13%), 6 (2%), 7 (1%), naringenin 4′-O-β-d-glucopyranoside (9, 4%), naringenin 5-O-β-d-glucopyranoside (10, 2%), and naringenin 4′,5-O-β-d-diglucopyranoside (11, 5%) were isolated from cultured E. perriniana cells, that had been treated with naringenin (3). Products, 7-O-β-d-gentiobiosyl-4′-O-β-d-glucopyranosylnaringenin (8) and naringenin 4′,5-O-β-d-diglucopyranoside (11), were hitherto unknown.     

Glycosylation of sesamol by cultured plant cells

The glycosylation of sesamol was investigated using cultured cells of Nicotiana tabacum and Eucalyptus perriniana. The cultured suspension cells of N. tabacum converted sesamol into its β-glucoside (7%) as well as the disaccharide, sesamyl 6-O-(β-D-glucopyranosyl)-β-D-glucopyranoside (β-gentiobioside, 30%). On the other hand, sesamyl 6-O-(α-L-rhamnopyranosyl)-β-D-glucopyranoside (β-rutinoside, 56%), together with the β-glucoside (3%), was produced when sesamol was incubated with suspension cells of E. perriniana.     

Acylated flavonoid tetraglycoside from Planchonia careya leaves

Phytochemical investigations of the aqueous extract of Planchonia careya leaves revealed two known flavonol glycosides, kaempferol 3-O-gentiobioside (1) and quercetin 3-O-glucoside (isoquercitrin) (2), and a novel acylated kaempferol tetraglycoside, kaempferol 3-O-[α-rhamnopyranosyl(1 → 3)-(2-O-p-coumaroyl)]-β-glucopyranoside, 7-O-[α-rhamnopyranosyl-(1 → 3)-(4-O-p-coumaroyl)]-α-rhamnopyranoside (3). Structural elucidation was achieved using UV, NMR, and mass spectrometry.     

Megastigmane and 7,9′-dinorlignan glycosides from the tubers of Stephania kaweesakii

Two isomers of megastigmane glycosides, (6R, 9S)-blumenol C 9-O-gentibioside (2) and (6S, 9S)-blumenol C 9-O-gentiobioside (3), and a new 7,9′-dinorlignan glycoside, stepdonorlignoside (4) were isolated from the tubers of Stephania kaweesakii. The structure determinations were considered based on the physical data and spectroscopic evidence. The absolute configurations of two megastigmanes were determined for the first time. Additionally, ten known compounds were isolated: (6R, 9S)-blumenol C 9-O-β-D-glucopyranoside, (+)-isolariciresinol 3a-O-β-D-glucopyranoside, salidroside, N-trans-caffeoyltyramine, (R)-isococlaurine, (R)-isococlaurine 4′-O-β-glucopyranoside, (−)-oblongine, (+)-magnocurarine, fordianoside, and (−)-cyclanoline.     

Five glycosides from the chinese drug ‘tong-guang-san’: The stems of marsdenia tenacissima

Five new glycosides were isolated from the Chinese crude drug ‘Tong-guang-san’: the stems of Marsdenia tenacissima (Roth.) Wight et Arn. (Asclepiadaceae). The structures of tenacissosides A-E were deduced on the basis of chemical and spectral evidence as tenacigenin B-I 3-O-β-D-glucopyranosyl-(1→4)-3-O-methyl-6-deoxy-β-D- allopyranosyl-(1→4)-β-D-oleandropyranoside, tenacigenin B-II 3-O-β-D-glucopyranosyl-(1 →4)-3-O-methyl-6-deoxy- β-Dallopyranosyl-(1 →4)-β-D-oleandropyranoside, tenacigenin B-III 3-O-β-Dglucopyranosyl-(1→4)-3-O-methyl-6- deoxy-β-D-allopyranosyl-(1 → 4)-β-D-oleandropyranoside, tenacigenin B-IV 3-O-β-D-glucopyranosyl-(1 →4)-3-O- methyl-6-deoxy-β-D-allopyranosyl-(1 → 4)-β-D-oleandropyranoside and tenacigenin B-V 3-O-β-D-glucopyranosyl- (1 → 4)-3-O-methyl-6-deoxy-allopyranosyl-(1 → 4)-β-D-oleandropyranoside, respectively.     

Steroidal saponins from the leaves of Beaucarnea recurvata

Thirteen steroidal saponins were isolated from the leaves of Beaucarnea recurvata Lem. Their structures were established using one- and two-dimensional NMR spectroscopy and mass spectrometry. Six of them were identified as: 26-O-β-d-glucopyranosyl (25S)-furosta-5,20(22)-diene 1β,3β,26-triol 1-O-α-l-rhamnopyranosyl-(1 → 2) β-d-fucopyranoside, 26-O-β-d-glucopyranosyl (25S)-furosta-5,20(22)-diene 1β,3β,26-triol 1-O-α-l-rhamnopyranosyl-(1 → 2)-4-O-acetyl-β-d-fucopyranoside, 26-O-β-d-glucopyranosyl (25R)-furosta-5,20(22)-diene-23-one-1β,3β,26-triol 1-O-α-l-rhamnopyranosyl-(1 → 2) β-d-fucopyranoside, 26-O-β-d-glucopyranosyl (25S)-furosta-5-ene-1β,3β,22α,26-tetrol 1-O-α-l-rhamnopyranosyl-(1 → 4)-6-O-acetyl-β-d-glucopyranoside, 26-O-β-d-glucopyranosyl (25S)-furosta-5-ene-1β,3β,22α,26-tetrol 1-O-α-l-rhamnopyranosyl-(1 → 2) β-d-fucopyranoside, and 24-O-β-d-glucopyranosyl (25R)-spirost-5-ene-1β,3β,24-triol 1-O-α-l-rhamnopyranosyl-(1 → 2)-4-O-acetyl-β-d-fucopyranoside. The chemotaxonomic classification of B. recurvata in the family Ruscaceae was discussed.     

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.     

Acetylated allose-containing flavonoid glucosides from Stachys anisochila

In continuation of our chemosystematic study of Stachys (Labiatae) we have isolated the previously reported isoscutellarein 7-O-[6″'-O-acetyl-β-D-allopyranosyl-(1 → 2)-β-D-glucopyranoside] (1) and 3′-hydroxy-4′-O-methylisoscutellarein 7-O-[6″'-O-acetyl-β-D-allopyranosyl-(1 → 2)-β-D-glucopyranoside] (4) and four new allose-containing flavonoid glycosides from S. anisochila. The new glycosides are hypolaetin 7-O-[6″'-O-acetyl-β-D-allopyranosyl-(1 → 2)-β-D-glucopyranside] (6) as well as the three corresponding diacetyl analogues of 1, 4 and 6, isoscutellarein 7-O-[6″'-O-acetyl-β-D-allopyranosyl-(1 → 2)-6″-O-acetyl-β-D-glucopyranoside], 3′-hydroxy-4′-O-methylisoscutellarein 7-O-[6″'-O-acetyl-β-D-allopyranosyl-(1 → 2)-6″-O-acetyl-β-D-glucopyranoside] and hypolaetin 7-O-[6″'-O-acetyl-β-D-allopyranosyl-(1 → 2)-6″-O-acetyl-β-D-glucopyranoside]. Extensive two-dimensional NMR studies (proton-carbon correlations, COSY experiments) allowed assignment of all ¹H NMR sugar signals and a correction of the ¹³C NMR signal assignments for C-2 and C-3 of the allose.     

Furostanol glycosides from Trigonella foenum-graecum seeds

Two new furostanol glycosides trigofoenosides A and D have been isolated from the Trigonella foenum-graecum seeds as their methyl ethers, A-1 and D-1. Their structures have been determined as (25S)-22-O-methyl-furost-5-ene-3β,26-diol, 3-O-α-L-rhamnopyranosyl (1 → 2)-β-D-glucopyranoside; 26-O-β-D-glucopyranoside (A-1) and (25S)-22-O-methyl-furost-5-ene-3β,26-diol, 3-O-α-L-rhamnopyranosyl (1 → 2)-[β-D-glucopyranosyl (1 → 3)]-β-D-glucopyranoside; 26-O-β-D-glucopyranoside (D-1).     

Entwicklung eines syntheseblocks der 3-O-β-d-galactopyranosyl-d-galactopyranose

In the presence of trimethylsilyl triflate, 1,2,3,4,6-penta-O-acetyl-β-d-galactopyranose reacted with benzyl 4-O-acetyl-2,6-di-O-benzyl-β-d-galactopyranoside to give benzyl 2,6-di-O-benzyl-3-O-β-d-galactopyranosyl-β-d-galactopyranoside further converted into the synthetic block 1,2,4,6-tetra-O-acetyl-3-O-(2,3,4,6-tetra-O-acetyl-β-d-galactopyranosyl)-β-d-galactopyranose. This, in the presence of a Lewis acid catalyst and with the corresponding glycosyl acceptors, gave 8-methoxycarbonyloctyl 3-O-β-d-galactopyranosyl-β-d-galactopyranoside and 8-methoxycarbonyloctyl O-β-d-galactopyranosyl-(1→3)-O-β-d-galactopyranosyl-(1→3)-2-acetamido-2-deoxy-α-d-galactopyranoside.     

Pyruvic acid-containing mono- and oligo-saccharides from rhizobium trifolii bart A

After partial, acid hydrolysis of the extracellular, acid polysaccharide from Rh. trifolii Bart A, the following products were isolated and characterized: 3,4-O-(1-carboxyethylidene)-d-galactose, 4,6-O-(1-carboxyethylidene)-d-galactose, 3-O-[3,4-O-(1-carboxyethylidene)-β-d)-galactopyranosyl]-d-glucose, 3-O-[4,6-O-(1-carboxyethylidene)-β-d-galactopyranosyl]-d-glucose, O-[3,4-O-(1-carboxyethylidene)-β-d-galactopyranosyl ]-(1→3)-O-d-glucopyranosyl-(1→4)-d-glucose, and O-[4,6-O-(1- carboxyethylidene)-β-d-galactopyranosyl]-(1→3)-O-β-d-glucopyranosyl-(1→4)-d-glucose. The presence of pyruvic acid linked either to O-3 and O-4 or to O-4 and O-6 of the d-galactopyranosyl group of these saccharides indicates that both structures may be present in the original polysaccharide.     

Isolation from a softwood xylan of oligosaccharides containing two 4-O-methyl-d-glucuronic acid residues

Partial hydrolysis of a larch arabino(4-O-methylglucurono)xylan afforded two series of oligouronides composed of 4-O-methyl- d-glucuronic acid and d-xylose residues. The first series included aldouronic acids up to the aldopentaouronic acid. Methylation analysis indicated that the aldopentao- and aldotetrao-uronic acids were mixtures of isomers. One aldotetraouronic acid was isolated and identified as O-β-d-Xylp-(1 → 4)-O-β-d-Xylp-(1 → 4)-O-(4-O-Me-α-d-GlcAp)-(1 → 2)-d-Xyl. The two isomeric aldotriouronic acids were separated from each other. The acids of the second series, which were composed of two uronic acids and 2-4 d-xylose residues, were identified as follows: O-β-d-Xylp-(1 → 4)-O-(4-O-Me-α-d-GlcAp)-(1 → 2)-O-β-d-Xylp-(1 → 4)-O(4-O-Me-α-d-GlcAp)-(1 → 2)-O-β-d-Xylp-(1 → 4)-d-Xyl, O-(4-O-Me-α-d-GlcAp)-(1 → 2)-O-β-d-Xylp-(1 → 4)-O-(4-O-Me-α-d-GlcAp)-(1 → 2)-O-β-d-Xylp-(1 → 4)-O-β-d -Xylp-(1 → 4)-D-Xyl, O-(4-O-Me-α-d-GlcAp)-(1 → 2)-O-β-d-Xylp-(1 → 4)-O-(4-O-Mec-α-d-GlcAp)-(1 → 2)-O-β-d-Xylp-(1 → 4)-D-Xyl, and O-(4-O-Me-α-d-GlcAp)-(1 → 2)-O-β-d-Xylp-(1 → 4)-O-(4-O-Me-α-d-GlcAp)-(1 → 2)-D-Xyl. The first three compounds were new acidic oligosaccharides. The 4-O-methyl-d-glucuronic acid in the second series was present in a larger proportion than in the first series, indicating that a large proportion of the uronic acid side-chains were located on two contiguous D-xylose residues in the backbone of the softwood xylan.     

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.     

The flavonoids of phragmites australis flowers

The major flavonoid constituents of Phragmites australis flowers are the C-glycosylflavones swertiajaponin, isoswertiajaponin and two new O-glycosides, the 3′-O-gentiobioside and the 3′-O-glucoside of swertiajaponin. Two unusual flavonol glycosides, rhamnetin 3-O-rutinoside and rhamnetin 3-O-glucoside, were also characterized from the same tissue.     

Three phenylpropanoid glycosides from Mussatia

Three new phenylpropanoid glycosides, mussatioside I, mussatioside II and mussatioside III were isolated from the methanolic extract of the bark of a new Mussatia species. On the basis of the chemical and spectral evidence their structures were determined as [β-(4′-hydroxyphenyl)ethyl-O-β-D-glucopyranosyl(6 → 1)]-O-β-D-xylopyranosyl(1 → 3)-α-L-(4-O-t-cinnamoyl)rhamnopyranoside, [β-(4′-hydroxyphenyl)-ethyl-O-β-D-glucopyranosyl(6 → 1)]-O-β-D-xylopyranosyl(1 → 3)-α-L-(4-O-dimethylcaffeoyl)rhamnopyranoside and [β-(4′-hydroxyphenyl)ethyl-O-β-D-glucopyranosyl(6 → 1)]-O-β-D-xylopyranosyl(1 → 3)-α-L-(4-O-p-methylcoumaroyl)rhamnopyranoside, respectively. M. hyacinthina was also found to contain mussatioside I.     

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.