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.     

Flavonoid glycosides from needles of Pinus massoniana

Seven flavonoids have been isolated from Pinus massoniana needles and identified as taxifolin and its 3′-O-β-D-glucopyranoside, (+)-catechin, naringenin-7-O-β-D-glucopyranoside and three new flavonoid glycosides, 6-C-methylaromadendrin 7-O-β-D-glucopyranoside, taxifolin 3′-O-β-D-(6″-O-phenylacetyl)-glucopyranoside and eriodictyol 3′-O-β-D-glucopyranoside.     

Phenolic glucosides from Prunus grayana

A new bitter phenylpropanoid glucoside, 2-(4-hydroxyphenyl)-ethyl-(6-O-caffeoyl)-β-D-glucopyranoside and a new bitter tannin-related compound, 3,4,5-trimethoxybenzoyl-β-D-glucopyranoside, have been isolated together with known compounds, 2-(3,4-dihydroxyphenyl)-ethyl-(6-O-caffeoyl)-β-D-glucopyranoside, 2-(3,4-dihydroxyphenyl)-ethyl-β-D-glucopyranoside and 6-O-caffeoyl-D-glucopyranose, from the bark of Prunus grayana. The structures of these compounds have been established on the basis of spectroscopic studies and chemical evidence.     

5-Methyl ether flavone glucosides from the leaves of Bruguiera gymnorrhiza

Two new 5-methyl ether flavone glucosides (7,4′,5′-trihydroxy-5,3′-dimethoxyflavone 7-O-β-D-glucopyranoside and 7,4′-dihydroxy-5-methoxyflavone 7-O-β-D-glucopyranoside) were isolated from the leaves of Thai mangrove Bruguiera gymnorrhiza together with 7,3′,4′,5′-tetrahydroxy-5-methoxyflavone, 7,4′,5′-trihydroxy-5,3′-dimethoxyflavone, luteolin 5-methyl ether 7-O-β-D-glucopyranoside, 7,4′-dihydroxy-5,3′-dimethoxyflavone 7-O-β-D-glucopyranoside, quercetin 3-O-β-D-glucopyranoside, rutin, kaempferol 3-O-rutinoside, myricetin 3-O-rutinoside and an aryl-tetralin lignan rhamnoside. The structure of a lignan rhamnoside was found to be related to racemiside, an isolated compound from Cotoneaster racemiflora, and also discussed. Structure determinations were based on analyses of physical and spectroscopic data including 1D- and 2D-NMR.     

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.     

Oxazoline synthesis of 1,2-trans-2-acetamido-2-deoxyglycosides. Glycosylation with 2-methyl-(3,4,6-tri-O-acetyl-1,2-dideoxy-α-D-galactopyrano)-[2′,1′:4,5]-2-oxazoline

The glycosylating activity of 2-methyl-(3,4,6-tri-O-acetyl-1,2-dideoxy-α-D-galactopyrano)-[2′,1′:4,5]-2-oxazoline has been tested in reaction with partially protected saccharides having free primary or secondary hydroxyl groups or with hydroxy amino acids. 3-O-(2-Acetamido-3,4,6-tri-O-acetyl-2-deoxy-β-D-galactopyranosyl)-N-benzyloxycarbonyl-L-serine benzyl ester (3), 6-O-(2-acetamido-2-deoxy-β-D-galactopyranosyl)-D-galactopyranose (5), p-nitrophenyl 2-acetamido-6-O-(2-acetamido-2-deoxy-β-D-galactopyranosyl)-2-deoxy-β-D-glucopyranoside (7), 6-O-(2-acetamido-2-deoxy-β-D-galactopyranosyl)-D-glucose (9), and 3-O-(2-acetamido-2-deoxy-β-D-galactopyranosyl)-D-glucose (11) were synthesized in high yield.     

Glycosidation at C-4 of 2-acetamido-2-deoxy-D-glucopyranose derivatives by koenigs-knorr type condensations

The condensation of 2,3,4,6-tetra-O-benzyl-D-glucopyranosyl bromide and 2,3,4,6-tetra-O-benzyl-D-mannopyranosyl chloride with benzyl 2-acetamido-3,6-di-O-benzyl-2-deoxy-α-D-glucopyranoside (1), under Koenigs-Knorr conditions, gave the fully benzylated derivatives of benzyl 2-acetamido-2-deoxy-4-O-α-D-glucopyranosyl-α-D-glucopyranoside, benzyl 2-acetamido-2-deoxy-4-O-β-D-glucopyranosyl-α-D-glucopyranoside, and benzyl 2-acetamido-2-deoxy-4-O-α-D-mannopyranosyl-α-D-glucopyranoside. Three further compounds, namely, benzyl 2-acetamido-3-O-benzyl-2-deoxy-6-O-(2,3,4,6-tetra-O-benzyl-D-glucopyranosyl)-α-D-glucopyranoside, benzyl 2-acetamido-3-O-benzyl-2-deoxy-6-O-(2,3,4,6-tetra-O-benzyl-D)-mannopyranosyl)-α-D-glucopyranoside, and benzyl 2-acetamido-3-O-benzyl-2-deoxy-4,6-di-O-(2,3,4,6-tetra-O-benzyl-D-mannopyranosyl)-α-D-glucopyranoside, were formed by reaction of the respective glycosyl halide with benzyl 2-acetamido-3-O-benzyl-2-deoxy-α-D-glucopyranoside present as contaminant in 1.     

Poliumoside,a caffeic glycoside ester from Teucrium belion

A new caffeic glycoside ester, poliumoside, has been isolated from the aerial parts of Teucrium belion. Its structure, [β-(3′,4′-dihydroxyphenyl)-ethyl]-(3,6-O-α-L-dirhamnopyranosyl)-(4-O-caffeoyl)-β-D-glucopyranoside, was established mainly by high-resolution ¹H NMR and ¹³C NMR spectroscopy.     

Study on Chemical Components from Derris taiwaniana and Their Lung Epithelial Cell Protect Effects

The ethanol extract of roots of Derris taiwaniana gave two undescribed compounds, 3,3′-dimethoxy-5′-hydroxystilbene-4-O-β-apiofuranosyl-(1→6)-β-D-glucopyranoside ( 1 ) and 4′,5-dihydroxy-3′-methoxyisoflavone-7-O-β-apiofuranosyl-(1→6)-β-D-glucopyranoside ( 2 ), along with thirty known components. Among them, compounds 14 , 16 – 17 , 23 , 26 – 32 were isolated from this genus for the first time. Their structures were established based on physico-chemical properties and spectroscopic data, the lung epithelial cell protective effects were evaluated using NNK-induced MLE-12 cells. Among them, 2α,3α-epoxy-5,7,3′,4′-tetrahydroxyflavan-(4β-8-catechin) ( 30 ) showed the best significant protective effect, speculated to be the key component of D. taiwaniana that plays a protective role in lung epithelial cells.     

Flavonoids and phenolic acids from the aerial parts of Alyssum alyssoides L. (Brassicaceae)

Two phenolic acids (1 and 2) and seven flavonoids (3–9) were isolated from the aerial parts of Alyssum alyssoides (Brassicaceae). All these compounds (1–9) were isolated from this particular species for the first time. Their structures were identified, on the basis of MS and NMR spectra as: p-hydroxy-benzoic acid (1), 3-methoxy-4-hydroxybenzoic acid (vanillic acid) (2), kaempferol 3-O-β-D-glucopyranoside (astragalin) (3), kaempferol 3-O-(6″-α-L-rhamnopyranosyl)-β-D-glucopyranoside (nicotiflorin) (4), quercetin 3-O-β-D-glucopyranoside (isoquercetin) (5), quercetin 3-O-β-D-galactopyranoside (hyperoside) (6), isorhamnetin 3-O-β-D-glucopyranoside (7), isorhamnetin 3-O-β-D-galactopyranoside (8) and isorhamnetin 3-O-(6″-α-L-rhamnopyranosyl)-β-D-glucopyranoside (narcissin) (9). The chemotaxonomic significance of these compounds was summarized.     

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.     

Glycosylation of 2-phenylpropionic acid and its ethyl ester in suspension cultures of Nicotiana tabacum,Dioscoreophyllum cumminsii and Aconitum japonicum

Suspension cultures of Nicotiana tabacum and Dioscoreophyllum cumminsii converted 2-(RS)-phenylpropionic acid and its ethyl ester into 2-(RS)-phenylpropionyl β-D-glucopyranoside, 2-(RS)-phenylpropionyl 6-O-β-D-glucopyranosyl-β-D-glucopyranoside and 6-O-β-D- glucopyranosyl-2-O-[2-(RS)-phenylpropionyl]-D-glucose which accumulated in the cells. A suspension culture of Aconitum japonicum converted these substrates into ethyl 6-O-[2-(RS)-phenylpropionyl]- β-D-glucopyranoside which was mostly excreted into the medium. The diastereomeric mixture of the glucosyl esters of 2-(RS)-phenylpropionic acid was resolved by HPLC to show the ratio of R:S was 1:1.     

The synthesis of 4′,6′-diacetamido-4′,6′-dideoxycellobiose hexa-acetate from lactose

Reaction of methyl 4′,6′-di-O-mesyl-β-lactoside pentabenzoate (8), synthesised via the 4′,6′-O-benzylidene derivative (6), with sodium azide in hexamethylphosphoric triamide gave three products. In addition to the required 4′,6′-diazidocellobioside (9), an elimination product, methyl 4-O-(6-azido-2,3-di-O-benzoyl-4,6-dideoxy-α-L-threo-hex-4-enopyranosyl)-2,3,6-tri-O-benzoyl-β-D-glucopyranoside (12), and an unexpected product of interglycosidic cleavage, methyl 2,3,6-tri-O-benzoyl-β-D-glucopyranoside (13), were formed. The origin of the latter product is discussed. The diazide 9 was converted into 4′,6′-diacetamido-4′,6′-dideoxycellobiose hexa-acetate (16) by sequential debenzoylation, catalytic reduction, acetylation, and acetolysis.     

Chromone acyl glucosides and an ayanin glucoside from Dasiphora parvifolia

Two new chromone acyl glucosides, 5-hydroxy-7-O-(6-O-p-cis-coumaroyl-β-D-glucopyranosyl)-chromone (1) and 5-hydroxy-7-O-(6-O-p-trans-coumaroyl-β-D-glucopyranosyl)-chromone (2), and a new flavonoid glucoside, ayanin 3′-O-β-D-glucopyranoside (3) were isolated from aerial parts of Dasiphora parvifolia, together with flavonoid glycosides (4–10), catechins (11, 12), and hydrolysable tannins (13, 14). The chemical structures of these compounds were elucidated on the basis of spectroscopic data. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity and the hyaluronidase inhibitory activity of these compounds were evaluated.     

7-O-methyl-(2R:3R)-dihydroquercetin 5-O-β-D-glucoside and other flavonoids from Podocarpus nivalis

In the course of a chemotaxonomic survey of New Zealand Podocarpus species, a number of new flavonoid glycosides have been isolated from P. nivalis. These are: luteolin 3′-O-β-D-xyloside, luteolin 7-O-β-D-glucoside-3′-O-β-D-xyloside, dihydroquercetin 7-O-β-D-glucoside, 7-O-methyl-(2R:3R)-dihydrokaempferol 5-O-β-D-glucopyranoside, 7-O-methyl-(2R:3R)-dihydroquercetin 5-O-β-D-glucopyranoside, 7-O-methylkaempferol 5-O-β-D-glucopyranoside and 7-O-methylquercetin 5-O-β-D-glucopyranoside. Diagnostically useful physical techniques for distinguishing substitution patterns in dihydroflavonols are discussed and summarized. Glucosylation of the 5-hydroxyl group in (+)-dihydroflavonols is shown to reverse the sign of rotation at 589 nm.     

Two phytoalexin glycosides from potato tubers infected with Phoma

Four coumarins and seven isoprenoid compounds have been identified in potato tubers infected with Phoma exigua var. foveata. Among these were the 7-O-β-D-glucopyranoside of 7-hydroxy-6,8-dimethoxycoumarin (isofraxidin) and the sesquiterpene 2-(11,12-dihydroxy-11-methylethyl)-6,10-dimethyl-spiro[4,5]dec-6-en-8-one and its 12-O-β-D-glucopyranoside, which apparently have not been previously identified in potato tubers. At least two diastereoisomers of the latter glucoside were present. Analysis of eight fluorescent compounds in different parts of infected potatoes was performed by an improved HPLC technique.     

Cyanogenic and phenylpropanoid glucosides from Prunus grayana

In a chemical examination of the bark ofPrunus grayana, three new phenylpropanoid glucosides, grayanoside A, grayanoside B and grayanin, have been isolated. The structures of these compounds have been established to be 2-(4-hydroxyphenyl)ethyl-(6-O-feruloyl)-β-D-glucopyranoside, 2-(3,4-dihydroxyphenyl)ethyl-(6-O-feruloyD-β-D-gluco and (2R)-[(6-O-caffeoyl)-β-D-glucopyranosyloxy]benzeneacetonitrile, respectively, on the basis of the spectroscopic studies and the chemical evidence.     

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.     

Two new penterpenoid saponins and a new diterpenoid glycoside from Hemsleya chinensis

Two new penterpenoid saponins, hemsloside-Ma4 (1) hemsloside-Ma5 (2), and a new diterpenoid glycoside, hemsloside-Ma6 (3), were isolated from the rhizomes of Hemsleya chinensis. By detailed analysis of the NMR spectra and chemical methods, the structures of new compounds were determined to be 3-O-β-l-arabinopyranosyl-(1 → 3)-O-(6′-methyl ester)-β-d-glucuropyranosyl-oleanolic acid-28-O-β-d-glucopyranosyl-(1 → 6)-O-β-d-glucopyranoside (1), 3-O-β-l-arabinopyranosyl-(1 → 3)-O-(6′-methyl ester)-β-d-glucuropyranosyl-oleanolic acid-28-O-β-d-xylopyranosyl-(1 → 6)-O-β-d-glucopy-ranoside (2), and 13ϵ-hydroxylabda-8(17), 14-dien-18-oic acid-18-O-α-l-rhamnopyranosyl-(1 → 2)-O-β-d-glucopyranosyl-(1 → 4)-O-α-l-rhamnopyranoside (3). Diterpenoid-type compound (3) was isolated from Hemsleya genus for the first time.     

Palmilycorine and lycoriside: acyloxy and acylglucosyloxy alkaloids from crinum asiaticum

Two new types of alkaloidal conjugates, a C₁₆-acyloxy derivative, named palmilycorine, and an acylglucosyloxy derivative, named lycoriside, were isolated from the fruits of Crinum asiaticum. The presence of these compounds was also detected in the fleshy scale leaves and in roots of this species. The structures of the two compounds were established as 1-O-palmitoyllycorine (1) and lycorine-1-O-(6′-O-palmitoyl-β-D-glucopyranoside)(2), respectively, on the basis of chemical transformation and comprehensive spectral evidence. The biological effects of the alkaloids were evaluated.