Phenolic glycosides from Phagnalon rupestre

Analysis of the butanol-soluble fraction from the methanolic extract of the aerial parts of Phagnalon rupestre (Asteraceae) has led to the isolation of seven phenolic compounds. Three have been identified on the basis of their NMR spectra as new natural compounds: the lignan 7,7'-bis-(4-hydroxy-3,5-dimethoxyphenyl)-8,8'-dihydroxymethyl-tetrahydrofuran-4-O-beta-glucopyranoside (1), the prenylhydroquinone glycoside 1-O-beta-glucopyranosyl-1,4-dihydroxy-2-(3'-hydroxy-3'-methylbutyl) benzene (2) and the acetophenone glycoside 12-O-beta-glucopyranosyl-9beta,12-dihydroxytremetone (3). The known flavonoids apigenin-7-O-beta-glucoside, luteolin-7-O-beta-glucoside, luteolin-7-O-beta-glucuronide and the acetophenone picein were also isolated.     

Lignan and megastigmane glycosides from Sauropus androgynus

A lignan diglycoside, (-)-isolariciresinol 3alpha-O-beta-apiofuranosyl-(1-->2)-O-beta-glucopyranoside, and a megastigmane glucoside, sauroposide, were isolated from the aerial part of Sauropus androgynus together with (+)-isolariciresinol 3alpha-O-beta-glucopyranoside, (-)-isolariciresinol 3alpha-O-beta-glucopyranoside, (+)-syringaresinol di-O-beta-glucopyranoside, guanosine and corchoionoside C. The structural elucidations were bases on analyses of physical and spectroscopic data.     

Glycosides from Phlomis lunariifolia

An aliphatic alcohol glycoside, lunaroside 1-octen-3-yl [O-beta-apiofuranosyl-(1-->6)-O-[beta-glucopyranosyl-(1-->2)]-beta-glucopyranoside, a phenylethanoid glycoside, lunariifolioside 2-(3,4-dihydroxyphenyl)ethylO-beta-apiofuranosyl-(1-->6)-O-[O-beta-apiofuranosyl-(1-->4)-alpha-rhamnopyranosyl-(1-->3)]-4-O-(E)-caffeoyl-beta-glucopyranoside and a flavone glycoside, luteolin 7-O-[4-O-acetyl-alpha-rhamnopyranosyl-(1-->2)]-beta-glucuronopyranoside, were isolated from the aerial parts of Phlomis lunariifolia, in addition to 15 known glycosides. Their structures were elucidated on the basis of extensive 1D and 2D NMR spectroscopic interpretation and chemical degradation.     

Cholestane and spirostane glycosides from the rhizomes of Dioscorea septemloba

Cholestane glycosides, dioseptemlosides A (1) and B (2), together with six spirostane glycosides, dioseptemlosides C-H (3-8), were isolated from the rhizomes of Dioscorea septemloba. Their structures were established on the basis of physical data, spectroscopic analysis (HRESIMS, 1D and 2D NMR), and chemical methods. Spirostane aglcones containing hydroxyl group at C-7, as found in compounds 4-7, were reported in the family Dioscoreaceae for the first time. These compounds did not show considerable inhibitory anti-tumor activities at a concentration of 10 microM.     

Cucurbitane, hexanorcucurbitane and octanorcucurbitane glycosides from fruits of Trichosanthes tricuspidata.

From the fruits of Trichosanthes tricuspidata, 14 cucurbitane glycosides (khekadaengosides A-J, M-N, cucurbitacin J 2-O-beta-glucopyranoside and cucurbitacin K 2-O-beta-glucopyranoside), a hexanorcucurbitane glucoside (khekadaengoside K) and octanorcucurbitane (khekadaengoside L) were isolated along with two known cucurbitane glucosides (cucurbitacin 2-O-beta-glucopyranoside and 25-O-acetyl-cucurbitacin 2-O-beta-glucopyranoside). Structural elucidations were based on chemical and spectroscopic analyses.     

Cinnamoyl glucosides of catechin and dimeric procyanidins from young leaves of Inga umbellifera (Fabaceae)

The rapidly growing, nearly achlorophyllous, young leaves of Inga umbellifera express high concentrations of mono and dimeric 3-O-gluco-cinnamoyl catechin/epicatechin, rare forms of substituted flavan-3-ols. Here we present structures for five novel compounds in this class: three monomers [catechin-3-O-beta-D-gluco(2-cinnamoyl)pyranoside, catechin-3-O-beta-D-gluco(6-cinnamoyl) pyranoside, catechin-3-O-beta-D-gluco(2,6-biscinnamoyl)pyranoside] and two dimeric procyanidins [catechin-3-O-beta-D-glucopyrano-(4alpha-->8)-catechin-3-O-beta-D-gluco(2-cinnamoyl)pyranoside and catechin-3-O-beta-D-glucopyrano-(4alpha-->8)-epicatechin-3-O-beta-D-gluco(6-cinnamoyl)pyranoside]. The young leaves of Inga umbellifera express high concentrations of 3-O-(cinnamoyl)glucosides of catechin and epicatechin.     

Steroidal saponins from the aerial parts of Tribulus pentandrus Forssk

Seven new steroidal glycosides named pentandrosides A(1)-G(7) were isolated from the EtOH extract of the aerial parts of Tribulus pentandrus. Pentandrosides A(1)-E(5) possess cholestane aglycones, pentandroside F(6) a furostan-type aglycone and pentandroside G(7) an unusual acyloxypregnane aglycone probably derived from the degradation of a furostan skeleton. Structure elucidation of 1-7 was accomplished through the extensive use of 1D- and 2D NMR experiments including 1H-1H (DQF-COSY, 1D-TOCSY) and 1H-13C (HSQC, HMBC) spectroscopy along with ESIMS and HRESIMS.     

Phenylethanoid and aliphatic alcohol glycosides from Acanthus ilicifolius

A phenylethanoid glycoside (ilicifolioside A) and an aliphatic alcohol glycoside (ilicifolioside B), have been isolated from the aerial parts of Acanthus ilicifolius, together with eight known compounds. Their structures were determined from spectroscopic analyses.     

Phenolic glycosides from Kaempferia parviflora

Three phenolic glycosides were isolated together with two known flavonol glycosides from the H2O-soluble fraction of rhizomes of Kaempferia parviflora. Their structures were determined to be rel-(5aS,10bS)-5a,10b-dihydro-1,3,5a,9-tetrahydroxy-8-methoxy-6H-benz[b]indeno[1,2-d]furan-6-one 5a-O-[alpha-L-rhamnopyranosyl-(1-->6)-beta-d-glucopyranoside] (1), its rel-5aS,10bR isomer (2), and (2R,3S,4S)-3-O-[alpha-L-rhamnopyranosyl-(1-->6)-beta-d-glucopyranosyl]-3'-O-methyl-ent-epicatechin-(2alpha-->O-->3,4alpha-->4)-(5aS,10bS)-5a,10b-dihydro-1,3,5a,9-tetrahydroxy-8-methoxy-6H-benz[b]indeno[1,2-d]furan-6-one 5a-O-[alpha-L-rhamnopyranosyl-(1-->6)-beta-D-glucopyranoside] (3). The structures were elucidated on the basis of analyses of chemical and spectroscopic evidence.     

Iridoid glycosides and cucurbitacin glycoside from Neopicrorhiza scrophulariiflora

Three iridoid glycosides, picrorosides A (1), B (2) and C (3), and a cucurbitacin glycoside, scrophoside A (4), were isolated from the rhizomes of Neopicrorhiza scrophulariiflora (Scrophulariaceae), along with two known iridoid glycosides, picrosides I (5) and II (6), and three known cucurbitacin glycosides (7-9). Their structures were elucidated on the basis of both chemical and spectroscopic data.     

Coumaroyl triterpene lactone, phenolic and naphthalene glycoside from stem bark of Diospyros angustifolia

From the ethanolic extract of stem bark of D. angustifolia three new compounds, a coumaroyl triterpene lactone, diospyrosooleanolide (1), a phenolic glycoside, diospyrososide (2) and a naphthalene glycoside, diospyrosonaphthoside (3) were isolated along with five known compounds (4-8). The structures of these compounds were established on the basis of spectroscopic and chemical evidences.     

A flavonol tetraglycoside from Sophora japonica seeds

A flavonol tetraglycoside, kaempferol 3-O-alpha-L-rhamnopyranosyl(1-->6)-beta-D-glucopyranosyl(1-->2)- beta-D-glucopyranoside-7-O-alpha-L rhamnopyranoside, together with nine known compounds were isolated from the seeds of Sophora japonica L. Their structures were elucidated on the basis of spectral and chemical evidence.     

A trinorsesterterpene glycoside from the North American fern Woodwardia virginica (L.) Smith

A new trinorsesterterpene glycoside was isolated from the ethanol extract of the American fern Woodwardia virginica having a 3-[6-(4,8-dimethyl-nona-1,3,7-trienyl)-4-hydroxy-2,6-dimethyl-cyclohex-1-enyl]-3-hydroxypropionic acid, as the aglycone and a saccharide moiety linked at C-4 to glucoses, xylose or arabinofuranose. The structure was elucidated using extensive spectroscopic analysis (1D and 2D NMR, MS, IR and UV) including determination of absolute stereochemistry by means of the MTPA and PGME derivatives and also by chemical methods.     

Glycolipids of the filamentous fungus Absidia corymbifera F-295

The lipids extracted with CHCl(3)/MeOH mixtures from mycelium of the lower filamentous fungus Absidia corymbifera F-295 were found to contain three glycolipids. Based on the IR, 1H and 13C NMR spectra, plasma-desorption ionisation (PDI) mass spectra as well as chemical degradation results, the glycolipids were established to be 1-O-beta-D-glucopyranosyl-2-N-(2'-D-hydroxyhexadecanoyl)-9-methylsphinga-4(E),8(E)-dienine (glucosyl ceramide) and 2-O-(6'-O-beta-D-galactopyranosyl)-beta-D-galactopyranosides of 2-D-hydroxy and erythro-2,3-dihydroxy fatty acids C(9), C(11), and C(13). They accounted for about 3.4, 0.8, and 0.4%, respectively, of the total lipids extracted. No lipids identical to the above monohydroxy and dihydroxy fatty acid glycosides have been reported.     

Chemical constituents from Lagopsis supina (Steph.) Ik.-Gal. ex Knorr

Phytochemical investigation of the whole plants of Lagopsis supina (Steph.) Ik.-Gal. ex Knorr. led to the isolation of 18 compounds (1–18), including ten phenylethanoid glycosides (1–10), one phenylmethanoid glycoside (11), four megastigmane glycosides (12–15), and three monoterpenoid glycosides (16–18). Lagopsides A (1) and B (2) were identified as new phenylethanoid glycosides. This is the first report of compounds 7, 11, 12, 15, and 16 from the Labiatae family, while compounds 4–6, 8–10, 13–14, and 17–18 were isolated from the genus Lagopsis for the first time. The chemotaxonomic significance of these isolated compounds was summarized.     

New glycosides from the leaves and rattan stems of Schisandra chinensis

Two new glycosides, vanillic acid 4-O-β-d-(6′-O-(Z)-2′'-methylbut-2′'-enoate)glucopyranoside (1), p-methoxycarvacrol-6-O-β-d-glucopyranoside (2), along with two known analogues (3-4), were isolated from the leaves and rattan stems of Schisandra chinensis. The structures of these isolates were determined by UV, HRESIMS, 1D and 2D NMR spectral analyses.     

A new 5-deoxyflavone glycoside from the aerial parts of Calea clausseniana

A new 5-deoxyflavone glycoside, identified as 7-O-(alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranosyl)-3',4',7-trihydroxyflavone (1), was isolated from the aerial parts of Calea clausseniana. Its structure was determined by spectral analysis.     

The structural basis of substrate recognition in an exo-beta-D-glucosaminidase involved in chitosan hydrolysis

Family 2 of the glycoside hydrolase classification is one of the largest families. Structurally characterized members of this family include enzymes with β-galactosidase activity (Escherichia coli LacZ), β-glucuronidase activity (Homo sapiens GusB), and β-mannosidase activity (Bacteroides thetaiotaomicron BtMan2A). Here, we describe the structure of a family 2 glycoside hydrolase, CsxA, from Amycolatopsis orientalis that has exo-β-d-glucosaminidase (exo-chitosanase) activity. Analysis of a product complex (1.85 Å resolution) reveals a unique negatively charged pocket that specifically accommodates the nitrogen of nonreducing end glucosamine residues, allowing this enzyme to discriminate between glucose and glucosamine. This also provides structural evidence for the role of E541 as the catalytic nucleophile and D469 as the catalytic acid/base. The structures of an E541A mutant in complex with a natural β-1,4-d-glucosamine tetrasaccharide substrate and both E541A and D469A mutants in complex with a pNP-β-d-glucosaminide synthetic substrate provide insight into interactions in the + 1 subsite of this enzyme. Overall, a comparison with the active sites of other GH2 enzymes highlights the unique architecture of the CsxA active site, which imparts specificity for its cationic substrate.     

Immunosuppressive pregnane glycosides from Periploca sepium and Periploca forrestii

Nine pregnane glycosides containing peroxy functions in their sugar moieties (1-5 and 11-14), five oligosaccharides (6-10), six pregnane glycosides (15-20), and five cardiac glycosides (21-25) were isolated from the root barks of Periploca sepium Bge. (Asclepiadaceae) and the roots of Periploca forrestii Schltr. (Asclepiadaceae), two traditional Chinese medicines used for the treatment of rheumatoid arthritis. Among them, 1-8 are hitherto unknown. Their structures were characterized on the basis of spectroscopic analyses. In pharmacological testing, compounds 1-5 and 11-14 were found to exhibit inhibitory activity against the proliferation of T lymphocyte in vitro with IC50 values ranging from 0.29microM to 1.97microM, while the other components showed no significant inhibitory activity.     

Cytotoxic farnesyl glycosides from Pittosporum pancheri

Bioassay guided purification of the ethanolic extract of the bark of New Caledonian Pittosporum pancheri Brongn. and Gris (Pittosporaceae) led to the isolation and characterization of two new farnesyl monoglycosides, pancherins A and B. The structure of these compounds were determined on the basis of spectroscopic studies. The new compounds displayed a significant activity in the in vitro cytotoxic assay against KB cancer cell line, and pancherin A inhibits weakly farnesyl protein transferase.