Medicinal flowers. VI. Absolute stereostructures of two new flavanone glycosides and a phenylbutanoid glycoside from the flowers of Chrysanthemum indicum L.: their inhibitory activities for rat lens aldose reductase

Two new flavanone glycosides, (2S)- and (2R)-eriodictyol 7-O-beta-D-glucopyranosiduronic acids, and a new phenylbutanoid glycoside, (2S, 3S)-1-phenyl-2,3-butanediol 3-O-beta-D-glucopyranoside, were isolated from the flowers of Chrysanthemum indicum L. cultivated in China together with eight flavonoids. The absolute stereostructures of the new compounds were determined on the basis of chemical and physicochemical evidence. Both of the new flavanone glycosides were found to show inhibitory activity for rat lens aldose reductase.     

Two new acylated flavanone glycosides from the leaves and branches of Phyllanthus emblica

Two new acylated flavanone glycosides, (S)-eriodictyol 7-O-(6"-O-trans-p-coumaroyl)-beta-D-glucopyranoside (1) and (S)-eriodictyol 7-O-(6"-O-galloyl)-beta-D-glucopyranoside (2) were isolated from the leaves and branches of Phyllanthus emblica together with a new phenolic glycoside, 2-(2-methylbutyryl)phloroglucinol 1-O-(6"-O-beta-D-apiofuranosyl)-beta-D-glucopyranoside (3), as well as 22 known compounds. Their structures were determined by spectral and chemical methods.     

Turpinionosides A-E: megastigmane glucosides from leaves of Turpinia ternata Nakai

From leaves of Turpenia ternata (Staphylaceae), one megastigmane and seven of its glucosides (1-8) were isolated. Megastigmane and two of the glucosides were found to be known compounds, namely, 3S,5R,6R,9S-tetrahydroxymegastigmane (1), corchoionoside C (2), and icariside B4 (3). The structures of compounds 4-8 (turpinionosides A-E, respectively) were elucidated by means of spectroscopic analyses, and then their absolute structures were determined by the modified Mosher's method to be (3S,5R,6S,9S)-3,6,9-trihydroxymegastigman-7-ene 3-O- and 9-O-beta-D-glucopyranosides (4, 5, respectively), (1S,3S,5R,6S,9R)-3,9,12-trihydroxymegastigmane 3-O-beta-D-glucopyranoside (6), (3S,4R,9R)-3,4,6-trihydroxymegastigman-5-ene 3-O-beta-D-glucopyranoside (7), and (2S,9R)-2,9-dihydroxymegastigman-5-en-4-one 2-O-beta-D-glucopyranoside (8).     

Glycosides of Atractylodes lancea

Five sesquiterpenoid glycosides (two guaiane-type glycosides and three eudesmane-type glucosides) and a glucoside of an acetylene derivative were newly isolated from the water-soluble portion of the methanolic extract of Atractylodes lancea rhizome together with 26 known compounds. Their structures were characterized as atractyloside A 14-O-beta-D-fructofuranoside, (1S,4S,5S,7R,10S)-10,11,14-trihydroxyguai-3-one 11-O-beta-D-glucopyranoside, (5R,7R,10S)-isopterocarpolone beta-D-glucopyranoside, cis-atractyloside I, (2R,3R,5R,7R,10S)-atractyloside G 2-O-beta-D-glucopyranoside, and (2E,8E)-2,8-decadiene-4,6-diyne-1,10-diol 1-O-beta-D-glucopyranoside on the basis of chemical and spectroscopic investigation. The presence of six characteristic guaiane-type glucosides in both rhizomes of A. lancea and Atractylodes japonica suggested a close chemotaxonomic relationship between them.     

Separation of flavanone enantiomers and flavanone glucoside diastereomers from Balanophora involucrata Hook. f. by capillary electrophoresis and reversed-phase high-performance liquid chromatography on a C18 column

A pair of flavanone glucoside diastereomers, (2R)- and (2S)-eriodictyol-5-O-beta-d-glucopyranoside (1a, 1b), was successfully separated by RP-C(18) high-performance liquid chromatography from Balanophora involucrata Hook. f. Some other compounds, including a pair of flavanone enantiomers, (2R)- and (2S)-eriodictyol (2a, 2b), and a pair of flavanone glucoside diastereomers, (2R)- and (2S)-eriodictyol-7-O-beta-d-glucopyranoside(3a, 3b), were separated by capillary electrophoresis from the same plant. The absolute configurations at C-2 of 1a and 1b were determined based on their circular dichroism spectra. Enzymatic hydrolysis of 1a and 1b by beta-d-glucosidase afforded (2R)- and (2S)-eriodictyol, respectively, which were used as the authentic standards for co-elution to determine the migration order of the enantiomers, 2a and 2b. We also report the first example of identifying the migration order of 2a and 2b and resolving the separation of 3a and 3b by capillary electrophoresis. In addition, 1a was unambiguously characterized for the first time by NMR spectra.     

Two new flavanone glycosides of Jasminum lanceolarium and their anti-oxidant activities

Two new flavanone glucosides, (2S)-5,7,3',5'-tetrahydroxy-flavanone 7-O-beta-D-allopyranoside (1) and (2S)-5,7,3',5'-tetrahydroxy-flavanone 7-O-beta-D-glucopyranosie (2) were isolated from the stems and leaves of Jasminum lanceolarium, along with five known compounds: Betulinaldehyde (3), betulinic acid (4), betulin (5), syringin (6) and Liriodendrin (7). Their structures were determined on the basis of spectroscopic and chemical methods. The isolated compounds were screened for their in vitro antioxidant activity through DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging assay. Compounds 2 demonstrated significant radical scavenging activity.     

Three new sesquiterpenoid glucosides of Ficus pumila fruit

As the glycosyl constituents of Ficus pumila L. fruits (Moraceae), three new sesquiterpenoid glucosides, pumilasides A, B and C were isolated together with benzyl beta-D-glucopyranoside, (E)-2-methyl-2-butenyl beta-D-glucopyranoside and rutin. Their structures were characterized as (1S,4S,5R,6R,7S,10S)-1,4,6-trihydroxyeudesmane 6-O-beta-D-glucopyranoside, (1S,4S,5S,6R,7R,10S)-1,4-dihydroxymaaliane 1-O-beta-D-glucopyranoside and 10 alpha, 11-dihydroxycadin-4-ene 11-O-beta-D-glucopyranoside by spectral and chemical methods.     

Allergy-preventive flavonoids from Xanthorrhoea hastilis

Allergy-preventive activity was demonstrated for an extract of resins from Xanthorrhoea hastilis R. BR. in a search for allergy-preventive substances from natural sources. By bioassay-directed fractionation of this plant extract, a new flavanone, 3',5'-dihydroxy-7,4'-dimethoxyflavanone (1), and two new chalcones, 3,5,2'-trihydroxy-4,4'-dimethoxychalcone (2) and 5,2'-dihydroxy-3,4,4'-trimethoxychalcone (3), were isolated together with five known compounds, 5'-hydroxy-7,3',4'-trimethoxyflavanone (4), 3'-hydroxy-7,4'-dimethoxyflavanone (5), liquiritigenin 7-methyl ether (6), 4,2'-dihydroxy-4'-methoxychalcone (7) and sakuranetin (8). The structures of 1, 2 and 3 were elucidated by spectroscopic methods. All of these compounds showed allergy-preventive effects.     

New alpha-tetralonyl glucosides from the fruit of Juglans mandshurica

Five new alpha-tetralonyl glucosides, juglanosides A-E (1-5) were isolated from the fresh rejuvenated fruit of Juglans mandshurica. Their structures were elucidated as (4S)-4-hydroxy-alpha-tetralone 4-O-beta-D-glucopyranoside (1), (4S)-4,5-dihydroxy-alpha-tetralone 4-O-beta-D-glucopyranoside (2), (4S)-4,6-dihydroxy-alpha-tetralone 4-O-beta-D-glucopyranoside (3), (4S)-4,5,8-trihydroxy-alpha-tetralone 4-O-beta-D-glucopyranoside (4), and (4S)-4,5,8-trihydroxy-alpha-tetralone 5-O-beta-D-glucopyranoside (5) on the basis of spectroscopic analysis and chemical evidence.     

The inhibition of superoxide anion generation in human neutrophils by Viscum coloratum

One new 1,3-diphenylpropane, viscolin (1), and one new flavanone, (2S)-7,4'-dihydroxy-5,3'-dimethoxyflavanone (2), together with thirty-nine known compounds, which included eleven known flavanones, two chromones, fourteen benzenoids, one inositol, two pyrimidines, four triterpenoids and five steroids, were isolated and characterized from Viscum coloratum. Structures of new compounds were determined by spectral analysis. Among them, viscolin (1) showed the most significant inhibition on superoxide anion generation by human neutrophils in response to fMLP (formyl-L-methionyl-L-leucyl-L-phenylalanine).     

Two new glycosides from the whole plants of Glechoma hederacea L

Two new glycosides, 7S,7'S,8R,8'R-icariol A(2)-9-O-beta-D-glucopyranoside (1) and 4-allyl-2-hydroxyphenyl 1-O-beta-D-apiosyl-(1-->6)-beta-D-glucopyranoside (2), were isolated from the dried whole plants of Glechoma hederacea L. (Labiatae) together with four known compounds, cistanoside E (3), dihydrodehydrodiconiferyl alcohol 4-O-beta-D-glucopyranoside (4), apigenin 7-O-beta-D-glucuronopyranoside (5) and luteolin 7-O-beta-D-glucopyranoside (6). The structures of the new compounds were elucidated on the basis of chemical and spectral analysis.     

Structure elucidation and NMR spectral assignments of four neolignan glycosides with enantiometric aglycones from Osmanthus ilicifolius

Four new 8-O-4' type neolignan glycosides with enantiometric aglycones, (7S,8R)-erythro-guaiacylglycerol-beta-O-4'-sinapyl ether 9-O-beta-D-glucopyranoside (1), (7R,8S)-erythro-guaiacylglycerol-beta-O-4'-sinapyl ether 9-O-beta-D-glucopyranoside (2), (7S,8R)-erythro- syringylglycerol-beta-O-4'-sinapyl ether 9-O-beta-D-glucopyranoside (3) and (7R,8S)-erythro- syringylglycerol-beta-O-4'-sinapyl ether 9-O-beta-D-glucopyranoside (4), were isolated from the leaves of Osmanthus ilicifolius. Their structures were established on the basis of NMR, circular dichroism (CD), MS and chemical data. The NMR assignments for the compounds were carried out using (1)H, (13)C, COSY, HMQC, HMBC and NOESY NMR experiments.     

Cucurbitacin B 2-sulfate and cucurbitacin glucosides from the root bark of Helicteres angustifolia

A new sulfated cucurbitacin, cucurbitacin B 2-sulfate (1) and a new cucurbitacin glucoside, cucurbitacin G 2-O-beta-D-glucopyranoside (2) together with two known cucurbitacin glucosides, arvenin I and arvenin III were isolated from the root bark of Helicteres angustifolia. The structures of these compounds were established on the basis of spectroscopic and chemical evidence. These four compounds taste of strong bitterness. Compound 1 is a first sulfated cucurbitacin found in plants.     

New acetylenic glucosides from Carthamus tinctorius

Two new acetylenic glucosides, 4',6'-acetonide-8Z-decaene-4,6-diyne-1-O-beta-D-glucopyranoside named carthamoside A(1) (1) and 4,6-decadiyne-1-O-beta-D-glucopyranoside named carthamoside A(2) (2), along with one known acetylenic glucoside, 8Z-decaene-4,6-diyne-1-O-beta-D-glucopyranoside (3), have been isolated from the air-dried flower of Carthamus tinctorius, these structures have been identified on the basis of spectroscopic methods.     

Megastigmane, benzyl and phenethyl alcohol glycosides, and 4,4'-dimethoxy-beta-truxinic acid catalpol diester from the leaves of Premna subscandens MERR

Extensive isolation work on the n-BuOH-soluble fraction obtained from the leaves of Premna subscandens, collected on Ishigaki island, Okinawa, afforded six compounds. Two were identified as megastigmane glucosides, 7-(3,5-dihydroxy-1,1,5-trimethylcyclohexylidene)-9-methylprop++ +-8-enyl 9-O-beta-D-glucopyranoside and 3-hydroxy-5,6-epoxy-beta-ionol 9-O-beta-D-glucopyranoside. The structures of the remaining four new compounds were elucidated to be a 2'-O-beta-D-apiofuranosyl derivative of 3-hydroxy-5,6-epoxy-beta-ionol 9-O-beta-D-glucopyranoside, named premnaionoside, benzyl alcohol beta-D-(2'-O-beta-D-xylopyranosyl)glucopyranoside, phenethyl alcohol beta-D-(2'-O-beta-D-glucopyranosyl)glucopyranoside, and 4,4'-dimethoxy-beta-truxinic acid catalpol diester by spectroscopic analyses.     

Cholinesterase inhibitory constituents from Onosma hispida

Hispidone, a new flavanone, has been isolated from Onosma hispida and assigned the structure (2S)-5,2'-dihydroxy-7,4',5'-trimethoxyflavanone (1) by spectroscopic methods. In addition, (2S)-5,2'-dihydroxy-7,5'-dimethoxyflavanone (2), benzoic acid (3), and 4-hydroxy benzoic acid (4) are also reported for the first time from this species.     

A new 5,11-epoxymegastigmane glucoside from Acanthus ilicifolius

From a China mangrove plant Acanthus ilicifolius Linn., a new compound, 5,11-epoxymegastigmane glucoside (1) was isolated along with one known compound of megastigmane glucosides, (6S, 9S)-roseoside (2). The structure of compound 1 was determined on the basis of 1D- and 2D-NMR techniques (DEPT, COSY, HMBC, HMQC, NOESY) and HR-FABMS. The structure of 1 was established as (1S, 3S, 5R, 6R, 7E)-5,11-epoxy-3-hydroxymegastigman-7-en-9-one-3-O-beta-D-glucopyranoside.     

Antiallergic agents from natural sources. 3. Structures and inhibitory effects on nitric oxide production and histamine release of five novel polyacetylene glucosides from Bidens parviflora WILLD

Five new polyacetylene glucosides, bidensyneosides A1, A2, B, C (1-4), and 3-deoxybidensyneoside B (5), have been isolated from the air-dried whole plant of Bidens parviflora WILLD. The structures were identified based on spectroscopic analysis, physicochemical properties, and application of the modified Mosher method to be 3(R),8(E)-8-decene-4,6-diyne-1,3-diol 1-O-beta-D-glucopyranoside (1), deca-3(R),8(Z) 8-decene-4,6-diyne-1,3-diol 1-O-beta-D-glucopyranoside (2), 3(R)-deca-4,6,8-triyne-1,3-diol 1-O-beta-D-glucopyranoside (3), 3(R),8(E)-8-decene-4,6-diyne-1,3,10-triol 1-O-beta-D-glucopyranoside (4), and 8(E)-8-decene-4,6-diyne-1,10-diol 1-O-beta-D-glucopyranoside (5), respectively. These compounds inhibited nitric oxide (NO) production in lipopolysaccharide and interferon-gamma activated murine macrophages (RAW264.7) and also inhibited histamine release from rat mast cells stimulated by the antigen-antibody reaction.     

Structure elucidation and NMR spectral assignments of three new lignan glycosides from Akebia trifoliata

Three new lignan glycosides (1-3) were isolated from the stems of Akebia trifoliata. Their structures were elucidated as (7R,8R,7'R,8'R)3,3',5,5'tetramethoxy-4,4'dihydroxy-7,9':7',9-diepoxylignan-4-O-beta-D-glucopyranoside (1), (7S,8S,8'R)-4,4',9-trihydroxy-3,3',5,5'-tetramethoxy-7,9'-epoxylignan-7'-one 9-O-beta-D-glucopyranoside (2), (7R,8R,8'S)-4,4',9-trihydroxy3,3',5,5'-tetramethoxy-7,9'-epoxylignan-7'-one 9-O-beta-D-glucopyranoside (3) by spectral analyses, primarily NMR, MS and CD. The NMR assignments for the compounds were carried out using 1H, 13C, DEPT, COSY, HSQC, HMBC and ROESY NMR experiments.