Proanthocyanidins and a phloroglucinol derivative from Rumex acetosa L.

From the ethyl acetate soluble fraction of an acetone–water extract of the aerial parts of Rumex acetosa L. (Polygonaceae), a variety of monomeric flavan-3-ols (catechin, epicatechin, epicatechin-3-O-gallate), A- and B-type procyanidins and propelargonidins (15 dimers, 7 trimers, 2 tetramers) were isolated with 5 so far unknown natural products. Dimers: procyanidin B1, B2, B3, B4, B5, B7, A2, epiafzelechin-(4β→8)-epicatechin, epiafzelechin-(4β→8)-epicatechin-3-O-gallate (new natural product), epiafzelechin-(4β→6)-epicatechin-3-O-gallate (new natural product), epiafzelechin-3-O-gallate-(4β→8)-epicatechin-3-O-gallate, B2-3′-O-gallate, B2-3,3′-di-O-gallate, B5-3′-O-gallate, and B5-3,3′-di-O-gallate. Trimers: procyanidin C1, epiafzelechin-(4β→8)-epicatechin-(4β→8)-epicatechin (new natural product), epicatechin-(4β→8)-epicatechin-(4β→8)-catechin, cinnamtannin B1, cinnamtannin B1-3-O-gallate (new natural product), tentatively epicatechin-(2β→7, 4β→8)-epiafzelechin-(4α→8)-epicatechin (new natural product), and epicatechin-3-O-gallate-(4β→8)-epicatechin-3-O-gallate-(4β→8)-epicatechin-3-O-gallate.Tetramers: procyanidin D1 and parameritannin A1. All compounds were elucidated by ESI-MS, CD spectra, 1D- and 2D-NMR experiments as free phenols or peracetylated derivatives and, in part, after partial acid-catalysed degradation with phloroglucinol.A more abundant proanthocyanidin polymer was also isolated, purified and its chemical composition studied by ¹³C NMR.In addition a so far unknown phloroglucinolglycoside (1-O-β-d-(2,4-dihydroxy-6-methoxyphenyl)-6-O-(4-hydroxy-3,5-dimethoxybenzoyl)-glucopyranoside) was isolated.     

Cyclisation of farnesyl pyrophosphate into sesquiterpenoids in ginger rhizomes (Zingiber officinale)

The atomic ratios (¹⁴C/³H) obtained in ar-curcumene, α-zingiberene, β-bisabolene obtained from the essential oil of rhizomes of Zingiber officinale which were fed with [2-¹⁴C, 2-³H₂], [2-¹⁴C, 4R-³H₁] and [2-¹⁴C, 5-³H₂]mevalonic acid and [1-³H₂]farnesylpyrophosphate (FPP) revealed that (a) (2E,6E)-isomer of FPP is isomerised to (2Z,6E)-isomer without loss of epimeric hydrogen that means without a redox process; (b) (2Z,6E)-FPP is cyclised to bisabolyl cation which is the penultimate precursor of α-zingiberene, ar-curcumene and β-bisabolene; and (c) two 1,2-hydrogen shifts take place during the formation of α-zingiberene whereas one 1,2 shift has been observed during the formation of ar-curcumene.     

Structure of xylan from culms of bamboo grass (Sasa senanensis Rehd.)

Xylan prepared from culms of kumaizasa (Sasa senanensis Rehd.), a representative species of bamboo grass, was hydrolyzed with-xylanase ofStreptomyces olivaceoviridis E-86. Four arabinoxylo-oligosaccharides and two glucuronoxylo-oligosaccharides were isolated from the enzymatic hydrolysate of the xylan by chromatography on a charcoal column, a Dowex 1-x8 column, a Toyo-pearl HW-40S column, and a LiChrospher 100 NH₂ column and on preparative paper chromatography. The results of the structural analyses of the saccharides showed that the isolated oligosaccharides had the structures of 3²--l-arabinofuranosyl-xylobiose, 3²--l-arabinofuranosyl-xylotriose, 3²--[-d-xylopyranosyl-(1 2)-l-arabinofuranosyl]-xylobiose, 3³--[-d-xylopyranosyl-(1 2)-l-arabinofuranosyl]-xylotriose, 2³--4-O-methyl-d-glucuronosyl-xylotriose, and 2³--d-glucuronosyl-xylotriose. From the structural analysis of the oligosaccharides derived from the xylan, kumaizasa xylan was concluded to be a kind of arabinoglucuronoxylan having not only stubs of singlel-arabinose and singled-glucuronic acid but also stubs of disaccharide units such as-d-xylopyranosyl-(1 2)-l-arabinofuranose.     

Cycloartane saponins from Astragalus peregrinus as modulators of lymphocyte proliferation

From Astragalus peregrinus, four cycloartane-type saponins have been isolated and their structures elucidated by spectral means as 20(R),24(S)-epoxy-9β,19-cyclolanostane-3β,6α,16β,25-tetrol 3-O-β- -glucopyranoside (1), 20(R),24(S)-epoxy-9β,19-cyclolanostane-3β,6α,16β,25-tetrol 3-O-α- -rhamnopyranosyl-(1→4)-β- -glucopyranoside (2), 20(R),24(S)-epoxy-9β,19-cyclolanostane-3β,6α,16β,25-tetrol 3-O-α- -rhamnopyranosyl-(1→2)-β- -glucopyranoside (3) and 20(R),25-epoxy-9β,19-cyclolanostane-3β,6α,16β,24(S)-tetrol (24-O-acetyl)- 3-O-α- -rhamnopyranosyl-(1→2)-(6′-O-acetyl)-β- -glucopyranoside (4). Compounds 2 and 3 showed to stimulate the proliferation of mouse splenocytes and were not significantly cytotoxic.     

Two new furostanol saponins from Tribulus terrestris L.

Two new furostanol glycosides, named tribufurosides I (1) J (2), were isolated from the fruits of Tribulus terrestris L. by a combination of chemical and spectroscopic methods. Its structures were established as 26-O-β-d-glucopyranosyl-(25S)-5α-furost-12-one-2α,3β,22α,26-tetraol-3-O-β-d-glucopyranosyl (1 → 2)-β-d-glucopyranosyl (1 → 4)-β-d-galactopyranoside (1) and 26-O-β-d-glucopyranosyl-(25R)-5α-furost-20(22)-en-12-one-2α,3β,26-triol-3-O-β-d-glucopyranosyl (1 → 4)-β-d-galactopyranoside (2).     

New bibenzyl glycosides from leaves of Camellia oleifera Abel. with cytotoxic activities

Studies on the chemical constituents of leaves of Camellia oleifera Abel. led to the isolation of 3 new bibenzyl glycosides. Their structures have been elucidated as 1-(3′,5′-dihydroxy)phenyl-2-(4″-O-β-D-glucopyranosyl)phenylethane (1), 1-(3′,5′-dimethoxy)phenyl-2-(4″-O-β-D-glucopyranosyl)phenylethane (2) and 1-(3′,5′-dimethoxy)phenyl-2-[4″-O-β-D-glucopyranosyl(6→1)-O-α-L-rhamnopyranosyl]phenylethane (3) through spectral studies including HR-ESI-MS, ¹H NMR, ¹³C NMR and 2D NMR experiments. All the above 3 bibenzyl glycosides showed cytotoxic activities to Hela and hep2 cell lines.     

Biochanin A triglycoside from Andira inermis

A new isoflavonol triglycoside, biochanin A 7-O-β- -apiofuranosyl-(1→5)-β- -apiofuranosyl-(1→6)-β- -glucopyranoside (1), was isolated from Andira inermis roots in addition to the known compounds genistein 7-O-β- -apiofuranosyl-(1→6)-β- -glucopyranoside and lanceolarin.     

Stiffness and wood variation of 3-year old<Emphasis Type="Italic"> Pinus radiata</Emphasis> clones

The objective of this study was to explore wood variation, especially modulus of elasticity ( moe), density, and microfibril angle ( mfa), in a three-year old Pinus radiata tree clone trial. Moreover, the study examined the potential for genetic selection of radiata pine clones with high moe using current acoustic technology. The clone selection criteria were based on growth traits, basic density, and sound velocity indices to mirror the range in wood density and moe amongst c. 1000 clones. The selected 22 clones, represented by two trees each, were measured for moe, spiral grain, wood density, compression wood percentage, and mfa. Good agreement was found between static moe and dynamic moe. Both static and dynamic moe measurements were found to be primarily dependent on mfa (clonal range 28–39 degrees). Although wood density (clonal range 300–400 kg/m³) did not have a significant influence on moe alone, it was significant in combination with mfa. Compression wood tended to reduce moe and inflate wood density. The opportunities for genetic selection of radiata clones with high stiffness seem promising as the 22 selected clones exhibited a two-fold range of static moe (2.2–4.7 GPa) and the clonal heritabilities ( ) for moe, density and mfa were high.     

Investigation on hydrogen abstraction from methyl glucoside by active oxygen species under oxygen delignification conditions III: effects of the origin of active oxygen species

Carbohydrate model compounds methyl β-d-glucopyranoside (MGPβ), methyl α-d-glucopyranoside (MGPα), and methyl β-d-mannopyranoside (MMPβ) and the deuterium compounds of MGPβ labeled at the anomeric or C-2 positions (MGPβ-1D, MGPβ-2D) were reacted with active oxygen species (AOS) generated in situ by reactions between O₂ and a co-treated phenolic lignin model compound, 4-hydroxy-3-methoxybenzyl alcohol (VAlc), under conditions simulating oxygen delignification (0.5 mol/l NaOH, 0.36 mmol/l Fe³⁺, 1.1 MPa O₂, 95°C). MGPβ was degraded more than MGPα but less than MMPβ when the pairs MGPβ/MGPα and MGPβ/MMPβ, respectively, were treated, which indicates that the configurational differences at the anomeric and C-2 positions influence the reactivity of AOS toward these compounds. When the pairs MGPβ/MGPβ-1D and MGPβ/MGPβ-2D were treated, no clear kinetic isotope effects were observed in either case. These results contrasted with those obtained when another phenolic compound, 2,4,6-trimethylphenol (TMPh), was used as the AOS generator instead of VAlc under exactly the same conditions. Clear kinetic isotope effects were observed when using TMPh. Because it is not easily accepted that the anomeric and C-2 hydrogen abstractions are minor reaction modes only for AOS generated in the VAlc system, it is suspected that the AOS do not show any clear kinetic isotope effect even though the AOS abstract an objective hydrogen.     

Phytochemical and antifungal studies on Terminalia mollis and Terminalia brachystemma

Phytochemical investigation of the stem bark of Terminalia mollis afforded friedelin (1), catechin with epicatechin (2), gallocatechin with epigallocatechin (3) and 3-O-methylellagic acid 4'-O-α-rhamnopyranoside (4). Arjunolic acid with 2α, 3β, 23-trihydroxy-urs-12-en-28-oic acid (5), 2α-hydroxyursolic acid (6), gallic acid (7), chebulanin (8) and 2'-O-galloylvitexin (9) were isolated from the leaf. Chebulanin (8), betulinic acid (10), ursolic acid (11), catechin (12), isoorientin (13), orientin (14), isovitexin (15) and punicalagin (16) were isolated from Terminalia brachystemma leaf. The first full unambiguous NMR assignments for (4) and (8), and revised assignments for (9), are reported. Compound (16) showed good activity against three Candida species.     

New clerodane diterpenoids from Casearia sylvestris

Two new clerodane diterpenoids 2β-methoxy-cleroda-3,13-dien-18-carboxy-15,16-olide (1) and 15ξ-methoxy-cleroda-3,12-dien-18-carboxy-15,16-olide (2) and one new nitrogen-containing clerodane diterpenoid 15-oxo-echinophyllin A (3), along with six known compounds, namely, echinophyllin A, (−)-patagonic acid, tyrosol, oplopanone, 4-hydroxy-4-methyl-2-[(1R)-1-(1-methylethyl)-4-oxopentyl]-2-cyclohexen-1-one and 1β,6α-dihydroxy-eudesman-4(15)-ene were isolated from the leaves of Casearia sylvestris. Their structures were determined by extensive NMR techniques.     

Synthesis of isoacteoside, a dihydroxyphenylethyl glycoside

The total chemical synthesis of isoacteoside (1), 2-(3,4-dihydroxyphenyl)ethyl 6-O-caffeoyl-3-O-(-l-rhamnopyranosyl)--d-glucopyranoside, is described. An acteoside acetate with benzyl groups at the catechols (3: 2-(3,4-dibenzyloxyphenyl)ethyl 2,6-di-O-acetyl-4-O-[3,4-bis(O-benzyl)caffeoyl]-3-O-(-l-rhamnopyranosyl)--d-glucopyranoside) was treated with a solution of methy-lamine in methanol (MeNH₂ in MeOH) to perform both deacetylation and caffeoyl migration, affording an isoacteoside derivative with benzyl groups at the catechols4b: 2-(3,4-dibenzyloxyphenyl)ethyl 6-O-[3,4-bis(O-benzyl) caffeoyl] -3-O-(-l-rhamnopyranosyl)--d-glucopyranoside —in 34% yield. Debenzylation of4b was successfully accomplished by catalytic transfer hydrogenation using 1,4-cyclohexadiene to give the target compound isoacteoside (1) in 54% yield.¹H and¹³C nuclear magnetic resonance spectral data of the synthesized isoacteoside (1) were identical with those of the natural isoacteoside isolated fromPaulownia tomentosa (Thumb.) Steud.Part of this research was presented at the 51st Annual Meeting of the Japan Wood Research Society, Tokyo, April 2001     

A new flavone glycoside from the seeds of Shorea robusta

A new flavonoid, 3,7-dihydroxy-8-methoxyflavone 7-O-α- -rhamnopyranosyl-(1→4)-α- -rhamnopyranosyl-(1→6)-β- -glucopyranoside (1), was isolated from the seeds of Shorea robusta.     

Chemical constituents of Tolpis species

Phytochemical research of two Tolpis species, T. webbii and T. sp., led to the isolation of three new compounds: 2,4′-dihydroxy-4-methoxybenzophenone (1) and the triterpenes 21α, 22α-epoxy-20α-hydroxy-20(30)-dihydrotaraxasterol (2) and 3β-hydroxytaraxaster-20-en-30-oic acid (3) together with 16 known compounds. The structures of the new compounds were elucidated by means of extensive IR, NMR, MS and X-ray analysis and by comparison of data reported in the literature.     

A new chlorosesquiterpene lactone from Ambrosia maritima

A new chloro-pseudoguaianolide-type sesquiterpene lactone, 11β-hydroxy-13-chloro-11,13-dihydrohymenin (1), was isolated from the Egyptian medicinal plant Ambrosia maritima. The structure was determined by spectroscopic methods, particularly high-resolution ¹H, ¹³C-NMR and 2D ¹H–¹H and ¹H–¹³C COSY NMR analysis.     

Stereochemistry and biosynthesis of 8-O-4′ neolignans in Eucommia ulmoides: diastereoselective formation of guaiacylglycerol-8-O-4′-(sinapyl alcohol) ether

Stereochemistry and biosynthesis of guaiacylglycerol-8-O-4′-(sinapyl alcohol) ether (GGSE), an 8-O-4′ neolignan, which consists of coniferyl and sinapyl alcohol moieties, in Eucommia ulmoides were investigated. Four 8-O-4′ neolignans, GGSE, syringylglycerol-8-O-4′-(coniferyl alcohol) ether (SGCE), guaiacylglycerol-8-O-4′-(coniferyl alcohol) ether (GGCE), and syringylglycerol-8-O-4′-(sinapyl alcohol) ether (SGSE), were synthesized. Their erythro and threo diastereomers were separated through acetonide derivatives, intermediates of the synthesis, and identified by means of nuclear magnetic resonance (NMR) spectroscopy. All of the erythro-acetonide derivatives have larger coupling constants (ca 9 Hz) for the C₇-H resonances than those of the threo ones (1.5–2 Hz). In the case of the four 8-O-4′ neolignans, the C₇-H coupling constants of the threo-isomers are not smaller than those of the erythro ones. GGSE isolated previously from this plant was identified as the erythro isomer by comparison of the ¹³C-NMR data with synthetic erythro-GGSE and threo-GGSE and the other 8-O-4′ neolignans mentioned as above. Administration of a mixture of [8-¹⁴C]coniferyl alcohol and [8-¹⁴C]sinapyl alcohol to excised shoots of E. ulmoides was carried out and the incorporation of ¹⁴C into erythro-[¹⁴C]GGSE was found to be higher than that in threo-[¹⁴C]GGSE. The occurrence of diastereoselective formation of erythro-GGSE by cross coupling of coniferyl and sinapyl alcohols is suggested.Part of this paper was presented at the 47th Lignin Symposium, Fukuoka, October 2002 and the 53rd Annual Meeting of the Japan Wood Research Society, Fukuoka, April 2003     

A new flavonoid from the aerial part of Thalictrum atriplex

A new flavone glycoside, identified as kaempferol 3-O-[3′″-acetyl-α- -arabinopyranosyl-(1′″–6″)]-β- -glucopyranoside (1), has been isolated from the aerial part of Thalictrum atriplex.     

Steroidal saponins from the leaves of Agave macroacantha

A new monodesmosidic spirostanol saponin, along with three known saponins was isolated from Agave macroacantha Zucc leaves. The structure of the new saponin was established as hecogenin-3-O-α-l-rhamnopyranosyl (1→4) β-d-xylopyranosyl (1→3)[β-d-glucopyranosyl (1→2)] β-d-glucopyranosyl (1→4) β-d-galactopyranoside. The ¹H and ¹³C resonances of the four compounds were assigned using a combination of 1D and 2D NMR techniques including ¹H, ¹³C, COSY, TOCSY, ROESY, HSQC and HMBC NMR and confirmed by mass spectrometry.     

Antioxidative compounds from leaves of Tahongai (<Emphasis Type="Italic">Klienhovia hospita</Emphasis>)

In our effort to find antioxidant agent, we focused on Tahongai (Kleinhovia hospita) which have been used traditionally in Indonesia as medicinal herbal to cure liver disease. Based on the biologically guided fractionation using DPPH radical scavenging assay, eleutherol and kaempferol 3-O-β-d-glucoside was isolated from the leaves of K. hospita. Kaempferol 3-O-β-d-glucoside (1) and eleutherol (2) scavenged the radical with IC₅₀ of 71.4 and 491.8 μM, respectively. In addition, both of the compounds did not exhibit cytotoxicity on HepG2 cells.     

Characterization of proanthocyanidin in hot water extract isolated from <Emphasis Type="Italic">Pinus radiata</Emphasis> bark

Proanthocyanidins (PAs) in the hot water extract prepared from Pinus radiata bark were isolated by a Sephadex LH-20 chromatography. The PAs were characterized using UV/Visible, FT-IR and ¹³C nuclear magnetic resonance (NMR) spectroscopic techniques, matrix-assisted laser desorption/ionization time of flight (MALDI-TOF) mass spectrometry (MS), and gel permeation chromatography (GPC) analysis. Bate-Smith acidic alcoholysis and FT-IR spectrum of the PAs indicated the predominant presence of the procyanidin (PC) structure. The ¹³C NMR spectrum revealed that the PAs comprise PC (94%) together with a small amount of prodelphinidin (PD, 6%), and also that they contain the higher trans configuration rather than the cis configuration of C2–C3. The MALDI-TOF MS results obviously proved the presence of PD units, but the maximum degree of polymerization (DP) was limited to octamer. The average molar mass (Mw, Mn), polydispersity (Mw/Mn), and DP of the pine bark PAs were 3,800 (Mw), 1,200 (Mn), 3.2, and 13, respectively.