Tricalysiosides P-U: Ent-kaurane glucosides and a labdane glucoside from leaves of Tricalysia dubia OHWI

Further extensive isolation work on the 1-BuOH-soluble fraction of a MeOH extract of Tricalysia dubia afforded five new ent-kaurane glucosides (4-8) and one new labdane glucoside (9), together with a known megastigmane glucoside, sammangaoside B (1), and monoterpene glucosides (2, 3). The structures of the new compounds were elucidated by analyses of one- and two-dimensional NMR spectroscopic data. The absolute configuration of the 9-position of sammangaoside B was revised to S and its total stereochemistry was established by the modified Mosher's method.     

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).     

Staphylionosides A-K: megastigmane glucosides from the leaves of Staphylea bumalda DC

Chemical investigation of leaves of Staphylea bumalda DC., collected in the suburbs of Hiroshima City, afforded 11 new megastigmane glucosides, named staphylionosides A-K (3-13), along with two known megastigmane glucosides (1, 2). The relative structures were elucidated from spectroscopic evidence, and the absolute structures of the aglycones were determined by means of the combination of beta-D-glucosylation-induced shift-trends and the modified Mosher's method.     

Pterisolic acids A-F, new ent-kaurane diterpenoids from the fern Pteris semipinnata

Six new ent-15-oxokauran-19-oic acid derivatives, named pterisolic acids A-F (1-6), were isolated from the ethanol extract of the fern Pteris semipinnata (Pteridaceae), and the structures of these new ent-kauranoids were elucidated on the basis of extensive spectroscopic studies and single crystal X-ray diffraction analysis.     

Glochidionionosides A-D: megastigmane glucosides from leaves of Glochidion zeylanicum (Gaertn.) A. Juss

Five megastigmane glucosides were isolated from the leaves of Glochidion zeylanicum. One of them was a known compound, blumenol C O-beta-D-glucopyranoside (1), and the structures of the four new compounds, glochidionionosides A-D (2-5), were mainly elucidated by spectroscopic methods, including a modified Mosher's method. The absolute configurations of the six-membered ring of glochidionionoside D (5) were deduced by beta-D-glucopyranosylation-induced shift trends in the (13)C-NMR spectra and confirmed by X-ray analysis as its p-bromobenzoate (5b), and the axis chirality of C-7 was determined to be R.     

Glochidionolactones A-F: butenolide glucosides from leaves of Glochidion zeylanicum (GAERTN) A. JUSS

From the leaves of Glochidion zeylanicum, six new butenolide glucoside, named glochidionolactones A-F, were isolated along with a known related compound, phyllanthurinolactone. The structures of glochidionolactones A-D and F were elucidated mainly by spectroscopic analyses. The absolute stereochemistry of glochidionolactone E was established by X-ray crystallographic analysis.     

A new ent-kaurane diterpenoid glycoside from the leaves of Cussonia bojeri,a Malagasy endemic plant

A new ent-kaurane diterpene glycoside, beta-D-glucopyranosyl 17-hydroxy-ent-kauran-19-oate-16-O-beta-D-glucopyranoside (4) was isolated from the dried leaves of Cussonia bojeri SEEM., together with four known compounds identified as 16beta,17-dihydroxy-kauran-19-oic acid (1), beta-D-glucopyranosyl 16beta,17-dihydroxy-(-)-kauran-19-oate (2), paniculoside IV (3), and rutin (5). The structure of 4 was deduced on the basis of chemical and spectroscopic evidence.     

Hymenosides A-F, six new hemiterpene glucosides from the Japanese fern Hymenophyllum barbatum

In the course of investigation of the bitter-tasting substances of the Japanese fern Hymenophyllum barbatum belonging to the family Hymenophyllaceae, six new hemiterpene glucosides called hymenosides A-F (1-6) have been isolated from the methanol extract, together with an acyclic bis-bibenzyl derivative, perrottetin H. This paper deals with the structure elucidation of the newly isolated glucosides.     

New megastigmane and tetraketide from the leaves of Euscaphis japonica

New megastigmane (1) and tetraketide (2) were isolated from the leaves of Euscaphis japonica and the structures were elucidated by means of spectroscopic and chemical evidence.     

Apteniols A-F, oxyneolignans from the leaves of Aptenia cordifolia

Investigation of the organic extract of Aptenia cordifolia leaves revealed six new oxyneolignans named apteniols A-F. The structures were determined by means of spectroscopic methods. The C₆C₃ units are linked by an oxygen atom at C4-C4′ or C4-C2′ and they are dihydrophenylpropanoid acid units. Their effects on germination and growth of Lactuca sativa L. have been studied in the range concentration 10⁻⁴-10⁻⁷ M.     

Myrsinionosides A-E: megastigmane glycosides from the leaves of Myrsine seguinii Lev

Eight megastigmane glycosides were isolated from the leaves of Myrsine seguinii collected in Okinawa. Three of them were found to be known compounds, i.e., ampelopsisionoside, alangionoside J, and linarionoside A. The structures of the new megastigmane glycosides were elucidated from the spectroscopic data and their absolute stereochemistries were determined in detail using a modified Mosher's method.     

Schefflerins A-G, new triterpene glucosides from the leaves of Schefflera arboricola

From the 1-BuOH-soluble fraction of a MeOH extract of leaves of Schefflera arboricola, collected in Okinawa, six new lupane glucosides, named schefflerins A-F (1-6) and one new dammarane glucoside, named schefflerin G (7), were isolated together with three known compounds, citroside A (8), and oleanane saponins, oleanolic acid (9) and echinocystic acid (10) 3-O-α-L-rhamnopyranosyl(1→4')-O-β-D-glucuronopynosides. Their structures were elucidated through a combination of spectroscopic analyses and the structure of schefflerin F (6) was determined by X-ray crystallographic method using SPring-8 synchrotron radiation.     

Radical-scavenging activities of new megastigmane glucosides from Macaranga tanarius (L.) MULL.-ARG

Four new megastigmane glucosides, named macarangiosides A-D (2-5), together with mallophenol B, lauroside E, methyl brevifolin carboxylate, and hyperin and isoquercitrin as a mixture were isolated from the leaves of Macaranga tanarius (L.) MULL.-ARG. (Euphorbiaceae). Their structures were elucidated by spectroscopic and chemical analyses. Macarangioside A-C (2-4) and mallophenol B were galloylated on glucose moiety and possessed the potent 2,2-diphenyl-picrylhydrazyl (DPPH) radical-scavenging activity.     

Two new megastigmane O-glucopyranosides from the leaves of Broussonetia papyrifera

Two new megastigmane O-glucopyranosides,named (2R,3R,5R,6S,9R)-3-hydroxy-5,6-epoxy-β-ionol-2-O-β-D-glucopyrano- side(1) and (2R,3R,5R,6S,9R)-3-hydroxyl-5,6-epoxy-acety-β-ionol-2-O-β-D-glucopyranoside(2) together with six known mega- stigmanes,were isolated from the leaves of Broussonetia papyrifera (Linn.) Vent.Their structures were established by chemical methods and spectroscopic techniques including 2D NMR.     

A new megastigmane glycoside, phoenixoside A, from Phoenix dactylifera

A new megastigmane glycoside, phoenixoside A (1), has been isolated from the n-butanol--soluble fraction of seeds of Phoenix dactylifera. The structure was characterized as (6S,7Z,9R)-hydroxy-3-oxo-ionol-9-O-beta-D-glucopyranosyl-(1" --> 6')-beta-D-glucopyranoside on the basis of 1D and 2D NMR spectroscopy, high-resolution mass spectrometry, and CD spectroscopy.     

Two new cyanogenic glucosides from the leaves of Hydrangea macrophylla

Chemical investigation of the ethanol extract of the aerial parts of Hydrangea macrophylla collected in the Sichuan Province of China resulted in the isolation of two new cyanogenic glucosides. Their structures were elucidated as [(2R)-2-β-D-glucopyranosyloxy)-2-(3,4-dimethoxy-phenyl)] acetonitrile (1) and {(2R)-2-[α-D-glucopyranosyl(1-->6)β-D-glucopyranosyloxy]-2-(3-hydroxy-4-methoxy-phenyl)}acetonitrile (2) on the basis of extensive spectroscopic analysis (1D, 2D NMR and HRESIMS) and chemical studies.     

A novel ent-kaurane diterpenoid from the Croton tonkinensis GAGNEP

A novel ent-kaurane diterpenoid, ent-1alpha-acetoxy-7beta,14alpha-dihydroxy-kaur-16-en-15-on has been isolated from leaves of Croton tonkinensis GAGNEP. Its structure was determined by a combination of spectroscopy, X-ray crystallographic analysis and the chemical reaction acetylation.     

Structure elucidation of five new iridoid glucosides from the leaves of Avicennia marina

A chemical examination of the mangrove plant Avicennia marina (Forrsk.) Vierh resulted in the isolation and characterization of five new iridoids, marinoids A-E (1-5), along with 2'-cinnamoyl-mussaenosidic acid (6), 2'-O-(4'-methoxycinnamoyl) mussaenosidic acid (7), 2'-O-(4'-hydroxycinnamoyl) mussaenosidic acid (8), and 3(R)-hydroxy-5-phenyl-4(E)-pentenoic acid (9). The structures of 1-5 were elucidated on the basis of 1D and 2D NMR (COSY, HMQC, HMBC, and NOESY) in association with IR and MS data analysis.