Astraciceran: a new isoflavan phytoalexin from Astragalus cicer

A new phytoalexin isolated from the fungus-inoculated leaflets of Astragalus cicer has been identified as 7-hydroxy-2′-methoxy-4′,5′-methylenedioxyisoflavan (astraciceran). The synthesis of astraciceran and its 3′,4′-methylenedioxy analogue is described.     

Eupatarone,A 2-acetylbenzofuran from Eupatorium sternbergianum

A new benzofuran, eupatarone, together with 2-hydroxy-4, 5-dimethoxybenzaldehyde, 12-hydroxy-2, 3-dihydroeuparine, spathulenol, precocene II, dammaradienol, dammaradienol acetate, 5, 3′-dihydroxy-7, 4′-dimethoxyflavanone and 5, 7-dihydroxy-4′-methoxyflavanone, have been isolated from aerial parts of Eupatorium sternbergianum.     

La 5′-méthoxybilobétine,une biflavone extraite du Ginkgo biloba

A new biflavone, I-5′-methoxybilobetin has been isolated from Ginkgo biloba leaves. ¹H and ¹³C NMR spectral data show that it is a II-4′, I-5, II-5, I-7, II-7-pentahydroxy-I-4′, I-5′-dimethoxy- [I-3′, II-8] biflavone.     

Two glycosides of a new dilignol from Pinus silvestris

The 4′-O-β-d-glucopyranoside and the 4′-O-α-l-rhamnopyranoside of 2,3-dihydro-7-hydroxy-2-(4′-hydroxy-3′- methoxyphenyl)-3-hydroxymethyl-5-benzofuranpropanol have been isolated and identified. Also isolated were two d-glucosides and an l-arabinoside of (+)-isolariciresinol and a l-rhamnoside, a d-xyloside and a d-glucoside of 1-(4-hydroxy-3-methoxyphenyl)- 2-[4-(3-hydroxypropyl)-2-hydroxyphenoxy]-1,3-propanediol.     

Three methylated flavones from Thymus vulgaris

Three highly oxygenated flavones were isolated from leaves of Thymus vulgaris. Their structures were determined by spectroscopic methods as 5, 6, 4′-trihydroxy- 7, 8, 3′-trimethoxyflavone (thymonin), 5, 4′-dihydroxy-6, 7, 3′-trimethoxyflavone (cirsilineol) and 5, 4′-dihydroxy-6, 7, 8, 3′-tetramethoxyflavone. These flavones are reported for the first time in the genus Thymus.     

Flavans from Zephyranthes flava

A new optically active flavan aglucone, 7-hydroxy-3′,4′-methylenedioxyflavan, and its 7-glucoside have been isolated from the bulbs of Zephyranthes flava, collected at flowering. Additionally, two known flavans, 7,4′-dihydroxy-3′-methoxyflavan and 7-methoxy-2′-hydroxy-4′,5′-methylenedioxyflavan, have been isolated for the first time from this species. The structures of these flavans have been established by comprehensive analyses (UV, IR, ¹H NMR, ¹³C NMR, mass spectrometry, [α]_D) of the compounds and their acetates, and also by chemical correlation.     

The neolignans (−)-carinatone and carinatin from Virola carinata

From the bark of Virola carinata two neolignans have been isolated: (?)-carcinatone, [(2S)-1-(3′,4′-dimethoxyphenyl)-2-(3″-allyl-5″-methoxy-6″-hydroxyphenyl) propanone] and carinatin, [5-allyl-7-methoxy-3-methyl-2-(3′,4′-dimethoxyphenyl)benzofuran].     

Flavonoids in the black rhizomes of Boesenbergia panduta

5-Hydroxy-7-methoxyflavanone, 5,7-dimethoxyflavanone, 5-hydroxy-7-methoxyflavone 5-hydroxy-7,4′-dimethoxyflavone, 5,7-dimethoxyfiavone, 5,7,4′-trimethoxyflavone, 5,7,3′,4′-tetramethoxyflavone, 5-hydroxy-3,7-dimethoxyflavone, 5-hydroxy-3,7,4′-trimethoxyflavone, 3,5,7-trimethoxyflavone and 5-hydroxy-3,7,3′,4′-tetramethoxyflavone have been isolated from the black rhizomes of Boesenbergia pandurata.     

Two new C-methylated flavonoids from Myrica gale

From the leaves of Myrica gale 2′,4′-dihydroxy-6′-methoxy-3′,5′-dimethylchalcone has been isolated. The fruits yielded 2′-hydroxy-4′,6′-dimethoxy-3′-methyldihydrochalcone. The constitutions were deduced from spectroscopic data and confirmed by synthesis.     

Flavonoids from Merrillia caloxylon

Three chalcones and three flavones isolated from the fruit of Merrillia caloxylon (Rutaceae) have been characterised. Two of the flavones and two of the chalcones are related structurally, i.e. 3′,4′,5,7-tetramethoxyflavone with 2′- hydroxy-3,4,4′,6′-tetramethoxychalcone and 3′,4′,5,5′,7-pentamethoxyflavone with 2′,3-dihydroxy-4,4′,6′- trimethoxychalcone. A minor constituent was tentatively characterized as 5-hydroxy-3′,4′,5′,6,7-pentamethoxyflavone and this is accompanied by 2-hydroxy-3,4,4′,5,6′-pentamethoxychalcone and 5-hydroxy-3′,4′,6,7-tetramethoxyfiavone.     

A pungent principle from Alpinia oxyphylla

A pungent diarylheptanoid isolated from Alpinia oxyphylla has been characterized as trans-1-(4′-hydroxy-3′-methoxyphenyl)-7-phenylhept-1-en     

Dilignol glycosides from needles of Picea abies

(2R,3R)-2 3-Dihydro-2-(4′-hydroxy-3′-methoxyphenyl)-3-(hydroxymethyl)-7-methoxy-5-benzofuranpropanol 4′-O-β-d-glucopyranoside [dihydrodehydrodiconiferyl alcohol glucoside], (2R,3R)-2 3-dihydro-7-hydroxy-2-(4′-hydroxy-3′-methoxyphenyl)-3-(hydroxymethyl)-5-benzofuranpropanol 4′-O-β-d-glucopyranoside and 4′-O-α-l-rhamnopyranoside, 1-(4′-hydroxy-3′-methoxyphenyl)-2- [2″-hydroxy-4″-(3-hydroxypropyl)phenoxy]-1, 3-propanediol 1-O-β-d-glucopyranoside and 4′-O-β-d-xylopyranoside, 2,3-bis[(4′-hydroxy-3′-methoxyphenyl)-methyl]-1,4-butanediol 1-O-β-d-glucopyranoside [(?)-seco-isolariciresinol glucoside] and (1R,2S,3S)-1,2,3,4-tetrahydro-7-hydroxy-1-(4′-hydroxy-3′-methoxyphenyl)-6-methoxy-2 3-naphthalenedimethanol α²-O-β-d-xylopyranoside [(?)-isolariciresinol xyloside] have been isolated from needles of Picea abies and identified.     

Bicyclo[3,2,1]octanoid,neolignans from Aniba simulans

Six bicyclo[3,2,1]octanoid neolignans, isolated from the benzene extract of Aniba simulans Allen (Lauraceae) trunk wood, are shown to derive from two basic structures: 1-allyl-8-hydroxy-6-(3′-methoxy-4′,5′-methylenedioxyphenyl)-7-methyl-3-oxobicyclo[3,2,1]octane, substituted by 4-hydroxy, 4-hydroxy-5-methoxy, 4-methoxy or 4,5-dimethoxy groups; and 1-allyl-8-hydroxy-6-(3′-methoxy-4′,5′-methylenedioxyphenyl)-7-methyl-4-oxobicyclo[3,2,1]oct-2-ene, substituted by 3-hydroxy or 3-hydroxy-5-methoxy groups. The structural proposals are based on spectral data, interconversions synthesis of a derivative from the known (2R,3S,3aS)-3a-allyl-5-methoxy-2-(3′-methoxy,4′,5′-methylenedioxyphenyl)-3-methyl-2,3,3a,6-tetrahydro-6-oxobenzofuran.     

Flavonoids from Gutierrezia texana var. texana

Eleven flavonoids, including two new compounds, were isolated from Gutierrezia texana: the structures of the new compounds are 5,7,2′,5′-tetrahydroxy-3,4′-dimethoxyflavone and 5′-acetoxy-5,7,2′-trihydroxy-3,4′-dimethoxyflavone. The nine known compounds are 5,4′,5′-trihydroxy-3,6,7,8-tetramethoxyflavone, 5,7,2′,5′-tetrahydroxy-3,6,4′-trimethoxyflavone, 5,7,3′-trihydroxy-3,4′-dimethoxyflavone, 5,7,3′,4′-tetrahydroxyflavone, 3,5,7,3′,4′- pentahydroxyflavone, 5,7,3′,4′-tetrahydroxy-3-methoxyflavone, 5,6,7,3′,4′,-pentahydroxy-3-methoxyflavone, 5,7,3′,4′-tetrahydroxy-3-methoxyflavone 7-O-glucoside and 3,5,7,3′,4′-pentahydroxyflavanone.     

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.     

Two new dihydrobenzofuran-type neolignans from Breynia fruticosa

(7S,8R,7′S)-9,7′,9′-Trihydroxy-3,4-methylenedioxy-3′-methoxy [7-O-4′,8-5′] neolignan (1) and (7S,8R,7′S)-9,9′-dihydroxy-3,4-methylenedioxy-3′,7′-dimethoxy [7-O-4′,8-5′] neolignan (2), two new natural dihydrobenzofuran-type neolignans, along with 9,9′-dihydroxy-3,4-methylenedioxy-3′-methoxy [7-O-4′,8-5′] neolignan (3) and (-)-machicendiol (4), were isolated from the whole plants of Breynia fruticosa. The structures of 1 and 2, including the absolute configurations, were determined by spectroscopic methods and circular dichroism (CD) techniques. The absolute configuration of 4 was confirmed by calculations of the OR spectrum, together with OR and ECD spectra of its p-bromobenzoate ester (4a).     

Neolignans from mezilaurus itauba

The wood bark of Mezilaurus itauba afforded in addition to seven known neolignans, three new compounds rel-(7R,8R,1′S,3′S)-Δ^5′,8′-5′-methoxy-3,4-methylenedioxy-1′,2′,3′,4′-tetrahydro-2′,4′-dioxo-7.3′,8.1′-neolignan, rel-(7S,8S,1′S, 2′S, 3′R, 4′S)-Δ^8′-2′,4′-dihydroxy-3,4-methylenedioxy-1′,2′,3′,4′,5′,6′-hexahydro-5′-oxo-7.3′,8.1′-neolignan and rel-(7S,8S)-Δ^8′-6′-hydroxy 5′-methoxy-3,4-methylenedioxy-7·O·2′,8.3′-neolignan. The latter compound has been detected previously in Aniba terminalis. The structures were elucidated by spectroscopic methods and comparison with related compounds.     

Two polymethoxyflavones from Ageratum houstonianum

Besides agecorynin C, eupalestin and lucidin dimethyl ether, two new highly oxygenated flavones were isolated from Ageratum houstonianum. Their structures were established by spectroscopic and degradative evidence as 5, 6, 7, 8, 2′, 3′, 4′, 5′-octamethoxyflavone and 5, 6, 7, 2′, 3′, 4′, 5′-heptamethoxyflavone.     

A pungent diarylheptanoid from Alpinia oxyphylla

From the neutral fraction of the methanolic extract of the fruit of Alpinia oxyphylla, a new pungent compound has been isolated, and is shown to be 1-(4′-hydroxy-3′-methoxyphenyl)-7-phenyl-3-heptanone. This compound is 125 times more pungent than zingerone.     

Benzofuranoid neolignans from Aniba simulans

Forteen neolignans, isolated from the benzene extract of Aniba simulans (Lauraceae) trunk wood, included the hitherto undescribed (2S, 3S, 5R)-5-allyl-5,7-dimethoxy-2-(3′,4′,5′-trimethoxyphenyl)-3-methyl-2,3,5,6-tetra-hydro-6-oxobenzofuran, (2R,3S,5R) -5-allyl-5-methoxy-2-(3′-methoxy-4′,5′-methylenedioxyphenyl)-3-methy1-2,3,5, 6-tetrahydro-6-oxobenzofuran, (2S,3S)-6-O-allyl -5-methoxy-2-(3′-methoxy-4′-5′-methylenedioxyphenyl)-3-methyl-2,3-dihydrobenzofuran, (2R,3S)-6-O-allyl-5-methoxy-2- (3′-methoxy-4′,5′-methylenedioxyphenyl)-3-methyl-2,3-dihydrobenzofuran and 7-allyl-6-hydroxy-5-methoxy-2-(3′-methoxy-4,5′ -methylenedioxyphenyl)-3-methylbenzofuran.