Eusiderins and other neolignans from an Aniba species

A previous report disclosed the presence of benzodioxan and bicyclo[3.2.1]octanoid neolignans in the benzene extract of the trunk wood of an Amazonian Aniba (Lauraceae) species. The chloroform extract of the same material contains additionally two new benzodioxan neolignans [rel-(7S,8R)-Δ^8′-7-hydroxy-3,4,5,5′-tetramethoxy-7.0.3′,8.0.4′-neolignan; rel-(7R,8R)-Δ^7′-3,4,5,5′-tetramethoxy-9′-oxo-7.0.3′,8.0.4′-neolignan], two new bicyclo[3.2.1]-octanoid neolignans [(7R,8S,1′S,2′S,3′S,4′R)-Δ^8′-2′,4′-dihydroxy-3,3′-dimethoxy-4,5-methylenedioxy-1′,2′,3′,4′,5′,6′-hexahydro-5′-oxo-7.3′,8.1′-neolignan; (7R,8S,1′R,2′S,3′S)-Δ^8′-2′-hydroxy-3,3′,5′-trimethoxy-4,5-methylenedioxy-1′,2′,3′,4′-tetrahydro-4′-oxo-7.3′,8.1′-neolignan] and a hydrobenzofuranoid neolignan [(7S,8R,1′S,5′S)-Δ^8′-3,3′,5′-tri-methoxy-4,5-methylenedioxy-1′,4′,5′,6′-tetrahydro-4′-oxo-7.0.2′,8.1-neolignan].     

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).     

An unusual porosin type neolignan from Licaria chrysophylla

The trunk wood of Licaria chrysophylla contains rel-(7S, 8R, 1′S, 5′S)-Δ^8′-3,3′,5′-trimethoxy-4,5-methylenedioxy-1′,4′,5′,6′- tetrahydro-4′-oxo-7.1′,8.0.2′-neolignan (chrysophyllin A), which differs from all other known benzofuranoid neolignans by showing 7.1′ (rather than 8.1′) and 8.0.2′ (rather than 7.0.2′) linkages between the propenylphenol and allylphenol derived moieties.     

Benzofuranoid Neolignans from Piper kadsura

In a continuing research for neolignans from Piper kadsura (Choisy) Ohwi, six benzofuranoid neolignans were isolated from the aerial part of the plant. Their structure determination were based on the spectroscopic analysis (UV, IR, MS, NMR and CD) and derivative synthesis. Three of the isolated compounds were identified as new structures: 7R, 8R, 1′S-△8′-3, 4-methylenedioxy-5′-methoxy-l′, 4′-dihydro-4′-oxo-7, 0, 2′, 8. l′-neolignan ( Ⅰ ), 7 R, 8 R, 1 ′ R- △8′ - 3,4- methylenedioxy- 1 ′- methoxy - 1′,6′- dihydro- 6′- oxo- 7.0.4′,8. 3′-neolignan (Ⅳ) and 7R, 8R, 1′S-△8′-3, 4-methylenedioxy-l′-methoxy-1′,6′-dihydro-6′-oxo-7.0.4′,8.3′-neolignan (Ⅴ). Known compounds among them are 7R, 8S,1′S-△8′-3, 4-methylenedioxy-5′-methoxy-1′, 4′-dihydro-4′-oxo-7. 0. 2′, 8. 1′-neolignan(Ⅱ), 7S, 8S, 1′R-△8′-3, 4, 5′-trimethoxy-1′, 4′-dihydro-4′-oxo-7.0. 2′, 8. 1′-neolignan (Ⅲ) and 75, 85, 1′S-△8′-3, 4, l′-trimethoxy-l′, 6′-dihydro-6′-oxo-7. 0. 4′, 8. 3′-neolignans (Ⅵ). All of them were isolated from the plant for the first time.     

Neolignans from Ocotea catharinensis

The trunk bark of Ocotea catharinensis yielded, besides the known bicyclo(3.2.1)octanoid neolignans canellin-C and 5′-methoxycanellin-C, two epimers rel-(1R,4S and 4R,5S,6R,7S,8R)-1-allyl-4,8-dihydroxy-3,5-dimethoxy-7-methyl-6-piperonyl-bicyclo(3.2.1)oct-2-enes and rel-(1R,5S,6R,7S,8R)-1-allyl-3,8-dihydroxy-5-methoxy-7-methyl-6-piperonyl-4-oxobicyclo(3.2.1)oct-2-ene. The hydrobenzofuranoid neolignans are represented by the equally novel (2S,3S,5R)-5-allyl-5,7-dimethoxy-3-methyl-2-piperonyl-2,3,5,6-tetrahydro-6-oxobenzofuran and (2R,3S,3aS)-3a-allyl-5,7-dimethoxy-3-methyl-2-piperonyl-2,3,3a,6-tetrahydro-6-oxobenzofuran.     

Neolignans from Aniba burchellii

Seven neolignans, isolated from the benzene extract of Aniba burchellii Kosterm. (Lauraceae), included the hitherto unknown (2S,3S,5S)-5-allyl-5-methoxy-3-methyl-2-(3′,4′-methylenedioxyphenyl)-2,3,5,6-tetrahydro-6-oxobenzofuran and (1R,5R,6R,7R)-1-allyl-6-(4′-hydroxy-3′-methoxyphenyl)-3-methoxy-7-methyl-4,8-dioxobicyclo-[3,2,1]oct-2-ene. The former structure was previously assigned to a constituent of A. terminalis Ducke which is in fact the 5R-epimer. In addition to the latter constituent, all other previously described 4-oxobicyclo[3,2,1]oct-2-ene neolignans had their absolute configuration established.     

Neolignans from Ocotea catharinensis

Bark, wood and leaves of Ocotea catharinensis contain respectively 10 (average yield 0.7%.), 15 (average yield 0.004%.) and one (yield 0.4%.) neolignans of the bicyclo[3.2.1]octanoid and the hydrobenzofuranoid structural types, including the new rel-(7S,8R,1′R,4′S,5′R,6′R)-Δ^8′-4′,6′-dihydroxy-5′-methoxy-3,4-methylenedioxy-3′-oxo-8.1′,7.5′-neolignan, (7S,8S)-Δ^{1′,3′,5′,8′}-5,3′,5′-trimethoxy-3,4-methylenedioxy-8.1′,7.O.6′,4.O.7′-neolignan, (7R,8S,1′R,3′R)-Δ^5′,8′-3,4,3′,5′-tetramethoxy-4′-oxo-8.1′,7.O.6′-neolignan and rel-(7R,8S,1′R,2′S)-Δ^4′,8′-2′-hydroxy-3,4-dimethoxy-3′-oxo-8.1′,7.O.2′-neolignan.     

Neolignans from Aniba lancifolia

The branches of the shrub Aniba lancifolia Kubitzki et Rodrigues (Lauraceae) contain besides 2-hydroxy-4,5- dimethoxyallylbenzene and its dimer cyclohexan-2-allyl- 5-en-4,5-dimethoxy-4-O-(2′-allyl-4′,5′-dimethoxyphenyl)-1-one (lancilin, 2) 6 further novel neolignans: (4S,2′R)- and (4R,2′E)-cyclohexan-2-allyl-2,5-dien-4,5-dimethoxy-4-[2′-(1′-guaiacyl)-propyl]-1-one (lancifolins A and B, 3a and 3b), (4S,2′R)- and (4R,2′R)-cyclohexan- 2-allyl-2,5-dien-4,5-dimethoxy-4-[2′-(1′-veratryl)-propyl]-1-one (lancifolins C and D, 3c and 3d), (4S,2′R)-and (4R,2′R)-cyclohexan-2-allyl-2,5-dien-4,5-dimethoxy-4-[2′-(1′-piperonyl)-propyl]-1-one (lancifolins E and F, 3e and 3f).     

Neolignans from Ocotea aciphylla

The trunk wood of the central Brazilian Ocotea aciphylla contains two hydrobenzofuranoid and three bicyclo[3.2.1]octanoid neolignans. The former comprise a novel representative of the rare ferrearin (3a-allyl-2-aryl-7a-hydroxy-3-methyl-2,3,3a,4,7,7a-hexahydro-7-oxobenzofuran) type.     

Neolignans from stem bark of ocotea veraguensis

The stem bark of Ocotea veraguensis has yielded nine neolignans of which five appear to be novel. The new neolignans, which were identified on the basis of spectral characteristics, are^* (7S,8R,1′S,2′S,3′R,4′S)-Δ^8′-2′,4′-dihydroxy-3,3′5′-trimethoxy-4,5-methylenedioxy-1′,2′,3′,4′-tetrahydro-7.3′,8.1′-neolignan, (7S,8R,1′S,3′S,4′S)-Δ^8′-4,4'-dihydroxy-3,3′,5′-trimethoxy-1′,2′,3′,4′-tetrahydro-2′-oxo-7.3′,8.1′-neolignan, (7S,8S,1′R)-Δ^8′-3′,5′-dimethoxy-3,4-methylenedioxy-1′,4′-dihydro-4′-oxo-7.0.2′,8.1′-neolignan, (7S,8S,1′R )-Δ^8′-1′-methoxy-3,4-methylenedioxy-1′,6′-dihydro-6′-oxo-7.0.4′,8.3′-neolignan and (7S,8S)-Δ^8′-2′,6′-dimethoxy-3,4-methylenedioxy-7.0.3′,8.4′,1′.0.7′-neolignan.     

Neolignans of Virola carinata bark

Four neolignans, dehydrodieugenol, its monomethylether, carinatone and carinatin have been isolated from the hexane fraction of the bark of Virola carinata. Three new neolignans were separated from the chloroform fraction and examined by spectroscopy and chemical reactions. Their structures were determined as (2S, 3S)-5-allyl- 7-methoxy-3-hydroxymethyl-2-(3′,4′-dimethoxyphenyl)-2,3-dihydrobenzofuran, (2S)- 1-(3′,4′-dimethoxyphenyl)-2-(3″-allyl-5″-methoxy-6″-hydroxyphenyl)propanone(1) ol(3), (1S,2S)-1-(3′,4′-dimethoxyphenyl)-2-(3″-allyl-5″-methoxy-6″-hydroxyphenyl) propanol(1) and called dihydrocarinatinol, carinatonol and carinatol, respectively.     

Neolignans from Virola carinata fruit

The fruits of Virola carinata contain the lignans (?)-cubebin, (?)-hinokinin and (+)-asarinin, besides four neolignans of the β-aryloxy-arylpropane type and two neolignans of the benzodioxane (eusiderin) type.     

Neolignans from Urbanodendron verrucosum

Branch wood of the shrub Urbanodendron verrucosum from the Atlantic forest of southern Brazil contains the benzofuranoid neolignans licarin-A, licarin-D, porosin and the novel porosin-B, as well as the tetrahydrofurane neolignans austrobailignan-7, calopiptin and the novel verrucosin. The acid-catalysed rearrangement of the porosins yields the corresponding dihydrofutoenones.     

Neolignans from Aniba ferrea

The trunk wood of the Amazonian Aniba ferra Kubitzki contains, besides three benzyl benzoates (1a, b, c) and dillapiol (2), four hydrobenzofuranoid and two bicyclo [3.2.1] octanoid neolignans. The former comprise two representatives (3a, b) of the novel ferrearin- (3a-allyl-2- aryl-7a-hydroxy-3-methyl-3a,4,7,7a-tetrahydro-7-oxobenzofuran type, and two further representatives (4a, b) of the known porosin-(3a-allyl-2-aryl-5-methoxy-3a,4,5,6-tetrahydro-6-oxobenzofuran) type. The latter comprises a new representative (5a) of the known canellin- (1-allyl-6-aryl-7-methylbicyclo [3.2.1] octane) type, and the methyl ether (6a) of a known guianin- (1-allyl-6-aryl-7-methyl-4-oxobicyclo [3.2.1] oct-2-en) type neolignan.     

Neolignans from Aniba citrifolia

The trunk wood of Aniba citrifolia contains hydrobenzofuranoid and bicyclo[3.2.1]octanoid neolignans.     

Natural occurrence of Erdtman's dehydrodiisoeugenol

The wood of Licaria aritu Ducke (Lauraceae) contains the neolignans licarin-A, (2S,3S)-2,3-dihydro-2-(4′-hydroxy-3′-methoxyphenyl)-7-methoxy-3-methyl-5-trans-propenylbenzofuran and licarin-B, (2S, 3S)-2,3-dihydro-7-methoxy-3-methyl-2-piperonyl-5-trans-propenylbenzofuran.     

Further lignoids from Virola sebifera

From the fruits of Virola sebifera 2,3-dibenzylbutanes were isolated together with tetralin and naphthalene neolignans. 2,3-Dimethyl-4-piperonyl-4-veratrylbutan-1-ol, a further constituent, probably arises by a retro-Friedel-Crafts reaction from a tetralin neolignan. An additional component was identified as a dimeric neolignan.     

Cytotoxic dihydrobenzofuran neolignans from Mappianthus iodoies

Three new dihydrobenzofuran neolignans, mappiodoinins A-C (1-3), together with nine known analogues (4 -12) were isolated from the stems and leaves of Mappianthus iodoies. Their structures with the absolute configurations were elucidated by extensive spectroscopic methods. This is the first time to find dihydrobenzofuran neolignans from the genus Mappianthus. All isolated compounds were evaluated for their cytotoxicities against five human cancer cell lines: HL-60, SMMC-7721, A-549, MCF-7 and SW-480 in vitro. Neolignans 1-12 showed significant cytotoxic effects against various human cancer cell lines with IC₅₀ values ranging from 0.16 to 18.62 μM.     

Neolignans from Virola elongata

The bark of Virola elongata contains the new 8.8′-neolignan, 1-(3,4-dimethoxyphenyl)2,3-dimethyl-4-piperonylbutan-1-one besides the known 8.8′, 2.7′-neolignans, 4-hydroxy-2,3-dimethyl-6,7-dimethoxy-4-piperonyl-1-tetralone and 4-hydroxy-2,3-dimethyl-5,6-methylenedioxy-4-piperonyl-1-tetralone.     

Benzofuranoid neolignans from Licaria armeniaca

The trunkwood of Licaria armeniaca (Nees) Kosterm. (Lauraceae) contains sitosterol, 6,7-dimethoxy-coumarin and two novel benzofuranoid neolignans: (2S, 3S, 3aR, 5R)-3a-allyl-5-methoxy- and 5,7-dimethoxy-2-(3′, 4′-methylenedioxyphenyl)-3-methyl-2,3,3a,4,5,6-hexahydro-6-oxobenzofurans.