O-Prenylated flavonoids from Dalbergia sissoo

A chalcone, 2,3-dimethoxy-4′-γ,γ-dimethylallyloxy-2′-hydroxychalcone (1) and an isoflavone, 7-γ,γ-dimethylallyloxy-5-hydroxy-4′-methoxyisoflavone (2) together with a known flavone, 7-hydroxy-6-methoxyflavone (3), a known isoflavone, biochanin A (4) and a known rotenoid, dehydroamorphigenin (5) were isolated from the root bark of Dalbergia sissoo. The structures of compounds 1–5 were elucidated on the basis of spectral and chemical studies.     

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.     

Antiplasmodial and other constituents from four Indonesian Garcinia spp.

Phytochemical investigations of four Garcinia spp. from Indonesia, i.e. Garcinia griffithii T. Anderson, Garcinia celebica L., Garcinia cornea L. and Garcinia cymosa K. Schum (Clusiaceae), have resulted in the isolation of a xanthone, 1,5-dihydroxy-3,6-dimethoxy-2,7-diprenylxanthone, 1,7-dihydroxyxanthone, isoxanthochymol, β-sitosterol-3-O-β-d-glucoside and stigmasterol-3-O-β-d-glucoside from the stem bark of G. griffithii; friedelin and 3β-hydroxy-23-oxo-9,16-lanostadien-26-oic acid or garcihombronane D from leaves of G. celebica; 23-hydroxy-3-oxo-cycloart-24-en-26-oic acid and epicatechin from stem bark of G. cornea; (±)-morelloflavone, morelloflavone-7-O-β-d-glucoside or fukugiside, the triterpene 3β-hydroxy-5-glutinen-28-oic acid and canophyllol from stem bark of G. cymosa. The xanthone and garcihombronane D displayed a selective activity against Plasmodium falciparum; isoxanthochymol and the triterpene β-hydroxy-5-glutinen-28-oic acid a broad but non-selective antiprotozoal activity.     

Toddanol and toddanone,two coumarins from Toddalia asiatica

Two new constituents isolated from the roots of Toddalia asiatica and designated as toddanol and toddanone have been characterized as 5,7-dimethoxy-6-(2-hydroxy-3-methylbut-3-enyl)coumarin (1) and 5,7-dimethoxy-6-(3-methyl-2-oxobutanyl)coumarin (3), respectively, by spectral analysis and interconversion experiments.     

Two anthraquinones from Ventilago calyculata

Two new anthraquinones have been isolated from the root bark of ventilago calyculata and their structures shown to be 2,4,8-trihydroxy-1-methoxy-3-methylanthraquinone and 2,4,8-trihydroxy-1,6-dimethoxy-3-methyl-anthraquinone.     

Neoflavonoids and the cinnamylphenol kuhlmannistyrene from Machaerium kuhlmannii and M. Nictitans

The trunkwood of Machaerium kuhlmannii contains methyl palmitate, 3-O-acetyloleanolic acid and sitosterol; the benzene derivatives 2,3-dimethoxyphenol, 2,6-dimethoxyphenol, 2-hydroxy-3-methoxyphenol, 2,3-dimethoxybenzaldehyde and methyl 3-(2-hydroxy-4-methoxyphenyl)-propionate; the isoflavonoids formononetin and (6aS,11aS)-medicarpin; the neoflavonoids (R)-3,4-dimethoxydalbergione, (R)-3,4-dimethoxydalbergiquinol, kuhlmanniquinol [(R)-3-(4-hydroxyphenyl)-3-(5-hydroxy-2,3,4-trimethoxyphenyl)-propene], dalbergin, kuhlmannin (6-hydroxy-7,8-dimethoxy-4-phenylcoumarin) and kuhlmannene (6-hydroxy-7,8-dimethoxy-4-phenylchrom-3-ene), as well as the cinnamylphenol kuhlmannistyrene [Z-1-(5-hydroxy-2,3,4-trimethoxybenzyl)-2-(2-hydroxyphenyl)-ethylene]. Five of these compounds, in addition to (R)-4′-hydroxy-3,4-dimethoxydalbergione, were also isolated from a trunkwood extract of M. nictitans. Structural assignments were confirmed by chemical interconversion and by the synthesis of (±)-kuhlmanniquinol.     

Flavonoids from two Lonchocarpus species of the Yucatan Peninsula

Leaves, stem bark and root of Lonchocarpus xuul and Lonchocarpus yucatanensis were studied separately. A chalcone, 2',4-dimethoxy-6'-hydroxylonchocarpin (), and the flavones 5,4'-dihydroxy-3'-methoxy-(6:7)-2,2-dimethylpyranoflavone (2) and 5,4'-dimethoxy-(6:7)-2,2-dimethylpyrano-flavone (3), together with the known carpachromene (4), were isolated from the leaves of both species. Similarly, the previously reported flavans xuulanin (5) and 3beta-methoxyxuulanin (6), together with the novel 3beta,4beta,5-trimethoxy-4'-hydroxy-(6:7)-2,2-dimethylpyranoflavan (7), 3-hydroxy-4,5-dimethoxy-(6:7)-2,2-dimethyl-pyranoflavan (8), and 3,4-dihydroxy-5-methoxy-(6:7)-2,2-dimethylpyranoflavan (10), were isolated from the stem bark and root of both species. Finally, the known 2',4'-dihydroxy-3'-(3-methylbut-2-enyl) chalcone (13) was obtained from the root of L. xuul only. The structures of the various metabolites were established by interpretation of their spectroscopic data.     

Pterocarpans and isoflavones from the root bark of Millettia micans and of Millettia dura

From the CH₂Cl₂/CH₃OH (1:1) extract of the root bark of Millettia micans, a new pterocarpan, (6aR,11aR)-3-hydroxy-7,8,9-trimethoxypterocarpan (1), named micanspterocarpan, was isolated. Similar investigation of the CH₂Cl₂/CH₃OH (1:1) extract of the root bark of Millettia dura gave a further new pterocarpan, (6aR,11aR)-8,9-methylenedioxy-3-prenyloxypterocarpan (2), named 3-O-prenylmaackiain, along with six known isoflavones (3-8) and a chalcone (9). All purified compounds were identified by NMR and MS, whereas the absolute configurations of the new pterocarpans were established by chriptical data analyses including quantum chemical ECD calculation. Among the isolated constituents, calopogonium isoflavone B (3) and isoerythrin A-4′-(3-methylbut-2-enyl) ether (4) showed marginal activities against the 3D7 and the Dd2 strains of Plasmodium falciparum (70–90% inhibition at 40 μM). Maximaisoflavone B (5) and 7,2′-dimethoxy-4′,5′-methylenedioxyisoflavone (7) were weakly cytotoxic (IC₅₀ 153.5 and 174.1 μM, respectively) against the MDA-MB-231 human breast cancer cell line. None of the tested compounds showed in-vitro translation inhibitory activity or toxicity against the HEK-293 human embryonic kidney cell line at 40 μM.     

Anthraquinones from Cassia sophera root bark

Two new anthraquinones have been isolated from the root bark of Cassia sophera and characterized as 1,8-dihydroxy-3,6-dimethoxy-2-methyl-7-vinylanthraquinone and 1,3-dihydroxy-5,7,8-trimethoxy-2-methylanthraquinone.     

Phenolic derivatives and an antifungal and cytototoxic labdane diterpenoid from the root bark of Turraeanthus mannii

The structures of two new compounds from the root bark of Turraeanthus mannii (Meliaceae) were determined as (3R,4R,3′R,4′R)-6,6′-dimethoxy-3,4,3′,4′-tetrahydro-2H,2′H-[3,3′]bichromenyl-4,4′-diol (1) and 15-acetoxy-labda-8(17),12E,14Z-trien-16-al (2) by means of spectroscopic analysis. Five further known compounds including one coumarin derivative, one chromenone, two labdane diterpenes and one pregnane steroid have been isolated from the same source. In antifungal and cytotoxic assays, 15-acetoxy-labda-8(17),12E,14Z-trien-16-al (2) was highly active against Mucor miehei and Artemia salina, respectively.     

Xanthones from Frasera albomarginata and F. speciosa

Seven 1-hydroxyxanthones have been isolated from the roots of Frasera albomarginata. There were 1-hydroxy-3,7-dimethoxy-, 1-hydroxy-3,5-dimethoxy-, 1,8-dihydroxy-3,5-dimethoxy-, 1-hydroxy-2,3,4,7-tetramethoxy-, 1-hydroxy-2,3,4,5-tetramethoxy-, 1-hydroxy-3,4,7-trimethoxy- and 1-hydroxy-2,3,5-trimethoxyxanthone. Six 1-hydroxyxanthones were obtained from the roots of F. speciosa. These were 1-hydroxy-2,3,4,5-tetramethoxy-, 1-hydroxy-2,3,4,7-tetramethoxy-, 1-hydroxy-2,3,5-trimethoxy-, 1,7-dihydroxy-2,3,4-trimethoxy-, 1,7-dihydroxy-2,3-dimethoxy- and 1,3-dihydroxy-4,5-dimethoxyxanthone.     

Coumarins from the Malagasy Cedrelopsis rakotozafyi Cheek and Lescot (Rutaceae)

A phytochemical analysis of the bark of the Malagasy Cedrelopsis rakotozafyi Cheek and Lescot (Rutaceae) yielded the novel 8-hydroxy-7-methoxy-6-(2R-hydroxy-3-methylbut-3-enoxy)-2H-1-benzopyran-2-one, and 7-hydroxy-6-(2R-hydroxy-3-methylbut-3-enoxy)-2H-1-benzopyran-2-one, 5,6,7-trimethoxy-2H-1-benzopyran-2-one, scoparone, scopoletin, lupeol and β-amyrin. The placement of Cedrelopsis within the Rutaceae is supported phytochemically by the typically Rutaceous coumarins isolated.     

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.     

Thonningine-A and thonningine-B: two 3-phenylcoumarins from the seeds of Millettia thonningii

The seeds of Millettia thonningii have yielded four isoflavones and three 4-hydroxy-3-phenylcoumarins, of which two are novel. On the basis of spectral analyses the novel compounds have been identified as 4-hydroxy-5,8-dimethoxy-3-(3′,4′-methylenedioxy)phenyl-2″-isopropenylfurano (4″,5″:6,7)coumarin (thonningine-A) and 4-hydroxy-5,8-dimethoxy-3-(4′-methoxy)phenyl-2″-isopropenylfurano(4″, 5″: 6,7)coumarin (thonningine-B).     

New coumarins from the umbels of Seseli sibiricum

Three new coumarins, seselinal, sesibiricol and sibirinol, and 12 known coumarins have been isolated from the umbels of Seseli sibiricum. The new coumarins have been characterized as 5, 7-dimethoxy-8-(2-methyl-2-formylpropyl)-2H-1-benzopyran-2-one, 5-(3-methylbut-2-enyloxy)-7-methoxy-8-(2-hydroxy-3-methylbut-3-enyl)-2H-1-benzopyran-2-one and 5,7-dimethoxy-8-(2-hydroxy-3-methylbut-3-enyl)-2H-1-benzopyran-2-one,respectively. The known ones were identified as sesibiricin, isosibiricin, osthol, coumurrayin, sesebrin, sesebrinol, sibiricin, imperatorin, bergapten, xanthotoxin, isopimpinellin and mexoticin.     

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).     

Cis-avicennol,a new pyranocoumarin from the root bark of Zanthoxylum elephantiasis

A new pyranocoumarin has been isolated from the root bark of Zanthoxylum elephantiasis and identified as cis-avicennol (6-(3-hydroxy-3-methyl-cis-but-1-enyl)-5-methoxy-2,2-dimethyl- 2H-benzo [1,2b:3,4b′] dipyran-8-one) on the basis of comparison of spectral data with that of trans-avicennol and conversion to tetrahydroavicennol. The usefulness of the lanthanide shift reagent Eu(fod)₃ in the assignment of cis configuration to the butenyl sidechain is briefly discussed.     

Calocalabaxanthone,the putative isoprenyl precursor of calabaxanthone from Calophyllum calaba

The bark of Calophyllum calaba var. calaba contains a new xanthone, 2,8-di-(3-methylbut-2-enyl)-1,3-dihydroxy-7-methoxyxanthone (calocalabaxanthone), the precursor of 5-hydroxy-8-methoxy-2,2-dimethyl-7-(3-methylbut-2-enyl)-2H,6H-pyano-(3,2-b)-xanthen-6-one (calabaxanthone). In addition the bark contains calabaxthone and the other constituents isolated earlier from Calophyllum calaba var. worthingtonii.     

Lignans from machilus thunbergii

Five new lignans, machilin A[(2S,3R)-2,3-dimethyl-1,4-dipiperonyl-butane], machilin B [(2S,3S)-2,3-dihydro-7-methoxy-3-methyl-2-piperon threo-2-(2-methoxy-4-trans-propenylphenoxy)-1-(4-hydroxy-3-methoxyphenyl)propan-1-ol], machilin E (erythro-1-acetoxy-2-(2-methoxy-4-trans-(3-hydroxy-1-propenyl)phenoxy]-l-piperonylpropane) were isolated from the bark of Machilus thunbergii and their structures were characterized.     

Pterocarpans from Swartzia laevicarpa

An ethanol extract of the trunkwood from Swartzia laevicarpa (Leguminosae) gave four (6aR,11aR)-8-hydroxy-3,9-dimethoxypterocarpans differentiated by additional 2-hydroxy, 2-hydroxy-10-methoxy, 4,10-dimethoxy and 2-hydroxy-4,10-dimethoxy substitution; besides two 8-hydroxy-6-methoxy-3-methylisocoumarins differentiated by 5-chloro and 7-chloro substitution; 5-hydroxy-7,8-dimethoxy-2-methylchromone and the known 8-hydroxy-5-methyl-3,4-dihydroxyisocoumarin.