New salicylic acid and isoflavone derivatives from Flemingia paniculata

A new salicylic acid derivative, 2-carboxy-3-(2-hydroxypropanyl)phenol (1), and four new isoflavones, 5,7,4'-trihydroxy-8-(1,1-dimethylprop-2-enyl)isoflavone (2), 5,7,2',4'-tetrahydroxy-8-(1,1-dimethylprop-2-enyl)isoflavone (3), 5,2',4'-trihydroxy-4' ',4' ',5' '(xi)-trimethyl-4' ',5' '-dihydrofurano-(7,6,2' ',3' ')isoflavone (4), and 5,2',4'-trihydroxy-7-(3-methylbut-2-enyloxy)isoflavone (5), were isolated from the stem bark of Flemingia paniculata. The structures of these compounds were established unambiguously by spectroscopic data interpretation. The biogenetic pathways to 1 and 2-4 have been postulated.     

Aromatase inhibitors from Broussonetia papyrifera.

Bioassay-guided fractionation of an ethyl acetate-soluble extract from the whole plants of Broussonetia papyrifera, using an in vitro aromatase inhibition assay, led to the isolation of five new active compounds, 5,7,2',4'-tetrahydroxy-3-geranylflavone (1), isogemichalcone C (8), 3'-[gamma-hydroxymethyl-(E)-gamma-methylallyl]-2,4,2',4'-tetrahydroxychalcone 11'-O-coumarate (9), demethylmoracin I (10), and (2S)-2',4'-dihydroxy-2' '-(1-hydroxy-1-methylethyl)dihydrofuro[2,3-h]flavanone (11), and 10 known (12-21) compounds which were also found to be active. Of these compounds, the most potent were 9 (IC(50) 0.5 microM), 11 (IC(50) 0.1 microM), isolicoflavonol (12, IC(50) 0.1 microM), and (2S)-abyssinone II (13, IC(50) 0.4 microM). Additionally, six new compounds, 5,7,3',4'-tetrahydroxy-6-geranylflavonol (2), 5,7,3',4'-tetrahydroxy-3-methoxy-6-geranylflavone (3), (2S)-7,4'-dihydroxy-3'-prenylflavan (4), 1-(2,4-dihydroxyphenyl)-3-(4-hydroxyphenyl)propane (5), 1-(2,4-dihydroxy-3-prenylphenyl)-3-(4-hydroxyphenyl)propane (6), and 1-(4-hydroxy-2-methoxyphenyl)-3-(4-hydroxy-3-prenylphenyl)propane (7), were isolated and characterized, but proved to be inactive as aromatase inhibitors, as were an additional 21 known compounds. The structures of the new compounds (1-11) were elucidated by spectroscopic methods. Structure-activity relationships in the aromatase assay were determined for the benzofurans, biphenylpropanoids, coumarins, and various types of flavonoids (chalcones, flavans, flavanones, and flavones) obtained among a total of 42 constituents of B. papyrifera.     

Antioxidant chalcone glycosides and flavanones from Maclura (Chlorophora) tinctoria

Four chalcone glycosides (1-4), including three new natural products, and three flavanones (5-7) were isolated from the methanol extract of stem bark of Maclura tinctoria. The new compounds have been characterized as 4'-O-beta-D-(2' '-p-coumaroyl)glucopyranosyl-4,2',3'-trihydroxychalcone (1), 4'-O-beta-D-(2' '-p-coumaroyl-6' '-acetyl)glucopyranosyl-4,2',3'-trihydroxychalcone (2), and 3'-(3-methyl-2-butenyl)-4'-O-beta-D-glucopyranosyl-4,2'-dihydroxychalcone (3); the known derivatives were elucidated as 4'-O-beta-D-(2' '-acetyl-6' '-cinnamoyl)glucopyranosyl-4,2',3'-trihydroxychalcone (4), eriodictyol 7-O-beta-D-glucopyranoside (5), naringenin (6), and naringenin 4'-O-beta-D-glucopyranoside (7). Their structures were determined by 1D and 2D NMR and ESIMS. The antioxidant activity of all the isolated compounds was determined by measuring free-radical-scavenging effects using two different assays, namely, the Trolox Equivalent Antioxidant Capacity (TEAC) assay and the coupled oxidation of beta-carotene and linoleic acid (autoxidation assay). The results showed that compound 3 was the most active in both antioxidant assays.     

Flavonoids from Dalbergia louvelii and their antiplasmodial activity

Four new flavonoids (1-4), along with 13 known compounds, were isolated from the heartwood of Dalbergia louvelii by following their potential to inhibit in vitro the growth of Plasmodium falciparum. Of the isolated compounds, four known compounds showed antiplasmodial activity with IC(50) values ranging from 5.8 to 8.7 microM, namely, (R)-4' '-methoxydalbergione (5), obtusafuran (6), 7,4'-dihydroxy-3'-methoxyisoflavone (7), and isoliquiritigenin (8). The structures of the new compounds were determined using spectroscopic techniques as 1-(3-hydroxyphenyl)-3-(4-hydroxy-2,5-dimethoxyphenyl)propane (1), spirolouveline (2), (3R)-7,2'-dihydroxy-4',5'-dimethoxyisoflavanone (3), and 3-(2,4-dihydroxy-5-methoxy)phenyl-7-hydroxycoumarin (4), respectively.     

Prenylated flavanones with anti-tyrosinase activity from Dalea boliviana

Three new prenylated flavanones, (2S)-5,7,2'-trihydroxy-5'-(1',1'-dimethylallyl)-8-prenylflavanone (1), (2S)-5,7,2'-trihydroxy-8,3'-diprenylflavanone (2), and (2S)-5,2'-dihydroxy-6',6'-dimethylchromeno-(7,8:2',3')-3'-prenylflavanone (3), and a known chromeno (dimethylpyrano) flavanone, obovatin (4), were isolated from the n-hexane extract of Dalea boliviana roots. The compounds were evaluated in vitro in relation to their inhibitory effect on the tyrosinase activity by using a spectrophotometric method.     

New neolignans that inhibit DNA polymerase beta lyase

Bioassay-directed fractionation of a methyl ethyl ketone extract of the roots of Endlicheria aff. resulted in the isolation of four new neolignans (1-4) and eight known compounds, namely, canellin A (5), canellin C (6), 3'-methoxyguianin (7), (7S,8R,1'S,5'S,6'R)-Delta(2',8')-3',6'-dihydroxy-5'-methoxy-3,4-methylenedioxy-4'-oxo-8.1',7.5'-neolignan (8), armenin-B (9), dillapiole (10), 1-allyl-2,6-dimethoxy-3,4-methylenedioxybenzene (11), and omega-hydroxyisodillapiole (12). The structures of the new compounds (1-4) were established as (7S,8R,1'S,5'S,6'R)-Delta(2',8')-5',6'-dihydroxy-3'-methoxy-3,4-methylenedioxy-4'-oxo-8.1',7.5'-neolignan, (7S,8R,1'S,5'S,6'R)-Delta(2',8')-3',5',6'-trihydroxy-3,4-methylenedioxy-4'-oxo-8.1',7.5'-neolignan, 2,4-dimethoxy-5,6-methylenedioxy-1-(2-propenyl)benzene, and 2,6-dimethoxy-3,4-methylenedioxycinnamyl alcohol, respectively, on the basis of spectroscopic interpretation.     

Four new flavones and a new isoflavone from Iris bungei

Four new irisflavones A-D (1-4) and irilin D (5) have been isolated from the underground parts of Iris bungei along with known isoflavones, irilins A-B (6-7) and tlatancuayin (8). The structures of the new compounds were determined using NMR and mass spectroscopic methods and were found to be 2',5,7-trihydroxy-3,6-dimethoxyflavone (1), 2',5-dihydroxy-3,6,7-trimethoxyflavone (2), 2',5,6'-trihydroxy-3,6,7-trimethoxyflavone (3), 3,3',5-trihydroxy-2',7-dimethoxyflavone (4), and 3',4',5,7-tetrahydroxy-6-methoxyisoflavone (5). The structures of irisflavones 1, 3, and 4 were confirmed by single-crystal X-ray diffraction studies.     

Mixed lignan-neolignans from Tarenna attenuata

Six new mixed lignan-neolignans and 20 known compounds were isolated from the whole plant of Tarenna attenuata. By analysis of physical and spectroscopic data, the structures of the new compounds were elucidated as (1R,5R,6R)-6-{4-O-[2-(1-(4-hydroxy-3-methoxyphenyl))glycerol]-3,5-dimethoxyphenyl}-3,7-dioxabicyclo[3.3.0]octan-2-one (1), 5' '-methoxyhedyotisol A (2), 4' '-O-(8-guaiacylglycerol)buddlenol A (3), 5' '-methoxy-4' '-O-(8-guaiacylglycerol)buddlenol A (4), 4,6-dimethoxy-5-hydroxy-3-hydroxymethyl-2-(3,4,5-trimethoxyphenyl)-2,3-dihydrobenzofuran (5), and 7-O-ethylguaiacylglycerol (6). Compounds 1, 5, 6, and 8 showed potent antioxidant activities against H2O2-induced impairment in PC12 cells, and compounds 1, 2, 5, and 7 scavenged DPPH radical strongly with IC50 values of 72, 87, 45, and 55 microM, respectively.     

Phenolic constituents of Phenax angustifolius

Fractionation of an ethanolic extract of the leaves of Phenax angustifolius has resulted in the isolation of two new lignans, 2-hydroxy-2-(3',4'-dihydroxyphenyl)methyl-3-(3' ',4' '-dimethoxyphenyl)methyl-gamma-butyrolactone (1) and 2-hydroxy-2-(4'-O-beta-D-glucopyranosyl-3'-hydroxyphenyl)methyl-3-(3' ',4' '-dimethoxyphenyl)methyl-gamma-butyrolactone (2), and three known compounds, vitexin, isovitexin, and quercetin 3-O-alpha-L-rhamnopyranoside. The structures of 1 and 2 were determined using spectroscopic methods.     

Phelligridins C-F: cytotoxic pyrano[4,3-c][2]benzopyran-1,6-dione and furo[3,2-c]pyran-4-one derivatives from the fungus Phellinus igniarius

Three unique pyrano[4,3-c][2]benzopyran-1,6-dione derivatives and a new furo[3,2-c]pyran-4-one, named phelligridins C-F (2-5), together with hispolon (8), (E)-4-(3,4-dihydroxyphenyl)but-3-en-2-one (9), 4-hydroxybenzaldehyde, protocatechualdehyde, syringic acid, protocatechuic acid, caffeic acid, isoergosterone, and octadecyl ferulate were isolated and identified from the ethanolic extract of Phellinus igniarius. Their structures were determined by spectroscopic methods including IR, MS, and 1D and 2D NMR experiments. The structures of the new compounds were characterized as 3-(4-hydroxystyryl)-8,9-dihydroxypyrano[4,3-c]isochromene-4-one (2), 3-(3,4-hydroxystyryl)-8,9-dihydroxypyrano[4,3-c]isochromene-4-one (3), 8,9-dihydroxy-3-[5',6'-dihydroxy-5' '-methyl-3' '-oxo-spiro[fural-2' '(3' 'H),1'-indene]-2'-yl]-1H,6H-pyrano[4,3-c][2]benzopyran-1,6-dione (4), and (3Z)-3-(3,4-dihydroxybenzylidene)-6-(3,4-dihydroxystyryl)-2,3-dihydro-2-methoxy-2-(2-oxo-propyl)furo[3,2-c]pyran-4-one (5), respectively. Some compounds including 2 and 3 showed in vitro selective cytotoxicity against a human lung cancer cell line (A549) and a liver cancer cell line (Bel7402). Possible biogenetic sequences to the formation of 1-9 are postulated.     

Neolignans, a coumarinolignan, lignan derivatives, and a chromene: anti-inflammatory constituents from Zanthoxylum avicennae

Eight new compounds, including four new neolignans, (7' S,8' S)-bilagrewin ( 1), (7' S,8' S)-5-demethoxybilagrewin ( 2), (7' S,8' S)-5- O-demethyl-4'- O-methylbilagrewin ( 3), and (7' S,8' S)-nocomtal ( 4), a new coumarinolignan, (7' S,8' S)-4'- O-methylcleomiscosin D ( 5), two new lignan derivatives, (+)-9'- O-( Z)-feruloyl-5,5'-dimethoxylariciresinol ( 6) and (+)-9'- O-( E)-feruloyl-5,5'-dimethoxylariciresinol ( 7), and a new chromene, ( E)-3-(2,2-dimethyl-2 H-chromen-6-yl)prop-2-enal ( 8), have been isolated from the stem wood of Zanthoxylum avicennae, together with 18 known compounds ( 9- 26). The structures of these new compounds were determined through spectroscopic and MS analyses. (7' S,8' S)-4'- O-Methylcleomiscosin D ( 5), cleomiscosin D ( 9), skimmianine ( 18), robustine ( 19), and integrifoliolin ( 23) exhibited inhibition (IC 50 < or = 18.19 microM) of superoxide anion generation by human neutrophils in response to formyl- l-methionyl- l-leucyl- l-phenylalanine/cytochalasin B (FMLP/CB). In addition, skimmianine ( 18) inhibited FMLP/CB-induced elastase release with an IC 50 value of 19.15 +/- 0.66 microM.     

New cytotoxic bis 5-alkylresorcinol derivatives from the leaves of Oncostemon bojerianum from the Madagascar rainforest

Bioassay-directed fractionation of a CH(2)Cl(2)-MeOH extract of the leaves of Oncostemon bojerianum resulted in the isolation of eight new 5-alkylresorcinols, named oncostemonols A-H (1-8), and two known derivatives, (8'Z)-1,3-dihydroxy-5-[16'-(3' ',5' '-dihydroxyphenyl)-8'-hexadecen-1'-yl]benzene (9) and (8'Z)-1,3-dihydroxy-5-[14'-(3' ',5' '-dihydroxyphenyl)-8'-tetradecen-1'-yl]benzene (10). The structures of the new compounds 1-8 were elucidated on the basis of extensive 1D and 2D NMR spectroscopic interpretation and chemical derivatization. All the compounds exhibited cytotoxic activity against the A2780 ovarian cancer cell line.     

New cyanogenic and alkyl glycoside constituents from Phyllagathis rotundifolia

Methanolic extracts of the leaves, stems, and roots of Phyllagathis rotundifolia collected in Malaysia yielded seven galloylated cyanogenic glucosides based on prunasin, with six of these being new compounds, prunasin 2',6'-di-O-gallate (3), prunasin 3',6'-di-O-gallate (4), prunasin 4',6'-di-O-gallate (5), prunasin 2',3',6'-tri-O-gallate (6), prunasin 3',4',6'-tri-O-gallate (7), and prunasin 2',3',4',6'-tetra-O-gallate (8). Also obtained was a new alkyl glycoside, oct-1-en-3-yl alpha-arabinofuranosyl-(1-->6)-beta-glucopyranoside (9). For compounds 3-8, the galloyl groups were individually linked to the sugar moieties via ester bonds. All new structures were established on the basis of NMR and MS spectroscopic studies. In addition, prunasin (1), gallic acid and its methyl ester, beta-glucogallin, 3,6-di-O-galloyl-D-glucose, 1,2,3,6-tetra-O-galloyl-beta-D-glucose, strictinin, 6-O-galloyl-2,3-O-(S)-hexahydroxydiphenoyl-D-glucose, praecoxin B, and pterocarinin C were isolated and identified. The isolation of 1 and its galloyl derivatives (3-8) from a Melastomataceous plant are described for the first time.     

New phenolic constituents from Smilax bracteata

From the methanol extract of Smilax bracteata rhizomes, six new phenolic compounds, (2S,3S)-5-O-beta-D-glucopyranosyloxy-6-methyl-3'-methoxy-3,7,3'-trihydroxyflavan (1), (2S,3S)-5-O-beta-D-glucopyranosyloxy-6-methyl-4'-methoxy-3,7,4'-trihydroxyflavan (2), 3beta-(3',5'-dihydroxyphenyl)-2alpha-(4' '-hydroxyphenyl)dihydrobenzofuran-5-carbaldehyde (3), (1-p-O-coumaroyl-6-O-feruroyl)-beta-D-fructofuranosyl-alpha-D-glucopyranoside (4), (1-p-O-coumaroyl-3,6-di-O-feruroyl)-beta-D-fructofuranosyl-alpha-D-glucopyranoside (5), and (6-O-feruroyl)-beta-D-fructofuranosyl-(6-O-acetyl)-alpha-D-glucopyranoside (6) were isolated together with five known compounds. Their structures were established by spectral data interpretation.     

Antifibrotic phenanthrenes of Dendrobium nobile stems

Two new phenanthrenes ( 1 and 6) and four new dihydrophenanthrenes ( 2- 5) were isolated from a methanolic extract of Dendrobium nobile stems, along with 13 known phenanthrenes and dihydrophenanthrenes ( 7- 19). By spectroscopic analysis, the structures of compounds 1- 6 were determined as 2,8-dihydroxy-3,4,7-trimethoxyphenanthrene ( 1), 3-hydroxy-2,4,7-trimethoxy-9,10-dihydrophenanthrene ( 2), 2,8-dihydroxy-3,4,7-trimethoxy-9,10-dihydrophenanthrene ( 3), 2-hydroxy-4,7-dimethoxy-9,10-dihydrophenanthrene ( 4), 2,2'-dihydroxy-3,3',4,4',7,7'-hexamethoxy-9,9',10,10'-tetrahydro-1,1'-biphenanthrene ( 5), and 2,3,5-trihydroxy-4,9-dimethoxyphenanthrene ( 6), respectively. Antifibrotic activity of compounds 1- 19 was evaluated employing HSC-T6, an immortalized rat hepatic stellate cell line, as an in vitro assay system by assessing cell proliferation.     

A new isoflavone from Genista corsica

A new isoflavone (1), dihydroisoderrondiol [(3' 'S,4' 'R)-5,7,3' ', 4' '-tetrahydroxy-2' ',2' '-dimethyl-3' ',4' '-dihydropyrano(5' ',6' ';3' ',4' ')isoflavone], was isolated from aerial parts of Genista corsica, together with 11 previously known compounds [daidzein, isoprunetin, isoderrone (2), ficuisoflavone (3), luteolin, luteolin 4'-O-beta-glucoside, luteolin 7-O-beta-glucoside, taxifolin, 5-methoxytaxifolin, sucrose, and D-pinitol]. The structure of 1 was elucidated by spectroscopic methods.     

Benzyl derivatives with in vitro binding affinity for human opioid and cannabinoid receptors from the fungus Eurotium repens

Bioassay-guided fractionation of the fungus Eurotium repens resulted in the isolation of two new benzyl derivatives, (E)-2-(hept-1-enyl)-3-(hydroxymethyl)-5-(3-methylbut-2-enyl)benzene-1,4-diol (1) and (E)-4-(hept-1-enyl)-7-(3-methylbut-2-enyl)-2,3-dihydrobenzofuran-2,5-diol (2), along with seven known compounds (3-9) including five benzaldehyde compounds, flavoglaucin (3), tetrahydroauroglaucin (4), dihydroauroglaucin (5), auroglaucin (6), and 2-(2',3-epoxy-1',3'- heptadienyl)-6-hydroxy-5-(3-methyl-2-butenyl)benzaldehyde (7), one diketopiperazine alkaloid, echinulin (8), and 5,7-dihydroxy-4-methylphthalide (9). The chemical structures of these compounds were established on the basis of extensive 1D and 2D NMR and HRMS data. Compounds 1-4 and 6 showed good binding affinity for human opioid or cannabinoid receptors. These findings have important implications for psychoactive studies with this class of compounds.     

Bioactive secondary metabolites from Boesenbergia pandurata of Myanmar and their preferential cytotoxicity against human pancreatic cancer PANC-1 cell line in nutrient-deprived medium

The chloroform extract of rhizomes of Boesenbergia pandurata demonstrated marked preferential cytotoxicity against human pancreatic PANC-1 cancer cells in nutrient-deprived medium. Bioactivity-directed investigation of this extract yielded four new secondary metabolites, geranyl-2,4-dihydroxy-6-phenethylbenzoate ( 1), 2',4'-dihydroxy-3'-(1'-geranyl)-6'-methoxychalcone ( 2), (1' R,2' S,6' R)-2-hydroxyisopanduratin A ( 3), and (2 R)-8-geranylpinostrobin ( 4), and twenty known compounds ( 5- 24). Among the known compounds, (2 S)-6-geranylpinostrobin ( 5), (+/-)-6-methoxypanduratin A ( 6), and (2 S)-7,8-dihydro-5-hydroxy-2-methyl-2-(4'-methyl-3'-pentenyl)-8-phenyl-2 H,6 H-benzo[1,2- b:5,4- b']dipyran-6-one ( 7) were isolated for the first time from a natural source. The structures of these compounds were elucidated using extensive spectroscopic techniques including CD measurements. All the isolated compounds showed varying degrees of in vitro preferential cytotoxicity against PANC-1 cells. Nicolaioidesin B ( 11) and panduratin A ( 17) were most potent, each showing a PC 100 at 2.5 microM.     

New furofuran and butyrolactone lignans with antioxidant activity from the stem bark of Styrax japonica

A new furofuran lignan, styraxlignolide B (1), and four new dibenzyl-gamma-butyrolactone lignans, styraxlignolides C-F (2-5), were isolated from the EtOAc-soluble fraction of stem bark of Styrax japonica. Known compounds, taraxerol (6), syringin (7), and (-)-pinoresinol glucoside (8), were also obtained. The structures of styraxligonolides B-F were determined as 2alpha-(4'-hydroxy-3'-methoxyphenyl)-6alpha-(3' ',4' '-methylenedioxyphenyl)-8-oxo-3,7-dioxabicyclo[3.3.0]octane 4'-O-(beta-D-glucopyranoside) (1), (2S,3S)-2alpha-(3' '-hydroxy-4' '-methoxybenzyl)-3beta-(4'-hydroxy-3'-methoxybenzyl)-gamma-butyrolactone 4'-O-(beta-D-glucopyranoside) (2), (2S,3S)-2alpha-(4' '-hydroxy-3' '-methoxybenzyl)-3beta-(4'-hydroxy-3'-methoxybenzyl)-gamma-butyrolactone 4'-O-(beta-D-glucopyranoside) (3), (2S,3S)-2alpha-(4' '-hydroxy-3' '-methoxybenzyl)-3beta-(4'-hydroxy-3'-methoxybenzyl)-gamma-butyrolactone 4' '-O-(beta-D-glucopyranoside) (4), and (2S,3S)-2alpha-(3' ',4' '-dimethoxybenzyl)-3beta-(4'-hydroxy-3'-methoxybenzyl)-gamma-butyrolactone 4'-O-(beta-D-glucopyranoside) (5) by spectroscopic means including 2D NMR. Compounds 1-8 were tested in vitro for antioxidant activity against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals. Styraxlignolide C (2), styraxlignolide D (3), styraxlignolide E (4), and (-)-pinoresinol glucoside (8) exhibited weak radical-scavenging activity in the DPPH assay, with IC50 values of 380, 278, 194, and 260 microM, respectively.     

Antiplatelet activities of newly synthesized derivatives of piperlongumine

Piperlongumine, a pyridone alkaloid isolated from Piper longum L., exhibited a potential inhibitory effect on washed rabbit platelet aggregation induced by collagen, arachidonic acid (AA) and platelet activating factor (PAF), without any inhibitory effect on that induced by thrombin. Piperlongumine was used as a lead compound for the synthesis of new antiplatelet agents. Seven synthetic compounds were newly synthesized from 3,4,5-trimethoxycinnamic acid (TMCA). They were 1-piperidin-1-yl-3-(3,4,5-trimethoxy-phenyl)prop-2-en-1-one (1'), 1-morpholin-4-yl-3-(3,4,5-trimethoxyphenyl)prop-2-en-1-one (2'), 1-(3,5-dimethylpiperidin-1-yl)-3-(3,4,5-trimethoxyphenyl)prop-2-en-1-one (3'), 1-(2-methylpiperidin-1-yl)-3-(3,4,5-tri-methoxyphenyl)prop-2-en-1-one (4'), 1-(3-hydroxypiperidin-1-yl)-3-(3,4,5-trimethoxyphenyl)- prop-2-en-1-one (5'), 1-[3-(3,4,5-tri-methoxyphenyl) acryloyl]-piperidin-2-one (6') and ethyl 1-[3-(3,4,5-trimethoxyphenyl)-acryloyl]piperidine-4-carboxylate (7'). Among those seven synthetic derivatives, 1-(3,5-dimethylpiperidin-1-yl)-3-(3,4,5-trimethoxyphenyl)prop-2-en-1-one (3') had the most inhibitory effect on platelet aggregation induced by collagen, AA and PAF.