Resveratrol oligomers and their O-glucosides from Cotylelobium lanceolatum

Three new resveratrol oligomers, cotylelophenol C (1) (resveratrol tetramer) and cotylelosides A (2) and B (3) (O-glucosides of resveratrol trimer), together with four known glucosides of resveratrol oligomers (vaticasides A, B, C, D) and piceid, were isolated from an acetone soluble part of stem of Cotylelobium lanceolatum (Dipterocarpaceae). The structures of new compounds were determined by spectral data analysis. The characteristic properties observed in the NMR spectra of 1 were also discussed.     

Occurrence of Stilbene Glucosides in Upuna borneensis

Four new stilbene glucosides, upunosides A ( 1 ), B ( 5 ), C ( 6 ), and D ( 7 ), were isolated from the stem of Upuna borneensis (Dipterocarpaceae) together with the three known glucosides 3, 4 , and 8 . Upunoside A ( 1 ) is the first natural instance of a glucoside of a resveratrol pentamer, and its aglycone has a dibenzo‐fused bicyclo[5.3.0]octadiene and two dihydrobenzofuran moieties. The relative structure of the aglycone was determined by spectral analysis including 1D and 2D NMR experiments.     

Occurrence of C-glucoside of resveratrol oligomers in Hopea parviflora

Investigation of the highly polar chemical constituents in the stem of Hopea parviflora (Dipterocarpaceae) resulted in the isolation of four new resveratrol derivatives, hopeasides A and B (1, 2) (resveratrol pentamers), C (3) (resveratrol trimer), and D (4) (resveratrol dimer) together with nine known resveratrol oligomers (5-13). The new structures have a common partial structure of the 1-hydroxy-1-(3,5-dihydroxy-2-C-glucopyranosylphenyl)-2-(4-hydroxyphenyl)ethane-2-yl group after oxidative condensation of (E)-resveratrol-10-C-β-glucopyranoside (14). The structures were determined by spectroscopic analysis including 2D-NMR and computer-aided molecular modeling. The biogenetic relationship of the isolates and NMR characteristics caused by steric hindrance are also discussed in this paper.     

Resveratrol tetramers with a C6-C3 or a C1 unit from Upuna borneensis

Investigation of the chemical constituents in the stem of Upuna borneensis (Dipterocarpaceae) resulted in the isolation of three new resveratrol derivatives, upunaphenols L (1), M (2) (resveratrol tetramers with a C(6)-C(3) unit) and N (3) (resveratrol tetramer with a C(1) unit). The structures have the same partial structure as vaticanol B (4). Upunaphenols L and M are new complex polyphenol compounds, lignostilbene. Their structures were determined by spectroscopic analysis including two dimensional NMR. Upunaphenol M was found to be an artifact generated by silica gel catalyzed methanolysis of 1.     

Chemical constituents in the leaves of Vateria indica

Comprehensive re-investigation of the chemical constituents in the leaves of Vateria indica (Dipterocarpaceae) resulted in the isolation of a novel resveratrol dimeric dimer having a C(2)-symmetric structure, vateriaphenol F (1), and two new O-glucosides of resveratrol oligomers, vateriosides A (2) (resveratrol dimer) and B (4) (resveratrol tetramer), along with a new natural compound (3) and 33 known compounds including 26 resveratrol derivatives. The absolute structures were elucidated by spectroscopic analysis, including two dimensional NMR and circular dichroism (CD) spectra.     

A New Oligostilbenoid from Rhizomes of Curculigo Sinensis

Curcusinol ( 1 ), a new resveratrol trimer, was isolated and identified from the rhizomes of Curculigo sinensis (Hypoxidaceae), together with five known phenolic compounds: curcapital ( 2 ), pilosidine ( 3 ), crassifoside A ( 4 ), curculigoside I ( 5 ) and phegopolin ( 6 ). The new compound 1 was determined as an oligostilbenoid on the basis of various spectroscopic methods, especially intensive 2D‐NMR (COSY, HMQC, HMBC and NOESY) techniques.     

Absolute Configuration of Resveratrol Oligomers Isolated from Hopea utilis

Phytochemical studies on a stem of Hopea utilis (Dipterocarpaceae) resulted in the isolation of two new resveratrol derivatives, namely hopeaside E ( 1 ; resveratrol trimer) and hopeaside F ( 2 ; resveratrol pentamer), together with ten known resveratrol derivatives, 3 – 12 . The structures of the new compounds were elucidated by spectroscopic analyses, including NMR experiments, and their absolute configurations were determined on the basis of a comparative configurational analysis using the β‐D ‐glucopyranosyl group and chiroptical data. The absolute configuration of (+)‐balanocarpol ( 3 ) was also determined by acid‐catalyzed skeletal conversion.     

Steroidal saponins from the roots of Smilax aspera subsp. mauritanica

Two new steroidal saponins (1, 2) were isolated from the roots of Smilax aspera subsp. mauritanica (POIR.) ARCANG. (Liliaceae), together with the known curillin G (3), asparagoside E (4), asparoside A (5), asparoside B (6) and the phenolic compound resveratrol (7). Their structures were established mainly on the basis of 600 MHz 2D-NMR spectral data. 3 exhibited antifungal activity against the human pathogenic yeasts Candida albicans, C. glabrata and C. tropicalis (minimum inhibitory concentrations of 25, 25 and 50 microg/ml, respectively) whereas the other compounds were inactive.     

Stilbenoids and Phenols in Acanthopanax brachypus

Three new stilbenoids, including α‐(3′‐O‐β‐D ‐glucopyranosyl‐5′‐methoxyphenyl)‐2‐methoxy‐3‐methylbenzofuran ( 1 ), 4‐methyl‐(E)‐resveratrol 3‐(2″‐p‐hydroxybenzoyl)‐O‐β‐D ‐glucopyranoside ( 2 ), and 5‐O‐methyl‐(E)‐resveratrol 3‐(6″‐acetyl)‐O‐β‐D ‐glucopyranoside ( 3 ), together with six known stilbenoids and phenols, acetovanillone 1‐(6′‐vanilloyl)‐O‐β‐D ‐glucopyranoside, eugenyl‐O‐β‐D ‐glucopyranoside, α‐(3′‐hydroxy‐5′‐methoxy‐2′‐methylphenyl)‐2‐hydroxybenzofuran, α‐(3′‐hydroxy‐5′‐methoxyphenyl)‐2‐hydroxybenzofuran, pinosilvin 3‐O‐β‐D ‐glucopyranoside, and (E)‐resveratrol 3‐(6″‐galloyl)‐O‐β‐D ‐glucopyranoside were isolated from the EtOH extract of the stem bark of Acanthopanax brachypus. Their structures were determined by spectral analysis including extensive 2D‐NMR spectral analyses. Compounds 2 and 3 exhibited weak cytotoxicity against human tumor A549 cell line (IC₅₀ values of 4.87 and 5.63 μM , resp.).     

Furostanol saponins from the fresh rhizomes of Polygonatum kingianum

Ten furostanol saponins were isolated as five pairs of 25R and 25S epimers from the fresh rhizomes of Polygonatum kingianum. Seven of them were identified as new compounds, (25S)-kingianoside D (2), (25S)-kingiano-side C (4), (25R,22)-hydroxylwattinoside C (5), kingianoside E (7), (25S)-kingianoside E (8), kingianoside F (9) and (25S)-kingianoside F (10), together with three known saponins, kingianoside C (1), kingianoside D (3), and 22-hydroxylwattinoside C (6). The structures of the new saponins were determinded by detailed analysis of their 1D and 2D NMR spectra, and by comparison of the spectral data with those reported.     

Complete assignments of 1H and 13C NMR data for three new arylnaphthalene lignan from Justicia procumbens

Three new arylnaphthalene lignans, named neojusticin C (1), procumbenoside C (2) and procumbenoside D (3), have been isolated from the whole plant of Justicia procumbens, together with three known ones, justicidinoside B (4), justicidinoside C (5), and diphyllin-1-O-beta-D-apiofuranoside (6). The complete assignments of 1H and 13C NMR data for three new lignans were first obtained by means of 2D NMR techniques, including HSQC and HMBC.     

Comparison of the phytoestrogen trans-resveratrol (3,4',5-trihydroxystilbene) structures from x-ray diffraction and solution NMR

The NMR-derived solution structure of trans-3,4',5-trihydroxystilbene (resveratrol) was compared with two recent literature crystal x-ray structures, resveratrol in complex with human transthyretin (TTR-RES) from 1DVS.pdb and resveratrol bound to chalcone synthase (CHS-RES) from 1CGZ.pdb. 1H and 13C NMR spectra of resveratrol were acquired in DMSO-d6. Assignments were obtained from an analysis of DQF-COSY, TOCSY, DEPT, HMQC/HSQC, HMBC and INADEQUATE NMR spectra. Past 1H and 13C NMR literature assignments are corrected. The dihedral angle 2-1-1'-2' provides an indication of the relative spatial orientation of the two phenolic rings. Values of 1.62, - 54.10 and 12.6 +/- 1.1 degrees were found for the 1DVS.pdb, 1CGZ.pdb and NMR resveratrol structures, respectively. The 1DVS.pdb resveratrol structure is 'flat' with the two phenolic rings along the same plane. The 1CGZ.pdb structure has these two rings almost orthogonal to each other, and the NMR structure has these two rings much closer to being along the same plane. The angles 1-alpha--alpha' and 1'-alpha'--alpha are along the same trace and of similar magnitude for the 1CGZ.pdb and NMR resveratrol structures. For the 1DVS.pdb resveratrol structure, these angles are about 7-10 degrees greater, with alpha and alpha' being 180 degrees out-of-phase from the other two structures. The alpha rings did not overlap, with the NMR result representing a 'median model' of the two x-ray structures.     

Three new oblongolides from Phomopsis sp. XZ-01, an endophytic fungus from Camptotheca acuminate

Four new metabolites, including three new oblongolides named C1, P1, and X1 (1-3) and 6-hydroxyphomodiol (10), along with eight known compounds--oblongolides B (4), C (5), D (6), O (7), P (8) and U (9), (3R,4aR,5S,6R)-6-hydroxy-5-methylramulosin (11), and (3R)-5-methylmellein (12)--were isolated from the endophytic fungal strain Phomopsis sp. XZ-01 of Camptotheca acuminate. Their structures were elucidated by spectroscopic analyses, including 1H- and 13C-NMR, 2D NMR (HSQC, HMBC, 1H-1H COSY and NOESY) and HR-FT-MS. Cytotoxic activities of these compounds were evaluated. Some of them showed weak selective activities.     

Resveratrol derivatives from Vatica albiramis

Three new stilbene derivatives, albiraminols A (1) (resveratrol hexamer), B (2) (resveratrol dimer), and vatalbinoside F (3) (mono-glucoside of resveratrol dimer), along with malibatol were isolated from acetone soluble portions of the stem of Vatica albiramis. The structures of the isolates were established on the basis of spectroscopic analyses, including a detailed NMR spectroscopic investigation. The biosynthetic aspects of the isolates are discussed in this paper. Compound 1 is composed of tetrameric resveratrol (vaticanol B (1A)) and dimeric resveratrol (1B) and is the first instance of the resveratrol derivative bearing a 5,6,11,12-tetrahydro-5,11-epoxydibenzo[a,e][8]annulene ring system. Compound 2 possesses a novel 4,5-dihydro-13-oxabenzo[3,4]azuleno[7,8,1-jkl]phenanthrene skeleton in the framework.     

Bioactive constituents from Chinese natural medicines. XXXII. aminopeptidase N and aldose reductase inhibitors from Sinocrassula indica: structures of sinocrassosides B(4), B(5), C(1), and D(1)-D(3)

From the methanolic extract of the whole plant of Sinocrassula indica (Crassulaceae), six new flavonol glycosides, sinocrassosides B(4) (1), B(5) (2), C(1) (3), D(1) (4), D(2) (5), and D(3) (6), were isolated together with 30 compounds. The structures of 1-6 were elucidated on the basis of chemical and physicochemical evidence. In addition, several constituents were found to show inhibitory effects on aminopeptidase N and aldose reductase.     

New C_(19)-Diterpenoid Alkaloids from the Roots of Delphinium

Three new C_(19)-diterpenoid alkaloids, giraldines A (1), B (3)and C (4), were isolated from the roots of Delphinium giraldiiDiels, together with three known C_(19)-diterpenoid alkaloids, di-hydrogadesine (5), tatsiensine (6) and siwanine A (7), as wellas their structures were elucidated by chemical evidence andspectral analyses, including IR, MS, 1D NMR and 2D NMR.     

Complete assignments of 1H and 13C NMR data for seven arylnaphthalide lignans from Justicia procumbens

Three new arylnaphthalide lignans named 6'-hydroxy justicidin A (1), 6'-hydroxy justicidin B (2) and 6'-hydroxy justicidin C (3) have been isolated from the whole plant of Justicia procumbens, together with four known ones, neojusticin A (4), chinensinaphthol methyl ester (5), isodiphyllin (6) and taiwanin C (7). The complete assignments of 1H and 13C NMR chemical shifts for the new lignans and the 13C NMR chemical shifts for the known lignans were obtained for the first time by means of 2D NMR techniques, including HSQC and HMBC.     

Complete assignments of 1H and 13C NMR data for trypanocidal eremantholide C oxide derivatives

The chemical transformations of eremantholide C (1), a trypanocidal sesquiterpene lactone isolated from Lychnophora trichocarpha Spreng., gave five new oxide derivatives: 3'-hydroxyeremantholide C (2), 1'-formyleremantholide C (3), 1'-carboxyeremantholide C (4), 1'-carbomethoxyeremantholide C (5) and sodium 1'-carboxylate of eremantholide C (6). The (1)H and (13)C NMR data of all these derivatives were assigned based on 1D and 2D techniques. The derivatives were evaluated against Y and CL strains of Trypanosoma cruzi. All of them were inactive against the Y strain. Compounds 2 and 5 displayed 100% activity on the CL strain while compounds 4 and 6 were partially active on the CL strain.     

Three new Anthraquinones,one new Benzochromene and one new Furfural glycoside from Lasianthus acuminatissimus

Three new anthraquinones, lasianthurin B (1), C (2), lasianthuoside D (3), a new benzochromene, lasianthurin D (4), and a new furfural glycoside, lasianthuoside E (5), together with one known compound 4- hydroxymethyl-2-furaldehyde (6) were isolated from an alcohol extract of the root of Lasianthus acuminatissimus. Their structures were elucidated on the basis of extensive spectroscopic data analysis (including 1D, 2D NMR, X-ray, and MS experiments) and comparsion to literature data.     

On the chemical constituents of Dipsacus asper

Bioassay-guided fractionation of 95% EtOH extract from the roots of Dipsacus asper lead to the isolation of some phenolic acids (caffeic acid, 2,6-dihydroxycinnamic acid, vanillic acid, 2'-O-caffeoyl-D-glucopyranoside ester, and caffeoylquinic acid) as the major active components, and five new iridoid glucoside dimers (1-5) and one new iridoid glucoside monomer (6), other known iridoid glycosides loganin, cantleyoside, triplostoside A, lisianthioside, 6'-O-beta-D-apiofuranosyl sweroside, as well as triterpenoids oleanic acid and akebiasaponin D. The structures of new compounds 1-6 were determined as dipsanosides C (1), D (2), E (3), F (4), G (5), and 3'-O-beta-D-glucopyranosyl sweroside (6) by spectroscopic, including 1D and 2D NMR techniques, and chemical methods.