Two new lignans from Dipteronia dyeriana

A new sesquilignan, 7＇,8＇-didehydroherpetotriol （1）, and a new lignan glycoside, （＋）-isolariciresinol-9＇-O-α-L-rhamnopyra- nosy1-（1→6）-[3-D-glucopyranoside （2）, were isolated from the branches of Dipteronia dyeriana. Their structures were elucidated by spectroscopic methods and chemical evidence. Compound 1 possessed inhibitory activity against human leukaemia K562 cells with an IC50 value of 39 μmol/L.     

Two new lignans from Horsfieldia kingii

Two new dibenzylbutyrolactol lignans and three known dibenzylbutyrolactone lignans were isolated from the twigs and leaves of Horsfieldia kingii. Their structures were elucidated by spectroscopic analysis. Cytotoxicity evaluation of these compounds against five human tumour lines showed no inhibitory effects.     

Synthesis and configuration of the nonadecenetriol isolated from seeds of Persea americana

In an effort to establish the relative as well as absolute configuration of the trypanocidally active natural nonadec-6-en-1,2,4-triol isolated from Persea americana, the (2S,4R), (2S,4S), and (2R,4R) isomers were synthesized. The stereogenic centers taken from enantiopure chiral epoxy building blocks derived from inexpensive and readily available D-glucolactone. The (2R,4R) isomer gave (1)H and (13)C NMR as well as specific rotation in excellent consistence with those reported for the natural triol.     

Two new eupodienone lignans from Gymnotheca chinensis

Two new eupodienone lignans, named gymnothelignan T(1) and gymnothelignan U(2) were isolated from the whole plants of endemicmedicinal plant of Gymnotheca chinensis(Saururaceae). The structures of the new compounds were elucidated by means of HRMS, 1D and 2D NMR. Compound 1 was tested for cytotoxic activity in HCT15, HCT116, A549, MCF-7 and HepG2 cells and exhibited no appreciable activity against these tested cell lines with IC50 values above 50 mmol/L.     

Three new monoterpenoids from the fruit of Genipa americana

Three new monoterpenoids, called genipacetal, genipamide, and genipaol, were isolated from the fruit of Genipa americana L. (Rubiaceae), along with the four known iridoids genipin, gardendiol, deacetyl asperulosidic acid methyl ester, and shanzhiside. Their chemical structures were determined on the basis of spectroscopic data.     

Two new aryltetralin lignans from the roots of Dolomiaea souliei

Two new aryltetralin-type lignans, dolomiaeasin A (1) and dolomiaeasin B (2), were isolated from the roots of Dolomiaea souliei. Their structures were elucidated by means of various spectroscopic analyses. The cytotoxicities of 1 and 2 were tested by the MTT method, and both compounds showed no significant cytotoxic activities against the A549 and A2780 human cancer cell lines. This is the first time that aryltetralin-type lignans were isolated from the genus Dolomiaea.     

Steroid saponins XIV. The structure of agavoside G from the leaves ofAgava americana

The complete structure of agavoside G, a new steroid glycoside of the furostanol series, has been shown.     

Arylnaphthalene lignans ofHaplophyllum dauricum. The structure of daurinol

The arylnaphthalene lignans justicidin B and daurinol I have been isolated from the epigeal part ofHaplophyllum dauricum (L.) G. Don.     

Isolation and characterization of new lignans from the leaves of Cestrum parqui

Three new compounds, a sesquilignans, an oxyneolignan and a norlignan, have been isolated from the aqueous fraction of Cestrum parqui. All of the compounds have been identified on the basis of their spectroscopic properties and tested on the species Lactuca sativa and Lycopersicon esculentum to evaluate their phytotoxic activity.     

Neglschisandrins C-D: two new dibenzocyclooctadiene lignans from Schisandra neglecta

Two new dibenzocyclooctadiene lignans, neglschisandrins C-D (1-2), were isolated from the stems of Schisandra neglecta. Their structures and stereochemistries were elucidated by spectroscopic methods, including 1D- and 2D-NMR and HR-ESI-MS techniques.     

Four new nonaoxygenated C18 dibenzocylcooctadiene lignans from Kadsura philippinensis

Four new nona-oxygenated C18 dibenzocyclooctadiene lignans, kadsuphilins C-F (1-4), were isolated from the EtOAc soluble portion of the alcoholic extract of the aerial parts of Kadsura philippinensis. The structures of 1-4 were elucidated on the basis of extensive spectroscopic analyses, including 2D NMR (HMQC, HMBC, and NOESY) experiments, comparison of the spectral data with those of the related metabolites. The stereochemistries of the biphenyl and octadiene moieties were deduced from circular dichorism (CD) and the NOESY spectra, respectively. The in vitro antiplatelet aggregation activity of metabolites 1-4 also have been evaluated.     

Neglschisandrins A-B: two new dibenzocyclooctene lignans from Schisandra neglecta

Two new dibenzocyclooctene lignans, neglschisandrins A-B (1-2), were isolated from the stems of Schisandra neglecta. Their structures and stereochemistries were elucidated by spectroscopic methods, including 1D- and 2D-NMR and HR-ESI-MS techniques.     

Two new stereoisomers of Tetrahydrofuranoid lignans from the flower buds of Magnolia fargesii

Two new stereoisomers of tetrahydrofuranoid lignans, 7S,8R,7'S,8'R- (1) and 7R,8S,7'S,8'R-3,4,3',4'-tetramethoxy-9,7'-dihydroxy-8.8',7.O.9'-lignan (2) along with nine known lignans including tetrahydrofuranoids (3, 4) and tetrahydrofurofuranoids (5-11) were isolated from a CHCl(3)-soluble fraction of the flower buds of Magnolia fargesii. Two tetrahydrofuranoids, magnostellin A (3) and lariciresinol dimethyl ether (4) were isolated from this species for the first time. The structures of these compounds (1-11) were identified by spectroscopic methods as well as by comparison with published values. Absolute configurations of new stereoisomers (1, 2) were determined by the Mosher's esterification method and Circular Dichroism (CD) studies. All the isolates (1-11) were evaluated for their antioxidant activities using modified superoxide radical-scavenging assay. Compounds 5-8 showed the potent superoxide radical-scavenging activities with the ED(50) values of 19.2, 19.2, 16.5, and 27.7 microM, respectively, as compared with standard antioxidants (BHA: 22.8 microM; Trolox: 940 microM).     

Application of capillary electrochromatography using macroporous polyacrylamide columns for the analysis of lignans from seeds of Schisandra chinensis

Capillary electrochromatography (CEC) using polymer-based monolithic stationary phase has been developed as a promising method for the determination of lignans of Schisandra chinensis. The columns were prepared by in situ copolymerisation of acrylamide, N,N'-methylenebisacrylamide, vinylsulfonic acid and lauryl acrylate in presence of poly(ethylene glycol) as a porogenic agent. The columns [33 cm (24.5 cm effective length) x 75 microm I.D.] were successfully used to analyse and quantify the major lignans in extract of the seeds of Schisandra chinensis. Good separations were achieved in less than 35 min. The calibration graphs were linear in the range 0.025-1.0 mg/ml of given lignan with correlation coefficients between 0.9951 and 0.9996. The inter-day reproducibility of the peak area were below 3.9% and the inter-day reproducibility of the migration time were below 4.2%. The results of quantitative CEC analyses were compared with those obtained by reversed-phase HPLC, the levels of schizandrin, gomisin A, gomisin N and wuweizisu C determined by CEC were in a good agreement with those determined by HPLC.     

Two new glycosides from the seeds of Cassia obtusifolia

Two new glycosides,nor-rubrofusarin-6-O-β-D-(6′-O-acetyl)glucopyranoside(1) and 1-desmethylaurantio-obtusin-2-O-β-D-glucopyranoside (2) were isolated from the seeds of Cassia obtusifolia and their structures were established by chemical and spectral evidences.     

A new lignan from the seeds of Sphaerophysa salsula

A novel lignan: sphaerophyside SC was isolated from ethanolic extract of the seeds of Sphaerophysa salsula (Pall.) DC. The structure of the compound was elucidated mainly on the basis of the 1D NMR and 2D NMR data.     

Two new triterpenes from the seeds of Trichosanthes cucumeroides

Two new triterpenes named 7-oxodihydrokarounitriol (1) and 7,11-dioxodihydrokarounidiol (2), and one known triterpene, 7-oxodihydrokarounidiol (3), were isolated from the unsaponifiable matter of the seeds of Trichosanthes cucumeroides. The structures of 1 and 2 were elucidated as (3alpha, 11beta, 13alpha, 14beta, 20alpha)-3,11,29-trihydroxy-13-methyl-26-norolean-8-ene-7-one, and (3alpha,13alpha,14beta,20alpha)-3,29-dihydroxy-13-methyl-26-norolean-8-ene-7,11-dione on the basis of extensive NMR (1H, 13C, 1H-1H COSY, DEPT, HMQC, HMBC and NOESY) and MS studies.