Triterpenoid Ester Saponins from Dipteronia dyeriana

The phytochemical investigation of Dipteronia dyeriana (Aceraceae) resulted in the isolation and identification of five new triterpenoid ester saponins, dipterosides A–E ( 1 – 5 ). Their structures were elucidated by spectroscopic methods and chemical evidence. The inhibitory activities of these compounds against human leukemia K562 and human hepatoma HepG2 cells were also evaluated.     

Cycloheximide Derivatives from the Fruits of Dipteronia dyeriana

The phytochemical investigation of Dipteronia dyeriana (Aceraceae) resulted in the isolation and identification of three new cycloheximide derivatives: dipteronines A–C ( 1 – 3 ). Their structures were elucidated based on the 1D‐ and 2D‐NMR spectra. Dipteronine A ( 1 ) is the first example of a 10,11‐secocycloheximide. Cytotoxic and antifungal activities of these isolates were also evaluated.     

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.     

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.     

Two lignans,one alkaloid,and flavanone from the twigs of Feroniella lucida

Four new compounds, two lignans; lucidenal and lucidanin (1 and 2), one alkaloid (3), and one flavanone (4) together with 26 known compounds (5–30), were isolated from the twigs of Feroniella lucida. The structures of the new compounds were determined on the basis of spectroscopic analyses. Lucidenal 1 showed cytotoxicity against HuCCA-1, A549, MOLT-3 and HepG2 cancer cell lines with IC₅₀ values of 4.27, 9.59, 2.31, and 6.50 μg/mL, respectively. A plausible biosynthetic pathway of 1 was proposed.     

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.     

Structural and spectroscopic characteristics of two new dibenzylbutane type lignans from Taxus baccata L.

Chromatographic separation of chloroform extracts of the heartwood of Taxus baccata L. has yielded two new dibenzylbutane type lignans, together with a known lignan. Their structures were established as 3′-demethylisolariciresinol-9′-hydroxy isopropylether (1) and 3-demethylisolariciresinol (2) and isolariciresinol (3) on the basis of 1D- and 2D-NMR spectroscopic analysis. Compounds 1 and 2 were identified as new lignans of isolariciresinol derivatives. Compound 1 is the first lignan with a hydroxyisopropyl group at C-9′. Molecular mechanic calculations of these compounds were carried out by using mm3 program. Furthermore, the conformations of these three compounds were computed with the semi-empirical molecular orbital methods AM1 and PM3 by using X-ray crystal structure results of similar compounds. So, three-dimensional, the most probable structure of these compounds were obtained, compared and discussed.     

Recent advances in the chemistry of lignans

The recent literature on the chemistry of simple lignans has been comprehensively reviewed.     

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).     

Two new lignans from the stem bark of Magnolia obovata and their cytotoxic activity

Two new lignans, 4-methoxymagnaldehyde B (1) and coumanolignan (2), were isolated from the stem bark of Magnolia obovata, together with 11 known compounds (3-13). The structures of compounds 1 and 2 were determined to be 5'-allyl-2'-hydroxyphenyl-4-methoxy-3-cinnamic aldehyde (1) and 6-allyl-8-(5'-allyl-2'-hydroxyphenyl)coumarin (2) on the basis of spectroscopic and physicochemical analyses including 2D NMR and high-resolution EI-MS. Compounds 1-8, 11, 12, and 13 were tested in vitro for their cytotoxic activities against the HeLa, A549, and HCT116 cancer cell lines. Among the compounds tested, compound 1 showed the strongest cytotoxic activity against the HCT116 cancer cell line, with an IC(50) value of 1.3 microg/ml.     

Two New Lignan Glycosides from Saussurea laniceps

Two new lignan glycosides, lanicepsides A and B ( 1 and 2 ), along with the eight known compounds 3 – 6 , epipinoresinol, syringin, ethyl caffeate, and 5,6,7‐trihydroxy‐4′‐methoxyflavone, including sesquiterpene lactones, lignans, and a flavone, were isolated from the ethanol extract of Saussurea laniceps. Their structures were determined by spectroscopic methods especially 1D‐ and 2D‐NMR techniques.     

Determination of lignans in Wuweizi by using magnetic bar microextraction and HPLC

In this paper, a magnetic bar microextraction was developed to extract schisandrin A, schisantherin A, and deoxyschizandrin from Wuweizi. The analytes were determined by HPLC. A stainless‐steel wire was inserted into the hollow of the hollow fiber to make the magnetic bar. The bar can be used to stir the extraction system and extract the analytes, and was isolated from the extract system by magnetic force. Several experimental parameters, including type and volume of extraction solvent, the number of magnetic bars, extraction temperature and time, stirring speed and NaCl concentration were investigated and optimized. The LODs for schisandrin A, schisantherin A, and deoxyschizandrin were 0.14, 0.06, and 0.10 μg/mL, respectively. The recoveries were in the range of 70.90–106.67% and the RSDs were < 8.84%. Compared with ultrasound‐assisted and Soxhlet extraction, when the present method was applied, the extraction time was shorter, the sample amount was smaller, and the consumption of organic solvent was lower.     

Two New Lignans from Phryma leptostachya L.

Haedoxancoside A ( 1 ), a new sesquilignan glycoside, and phrymarolin V ( 2 ), a new lignan, together with two known compounds, were isolated from Phryma leptostachya L. Their structures were determined on the basis of comprehensive spectroscopic analysis, mainly 1D‐ and 2D‐NMR spectroscopy as well as mass spectrometry. This is the first report of a sesquilignan glycoside isolated from a species of the Phrymaceae family.     

Identification and quantification of lignans in wheat bran by gas chromatography-electron capture detection

Whole grain cereals are an important source of bioavailable lignans, the group of compounds with potential anti-cancerogenic, antioxidant, anti-proliferative, pro-apoptotic, and antiangiogenic properties. The aim of this work was to develop a sensitive method for determination of wheat bran lignans. The analysis of lignans secoisolariciresinol, hydroxymatairesinol, lariciresinol, matairesinol, pinoresinol, syringaresinol is based on derivatization with pentafluoropropionic anhydride (PFPA) and gas chromatography-electron capture detection (GC-ECD), using styrene glycol as internal standard. To our knowledge, this is the first time that EC detection has been used for lignan analysis. The results show that the technique is reproducible and sensitive enough for detecting lignans in wheat at parts-per-billion (ppb) levels, except for hydroxymatairesinol. The method developed showed good recovery (85-105%) and precision (4-20%) for five types of lignans and thus represents a simpler and more affordable alternative to state-of-the-art wheat lignan liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis.     

Two novel polycyclic spiro lignans from Gymnotheca involucrata

Two novel lignans, gymnothespirolignans A (1) and B (2), possessing a rare polycyclic spiro skeleton, were isolated from the endemic plant of Gymnotheca involucrata Pei. Their structures were determined by spectroscopic evidences and the absolute configurations were confirmed by single crystal X-ray diffraction analysis. Compounds 1 and 2 showed promising antiviral activities against RSV with an IC₅₀ value of 31.87 and 17.51 μM, respectively.     

Transformations of lignans. Part 10: Acid-catalysed rearrangements of arboreol and wodeshiol and conversion of gmelanone oxime into a dihydropyranone derivative

The synthesis of gmelanone 2 by a pinacol-type rearrangement of arboreol 1 supports its biogenesis and confirms its relative and absolute configuration. The further transformation of gmelanone oxime 12 into the dihydropyranone oxime 13 supports the intermediacy of gmelanone like intermediates in the rearrangements of furofuran lignans to pyran derivatives. In contrast, acid-catalysed rearrangement of wodeshiol 7 affords the dihydropyranone 8.     

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.     

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.