A new triterpene and dibenzocyclooctadiene lignans from Schisandra propinqua (WALL.) BAILL

A new triterpene and two new natural dibenzocyclooctadiene lignans were isolated from the stems of Schisandra propinqua. In addition, three known lignans, octadecanoic acid, 2,3-dihydroxypropyl ester and beta-sitosterol were isolated. The structures of the new triterpene and new natural products were elucidated base on spectral analysis, including 1D and 2D NMR experiments. The isolates were tested for their cytotoxic effects against several tumor cell lines by MTT assay.     

满山香中的联苯环辛二烯木脂素

满山香[Schisandra propinqua(Wall.)Hook.f.et Thoms]为五味子科植物,云南民间代五味子药用^[1],由于从五味子科植物中已分离到不少保肝降酶,抗艾滋病毒,抗癌和PAF拮抗等活性成分,其研究受到重视^[2-4],主含满山香根和提取物的复方注射液曾在云南省几所医院临床用于治疗肺癌,但其研究仅分离鉴定了两个三萜 酸([2],为进一步寻找有效成分,我们对满山香茎藤进行了研究,从中分得8种联苯环辛二烯木脂素,经波谱和分析鉴定它们的结构为：acetylgomisin R(1) angeloylgomisin R(2),gomisinA(3),gomisin B(4),gomisinN(5),gomisinO(6),6-O-benzoylgomosin O(7)和Schisantherin A(8),1为新化合物,2系首次从五味子属植物中分得,其它均为首次从满山香中分得。     

The chemical constituents from Schisandra propinqua var intermedia

A new cirmamic acid monoterpenoid ester, intermedin C (1), was isolated from the aerial parts of Schisandra propinqua vat. intermedia. The structure of 1 was elucidated by spectroscopic methods including extensive 1D and 2D NMR techniques.     

神农架地区五味子科植物成分的研究 I: 铁箍散茎和根的化学成分研究

用铁箍散的茎和根中分得六个化合物, 其中一个是新化合物, 命名为表恩施辛(1,epienshicine), 在体外具有抗癌活性. 其结构由光谱分析和化学转化确定为1-氧代-2R, 3S-二甲基-4R-(3-甲氧基-4-羟基苯)-6,7-次甲二氧基四氢萘. 其余五个为已知物, 分别鉴定为恩施辛(2,enshicine),isoschizandrolic acid(3), 去氧五味子素, β-谷甾醇和硬脂酸, 其中3系首次自天然界获得.     

A novel 8.O.6'-neolignan from Taxillus theifer

A new 8.O.6'-neolignan, threo-(7R,?8R)-7-acetoxy-3',4'-dimethoxy-3,4-dimethoxy-Δ-(8')-8.O.6'-neolignan (1) along with two known lignans (2) and (3), was isolated from the leaves and stems of Taxillus theifer. Structural elucidation was carried out by 1-D and 2-D-NMR spectroscopic methods, and the absolute configurations of C-7 and C-8 in 1 were determined on the basis of circular dichroism. Compound 2 is threo-7-acetoxy-3'-methoxy-3,4-dimethoxy-Δ-(7')-8.O.4'-neolignan obtained from a natural source for the first time, previously derived from a synthesis study of 8,4'-oxyneolignans.     

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).     

Heteroclitins N – Q,New Compounds from Stems of Kadsura heteroclita (Roxb.) Craib

From the stems of Kadsura heteroclita (Roxb .) Craib , a new novel C₁₉ homolignan, heteroclitin N ( 1 ), as well as three new lignans, heteroclitins O? Q ( 2 – 4 ), were isolated. Their structures were elucidated based on spectral analysis, including 1D and 2D NMR experiments. There is an additional spirocyclic oxirane system in heteroclitin O ( 2 ), which is the first example of a lignan with an oxirane ring in a spirobenzofuranoid dibenzocyclooctene structure in the genus Kadsura.     

Asymmetric total synthesis of dibenzocyclooctadiene lignan natural products

[structure: see text] Full details of the asymmetric total syntheses of the dibenzocyclooctadiene lignans interiotherin A, angeloylgomisin R, gomisin O, and gomisin E (epigomisin O) are presented. The syntheses were based on a unified synthetic strategy involving a novel crotylation using the Leighton auxiliary that occurred with excellent asymmetric induction (>98:2 enantiomeric ratio), a diastereoselective hydroboration/Suzuki-Miyaura coupling reaction sequence, and an atropdiastereoselective biarylcuprate coupling, both of which occurred with total (>20:1) stereocontrol. The syntheses were achieved in six to eight steps from simple aromatic precursors.     

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.     

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.     

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.     

New lignans from the heartwood of Chamaecyparis obtusa var. formosana

Four new lignans, 3',4'-O,O-demethylenehinokinin (1), chamalignolide (2), 8'beta-hydroxyhinokinin (3) and 7beta,8beta-epoxyzuonin A (4), as well as (-)-hinokinin (5), and (-)-zuonin A (6), were isolated from the heartwood of Chamaecyparis obtusa var. formosana. The structures of these lignans were unambiguously determined by spectroscopic methods. And the absolute configuration of 1 was elucidated with a circular dichroism (CD) spectrum.     

Antioxidant activity of aryltetralone lignans and derivatives from Virola sebifera (Aubl.)

Aryltetralone lignans bearing methylenedioxy groups (1a-b; 2a-b) were isolated from seeds of Virola sebifera. Their antioxidant activities were evaluated by inhibition of lipid peroxidation as indicated by TBARS and chemiluminescence emission (CL) assays. The lignan 1c, 'having a 2'-hydroxy-4',5'-methylenedioxyphenyl group, was the most active compound with TBARS/CL Q 1/2 values of 0.89 and 0.10 microg/mL, respectively. The catechol derivatives 3 and 4, obtained by demethylenation of lignans 1a and 2a, were of similar activity to 1c, and all were much more effective as antioxidants than alpha-tocopherol.     

The anti-HBsAg (human type B hepatitis, surface antigen) and anti-HBeAg (human type B hepatitis, e antigen) C18 dibenzocyclooctadiene lignans from Kadsura matsudai and Schizandra arisanensis

The C(18) dibenzocyclooctadiene lignans including three novel schizanrin F (1), G (2), H (3), along with the known kadsurarin (4), were isolated from Kadsura matsudai. A new C(19) homolignan named schiarisanrin E (5), together with the known C(18) lignans, gomisin B (6), G (7) and (+)-gomisin K(3) (8) were obtained from Schizandra arisanensis. Gomisin B, G and (+)-gomisin K(3) showed moderate to strong activity for antihepatitis in anti-HBsAg (human type B hepatitis, surface antigen) and/or anti-HBeAg (human type B hepatitis, e antigen) tests. The structural elucidations of new compounds 1-3 and 5 were based on two-dimensional (2D) NMR techniques including COSY, HMQC, HMBC, NOESY and CD spectra. Preliminary structure-activity relationship studies for these isolated lignans are also discussed.     

Evaluation of the Antioxidant and Antiradical Properties of Some Phyto and Mammalian Lignans

In this study, the antioxidant and antiradical properties of some phyto lignans (nordihydroguaiaretic acid, secoisolariciresinol, secoisolariciresinol diglycoside, and α-(-)-conidendrin) and mammalian lignans (enterodiol and enterolactone) were examined by different antioxidant assays. For this purpose, radical scavenging activities of phyto and mammalian lignans were realized by 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) radical (ABTS^•+) scavenging assay and 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) scavenging assay. Additionally, the reducing ability of phyto and mammalian lignans were evaluated by cupric ions (Cu²⁺) reducing (CUPRAC) ability, and ferric ions (Fe³⁺) and [Fe³⁺-(TPTZ)2]³⁺ complex reducing (FRAP) abilities. Also, half maximal inhibitory concentration (IC₅₀) values were determined and reported for DPPH^• and ABTS^•+ scavenging influences of all of the lignan molecules. The absorbances of the lignans were found in the range of 0.150–2.320 for Fe³⁺ reducing, in the range of 0.040–2.090 for Cu²⁺ reducing, and in the range of 0.360–1.810 for the FRAP assay. On the other hand, the IC₅₀ values of phyto and mammalian lignans were determined in the ranges of 6.601–932.167 µg/mL for DPPH^• scavenging and 13.007–27.829 µg/mL for ABTS^•+ scavenging. In all of the used bioanalytical methods, phyto lignans, as secondary metabolites in plants, demonstrated considerably higher antioxidant activity compared to that of mammalian lignans. In addition, it was observed that enterodiol and enterolactone exhibited relatively weaker antioxidant activities when compared to phyto lignans or standard antioxidants, including butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA), Trolox, and α-tocopherol.     

Lignans from the Bark of Magnolia kobus

The Et₂O‐soluble fraction from the bark of Magnolia kobus led to the isolation of two new lignans, (+)‐(7α,7′α,8α,8′α)‐3′,4,4′,5,5′‐pentamethoxy‐7,9′: 7′,9‐diepoxylignan‐3‐ol ( 1 ) and (+)‐(7α,7′α,8α,8′α)‐4,5‐dimethoxy‐3′,4′‐(methylenedioxy)‐7,9′: 7′,9‐diepoxylignan‐3‐ol ( 2 ), along with five known lignans 3 – 7 . Their structures were established on the basis of various spectroscopic analyses including 1D‐ (¹H, ¹³C, and DEPT) and 2D‐NMR (COSY, NOESY, HMQC, and HMBC) and by comparison of their spectral data with those of related compounds.     

Three new compounds from Kadsura longipedunculata

Two new tetrahydrofuran lignans, kadlongirins A and B (1, 2), a new cadinane-type sesquiterpenoid, 2,7-dihydroxy-11,12-dehydrocalamenene (3), together with seven known lignans, grandisin, fragransin B1, vladirol F, kadsuralignan C, otobaphenol, isoanwulignan, and 4-[4-(3,4-dimethoxyphenyl)-2,3-dimethylbutyl]-2-methoxy-phenol, were isolated from the leaves and stems of Kadsura longipedunculata. The structures of these new compounds were elucidated by spectroscopic methods. Compound 2 exhibited weak anti-human immunodeficiency virus-1 activity with an EC50 value of 16.0 microg/ml, and therapeutic index (TI) value of 6.7.     

Arylnaphthalide lignans from Cleistanthus collinus

Chemical examination of the aerial parts of Cleistanthus collinus afforded the arylanphthalide lignans, cleistanone (1), diphyllin (2), cleistanthins A (3), C (4) and D (5), and 4-O-(3"-O-methyl-beta-D-glucopyranosyl)-diphyllin (6). The first compound is a new member of the rare group of arylnaphthalide lignans containing an alkoxy group on the lactone ring. The structure of the compound was determined from its spectral data, chemical transformations and partial synthesis from diphyllin (2). The new lignan, 1 and its acetyl derivative, 7 were found to exhibit cytotoxicity against MT(2) cell lines.     

木脂素类化合物的全合成研究

综述了本研究小组近几年在木脂素全合成研究中取得的新进展。主要包括三部分：通过β-酮酸酯偶联反应来合成去甲二氢愈创木酸及多种其它类型木脂素;通过氧化银偶联和DDQ合环首次合成黄酮木脂素(±)-Sinaiticin;通过Sharpless不对称双羟化为关键步骤首次手性合成1,4-苯并二氧六环类新木脂素。     

New seco-dibenzocyclooctadiene lignans with nitric oxide production inhibitory activity from the roots of Kadsura longipedunculata

Four new seco-dibenzocyclooctadiene lignans,kadlongilignans A-D(1-4),consisting of a rare 6,7-seco-(1),two 15,16-seco-(2 and 3) and a 9,10-seco-dibenzocyclooctadiene(4) lignans,were isolated from the roots of Kadsura longipedunculata.Their structures were elucidated by spectroscopic analysis,including extensive NM R,MS and ECD(electronic circular dichroism) spectra.Compounds 3 and 4 exhibited potent inhibitory activities against NO(nitric oxide) production of LPS(lipopolysaccharide)-induced murine macrophages with the inhibition rates of 36.3% and 26.9%,respectively.