Diterpenoids from the Wood of Cunninghamia konishii

Investigation of the wood of Cunninghamia konishii resulted in the isolation and characterization of one new abietane diterpenoid, (6α,7β)‐7,8‐epoxy‐6‐hydroxyabieta‐9(11),13‐dien‐12‐one ( 1 ), and two new labdane diterpenoids, (12R)‐12‐hydroxylabda‐8(17),13(16),14‐trien‐19‐oic acid ( 2 ) and (12R)‐12‐hydroxylabda‐8(17),13(16),14‐trien‐18‐oic acid ( 3 ). The structures of these new compounds were elucidated by analysis of their spectroscopic data.     

New Labdane‐Type Diterpenoids from Amentotaxus argotaenia

A new labdane diterpene, amentotaxin A ( 1 ), and an unprecedented dinorlabdane diterpene, amentotaxin B ( 2 ), were isolated from the stems of Amentotaxus argotaenia (Hance) Pilger , together with seven known compounds. Their structures were identified by in‐depth spectroscopic and mass‐spectrometric analyses.     

New Labdane‐Type Diterpenoids from Leonurus heterophyllus

Chemical investigation of the aerial part of Leonurus heterophyllus led to the isolation and characterization of the seven labdane‐type diterpenoids 1 – 7 , including six new ones, 1 – 6 . Compounds 4 and 5 were isolated as a C(15) epimer pair. The determination of the structures and relative configurations of the new compounds were mainly based on 1D‐ and 2D‐NMR spectroscopic methods, and comparison of their NMR data with related compounds. The structure of compound 7 was confirmed by X‐ray crystallographic analysis.     

Isomeric ent‐Labdane‐Type Diterpenoids from the Stems of Rhizophora mucronata

Two new constitutional isomers of ent‐labdane‐type diterpenoids, 1 and 2 , with an unusual seven‐membered lactone moiety (i.e., 1 ), together with two known compounds, 3 and 4 , were isolated from the acetone extract of Rhizophora mucronata. Their structures were elucidated as rhizomucronol A and B ( 1 and 2 , resp.) by spectroscopic analyses and chemical evidence. The absolute configuration of 2 was established by applying the Mosher ester procedure.     

Nine New ent‐Labdane Diterpenoids from the Aerial Parts of Andrographis paniculata

Nine new ent‐labdane‐type diterpenoids ( 1 – 9 ), mostly in the form of the corresponding 16,15‐lactones, were isolated from the 85%‐EtOH extract of the aerial parts of Andrographis paniculata Nees. , together with nine known compounds ( 10 – 18 ). Their structures were deduced by in‐depth NMR spectroscopy and high‐resolution mass spectrometry.     

Bisyinshanic Acids A and B,Two Novel Diterpene Dimers from the Roots of Euphorbia yinshanica

Two novel diterpene dimers with a bismagdalenic acid skeleton, bisyinshanic acids A and B ( 1 and 2 , resp.), along with eight known diterpenoids ( 3 – 10 ), were isolated from the roots of Euphorbia yinshanica. Their structures were elucidated on the basis of spectroscopic evidence.     

Two New Rosane‐Type Diterpenoids from Euphorbia ebracteolata Hayata

Two new diterpeniods, euphebracteolatins A and B ( 1 and 2 , resp.) were isolated from Euphorbia ebracteolata Hayata , along with two known ones (3R)‐ent‐rosa‐1(10),15‐dien‐3α‐ol ( 3 ) and yuexiandajisu D ( 4 ). The structures were established by extensive spectroscopic analyses and comparison with literature data.     

Flavonol Glycosides with α‐Glucosidase Inhibitory Activities and New Flavone C‐Diosides from the Leaves of Machilus konishii

Seventeen flavonoids, five of which are flavone C‐diosides, 1 – 5 , were isolated from the BuOH‐ and AcOEt‐soluble fractions of the leaf extract of Machilus konishii. Among 1 – 5 , apigenin 6‐C‐β‐D ‐xylopyranosyl‐2″‐O‐β‐D ‐glucopyranoside ( 2 ), apigenin 8‐C‐α‐L ‐arabinopyranosyl‐2″‐O‐β‐D ‐glucopyranoside ( 4 ), and apigenin 8‐C‐β‐D ‐xylopyranosyl‐2″‐O‐β‐D ‐glucopyranoside ( 5 ) are new. Both 4 and 5 are present as rotamer pairs. The structures of the new compounds were elucidated on the basis of NMR‐spectroscopic analyses and MS data. In addition, the ¹H‐ and ¹³C‐NMR data of apigenin 6‐C‐α‐L ‐arabinopyranosyl‐2″‐O‐β‐D ‐glucopyranoside ( 3 ) were assigned for the first time. The isolated compounds were assayed against α‐glucosidase (type IV from Bacillus stearothermophilus). Kaempferol 3‐O‐(2‐β‐D ‐apiofuranosyl)‐α‐L ‐rhamnopyranoside ( 12 ) was found to possess the best inhibitory activity with an IC₅₀ value of 29.3 μM .     

Labdane-type diterpenoids from the wood of Cunninghamia konishii

Five new labdane-type diterpenes, 12beta,19-dihydroxymanoyl oxide (1), 8(17),13-labdadien-12,15-olid-19-oic acid (2), 12,15-epoxy-8(17),13-labdadien-18-oic acid (3), 8alpha-hydroxy-11E,13Z-labdadien-15-al (4), and (13R)-13-hydroxy-8(17), 11E,14-labdatrien-18-oic acid (5) were isolated from the wood of Cunninghamia konishii. Their structures were elucidated by two-dimensional NMR spectroscopy.     

柔软肉芝软珊瑚中的新二萜内酯

肉芝软珊瑚Sarcophytum是珊瑚纲,八放珊瑚亚纲,软珊瑚目中的一个属,软珊瑚肉质柔软而不被海洋中的动物所吞食,这被认为是与其次生代谢产物中含有能驱赶其它生物的化学防御物质有关,从而引起了化学家和药物学家的重视^[1,2],例如从乳白肉芝软珊瑚Sarcophytum glaucum和第氏肉芝办珊瑚Sarcophyton decasyi中均分离得到细胞毒活性相当强的二萜内脂Sarcophine^[3-5],Bernstein^[3]认为这类物质可能是软珊瑚的化学防御物质之一,最近我们在研究柔软肉芝软珊瑚Sarcophyton molle Tix.Dur.的次生代谢产物过程中,分离到两个在生源上与Sarcophine有密切关系的二萜内酯 Sarcophinone(1)^[6,7]和iso-Sarcophinone(2),其中2是新化合物。体外的生理活性试验显示,化合物1和2对艾氏腹水瘤细胞和水鼠S180肿瘤细胞均有显著抑制作用,本文报道了Sarcophinone(1)和iso-Sarcophinone(2)的分离和结构测定。     

Oligoepicatechins from the Leaves of Machilus konishii

Epicatechin ( 3 ) and five oligomers ( 2 , 4 , 5 , 10 , 11 ) together with five other type compounds were isolated and characterized from n‐BuOH and EtOAc soluble fractions of the ethanol extract of the leaves of Machilus konishii Hayata. Their structures were elucidated by means of MS and NMR spectroscopic analyses. Dehydrodiepicatechin A ( 11 ) is the first occurrence as a natural product although it has been prepared from epicatechin. The stereochemistry of 11 is elucidated for the first time on the basis of 1D NOESY and chemical model analyses. Tiliroside ( 7 ) and kaempferol 3‐O‐α‐L‐(2″,4″‐di‐E‐p‐coumaroyl)‐rhamnopyranoside ( 8 ) showed moderate inhibitory activity against α‐glucosidase.     

A New Bislabdane-type Diterpenoid from Cunninghamia lanceolata

Cunninghmia lanceolata Hook. is a traditional Chinese medicine used for thetreatment of hernia, arthritis and strangury. its chemical constituents have beenexamined]' 2' 3' '. In a previous paper we reported a bislabdane-type diterpenoidlanceolatic acid from the roots of the plant 5. Further chemical studies on this plantled to the isolation of another new bislabdane-type diterpenoid, named lanceolatin(I ).Compound I was obtained as white amorphous powder. mp 232-234 'C, [a]."-24 (c 0. 10, C…     

New Acyclic 12‐Hydroxygeranylgeraniol‐Derived Diterpenoids from the Seeds of Carpesium triste

Five new acyclic 12‐hydroxygeranylgeraniol‐derived diterpenoids, i.e., 1 – 5 , were isolated from the seeds of Carpesium triste. The structures including the absolute configurations of the new compounds were elucidated by spectroscopic methods. All the compounds, except for 2 , were evaluated for their in vitro cytotoxic activity against cultured SMMC‐7721 (human hepatoma), HL‐60 (human promyelocytic leukemia), and L02 (human hepatocyte) cells.     

Cassane‐Type Diterpenoids from the Seeds of Caesalpinia magnifoliolata

Two novel cassane‐type diterpenes, named magnicaesalpin ( 1 ) and neocaesalpin O ( 2 ), together with three known compounds, caesalmin D ( 3 ), caesalmin E ( 4 ), and neocaesalpin L ( 5 ), were isolated from the MeOH extract of seeds of Caesalpinia magnifoliolata Metc . Their structures were determined by spectroscopic methods, (1D‐ and 2D‐NMR, HR‐EI‐MS) and X‐ray analysis, as well as by comparison of their spectral data with those of related compounds.     

10β‐Acetoxy‐8α,9α‐epoxy‐14β‐hydroxy‐7‐oxodolastane – A New Diterpene Isolated from the Brazilian Brown Macroalga Canistrocarpus cervicornis

Chemical investigation on the nonpolar extract of the Brazilian brown alga Canistrocarpus cervicornis (Dictyotaceae) has led to the isolation of a new diterpene 1 and four known seco‐dolastane diterpenes 2 – 5 . Their chemical structures were elucidated by 1D‐ and 2D‐NMR spectroscopy, and the data was compared with the literature. A full X‐ray diffraction analysis confirmed the absolute configuration of 1 .     

Two ent‐Kaurane Diterpenoids from Rubus corchorifolius L. f.

A further chemical investigation of the plant Rubus corchorifolius L. f., collected in Hunan Province, afforded two new ent‐kauranoids 6 and 7 . Their structures were elucidated by various spectroscopic methods.     

Caesaljaponins A and B: New Cassane‐Type Furanoditerpenoids from the Seeds of Caesalpinia decapetala var. japonica

Two new cassane‐type furanoditerpenoids, designated caesaljaponin A and caesaljaponin B ( 1 and 2 , resp.), were isolated from seeds of Caesalpinia decapetala var. japonica. The structures were elucidated by spectroscopic data, and the absolute configuration of 1 was determined by X‐ray crystallographic analysis using the anomalous scattering of CuK_α radiation.     

New Verticillane‐Type Diterpenoids from the Taiwanese Soft Coral Cespitularia hypotentaculata

Investigation of the MeOH/CH₂Cl₂ extract of the soft coral Cespitularia hypotentaculata collected in Taiwan has resulted in the isolation of four new verticillane‐type diterpenoids, cespihypotins M–P ( 1 – 4 ). Compounds 2 and 3 are C(20)‐epimers. Compound 4 with a C?O group at C(10) and a methoxycarbonyl group at C(12) may be an important precursor of cespitularins and cespihypotins. The structures of these compounds were determined on the basis of spectroscopic analyses.