Showing papers on "Diterpene published in 1985"
TL;DR: Two new diterpenes, (13 E )-labd-13-ene-3β,8α,15-triol and (13E )-3α-8α-dihydroxylabd- 13-en-15-oic acid have been isolated from an unclassified Acacia sp.
47 citations
TL;DR: Five new o -naphthaquinone diterpenes, tanshindiol A, t Hanshinone C, nortanshin one and 3α-hydroxytanshinone IIA, have been isolated from the roots of Salvia miltiorrhiza as minor components.
44 citations
TL;DR: The structures 1-5 of the individual daphnane type irritant EXCOECARIA factors were elucidated by spectroscopic means and their irritant activities were determined quantitatively on the mouse ear.
Abstract: From leaves of E. OPPOSITIFOLIA the irritant EXCOECARIA factor O (1) was isolated. Its structure 1 was shown to be identical with that of a factor obtained by transesterification of the cryptic EXCOECARIA factor group O (')(z) from the latex of the plant. From the non-irritant ethyl acetate fractions of the latices of E. AGALLOCHA, E. OPPOSITIFOLIA and E. BICOLOR, three TLC-homogenous non-irritant mixtures A (')(z), O (')(z) and B (')(z) were isolated and shown to represent non-separable cryptic EXCOECARIA factor groups containing 9,13,14-orthoesters of 5beta-hydroxyresiniferonol esterified in 20-position. The mixtures may be activated by mild treatment with sodium methoxide to generate mixtures of highly irritant factor groups A (z), O (z) and B (z) together with mixtures of aliphatic acid methylesters. The former may be separated partially by reversed phase TLC and yielded EXCOECARIA factors O (1), O (2), A (3), B (3) and B (4) together with residual non-separable factor groups. The structures 1-5 of the individual daphnane type irritant EXCOECARIA factors were elucidated by spectroscopic means. Their irritant activities were determined quantitatively on the mouse ear. The mixtures of methyl esters of aliphatic acids were analyzed by GC. Thus the complete structures of the cryptic factor groups from latex were deduced.
43 citations
TL;DR: Chemical investigations of two new species of Udotea, reinvestigation of Tydemania expeditionis and Chlorodesmis fastigiata, as well as studies of Caulerpa brownii, have led to the isolation of four new related diterpenoids and several previously described metabolites.
39 citations
TL;DR: Comparison of structures and biological activities of 12,13-diesters of 4-deoxyphorbol of Euphorbia factors isolated indicates that - for a distinct total number of C-atoms in the acyl moiety - an increasing number of conjugated double bonds may increase the irritant but decrease the tumor-promoting activity.
Abstract: The irritant and tumor-promoting constituents of latex of Euphorbia tirucalli L. originating from South Africa were isolated. They were identified as irritant ingenane and tigliane type diterpene esters derived from unsaturated aliphatic acids and acetic acid and the polyfunctional diterpene parent alcohols 4-deoxyphorbol, phorbol and ingenol, respectively. The irritant and tumor-promoting esters of 4-deoxyphorbol are predominant and were fully characterized chemically and biologically. They are positionally isomeric 12,13-acylates, acetates e.g. Euphorbiafactors Ti1-Ti4. As acyl groups they carry homologous, highly unsaturated aliphatic acids of the general structure CH3-(CH2)m-(CH = CH)n-COOH (m = 2,4; n = 1,2, 3,4,5; N = 2n + m + 2). Corresponding diesters of 4-deoxy-4 alpha-phorbol are also present which are biologically inactive. Comparison of structures and biological activities of 12,13-diesters of 4-deoxyphorbol indicates that--for a distinct total number of C-atoms (N) in the acyl moiety--an increasing number of conjugated double bonds (n) may increase the irritant but decrease the tumor-promoting activity. Replacement of the hydroxyl function at C-4 (phorbol-12,13-diesters) by hydrogen (corresponding 4-deoxyphorbol-12,13-diesters) does not essentially alter biological activities. Epimerization of 4-deoxyphorbol-12,13-diesters at C-4 abolishes biological activities. The specific chemical properties demonstrated for the diterpene ester irritants contained in the latex of E. tirucalli and hence in all plant parts may be useful in trials to abolish the potential risk of cancer involved especially in occupational mass production and handling of the plant. Some of the structure activity relations of the Euphorbia factors isolated made them excellent tools in experimental cancer research for the analysis of mechanisms of tumorigenesis.
38 citations
TL;DR: Tetracyclic diterpene hydrocarbons containing the kaurane, phulocladane (13β-kaurane), and beyerane skeletons have been identified in some Australian petroleums and sediment extracts; these compounds are useful biological markers for higher plants.
Abstract: Tetracyclic diterpene hydrocarbons containing the kaurane, phulocladane (13β-kaurane), and beyerane skeletons have been identified in some Australian petroleums and sediment extracts; these compounds are useful biological markers for higher plants.
36 citations
TL;DR: By means of partition and preparative TLC, two pro-inflammatory diterpene esters were isolated from Euphorbia peplus and the new ester ingenol 20- O -octanoate exhibited an ID 50 of 1.0 μg also on mice skin.
35 citations
TL;DR: One new furanoheliangolide derivative is isolated from a Texas population of Helianthus annuus, and three previously characterized diterpene acids, grandifloric acid, ciliaric acid and 17-hydroxy-ent-isokaur-15(16)-en-19-oic acid were the principal constituents of this population.
34 citations
TL;DR: The diterpene rosmanol, previously isolated from Rosmarinus officinalis, has been isolated from the flowers of Salvia canariensis and its structure revised as 7α, 11,12-trihydroxyabieta-8,11,13-trien-20-oic acid 20,6-lactone, on the basis of chemical evidence and an X-ray diffraction analysis as mentioned in this paper.
27 citations
TL;DR: From the marine sponge Spongionella gracilis, a degraded C19 terpene diacetate (2 ) has been isolated and its structure elucidated by spectral analysis, including 2D-NMR, and chemical evidence.
25 citations
TL;DR: An alcoholic extract of Diarthron vesiculosum seed has yielded two novel daphnane diterpene esters, vesICulosin and isovesicULosin, which apparently are biosynthetic precursors of 3.
Abstract: An alcoholic extract of Diarthron vesiculosum seed has yielded two novel daphnane diterpene esters, vesiculosin and isovesiculosin. Compounds 1 and 2 undergo rapid interconversion to an equilibrium mixture containing approximately 80% 1 and 20% 2 in solution at elevated temperatures. At 25 degrees or below, 1 and 2 may be isolated and stored for extended periods with minimal interconversion. Excoecariatoxin and simplexin are the major daphnane orthoesters present in D. vesiculosum, and 1 and 2 apparently are biosynthetic precursors of 3. Isolation of these compounds was monitored by bioassay against PS leukemia (in vivo), and structures were determined by 1H nmr, 13C nmr, ms, and comparison with known compounds.
TL;DR: In this paper, the stem bark of Xylopia acutiflora yielded a dimeric diterpene derived via Diels-Alder condensation of kaurene and labdane monomers.
TL;DR: The chloroform extract of the aerial parts of Mikania congesta, afforded four new geranylnerol derivatives, new analogs of deoxyelephantopin, a new melampolide and several known compounds.
TL;DR: In this paper, five new toxic diterpenes, euphohelins A, B, C, D, and E, have been isolated from the plant Euphorbia helioscopia L, and their stereostructures have also been elucidated on the basis of their spectral data coupled with some chemical evidence.
Abstract: Five new toxic diterpenes, euphohelins A, B, C, D, and E, have been isolated from the plant Euphorbia helioscopia L., and their stereostructures have also been elucidated on the basis of their spectral data coupled with some chemical evidence: euphornin, the known toxic diterpene, has been successfully converted into euphohelin A.
TL;DR: The structure and stereochemistry of phlogantholide-A, a new diterpene lactone isolated from the leaves of Phlogacanthus thyrsiflorus has been determined as 2β,15,18-trihydroxy- ent -labd-8(17),13dien-16-oic lactone by chemical and spectroscopic means as mentioned in this paper.
TL;DR: Cinncasiol E, a hexacyclic diterpene of a new skeletal type, was isolated from a fraction with antiallergic activity obtained from a water extract of Cinnamomi cortex.
TL;DR: Thirteen new labdane-type diterpenes have been isolated from the seeds of Sciadopitys verticillata together with six known ones, sciadin, Sciadinone, dimethyl sciadinonate, lambertianic acid and its methyl ester and trans-communic acid.
TL;DR: The title diterpene, a rare example of the naturally occurring ent-atis-13-ene type, has been isolated as the 2-benzylidene derivative from the heartwood hexane extract of Androstachys johnsonii Prain this article.
Abstract: The title diterpene, a rare example of the naturally occurring ent-atis-13-ene type, has been isolated as the 2-benzylidene derivative from the heartwood hexane extract of Androstachys johnsonii Prain. Its structure was determined by n.m.r. and X-ray crystallography. It is suggested that the title compound is biogenetically produced from an ent-12-oxybeyer-15-ene precursor. An interesting reaction reported here was found to convert a vicinal diol into a monoketone using the diethyl azodicarboxylate–triphenylphosphine–benzoic acid system.
TL;DR: In this article, three diterpene acids, representing a new class of bicyclic diterpenes, have been isolated from Bertya dimerostigma F. Muell.
TL;DR: The new clerodane diterpene 1 was isolated from the aerial parts of Baccharis tucumanensis (Compositae) and its structure has been determined from spectral data combined with chemical transformations.
TL;DR: The aerial parts of two collections of Mikania periplocifolia gave, in addition to mikanolide, miscandenin and several other known sesquiterpene dilactones related to them, the new dilactone 3β-hydroxy-11βH,13-dihydroisabelin, 11βH and mikaperiplocolide and three new geranylnerol derivatives.
TL;DR: In this paper, a diterpene acid related to erythroxydiol Z was isolated by NMR techniques and its structure was elucidated by NER techniques.
TL;DR: The structure of a new diterpene, also isolated from Eremophila fraseri, has been determined by X-ray crystallographic methods as discussed by the authors, which incorporates a tricyclo[6.2.1.5]undecane ring system.
Abstract: The resin components of different collections of the highly variable Eremophila fraseri F. Muell. Have been examined. Five new eremane diterpene acids have been characterized and evidence for their structures is presented. The structure of a new diterpene, also isolated from E. fraseri, has been determined by X-ray crystallographic methods. The carbon skeleton of this new diterpene incorporates a tricyclo[6.2.1.01,5]undecane ring system.
TL;DR: In this article, the aerial parts of Gutierrezia solbrigii were investigated by high-field 1H NMR spectroscopy, yielding nine new entlabdane derivatives, an aromatic ester and five alicyclic diterpenes.
TL;DR: In this paper, a new isopimarane diterpenoid, isoakhdartriol, was isolated in very small amount from the aerial part of Amaracus akhdarensis.
TL;DR: The structure of a tricyclic diterpene (1) isolated from an unclassified Higginsia sp. has been determined by X-ray crystallographic methods as mentioned in this paper, and the structures of two related co-metabolites have been deduced from a comparison of their spectroscopic properties with those of (1).
Abstract: The structure of a new tricyclic diterpene (1) isolated from an unclassified Higginsia sp. has been determined by X-ray crystallographic methods. The structures of two related co-metabolites have been deduced from a comparison of their spectroscopic properties with those of (1).
TL;DR: A new geranylgeraniol type diterpene, named viguieric acid, was isolated from the dichloromethane extracts of V. deltoidea as mentioned in this paper.
TL;DR: The structure of 2-keto-19-hydroxyteuscordin, (12S)-15,16-epoxy-2-ketoencoderin-neo-clerodane-13(16),14-dien-18β,6β:20,12-diolide, was established by chemical and spectroscopic means as discussed by the authors.
TL;DR: The leaves of Amphibolis antartica from Shark Bay, Western Australia contain a previously unreported cleistanthene hydrocarbon, and other collections of the sea grass near Perth also contained sandaracopimaradiene and isopamaradiene.
TL;DR: The aerial parts of Melampodium leucanthum afforded a novel diterpene-γ-lactone, 1,6,7-trihydroxy-17-acetoxymelcantholide, and two new sesquiter pene dilactones as mentioned in this paper.