Cadinane Sesquiterpene Research Articles

Terpenoids from the tuber of Cremastra appendiculata

Two new terpenoids including a cadinane sesquiterpene (1), and an ent-kaurane diterpene diglycoside (2), together with a known triterpene containing 32 carbons (3), have been isolated from the ethanolic extract of Cremastra appendiculata. Their structures were established by the spectroscopic methods including the IR, MS, 1D-, and 2D-NMR experiments as ( − )-cadin-4,10(15)-dien-11-oic acid (1), ( − )-ent-12β-hydroxykaur-16-en-19-oic acid, 19-O-β-d-xylopyranosyl-(1 → 6)-O-β-d-glucopyranoside (2), and (+)-24,24-dimethyl-25,32-cyclo-5α-lanosta-9(11)-en-3β-ol (3). Compounds 1–3 were evaluated against several human cancer cell lines. Compound 3 showed in vitro-selective cytotoxicity against human breast cancer cell lines (MCF-7) with an IC50 of 3.18 μM, but 1 and 2 were inactive (IC50>10 μg/ml).

Germacrene D cyclization: an Ab initio investigation.

Essential oils that contain large concentrations of germacrene D are typically accompanied by cadinane sesquiterpenoids. The acid-catalyzed cyclization of germacrene D to give cadinane and selinane sesquiterpenes has been computationally investigated using both density functional (B3LYP/6-31G(*)) and post Hartree-Fock (MP2/6-31G(* *)) ab initio methods. The calculated energies are in general agreement with experimentally observed product distributions, both from acid-catalyzed cyclizations as well as distribution of the compounds in essential oils.

Structure and Absolute Configuration of Clerodane Diterpene Glycosides and a Rearranged Cadinane Sesquiterpene Glycoside from the Stems of Tinospora sinensis

Three new clerodane diterpene glycosides, tinosposinensides A-C ( 1- 3), and a new rearranged cadinane sesquiterpene glycoside, tinosinenside ( 4), were isolated from the stems of Tinospora sinensis. The structure including the relative configuration was elucidated on the basis of spectroscopic analysis. The absolute configuration was determined by application of the modified Mosher's method and chemical transformation. The inhibitory activities of the isolated compounds against alpha-glucosidase are also described.

A New Cadinane Sesquiterpene with Significant anti‐HIV‐1 Activity from the Cultures of the Basidiomycete Tyromyces chioneus.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

Three New Cadinene Derivatives from Xenia Puerto‐Galerae

AbstractChromatographic investigation of an acetone extract of the octocoral Xenia puerto‐galerae afforded three new cadinene sesquiterpenes; 8‐epi‐xenitorin A (1), 10‐epi‐xenitorin C (2), and 7‐isopropenyl‐4,10‐dimethyl‐2,3,4,5‐tetrahydronaphthalene (3), in addition to four known cadinene analogs (4, 11–13) and six xenicanes (5–10). The structures were elucidated through spectroscopic analysis, especially 2D NMR. A biogenetic pathway of 1–3 and analogs was proposed.

In vivo transformations of artemisinic acid in Artemisia annua plants

Artemisinic acid labeled with both 13C and 2H at the 15-position has been fed to intact plants of Artemisia annua via the cut stem, and its in vivo transformations studied by 1D- and 2D-NMR spectroscopy. Seven labeled metabolites have been isolated, all of which are known as natural products from this species. The transformations of artemisinic acid—as observed both for a group of plants, which was kept alive by hydroponic administration of water and for a group, which was allowed to die by desiccation—closely paralleled those, which have been recently described for its 11,13-dihydro analog, dihydroartemisinic acid. It seems likely therefore that similar mechanisms, involving spontaneous autoxidation of the Δ 4,5 double bond in both artemisinic acid and dihydroartemisinic acid and subsequent rearrangements of the resultant allylic hydroperoxides, may be involved in the biological transformations, which are undergone by both compounds. All of the sesquiterpene metabolites, which were obtained from in vivo transformations of artemisinic acid retained their unsaturation at the 11,13-position, and there was no evidence for conversion into any 11,13-dihydro metabolite, including artemisinin, the antimalarial drug, which is produced by A. annua. This observation led to the proposal of a unified biosynthetic scheme, which accounts for the biogenesis of many of the amorphane and cadinane sesquiterpenes that have been isolated as natural products from A. annua. In this scheme, there is a bifurcation in the biosynthetic pathway starting from amorpha-4,11-diene leading to either artemisinic acid or dihydroartemisinic acid; these two committed precursors are then, respectively, the parents for the two large families of highly oxygenated 11,13-dehydro and 11,13-dihydro sesquiterpene metabolites, which are known from this species.

A New Cadinane Sesquiterpene with Significant Anti-HIV-1 Activity from the Cultures of the Basidiomycete Tyromyces chioneus

A new cadinane sesquiterpene (4beta,14-dihydroxy-6alpha,7betaH-1(10)-cadinene, 1) was isolated from the cultures of the basidiomycete, Tyromyces chioneus. Its structure was established on the basis of spectral measurements (MS, IR, 1D and 2D NMR experiments). 1 showed significant anti-HIV-1 activity with EC50=3.0 microg/ml (SI=25.4).

Cadinane sesquiterpenoids of Phomopsis cassiae, an endophytic fungus associated with Cassia spectabilis (Leguminosae)

Five cadinane sesquiterpenes derivatives were isolated by bioassay-guided fractionation from Phomopis cassiae, an endophytic fungus isolated from Cassia spectabilis. The structures of the two diastereoisomeric 3,9,12-trihydroxycalamenenes ( 1, 2); 3,12-dihydroxycalamenene ( 3); 3,12-dihydroxycadalene ( 4) and 3,11,12-trihydroxycadalene ( 5) were established on the basis of analyses of 1D and 2D NMR and HRTOFMS experiments. Antifungal activity of the isolates was evaluated against Cladosporium sphaerospermum and Cladosporium cladosporioides, revealing 5 as the most active compound.

Xenicane-Type Diterpenes with Cytotoxicity from Xenia florida

Chromatographic investigation of an acetone extract of the octocoral Xenia florida afforded three new xenicane diterpenes, namely, florxenilide A (1), florxenilide B (2), and florxenilide C (3), in addition to seven known xenicane diterpenes and two known cadinene sesquiterpenes. Structures were elucidated through spectroscopic analysis, especially 2D NMR, and chemical derivatization. The absolute configuration of 1 was determined by NOESY, CD, and Mosher's methods. Florxenilides A (1) and B (2) exhibited cytotoxicity against human colon cancer (WiDr) cells at 4.5 and 3.7 muM, respectively.

Novel Cadinane and Norcadinane Sesquiterpenes and a New Propanoate fromGoldfussia psilostachys

Three new compounds, goldfussins A (1) and B (2) and goldfussinol (3), and sixteen known compounds were isolated from the ethanolic extract of the whole plants of Goldfussia psilostachys. The structures of the new compounds were elucidated as a novel cadinane sesquiterpene, 1,8-dimethyl-5-hydroxymethyl-9-oxo-6,7,8,9-tetrahydronaphtho[2,1- b]furan (1), a novel norcadinane sesquiterpene, 4-acetyl-3-hydroxy-1-hydroxymethyl-6-methyl-5-oxo-5,6,7,8-tetrahydronaphthalene (2) and methyl 3-hydroxy-2-(3,5-dimethoxy-4-hydroxyphenyl)-propanoate (3) on the basis of spectral data.

In vivo transformations of dihydroartemisinic acid in Artemisia annua plants

[15- 13C 2H 3]-dihydroartemisinic acid ( 2a ) and [15-C 2H 3]-dihydroartemisinic acid ( 2b ) have been fed via the root to intact Artemisia annua plants and their transformations studied in vivo by one-dimensional 2H NMR spectroscopy and two-dimensional 13C– 2H correlation NMR spectroscopy ( 13C– 2H COSY). Labelled dihydroartemisinic acid was transformed into 16 12-carboxy-amorphane and cadinane sesquiterpenes within a few days in the aerial parts of A. annua, although transformations in the root were much slower and more limited. Fifteen of these 16 metabolites have been reported previously as natural products from A. annua. Evidence is presented that the first step in the transformation of dihydroartemisinic acid in vivo is the formation of allylic hydroperoxides by the reaction of molecular oxygen with the Δ 4,5-double bond in this compound. The origin of all 16 secondary metabolites might then be explained by the known further reactions of such hydroperoxides. The qualitative pattern for the transformations of dihydroartemisinic acid in vivo was essentially unaltered when a comparison was made between plants, which had been kept alive and plants which were allowed to die after feeding of the labelled precursor. This, coupled with the observation that the pattern of transformations of 2 in vivo demonstrated very close parallels with the spontaneous autoxidation chemistry for 2 , which we have recently demonstrated in vitro, has lead us to conclude that the main ‘metabolic route’ for dihydroartemisinic acid in A. annua involves its spontaneous autoxidation and the subsequent spontaneous reactions of allylic hydroperoxides which are derived from 2 . There may be no need to invoke the participation of enzymes in any of the later biogenetic steps leading to all 16 of the labelled 11,13-dihydro-amorphane sesquiterpenes which are found in A. annua as natural products.

Bioactive terpenes from the soft coral Heteroxenia sp. from Mindoro, Philippines.

A marine soft coral species of the genus Heteroxenia collected from Mindoro Island, Philippines yielded two cadinene sesquiterpenes, (+)-alpha-muurolene (1) and a novel derivative (+)-6-hydroxy-alpha-muurolene (2), as well as the biologically active polyhydroxysterol, sarcoaldosterol A (3). The structure of the novel compound was unambiguously established on the basis of NMR spectroscopic (1H, 13C, COSY, 1H-detected direct and long range 13C-1H correlations) and mass spectrometric (EIMS) data. All compounds were active against the phytopathogenic fungus Cladosporium cucumerinum. The isolated terpenes were also active in the brine shrimp lethality test.

Three sesquiterpenes from Artemisia annua

The dried leaves of Artemisia annua, collected from Sichuan Province in Southern China, have yielded an unusual cadinane sesquiterpene oxygenated at the 7-position and a novel eudesmane sesquiterpene, in addition to several known sesquiterpenes and flavanoids.

A novel endoperoxide and related sesquiterpenes from Artemisia annua which are possibly derived from allylic hydroperoxides

Seven novel cadinane sesquiterpenes, including the seven-membered endoperoxide lactone arteannuin H ( 1), two six-membered lactones arteannuins I ( 4) and J ( 5), three five-membered lactones arteannuins K-M ( 6–8) and a keto acid arteannuin N ( 9) have been isolated from the dried leaves of Artemisia annua in addition to the known compounds dihydroartemisinic acid ( 27), dihydroarteannuin B ( 24) and dihydro- epi-deoxyarteannuin B ( 22). It is proposed that these novel sesquiterpenes are biogenetically related to dihydroartemisinic acid via intermediate secondary and tertiary allylic hydroperoxides.

Tinocordiside, a New Rearranged Cadinane Sesquiterpene Glycoside from Tinospora cordifolia

A rearranged cadinane sesquiterpene glycoside named tinocordiside (1), consisting of a tricyclic skeleton with a cyclobutane ring, has been isolated from the immunomodulatory aqueous fraction of the Indian medicinal plant Tinospora cordifolia. The structure has been established by spectroscopic and chemical methods.

Ganomastenols A, B, C and D, cadinene sesquiterpenes, from Ganoderma mastoporum

Four new cadinene sesquiterpenes, named ganomastenols A-D, have been isolated from the cultured mycelia and its broth of Ganoderma mastoporum. Their structures were elucidated by spectral data.

Intramolecular Diels-Alder approach to cadinane and amorphane sesquiterpenes

A synthetic route to both cadinane and amorphane type sesquiterpenes is described. Successful implementation of this route showed the structures previously considered for cadinenal and dehydrocadinenal to be incorrect, but confirmed both the relative and absolute configurations proposed for pernetic acid C and pernetic acid B

Carbocyclic synthesis via boranes: stereochemical implications of boron annulation

Boron annulation, hydroboration-carbonylation, of substituted 1,5,9-decatrienes was utilized to prepare the cadinane sesquiterpene system. Stereochemical aspects of the triene hydroboration process and the carbonylation reaction have been analyzed through glc separation of boronate esters. Structural assignments for these esters and their oxidation (H 2O 2/NaOH) products were made through high field 1H-NMR and other physical and spectral considerations.

Syntheses of cadinanes. Synthetic correlation of absolute configuration between the cadinane sesquiterpenes and monoterpenes of the [formula omitted]-menthane series

Syntheses of cadinanes. Synthetic correlation of absolute configuration between the cadinane sesquiterpenes and monoterpenes of the [formula omitted]-menthane series