Eudesmane Skeleton Research Articles

Insecticidal, antifeedant and acetylcholinesterase inhibitory activity of sesquiterpenoids derived from eudesmane, their molecular docking and QSAR

This work evaluated the insecticidal, antifeedant and AChE inhibitory activity of compounds with eudesmane skeleton. The insecticidal activity was tested against larvae of Drosophila melanogaster and Cydia pomonella, the compounds 3 and 4 were the most active (LC50 of 104.2 and 106.7 μM; 82.0 and 84.4 μM, respectively). Likewise, the mentioned compounds were those that showed the highest acetylcholinesterase inhibitory activity, with IC50 of 0.26 ± 0.016 and 0.77 ± 0.016 μM, respectively. Enzyme kinetic studies, as well as molecular docking, show that the compounds would be non-competitive inhibitors of the enzyme. The antifeedant activity on Plodia interpunctella larvae showed an antifeedant index (AI) of 99% at 72 h for compounds 16, 27 and 20. The QSAR studies show that the properties associated with the polarity of the compounds would be responsible for the biological activities found.

Artemlavanins A and B from Artemisia lavandulaefolia and Their Cytotoxicity Against Hepatic Stellate Cell Line LX2

Two new sesquiterpenoids, artemlavanins A (1) and B (3), together with fifteen known compounds (2 and 4−17) were isolated from the EtOH extract of Artemisia lavandulaefolia. The structures of new compounds were elucidated by extensive spectroscopic analyses (HRESIMS, 1D and 2D NMR) and ECD calculations. Compound 1 was a sesquiterpenoid lactone possessing a rearranged eudesmane skeleton; compounds 2–5, 6–8, 9 and 10–12 belonged to the eudesmane, guaiane, oppositane and farnesane sesquiterpenoids, respectively; compounds 13–17 were the phenyl derivatives with a 4-hydroxyacetophenone moiety. Twelve compounds (1–3, 5–7, 10–12, 14, 15 and 17) displayed cytotoxicity against hepatic stellate cell line LX2 (HSC-LX2) with IC50 values ranging from 35.1 to 370.3 μM. Compounds 2, 7, 10–12 and 17 exhibited the stronger cytotoxicity than silybin (IC50, 169.6 μM) with IC50 values of 82.1, 35.1, 95.0, 83.8, 81.6 and 90.1 μM. Compound 7 as the most active one showed significant inhibition on the deposition of human collagen type I (Col I), human hyaluronic acid (HA) and human laminin (HL) with IC50 values of 10.7, 24.5 and 13.3 μM.Graphic

Growth-inhibitory activity of components in Cryptomeria japonica leaves against Robinia pseudoacacia

ABSTRACT Extracts obtained from Cryptomeria japonica leaves were tested for growth inhibition activity against Robinia pseudoacacia seeds, which is known as a representative invasive plant in temperate forests. Inhibitory activities against radicle and hypocotyl growth were found in hexane and ethyl acetate extracts but showed no or weak activity on seed germination. The extracts also showed inhibitory activity against Trifolium repens as a representative weed. The active extracts were fractionated by silica gel column chromatography and cryptomeridiol was isolated as an active compound. Comparison of activities between cryptomeridiol and β-eudesmol indicated that the diol structure of the eudesmane skeleton was important in causing the inhibitory activities.

Protosalvinia revisited, new evidence for a land plant affinity

The Upper Devonian Protosalvinia phytoclasts from Ohio Shale and its host rock were analyzed using GC/MS, GC-ir/MS, in situ FTIR and pyrolysis–GC/MS, in order to determine its chemical composition and to discuss the taxonomic position of this enigmatic fossil. Based on molecular ratios, the maturity of the organic matter present in the phytoclasts and rocks is comparable to a bituminous rank coal. Diagenetic products of Chlorobiaceae carotenoids were observed in the hosting rocks of Protosalvinia, indicating that anoxia prevailed during the sedimentary deposition. The soluble organic matter of phytoclasts shows land-derived biomarkers including long chain n-alkanes with a slight odd/even predominance and bicyclic sesquiterpenes with eudesmane skeletons. The carbon isotopic composition of n-alkanes is consistent with a land plant origin. The macromolecular fraction of Protosalvinia consists of a condensed aromatic network. The pyrolysis products of the phytoclasts show polycyclic aromatic hydrocarbons commonly observed in coals, including naphthalenes, phenanthrenes and dibenzofurans. Based on what is known about the thermal evolution of organic matter, these components could derive from demethylation and condensation of phenylpropanoids or polysaccharides present in the original structure of Protosalvinia. The former components are exclusively metabolized by land plants.

English

Sesquiterpenes are formed from countless biogenetic pathways and are therefore a constant challenge to spectroscopists in structure elucidation. In this study, we explore the ability of generalized regression neural network (GRNN), an architecture of artificial neural networks (ANNs), to predict the substituent types on eudesmanes, one of the most representative skeletons of sesquiterpenes. Carbon-13 (13C) nuclear magnetic resonance (NMR) chemical shift values of skeletons of 291 eudesmane sesquiterpenes were used as the input data used for the network. Each substituent type on the skeleton of the different compounds were coded and used as the output data for the network. These data were used to train the network. After training, the network was simulated using 34 test compounds. The results showed that the GRNN had between 73.33 to 100% recognition rates of the test compounds. GRNN could therefore be a powerful aid in the structural elucidation of organic compounds.   Key words: Artificial neural networks (ANNs), generalized regression neural network (GRNN), eudesmane skeleton, sesquiterpenes, structural elucidation.

Cytotoxic effect of eudesmanolides isolated from flowers of Tanacetum vulgare ssp. siculum.

A phytochemical analysis of the dichloromethane extract from the flowers of a subspecies of Tanacetum vulgare growing in Sicily was carried out. Five known sesquiterpene lactones with the eudesmane skeleton have been isolated and the cytotoxic activity of these compounds was tested in vitro on A549 (human lung carcinoma epithelial-like) and V79379A (Chinese hamster lung fibroblast-like) cells using the tetrazolium salt reduction (MTT) assay. All of tested compounds induced high time- and concentration-dependent cytotoxic effects.

Insecticidal activity of sesquiterpenes skeleton synthesized by the conventional Robinson annulations reaction on Drosophila melanogaster

This work presents the insecticidal activity of known sesquiterpenes with eudesmane skeleton synthesized by the conventional Robinson annulations reaction using dihydrocarvone and ethylvinylketone. The insecticidal activity was assayed against Drosophila melanogaster.

Structurally Diverse Terpenoids from the Rhizomes ofCyperus rotundusL.

An extract of the rhizomes of Cyperus rotundus L. afforded two new sesquiterpenoids (2 and 3) with rearranged secoeudesmane and germacrane skeletons, and a new 9,10-seco-cycloartane triterpenoid (9), as well as seven previously reported terpenoids, including a monoterpenoid (1), five sesquiterpenoids (4-8) with guaiane, patchoulane, and eudesmane skeletons, and a 3,4- seco-dammarane nortriterpenoid (10). The structures of 1-10 were elucidated by extensive spectroscopic methods and comparison with the literature data. The structures of 2 and 6 were confirmed by single-crystal X-ray diffraction analysis. The carbon skeleton of 2 is the third example reported thus far of such a skeleton and the 9,10-seco-cycloartane framework of 9 has rarely been found from a natural source. Compound 7 was a new natural product and compounds 1-5 and 7-10 were discovered from the genus Cyperus for the first time. This study may provide some useful information for the chemotaxonomy for the plant Cyperus rotundus.

The Bark Essential Oil Composition and Chemotaxonomical Appraisal of Cedrelopsis Grevei H. Baillon from Madagascar

Cedrelopsis grevei is an aromatic and endemic tree of Madagascar. Its essential oil, resulting from its bark, and known under the name katrafay oil, is used in Madagascar in traditional medicine and in aromatherapy in the areas of the North. The chemical composition of this oil shows a great variability. This work proposed to study some determinants of this variability. Sampling was carried out tree by tree, in six representative sites of the distribution area of the species, followed by distillation and analysis by GC-MS. Twenty one samples were thus analyzed and 71 molecules were identified in at least one sample. A principal components analysis was performed considering the thirteen principal compounds identified in these essential oils. Four chemical patterns were distinguished. The first is characterized by eudesmane skeletons, mainly represented by selinenes (3.4-17.2%) and eudesmols (9.9-37.8% and 0-11.1% for the α- and γ- isomers, respectively); the second is rich in α-pinene (2.1-30.0%) and copaborneol (4.7-20.0%); the third is dominated by α-copaene (5.9-11.8%) and ishwarane (13.7-22.1%), and the last by cadinane skeletons (cadinenes 0.5-35.2%, T-muurolol 0-11.8% and α-cadinol 0-6.7%). Variable amounts of α-bisabolol were found in samples belonging to these four groups. Our study indicates a linkage between the zone of gathering and the essential oil chemical composition. There was not much variability between trees in the same zone, but there were big differences from one zone to another. These results make it possible to propose methods for sustainable collection and durable management of the species.

Sesquiterpene Lactones from Anthemis melanolepis

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Sesquiterpene Lactones from Anthemis melanolepis

AbstractFrom the aerial parts of A. melanolepis, two new sesquiterpene lactones, melanolepin B ( = 1α,4β,8α‐trihydroxyeudesm‐11(13)‐en‐12,6α‐olide; 1) and melanolepin C (= 1α,10β‐epoxy‐8β‐hydroxygermacra‐4(15),11(13)‐dien‐12,6α‐olide; 2), were isolated, together with four known compounds, desacetyllaurenobiolide, dentatin A, taraxasterol, and (3S,5R)‐loliolide. Compound 1 was found to have the rare cis‐fused eudesmane skeleton. The structures of the isolated compounds were established by means of NMR (1H, 1H‐COSY, 1H,13C‐HSQC, HMBC, NOESY) and MS analyses.

Halichonadins A–D, new sesquiterpenoids from a sponge Halichondria sp.

A new dimeric sesquiterpenoid with two eudesmane skeletons through a urea linkage, halichonadin A ( 1 ), as well as three new eudesmane sesquiterpenoids having a carbamate, an isonitrile, or an amino functionality, halichonadins B ( 2 ), C ( 3 ), and D ( 4 ), respectively, have been isolated from a marine sponge Halichondria sp., and the gross structures and relative stereochemistry of 1– 4 were elucidated on the basis of spectral data and chemical means.

A novel approach for introduction of C-1 oxygenated group on decalin skeleton: first asymmetric total synthesis of 1α,6α-dihydroxy-eudesm-3-ene

This paper describes a novel approach for introduction of C-1 hydroxy on decalin ring system starting from (−)-carvone. Utilizing the substrate controlled Mukaiyama aldol reaction and alkaline cyclization as key steps, the C-1 oxygenated decalin eudesmane skeleton 2′ and its four isomers were synthesized efficiently. What's more, X-ray structural analysis confirmed sufficiently that something was wrong about the structure of natural product: 1β,6β-dihydroxy-7- epi-eudesm-3-ene as reported by the literature.

Novel approach for the introduction of a C-1 oxygenated group on the decalin skeleton: first asymmetric total synthesis of 1S,6S-dihydroxy-eudesm-3-ene.

This paper describes a novel approach for the introduction of a C-1 hydroxyl on the decalin ring system, starting from (-)-carvone. Utilizing the substrate-controlled Mukaiyama aldol reaction and alkaline cyclization as key steps, the C-1 oxygenated decalin eudesmane skeleton 2' and its four isomers were synthesized efficiently. Furthermore, X-ray structural analysis showed that the claimed structure for the natural product is incorrect.

Novel approach for the stereocontrolled construction of eudesmane skeleton: a concise synthesis of (+/-)-balanitol.

[structure: see text] A novel method for the stereocontrolled construction of the eudesmane ring system based on a cationic cyclization is presented, and the approach is exemplified in a short and efficient total synthesis of (+/-)-balanitol (2).

An Efficient Synthetic Strategy for Introduction of C3‐C4 Double Bond into Eudesmane Skeleton: First Total Synthesis of (+)‐Chrysanthemol

AbstractThe first enantioselective synthesis of (+)‐chrysanthemol 1 was carried out starting from (+)‐dihydrocarvone in ten steps. In our studies, a facile synthetic strategy has been developed for introduction of C3‐C4 double bond into a eudesmane skeleton.

Synthesis of 3-Oxa-guaianolides from Santonin

This article reports on the transformation of santonin into two C 10-epimeric 3-oxa-guaianolides which are 8-deoxyderivatives of several natural 3-oxaguaianolides isolated from Achillea species. The synthesis involved the photochemical rearrangement of the eudesmane skeleton into a guaiane skeleton and the transformation of the cyclopentane ring into a furan moiety with the concomitant loss of C 3. Comparison of the NMR data of the synthetic products with those of the natural products confirms the β orientation of the hydroxyl group at C 10 in the products isolated from Achillea.

An easy route to 11-hydroxy-eudesmanolides. Synthesis of (±) decipienin A

The preparation of 11-hydroxy-eudesmanolides with the stereochemistry found in the Umbelliferae family of plants is described. The decalin system of the eudesmane skeleton is produced by the addition of 5-methyl-2-furyllithium to 3-ethoxycyclohex-2-enone and acidic treatment of the resulting adduct. The stereochemistry of the decalones obtained by this method has been corrected. The α-hydroxy-γ-lactone moiety is obtained by condensation of the appropriate decalone with methyl pyruvate and subsequent reduction under Luche conditions. The usefulness of this procedure has been proven in the synthesis of decipienin A.

First Total Synthesis of (+)-Chrysanthemol

The first total synthesis of (+)-chrysanthemol (1) has been described starting from (+)-dihydrocarvone (4). The features of our synthesis are the high yield introduction of C3-C4 double bond into eudesmane skeleton and rearrangement of epoxide to allylic alcohol promoted by BF3·OEt2-Bu4NI reagent. In our synthesis, (+)-α-eudesmol (5) has been used as a key intermediate.

Minor components with smooth muscle relaxing properties from scented myrrh (Commiphora guidotti).

All sesquiterpenes present in a sample of scented myrrh were isolated and characterised. Seven compounds, with cadinane, guaiane, oplopane, and eudesmane skeletons, were obtained, of which two are new and two are reported from a natural source for the first time. The major component, T-cadinol, has previously been shown to possess smooth muscle-relaxing properties, and the major purpose of the investigation was to compare the effects of the minor and more polar sesquiterpenes with that of T-cadinol in the rat aorta. Like T-cadinol, the minor sesquiterpenes are more efficient in reducing K(+)-induced contractions than those induced by the alpha-adrenoceptor agonist phenylephrine, however, they were all less potent than T-cadinol.