Eremophilane Sesquiterpenoids Research Articles

Eremophilane, bakkane, secoeremophilane, and secobakkane sesquiterpenoids from Ligularia virgaurea collected in China

Secobakkane B (C-6/C-7 cleaved secobakkane type aldehyde), secovirgaurenols B and C (C-8/C-9 cleaved secoeremophilane type), a 1β,10β-epoxyfuranoeremophilane, two 1β,10β-epoxyeremophilanolides, and fukinospirolide C (bakkane-type lactone), as well as 33 known compounds were isolated from three samples of Ligularia virgaurea collected in China. Two of the three analyzed samples were grouped in the neoadenostylone (N) type, and the rest, a mixture of the 6-hydroxyeuryopsyn (H) and cacalol (C) types, out of five chemotypes found in this species.

Eremophilane Sesquiterpenoids and Nor- and Dinorsesquiterpenoids from Ligularia virgaurea Collected in China

Four samples of Ligularia virgaurea collected in China afforded three new eremophilane sesquiterpenoids, one new norsesquiterpenoid, and two new dinorsesquiterpenoids as well as 28 known compounds. All the four samples belonged to the ligularol type (L type), one of the five chemotypes we have described for this species. The configuration of the previously reported eremophila-7(11),9-dien-12,8-olide is revised to be H-8α. The absolute configuration of ethyl 8-oxoeremophila-7(11),9-dien-12-oate was established to be 4 S,5 R by a DFT calculation.

Chemical constituents from Ligularia purdomii (Turrill) Chittenden

The first phytochemical investigation on the roots of Ligularia purdomii led to the isolation and identification of 18 compounds, including two eremophilane sesquiterpenoids (1 and 2), three benzofuran derivatives (3–5), a triterpenoid (6), two steroids (7 and 8), nine phenolic components (9–17), and a monofatty glyceride (18). The structural elucidation of the isolated compounds was performed by spectroscopic data and comparison with the literature. Compounds (−)-syringaresinol (11), scopoletin (13), 3,5-dimethoxy-4-hydroxy-benzaldehyde (14), and glycerol monolinoleate (18) have not been recorded in Ligularia genus previously. The chemotaxonomic significance of these isolated compounds has been summarized.

Vetiverianines A, B, and C: Sesquiterpenoids from Vetiveria zizanioides Roots.

Three new sesquiterpenoids-vetiverianines A (1), B (2), and C (3)-and a known eudesmane sesquiterpenoid (4) were isolated from the roots of Vetiveria zizanioides. Vetiverianine A (1) has a unique carbon framework comprising a rigid tricyclic ring system. Vetiverianines B (2) and C (3) are new eremophilane sesquiterpenoids. The structures of sesquiterpenoids 1-3, including the absolute configurations, were determined by NMR spectroscopic, X-ray crystallography, and vibrational circular dichroism data analysis. Vetiverianine C (3) exhibited weak cytotoxic activity against HL-60 cells.

Structure and cytotoxic evaluation of five 12-oxygenated eremophilanes from Ligularia lingiana

Five new 12-oxygenated eremophilane sesquiterpenoids bearing a B-ring enone system were isolated from Ligularia lingiana S.W. Liu (Asteraceae) collected in China. Compound 5 was a Diels–Alder adduct of 3α-angeloyloxy-7βH-8-oxoeremophila-9,11(13)-dien-12-al and the monoterpene, ocimene. Compound 1 showed cytotoxic activities against HeLa, HL60, Jurkat, and NIH-3T3 cells at IC50 0.0407, 0.440, 0.313, and 3.48 μM, respectively.

Norbisabolane and eremophilane sesquiterpenoids from cultures of the Basidiomycete Polyporus ellisii

Three new 11,12,15-norbisabolane sesquiterpenoids, polisins A–C (1–3), and four new eremophilane sesquiterpenoids, polylisins A–D (4–7), were isolated from cultures of the Basidiomycete Polyporus ellisii. These new structures were elucidated based on extensive spectroscopic studies and the structures of polisin A (1) and polylisin A (4) were confirmed by single-crystal X-ray crystallographic analysis. All compounds were evaluated for their inhibitory activities against two isozymes of 11β-hydroxysteroid dehydrogenases (11β-HSD1 and 11β-HSD2).

ChemInform Abstract: Eremophilane Sesquiterpenoids from Farfugium japonicum.

AbstractNew eremophilane sesquiterpenoid (I) is isolated from the rhizome of Farfugium japonicum, together with three known eremophilane sesquiterpenoids.

Cytotoxic eremophilane sesquiterpenoids from the saprobic fungus Berkleasmium nigroapicale BCC 8220

Berkleasmins A–E, five new eremophilane sesquiterpenoids were isolated from the saprobic fungus Berkleasmium nigroapicale BCC 8220. The structures of the new compounds were elucidated by analyses of NMR spectroscopic and mass spectrometry data in combination with chemical means. Berkleasmins A and C exhibited cytotoxic activity against cancer cell-lines (NCI-H187, MCF-7, and KB) as well as nonmalignant Vero cells with IC 50 values of 1.1–7.5 μg/mL, and these compounds also showed antimalarial activity with respective IC 50 of 3.1 and 2.8 μg/mL.

Heteroaryl Radicals: A Furyl Radical in the Synthesis of the Tricyclic ­Framework of Eremophilane Sesquiterpenoids

Studies on the intramolecular addition of thieno and furan radicals to alkenyl groups are reported. The radicals undergo a 6-endo-trig selective cyclization to alkenyl systems resulting in a linearly annulated tricyclic moiety.

Terpenoids from the Flower ofCacalia Tangutica

A thorough investigation of Cacalia tangutica (Franch.) Hand-Mazz afforded two new epimeric eremophilane sesquiterpenoids, 7β- H-3α-angeloyloxy-9-ene-11,12-epoxy-8-oxoeremophilane (1) and 7α-H-3α-angeloyloxy-9-ene-11,12-epoxy-8-oxoeremophilane (2), as well as four known sesquiterpenes, petasol (3), oplopanone (4), 4,5-epoxy-β-caryophyllene (5), 4(15)-eudesmene-1β,6α-diol (6), and three known monoterpenes, 1β,2α-dihydroxy-p-menth-5-ene (7), 5α-hydroxy-2-oxo-p-menth-6(1)-ene (8), 5β-hydroxy-2-oxo-p-menth-6(1)-ene (9), and two known triterpenes, maniladiol 3-O-palmitate (10), taraxasteryl palmitate (11). The new compounds were characterized by means of spectroscopic methods including 1D, 2D NMR and HRESIMS, and the known ones were established on the basis of comparing their NMR data with those of the corresponding compounds in the literature. In addition, cytotoxicity against selected cancer cells (HL-60, HO-8910 and A-549) of compounds 1-4, 6, 7,10 were measured in vitro.

Novel Sesquiterpenoids from the Fermentation of Xylaria persicaria Are Selective Ligands for the NPY Y5 Receptor.

Neuropeptide Y (NPY) is a polypeptide found in the peripheral and central nervous system and is involved in the regulation of feeding. Antagonists of NPY receptor activation could therefore have potential for development as antiobesity drugs. Fermentation of an isolate of Xylaria persicaria yielded two novel eremophilane sesquiterpenoids xylarenals A (1) and B (2). These compounds are selective for the NPY Y5 receptor but have only modest affinity. The isolation, structure elucidation, and biological activities of these compounds are described.

Novel Sesquiterpenoids from the Fermentation of Xylaria persicaria Are Selective Ligands for the NPY Y5 Receptor

Neuropeptide Y (NPY) is a polypeptide found in the peripheral and central nervous system and is involved in the regulation of feeding. Antagonists of NPY receptor activation could therefore have potential for development as antiobesity drugs. Fermentation of an isolate of Xylaria persicaria yielded two novel eremophilane sesquiterpenoids xylarenals A (1) and B (2). These compounds are selective for the NPY Y5 receptor but have only modest affinity. The isolation, structure elucidation, and biological activities of these compounds are described.

On catalyzed additions of trans-piperylene to 2-cyclohexenones. A short route to potential precursors of eremophilane sesquiterpenoids

A chemical correlation is described by which the two adducts resulting from a catalyzed addition of trans-piperylene to 2-methyl-2-cyclohexenone, 7 and 8, are proven to be stereoisomers. Various reaction conditions for the addition of trans-piperylene to 2-cyclohexenone are also summarized.

Synthesis of optically active eremophilane sesquiterpenoids from sabinene

AbstractAn efficient route to optically pure sesquiterpenoids of the nootkatane type is described. Stereoselective Michael‐type addition of (‐)‐3‐methylsabinaketone (9) to trans‐3‐penten‐2‐one is used to create the asymmetric centers at C(4) and C(5) in the tricyclic ketone 12. Practical procedures for the conversion of 12 into (‐)‐α‐vetivone (17) and (‐)‐nootkatone (18) are presented.

Stereoselective synthesis of eremophilane sesquiterpenoids from β‐pinene

Abstract2‐Methyl‐4‐isopropylidenecyclohexanone (7) can be obtained in good yield from β‐pinene (2) in a 5‐step sequence. Key step is the acid‐catalysed ring opening of cis‐3‐methylnopinone (5) to give 4‐(l′‐hydroxyisopropyl)‐2‐methylcyclohexanone (6, XOH). Robinson annulation of 7 with trans‐3‐penten‐2‐one proceeds stereoselectively to give α‐vetivone (10). Similar annulation of the isopropenyl isomer (8) affords 7‐epi‐nootkatone (11). 10 can be converted in good yield to nootkatone (13).