Cytotoxic sesquiterpenes from Ligularia platyglossa

Four sesquiterpene lactones including an eremophilenolide dimer, named as biligulaplenolide, 1, 8beta-hydroxy-1-oxo-(14alpha,15alpha eremophil-7(11),9(10)-dien-12,8alpha-olide, 2, 1-hydroxy-2-oxo-(14alpha,15alpha eremophil-1(10),7(11),8(9)-trien-12,8-olide, 3, 4alpha,8beta,9alpha-trihydroxy- 5alphaEta-7(11)-eudesmen-12,8alpha-olide, 4, along with two known ones, 10alpha-hydroxy-1-oxo-eremophil-7(11),8(9)-dien-12,8-olide, 5, and furanoeremophil-1(10)-ene-2,9-dione, 6, were isolated from the underground organs of Ligularia platyglossa (Franch.) Hand.-Mazz. Their structures were elucidated by spectroscopic methods including single-crystal X-ray diffraction analysis (2 and 3). Their in vitro cytotoxicities against seven cancer cell lines (BGC-823, A549, HL-60, B16, SMMC-7721, BEL7402, Hela) were evaluated. Compounds 2, 3, 5 showed cytotoxic activities on HL-60 cancer cells with IC50 in the range of 24.0 to 51.1 microM, whereas compound 3 exhibited only weak cytotoxic activity against the B16, BEL7402 and Hela cancer cells. Flow cytometric analysis indicated that compound 3 induces Hela cells to apoptotic death after 48 h treatment with 0.38 mM of this compound.     

Two new guaiane sesquiterpenes from Datura metel L. with anti-inflammatory activity

Chemical investigation of an acidic methanol extract of the whole plants of Datura metel resulted in the isolation of two new guainane sesquiterpenes, 1β,5α,7β-guaiane-4β,10α,11-triol (1) and 1α,5α,7α-11-guaiene-2α,3β,4α,10α,13-pentaol (2), along with eight known compounds: pterodontriol B (3), disciferitriol (4), scopolamine (5), kaempferol 3-O-β-d-glucosyl(1 → 2)-β-d-galactoside 7-O-β-d-glucoside (6), kaempferol 3-O-β-glucopyranosyl(1 → 2)-β-glucopyranoside-7-O-α-rhamnopyranoside (7), pinoresinol 4′′-O-β-d-glucopyranoside (8), (7R,8S,7′S,8′R)-4,9,4′,7′-tetrahydroxy-3,3′-dimethoxy-7,9′-epoxy-lignan-4-O-β-d-glucopyranoside (9), and (7S,8R,7′S,8′S)-4,9,4′,7′-tetrahydroxy-3,3′-dimethoxy-7,9′-epoxylignan-4-O-β-d-glucopyranoside (10). Their structures were elucidated by extensive spectroscopic methods, including 1D and 2D NMR and MS spectra. Compounds 2-4 and 6-10 were shown to have modest anti-inflammatory effects through inhibition of NO production in LPS-stimulated BV cells.     

Two new isodrimene sesquiterpenes from the fungal culture broth of Polyporus arcularius

Two new isodrimene sesquiterpene derivatives, 2(S)-hydroxyalbicanol (1, =(2S,4aS,8S,8aS)-8-(hydroxymethyl)-4,4,8a-trimethyl-7-methylenedecahydronaphthalen-2-ol) and 2(S)-hydroxyalbicanol 11-acetate (2, =((1S,4aS,7S,8aS)-7-hydroxy-5,5,8a-trimethyl-2-methylenedecahydronaphthalen-1-yl)methyl acetate) were isolated from the culture broth of the fungus Polyporus arcularius, together with two phenylpropanediols, (1S,2S)- and (1R,2S)-1-phenyl-1,2-dihydroxypropane (3, 4). Compound 3 is reported as a naturally occurring compound for the first time. The structures of the compounds were elucidated on the basis of spectroscopic analysis. Compound 1 exhibited growth inhibition of lettuce seedlings with IC₅₀ values of 1.3 mM to hypocotyl and 1.7 mM to radicle.     

Two new sesquiterpenes from Laurus azorica

The structures of a new eudesmane sesquiterpene, lauradiol, and a new secoeudesmane, azoridione, have been determined by spectroscopic methods. These compounds and the known sesquiterpenic alcohols, clovanediol and caryophyllenol II, have been isolated from the aerial parts of Laurus azorica.     

Two guaianolides from calea solidaginea

The isolation and structure elucidation of two new guaianolides, solidaginolides A(1) and B(5), from Calea solidaginea are reported. The structures of the new compounds were established by spectroscopic methods.     

Eudesmane sesquiterpenes from Eupatorium Quadrangulare

The aerial part of Eupatorium quadrangulare afforded in addition to known compounds, a possible biosynthetic intermediate, quadrangulin A, of the eudesmanolides found in this species.     

Eremophilane-type glucosides from the leaves of Ligularia calthifolia Maxim

Three eremophilane-type glucosides (1–3) along with three known congeners alticolosides A, B and D (4–6) have been isolated from the leaves of Ligularia calthifolia Maxim. (Asteraceae). The structures of 1–3 have been elucidated by spectroscopic analysis as well as by chemical transformations. A distinctive feature of the compounds 1–3 is the presence of an acetyl group in the glucose residues. The compounds were non-cytotoxic against human normal prostate cells as well as prostate cancer cells.     

Three new terpenoids from the Eupatorium chinense

Three new terpenoids compounds (1–3) were obtained from ethyl acetate fraction, which was yielded from Eupatorium chinense’s ethanol extract. Their structures were determined on the basis of 1D and 2D NMR spectroscopy, including ¹H-¹H COSY, HMBC, HSQC and NOESY experiments. All of the isolated compounds were tested in vitro for their cytotoxic activities against the HepG₂, HGC-27 and MDA-MB-231 cancer cell lines.     

Two new pterosin sesquiterpenes from Pteris multifida Poir

Two new pterosin sesquiterpenes named as 2R,3R-13-hydroxy-pterosin L 3-O-β-d-glucopyranoside (1) and 2R,3S-acetylpterosin C (2), along with a known one, 2S,3S-acetylpterosin C (3), were isolated from the whole plant of Pteris multifida and the 1D and 2D NMR data of 3 were reported for the first time in this paper. Their structures were elucidated on the basis of mass and spectral evidence. Compounds 1–3 showed cytotoxicity against HL 60 cells (human leukemia) with the IC₅₀ values of 14.6, 48.3 and 35.7 μM, respectively.     

Two novel hydroquinones from the roots of Arnebia guttata Bge

Two novel hydroquinone derivatives, named guttaquinol A and B (1, 2), together with fifteen known compounds (3–17), were isolated from the roots of Arnebia guttata Bge.. Spectroscopic methods, including NMR, HR-MS, ECD, and data from the literature were used to determine the chemical structures (including the absolute configurations) of the compounds. The chemotaxonomic significance of the isolated compounds was also discussed.     

Isolation and structure characterization of two new diterpenoids from Clerodendrum bungei

Two new diterpenoids, 3β-(β-d-glucopyranosyl)isopimara-7,15-diene-11α,12α-diol (1), and 16-O-β-d-glucopyranosyl-3β-20-epoxy-3-hydroxyabieta-8,11,13-triene (2), along with three known ones were isolated from the roots of Clerodendrum bungei. These compounds were purified, and their structures were elucidated by extensive spectroscopic analyses, especially 2D NMR experiments. All compounds were evaluated for cytotoxicity against several tumor cell lines.     

Tricyclic sesquiterpenes and further diterpenes from Espeletiopsis species

The investigation of five Espeletiopsis and two Coespeletia species afforded, in addition to numerous known compounds, two new kaurene derivatives 19-acetoxy-ent-kaurene and 17-oxo-ent-kaur- 15-en-19-oic acid, as well as two new tricyclic sesquiterpenes, one being the previously reported oxidation product of copaborneol and the second one the 5-oxo derivative of silphiperfol-6-ene. The structures were elucidated by NMR studies and by chemical transformations. The chemotaxonomic situation is discussed briefly.     

Three new eremophilane sesquiterpenes and one new related derivative from Nemania sp. HDF-Br-5, an endophytic fungus of the endangered conifer Pseudotsuga gaussenii Flous

Three new (psganpenes A-C), one known eremophilane sesquiterpene and one newrelated derivative (psganpene D) were isolated from the culture of endophytic fungus Nemania sp. HDF-Br-5, which derived from Pseudotsuga gaussenii Flous, anendangered conifer endemic to China. Their structures were deduced by extensive spectroscopic methods. All isolates were screened for cytotoxicity and antibacterial activity. Psganpene D showed promising cytotoxicity against KB, HCT116 and Hela cell strains, with IC₅₀ values in the range of 15.1–32.3 μM.     

Sesquiterpene lactones from Viguiera deltoidea

Three sesquiterpene lactones, 2′,3′-dihydroniveusin-A, 2′,3′-dihydroniveusin-B and 3-acetylchamissonin, were isolated from the dichloromethane extract of leaves of Viguiera deltoidea. The structures were established on the basis of physical and spectroscopic data and that of 3-acetylchamissonin was also confirmed by X-ray analysis.     

Two new elemanolides from Onopordon leptolepis

The investigation of the polar fractions of the aerial parts of O. leptolepis afforded two new elemanolides, their structures being elucidated by spectroscopic methods and by partial synthesis starting with onopordopicrin.     

Rare hydroperoxyl guaianolide sesquiterpenes from Pulicaria undulata

Pulicaria species, such as Pulicaria undulata, are rich in sesquiterpene lactones. The methylene chloride/methanol (1:1) extract of P. undulata resulted in the isolation of new sesquiterpenes (1–4), as well as previously reported metabolites (5–14). Structures were elucidated by spectroscopic analyses. Using a mouse peritoneal macrophage bioassay, lipopolysaccharide-induced nitric oxide inhibition was observed with the eudesman-type sesquiterpene 1β,4β-dihydroxy-5αH,7αH,8α-guaia-10(14),11(13)-dien-8β,12-olide (11) at an EC₅₀ of 7.2 μM.     

Zoapatanolides C and D,two guaianolides from Montanoa tomentosa

Further investigation of Montanoa tomentosa afforded two new guaianolides as well as the known pumilin and the previously isolated heliangolide zoapatanolide A. The structures were established on the basis of spectroscopic studies and chemical evidence.     

A eudesmane acid from Montanoa speciosa

The major constituent of a leaf-surface methylene dichloride wash of Montanoa speciosa was a eudesmane acid, 1,2-dehydro-3-oxo-costic acid.