Circular dichroism and optical rotatory dispersion of sesquiterpene lactones

Stöcklin, W.; Waddell, Thomas G.; Geissman, T. A.

doi:10.1016/s0040-4020(01)92818-2

Cited by 140 publications

(49 citation statements)

References 56 publications

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“…The spectrum also revealed that H-14 was correlated with H-8 and H-15, and H-9 displayed a cross peak with Me-17, supporting an α-orientation for both the 12-hydroxy group and Me-17. The CD curve of 3 also showed a negative Cotton effect for the γ-lactone chromophore at λ max 226 nm in EtOH, indicating that the chirality at C-12 was R. 21) Combined with NOESY data (Fig. 3), the absolute configuration of 3 was determined to be 6β-O-cinnamoyloxy-12α-hydroxy-(13) 15-en-16,12-olide-18-cassaneol, as shown in Fig.…”

Section: Resultsmentioning

confidence: 89%

“…12) Because the absolute configuration of known compound 1a was unresolved, the absolute stereochemistry was determined from the circular dichroism (CD) curves for the γ-lactone chromophore. [20][21][22] The sign of the CD curve in EtOH (λ max 225 nm) was negative, indicating that the chirality at C-12 in compound 1a was R, as shown in Fig. 1.…”

Section: Resultsmentioning

confidence: 91%

“…The absolute configuration of 5 was deduced from the CD curve. 21,24) The strong negative Cotton effect for the γ-lactone chromophore at λ max 225 nm in EtOH indicated that the chirality at C-12 was R. Therefore, the structure of 5 was established to be 6β-O-2′,3′-dihydrocinnamoyloxy-(13) 15-en-16, 12-olide-18-cassaneoic acid. Cassane diterpene lactones deoxygenated at C-12 appear to be rare in nature.…”

Section: Resultsmentioning

confidence: 99%

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New Cassane-Type Diterpenoids of <i>Caesalpinia echinata</i> (Leguminosae) Exhibiting NF-κB Inhibitory Activities

Mitsui

Ishihara

Hayashi

et al. 2014

CHEMICAL & PHARMACEUTICAL BULLETIN

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Seven new cassane-type diterpenoids, echinalides A-G (1-7), were isolated from the stem of Caesalpinia echinata LAM. (Leguminosae). The structures were established on the basis of their chemical properties and spectroscopic evidence, including two dimensional (2D)-NMR analysis. These compounds were assessed for inhibitory activity against nuclear factor κB (NF-κB). Echinalides C and D, in particular, significantly inhibited NF-κB-responsive reporter gene expression at 5.0 µM, an effect almost equivalent to that of parthenolide, a known potent inhibitor of NF-κB.

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Section: Resultsmentioning

confidence: 89%

Section: Resultsmentioning

confidence: 91%

Section: Resultsmentioning

confidence: 99%

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New Cassane-Type Diterpenoids of <i>Caesalpinia echinata</i> (Leguminosae) Exhibiting NF-κB Inhibitory Activities

Mitsui

Ishihara

Hayashi

et al. 2014

CHEMICAL & PHARMACEUTICAL BULLETIN

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“…Furthermore, the CD spectrum of 5 showed first positive (254 nm) and second negative (233 nm) Cotton effects. Taken in light of Geissman's rule, 6,7) the stereochemistry of the g-lactone at C 12Ј,6Ј was estimated to be a cis-fused lactone.…”

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confidence: 99%

New Sesquiterpenoids from the New Zealand Liverwort Chiloscyphus subporosus

Nagashima

Murakami

Takaoka

et al. 2004

CHEMICAL & PHARMACEUTICAL BULLETIN

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The liverworts contain various types of lipophilic terpenoids and aromatic compounds.1,2) Their chemical constituents are valuable as chemosystematic and genetic markers.1,2) Additionally, it is known that geographic differences in the main components are occasionally observed in the same species. [1][2][3] We have already reported the isolation and structural determination of a number of terpenoids and aromatic compounds with novel skeletons.1,2) As part of a search for novel compounds and biologically active substances in the Hepaticae, we are studying the chemical constituents of the southern hemispheric liverworts. A number of endemic liverwort species have been found in New Zealand, which are not related to those found in Japan. 4)The New Zealand liverwort Chiloscyphus subporosus (MITT.) J. J. ENGEL & R. M. SCHUST. was chemically analyzed to give a new aromadendrane-type sesquiterpenoid (1) and an aromadendrane-guaianolide-type dimer (2), together with 5,8-epidioxy-6-eudesmene (3) and ent-spathulenol 5) (4). Here we report on the isolation and structural characterization of the new compounds. Results and DiscussionA combination of chromatography on silica gel, Sephadex LH-20, and preparative HPLC of the ether extract of C. subporosus resulted in the isolation of compounds 1-4.The IR spectrum of 1 showed the presence of a g-lactone) and the electron impact mass spectrometry (EI-MS) confirmed the molecular ion peak at m/z 232. Fig. 1. The long-range 1 H-13 C correlations were observed by the heteronuclear multiple bond correlation (HMBC) spectrum of 1, as shown in Fig. 1. Consequently, the structure of 1 was clarified to be 4(15)-aromadendren-12,5-olide. The phase-sensitive nuclear Overhauser enhancement and exchange spectroscopy (PH-NOESY) spectrum of 1 showed NOEs between i) H-13 and H-6, H-7, ii) H-10 and H-8a, iii) H-14 and H-2a, and iv) H2a and H-3a. However, its PHNOESY spectrum did not provide clear information on the stereochemistry. X-Ray crystallographic analysis demonstrated the stereochemistry of 1 by its ORTEP drawing, as shown in Fig. 2. Accordingly, the stereostructure of 1 was established to be 4(15)-aromadendren-12,5a-olide or its enantiomer.The IR spectrum of compound 2 showed absorption as- A new aromadendrane-type sesquiterpenoid, 4(15)-aromadendren-12,5a a-olide and an aromadendrane-guaianolide dimer have been isolated from the New Zealand liverwort Chiloscyphus subporosus. Their structures were established by extensive NMR techniques and X-ray crystallographic analysis.

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“…In addition, it was reported that the absolute stereostructures of compounds with an α-methylene-γ-lactone moiety such as xanthanolides were determined based on circular dichroic (CD) spectra. 15,16) Therefore, the absolute configurations of the 8-position on 4 and 5 were confirmed from CD spectra. Namely, the CD spectra of xanthanol (6) and isoxanthanol (7) with the 7R and 8S configurations showed positive Cotton effects at 254 nm (Δε +0.19 in MeOH) and 252 nm (Δε +0.19 in MeOH) for the 8S configuration in the α-methylene-γ-lactone, respectively.…”

Section: Resultsmentioning

confidence: 76%

Sesquiterpenes from an Egyptian Herbal Medicine, Pulicaria undulate, with Inhibitory Effects on Nitric Oxide Production in RAW264.7 Macrophage Cells

et al. 2012

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The methylene chloride-methanol (1 : 1) extract from the air-dried aerial parts of wild Pulicaria undulata collected in North Sinia, Egypt, showed inhibitory effects on lipopolysaccharide (LPS)-induced production of nitric oxide (NO) in RAW264.7 macrophages. From the extract, three new sesquiterpenes named 5α-hydroperoxyivalin, 8-epi-xanthanol, and 8-epi-isoxanthanol were isolated together with four known sesquiterpenes. The structure of each new sesquiterpenes was determined on the basis of physicochemical and chemical evidence. In addition, all the sesquiterpenoids significantly inhibited the production of NO. Ivalin (IC 50 2.0 μM) and 2α-hydroxyalantolactone (1.8 μM) showed particularly strong inhibitory effects, but had strong cytotoxic effects as well. Furthermore, ivalin and 2α-hydroxyalantolactone concentration-dependently reduced inducible NO synthase (iNOS) protein levels in RAW264.7 cells.

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Circular dichroism and optical rotatory dispersion of sesquiterpene lactones

Cited by 140 publications

References 56 publications

New Cassane-Type Diterpenoids of <i>Caesalpinia echinata</i> (Leguminosae) Exhibiting NF-κB Inhibitory Activities

New Cassane-Type Diterpenoids of <i>Caesalpinia echinata</i> (Leguminosae) Exhibiting NF-κB Inhibitory Activities

New Sesquiterpenoids from the New Zealand Liverwort Chiloscyphus subporosus

Sesquiterpenes from an Egyptian Herbal Medicine, Pulicaria undulate, with Inhibitory Effects on Nitric Oxide Production in RAW264.7 Macrophage Cells

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