Eudesmane sesquiterpenoids with inhibitory effects on NO production from Artemisia princeps.

Five undescribed eudesmane methyl esters (1-5), three undescribed eudesmane-12,6-olides (6-8), and 21 known analogues (9-29) were isolated from the aerial part of Artemisia princeps Pamp. Their structures were established by detailed analysis of the NMR and HRESIMS data. The absolute configurations of 1-8 were determined based on single-crystal X-ray diffraction analysis and ECD calculations. Moreover, the inhibitory effects on LPS-induced NO production in BV-2 microglial cells of all the isolated compounds were assessed. Except for compounds 2, 4, 10, and 11, the others showed significant inhibitory activities, with IC50 values of 0.73-18.66 µM, wherein the potential structure-activity relationship was also discussed.

Two new sesquiterpenoids from the fruits of Alpinia oxyphylla.

Two undescribed sesquiterpenoids, including one nor-eudesmane type (1) and one guaiane type (2), together with two known analogues (3-4) have been isolated and identified from the fruits of Alpinia oxyphylla. The structures of these new compounds were elucidated by extensive spectroscopic analyses (1D-, 2D-NMR, HRESIMS, IR, UV) and NMR calculations with DP4+ analysis. The anti-inflammatory activities of all isolates were evaluated by measuring their inhibitory effects on PGE2 production in LPS stimulated RAW 264.7 macrophages.

Polyhydroxylated eudesmane sesquiterpenoids and sesquiterpenoid glucoside from the flower buds of Tussilago farfara.

Chemical fractionation of the n-BuOH partition, which was generated from the EtOH extract of the flower buds of Tussilago farfara, afforded a series of polar constituents including four new sesquiterpenoids (1-4), one new sesquiterpenoid glucoside (5) and one known analogue (6) of the eudesmane type, as well as five known quinic acid derivatives (7-11). Structures of the new compounds were unambiguously characterized by detailed spectroscopic analyses, with their absolute configurations being established by X-ray crystallography, electronic circular dichroism (ECD) calculation and induced ECD experiments. The inhibitory effect of all the isolates against LPS-induced NO production in murine RAW264.7 macrophages was evaluated, with isochlorogenic acid A (7) showing significant inhibitory activity.

Sesquiterpenoids and their glycosides from Dobinea delavayi (Baill.) Baill.

Eight undescribed sesquiterpenoids, including two eudesmane glycosides dobinosides A and B, five eudesmane aglycones dobinins Q-U, and one germacrane dobinin P, were isolated from the 80% ethanol extract of roots of Dobinea delavayi. Their structures were elucidated by extensive spectroscopic data (1D and 2D NMR, HR-ESI-MS) and single-crystal X-ray diffraction analysis. Dobinoside A, dobinins Q and R, as well as six reported eudesmane sesquiterpenoids, were evaluated for their in vivo antimalarial activities against Plasmodium yoelii BY265RFP in mice. A summary of preliminary structure-activity relationship of eudesmane sesquiterpenoids for in vivo antimalarial activity was described.

Polyhydroxylated eudesmane sesquiterpenoids and sesquiterpenoid glucoside from the flower buds of Tussilago farfara / 中国天然药物

Chemical fractionation of the n-BuOH partition, which was generated from the EtOH extract of the flower buds of Tussilago farfara, afforded a series of polar constituents including four new sesquiterpenoids (1-4), one new sesquiterpenoid glucoside (5) and one known analogue (6) of the eudesmane type, as well as five known quinic acid derivatives (7-11). Structures of the new compounds were unambiguously characterized by detailed spectroscopic analyses, with their absolute configurations being established by X-ray crystallography, electronic circular dichroism (ECD) calculation and induced ECD experiments. The inhibitory effect of all the isolates against LPS-induced NO production in murine RAW264.7 macrophages was evaluated, with isochlorogenic acid A (7) showing significant inhibitory activity.

Eudesmane sesquiterpenes from Chinese liverwort are substrates of Cdrs and display antifungal activity by targeting Erg6 and Erg11 of Candida albicans.

We isolated twelve sesquiterpenes from Chinese liverwort Tritomaria quinquedentata (Huds.) Buch., including four new compounds. Among them, five eudesmane sesquiterpenes were ineffective against Candida albicans wild strain SC5314 but active towards efflux pumps-deficient strain DSY654 using Alamar blue assay. Further test of the most active agent of ent-isoalantolactone (8, ent-iLL) showed that it also inhibited the yeast-to-hyphal switch of DSY654 cells. The intracellular content measurement using high performance liquid chromatography (HPLC) revealed that ent-iLL was intracellularly accumulated in C. albicans when efflux pumps were deficient or inhibited by Cdrs inhibitor riccardin D, suggesting that the activity of ent-iLL was compromised by efflux pumps Cdrs. Moreover, ent-iLL potentially inhibited the activity of Erg11 and Erg6 of DSY654 and thereby resulted in the alteration of sterol composition by decreasing ergosterol contents and increasing zymosterol and lanosterol accumulation. Our study demonstrated that eudesmane sesquiterpenes, as the substrates of Cdrs, could interfere with sterol synthesis of C. albicans to exert antifungal activity when co-applied with Cdrs inhibitors.

Crystal structure of 4α-hy-droxy-5α,8ß(H)-eudesm-7(11)-en-8,12-olide monohydrate.

The title compound, C15H22O3·H2O, is a natural producr isolated from Chloranthus japonicus, which is a eudesmane sesquiterpenoid. The two trans-fused six-membered rings have chair confomations. In the crystal, O-H⋯O hydrogen bonds link the components into corrugated layers parallel to the bc plane. There are C-H⋯O inter-actions present within and between the layers.