Germacranolide, Guaianolide und Xanthanolide aus Blüten vonArnica mollisund Röntgenstrukturanalyse von Baileyinacetat¹

Abstract

The flowers of ARNICA MOLLIS afforded, in addition to baileyin ( 1A), baileyin acetate ( 1B), xanthalongin ( 3), and 2-deacetoxy-11alpha,13-dihydroxanthuminol ( 6), the new 1,5- CIS-guaianolides arnimollin acetate ( 2A) and arnimollin tiglinate ( 2A) and the new xanthanolides 11beta3,13-dihydroxanthalongin ( 4) and 11alpha,13-dihydroxanthalongin ( 5). No traces of helenanolides were discernible. The structures were elucidated mainly by high-field NMR spectroscopy. The stereochemistry of 1B has been revised on the basis of an X-ray crystallographic study to be a 4alpha,5beta-epoxygermacrolide instead of a 4alpha,5beta-epoxymelampolide. The implications for the biosynthesis of CIS- and TRANS-fused guaianolides are discussed. The co-occurrence of 1A with CIS-fused guaianolides and xanthanolides (no helenanolides) in A. MOLLIS and with TRANS-fused guaianolides and helenanolides (no xanthanolides) in A. ACAULIS supports the hypothesis that germacrolides represent the biogenetic precursors for CIS- and TRANS- fused guaianolides.

Bioactive Sesquiterpenes and Lignans from the Fruits of Xanthium sibiricum

“…Compound 2 was isolated as a yellow, amorphous powder and was assigned a molecular formula of C 15 ,d,1.8 Hz), and three olefinic protons, δ H 5.31 (1H, brs), 5.15 (1H, brs), and 6.33 (s) ( Table 1). The 13 C NMR and DEPT data exhibited the presence of an ester carbonyl carbon (δ C 172.9), six olefinic carbons (δ C 152.7, 150.…”

“…The other isolated compounds were inactive (IC 50 > 10 μM) for the inhibition of NO production. The in vivo anti-inflammatory activities of compounds 8,11,13,15,16, and 17 were tested. As a result, compounds 13 and 17 were found to exhibit anti-inflammatory activity against croton oil-induced ear edema in mice with inhibition rates of 46.9% and 37.7%, respectively, at a dose of 50 mg/mL.…”

“…Dexamethasone was again used as the positive control, with an inhibition rate of 70.5%, at a dose of 1 mg/mL. Compounds 8,11,15,and 16 gave negative data, with inhibition rates of less than 20.0%. Other isolated compounds, which were insufficient in quantity for the in vivo antiinflammatory activity assay, were not investigated in this manner.…”

11α,13- and 11β,13 -Dihydro-4H-xanthalongin 4-O-β-Glucopyranosides: New Sesquiterpene Lactone Glycosides from Flowers ofArnica amplexicaulisandA. mollis1,*

“…Besides the sesquiterpene lactones from both A rn/ca species the triterpenes a-and /3-amyrin, the sterols campesterol, stigmasterol and $-sitosterol and the coumarin esculetin were isolated and identified by direct comparison with the authentic compounds by TLC, GC, and GO/MS analysis, esculetin also by its spectroscopic data (Hi, UV, 'H-NMR) (11). Additionally from A. amplexicoal/s 1 0-acetoxy-8 ,9-epoxy-thymolisobutyrate (12) and from A. inollis loliolide (13) and scopoletin (11) were isolated and identified by UV, IR, MS, and 1H-NMR analysis (for data see ii).…”

“…Additionally from A. amplexicoal/s 1 0-acetoxy-8 ,9-epoxy-thymolisobutyrate (12) and from A. inollis loliolide (13) and scopoletin (11) were isolated and identified by UV, IR, MS, and 1H-NMR analysis (for data see ii).…”