New Sesquiterpene Lactones from Arnica Tincture Prepared from Fresh Flowerheads ofArnica montana

Abstract

Investigation of an ethanolic extract prepared from fresh Arnica montana flowers afforded three new 1,5- trans-guaianolides, of which 11alpha,13-dihydro-2-O-tigloylflorilenalin and the respective 2-O-isovaleryl derivative are reported for the first time. Additionally, three new and one known 2beta-ethoxy-2,3-dihydrohelenalin esters were isolated. GC/MS studies of the extract after a two year storage at 4 degrees C demonstrated that the latter were artefacts that had been formed by addition of ethanol to the cyclopentenone structure of helenalin. Formation of these adducts gave compounds possessing an inhibitory activity comparable to that of 11alpha,13-dihydrohelenalin derivatives in the NF-kappaB EMSA and the IL-8 ELISA in vitro assays as well as in the in vivo croton oil-induced mouse ear edema test for one adduct, namely 2beta-ethoxy-6-O-acetyl-2,3-dihydrohelenalin. As expected, 6-O-(2-methylbutyryl)- and 6-O-methacryloyl-helenalin exhibited a stronger activity in the NF-kappaB EMSA and IL-8 ELISA. Sesquiterpene lactones seem to be the most important NF-kappaB inhibiting compounds in the Arnica extract. Bioguided fractionation using the luciferase reporter gene assay resulted in the isolation of only moderately active compounds, such as 6-acetoxy-2,2-dimethylchroman-4-one and 10-acetoxy-8,9-epoxythymol isobutyrate.

Anti‐inflammatory and immune‐regulatory mechanisms prevent contact hypersensitivity to Arnica montana L.

“…Consequently, priming of T cells in the draining lymph nodes in the sensitization phase of CHS and the recruitment of effector cells to inflamed skin following elicitation might be significantly impaired as shown in our skin homing assays. Interestingly, we have previously shown that SL can also inhibit irritant contact dermatitis induced by croton oil (32,33). These findings suggest that similar mechanisms are involved in the initiation of skin inflammation in allergic and irritant contact dermatitis.…”

Interactions of Chemicals and Metal Ions with Proteins and Role for Immune Responses

“…Again, isolated helenalin derivatives or Central European Arnica tincture exhibited a stronger NF-κB inhibitory activity compared to isolated dihydrohelenalin derivatives and Spanish Arnica tincture [54,60,61].…”

Guaianolides and a seco-Eudesmane from the Resinous Exudates of Cushion Bush (Leucophyta brownii) and Evaluation of Their Cytostatic and Anti-inflammatory Activity

“…Leucophytalin B (6) was obtained as a colorless oil and assigned the molecular formula C 17 Furthermore, the cis-configured α,β-unsaturated γ-lactone moiety in 6 was confirmed by the key HMBC correlations of H-13a, H-13b to C-7, C-11, and C-12, by the chemical shifts of H-7 (δ H 3.29) and H-8 (δ H 4.72), and by the coupling constants between H-7 and H-8 (J = 8.8 Hz) and H-7 and H13a, H-13b (J = 3.2 and 2.8 Hz). 35−37 The main difference between the 13 C NMR data of 6 and 4 (Table 2) was that the signals of the oxymethine at C-2 [δ C 58.3] and the sp 3 oxygenated tertiary carbon at C-1 [δ C 71.9] in 4 were deshielded to δ C 70.8 and 105.7, respectively, in 6.…”