title: Sesquiterpene lactones in Arnica montana: helenalin and dihydrohelenalin chemotypes in Spain.
abstract: An analytical RPLC method for sesquiterpene lactones in Arnica montana has been extended to include quantitative analyses of dihydrohelenalin esters. LC-ESI-MS-MS distinguished the isomeric helenalin and dihydrohelenalin esters. The dihydrohelenalin esters have lower response factors for UV detection than do helenalin esters, which must be taken into account for quantitative analyses. Analyses of flowers from 16 different wild populations of A. montana in Spain showed differing proportions of helenalin and dihydrohelenalin esters. For the first time a chemotype with high levels of helenalin esters (total helenalins 5.2-10.3 mg/g dry weight) is reported in Spanish A. montana. These samples were from heath lands at high altitude (1330-1460 m), whereas samples from meadows and peat bogs at lower altitudes were the expected chemotype with high levels of dihydrohelenalin esters (total dihydrohelenalins 10.9-18.2 mg/g). The phenolic compounds, both flavonoid glycosides and caffeoylquinic acids, in Spanish A. montana are reported for the first time. The levels of several of these compounds differed significantly between samples from heath lands and samples from peat bogs or meadows, with the heath land samples being most similar to central European A. montana in their phenolic composition.
authors.affiliation: New Zealand Institute for Crop & Food Research Ltd., University of Otago, Dunedin 9054, New Zealand. perryn@crop.cri.nz
authors.forename: Nigel B
authors.initials: NB
authors.lastname: Perry
authors.forename: Elaine J
authors.initials: EJ
authors.lastname: Burgess
authors.forename: Manuel A
authors.initials: MA
authors.lastname: Rodríguez Guitián
authors.forename: Rosa
authors.initials: R
authors.lastname: Romero Franco
authors.forename: Elvira
authors.initials: E
authors.lastname: López Mosquera
authors.forename: Bruce M
authors.initials: BM
authors.lastname: Smallfield
authors.forename: Nigel I
authors.initials: NI
authors.lastname: Joyce
authors.forename: Roger P
authors.initials: RP
authors.lastname: Littlejohn
mesh_terms: D018650:Arnica / Q000737:chemistry*; D002853:Chromatography, Liquid / Q000379:methods; D035264:Flowers; D007536:Isomerism; D007783:Lactones / Q000302:isolation & purification*; D010636:Phenols / Q000302:isolation & purification*; D010936:Plant Extracts / Q000737:chemistry*; D012717:Sesquiterpenes / Q000302:isolation & purification*; D045789:Sesquiterpenes, Guaiane; D013030:Spain
chemical_list: D007783:Lactones; D010636:Phenols; D010936:Plant Extracts; D012717:Sesquiterpenes; D045789:Sesquiterpenes, Guaiane; C001329:helenalin