Arnica (Asteraceae) phylogeny revisited using RPB2: complex patterns and multiple d-paralogues.

The region coding for the second largest subunit of RNA polymerase II (RPB2) was explored for resolving interspecific relationships in Arnica and lower level taxa in general. The region between exons 17 and 23 was cloned and sequenced for 33 accessions of Arnica and four outgroup taxa. Three paralogues of the RPB2-d copy (RPB2-dA, B and C) were detected in Arnica and outgroup taxa, indicating that the duplications must have occurred before the divergence of Arnica. Parsimony and Bayesian analyses of separate alignments of the three copies reveal complex patterns in Arnica, likely reflecting a history of lineage sorting in combination with apomixis, polyploidization, and possibly hybridization. Cloned sequences of some taxa do not form monophyletic clades within paralogues, but form multiple strongly supported clades with sequences of other taxa. Some well supported groups are present in more than one paralogue and many groups are in line with earlier hypotheses regarding interspecific relationships within the genus. Low levels of homoplasy in combination with relatively high sequence variation indicates that the introns of the RPB2 region could be suitable for phylogenetic studies in low level taxonomy.

Secondary chemistry and ribosomal DNA data congruencies in Arnica (Asteraceae).

To investigate possible congruencies between DNA sequence data and secondary chemistry, we compared nuclear ribosomal DNA (nrDNA) sequence data, sesquiterpene lactone (STL) contents, and cytometric data from 35 accessions of 16 Arnica (Asteraceae) species and two outgroup taxa (Layia hieracioides and Madia sativa), using phylogenetic inference and principal component analysis (PCA). Several groups supporting multiple accessions of the same species (of A. montana, A. longifolia, A. gracilis, and A. chamissonis) are congruent between the phylogenetic trees based on nrDNA and STL data. Sesquiterpene lactone profiles were found to be highly consistent within multiple samples of A. montana and A. longifolia respectively. Moreover, sesquiterpene lactone data support subspecies classifications of A. chamissonis and A. parryi, with additional support from DNA sequence data and cytometric data. Morphology, STL data (PCA), cytometric data and DNA sequence data suggest a hybrid origin of one accession (A. gracilis × longifolia). In A. gracilis, A. latifolia, and Layia hieracioides, previously not investigated for STLs, we found large amounts of xanthalongin derivatives. This is the first time STLs have been reported from subtribe Madiinae. © The Willi Hennig Society 2009.

Screening for anti-inflammatory activity of 12 Arnica (Asteraceae) species assessed by inhibition of NF-kappaB and release of human neutrophil elastase.

Several species in the genus Arnica have been used in traditional medicine to treat inflammatory-related disorders. Extracts of twelve Arnica species and two species closely related to arnica ( Layia hieracioides and Madia sativa) were investigated for inhibition of human neutrophil elastase release and inhibition of transcription factor NF-kappaB. Statistical analyses reveal significant differences in inhibitory capacities between extracts. Sesquiterpene lactones of the helenanolide type, of which some are known inhibitors of human neutrophil elastase release and NF-kappaB, are present in large amounts in the very active extracts of A. montana and A. chamissonis. Furthermore, A. longifolia, which has previously not been investigated, shows a high activity similar to that of A. montana and A. chamissonis in both bioassays. Sesquiterpene lactones of the xanthalongin type are present in large amounts in A. longifolia and other active extracts and would be interesting to evaluate further. COX-2:cyclooxygenase 2 EMSA:electrophoretic mobility shift assay fMLP: N-formyl-methionyl-leucyl-phenylalanine HaCaT:human keratinocyte HNE:human neutrophil elastase IkappaB:inhibitory subunit of kappaB iNOS:inducible nitric oxide synthase NF-kappaB:nuclear factor kappaB PAF:platelet activating factor STL:sesquiterpene lactone TNF-alpha:tumor necrosis factor alpha.