|Baser, Husnu Can|
Submitted to: Plant Genetic Resources
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/21/2005
Publication Date: 8/12/2005
Citation: Tabanca, N., Douglas, A.W., Bedir, E., Dayan, F.E., Kirimer, N., Baser, H.K., Aytac, Z., Khan, I.A., Scheffler, B.E. 2005. Patterns of essential oil relationships in pimpinella (umbelliferae) based on phlyogenetic relationships using nuclear and chloroplast sequences. Plant Genetic Resources. 3(2):149-169. Interpretive Summary: Herbal plants are used as a source of novel chemicals that can have valuable properties. Therefore it is of interest to find related compounds to see if they have improved properties. Related species are the logical source for such derivatives. This paper deals with determining the genetic relationship of 26 species of Pimpinella (common source of aniseed - licorice flavor) using nuclear and chloroplast DNA sequences to determine the relationship. In addition, 16 species were examined to determine their composition for essential oils. The distribution of the compounds and correlating that information with the genetic relationship provides information regarding the presence and perhaps evolution of the different classes of compounds.
Technical Abstract: Water-distilled essential oils from the fruits, leafy branches and the roots of 19 Pimpinella species growing in Turkey and their phylogenetic relationships to one another were examined. Phytochemical investigation of the essential oils resulted in the isolation of 16 phenylpropanoids, 4 sesquiterpenes and 2 azulene-type norsesquiterpenes. The structures of the isolated compounds were determined primarily from 1D- and 2D NMR experiments as well as LC-MS and GC-MS. Phylogenetic relationships among 26 species were evaluated using ITS 1, ITS 4 nuclear rDNA and psbA-trnH cpDNA sequences. In this study, the significance and occurrence of phenylpropanoids, azulenes and geijerenes are discussed from a phylogenetic, chemical and biosynthetic perspective. The distribution of the different classes of compounds and their associations with one another, given our knowledge regarding their biosynthetic pathways, indicates that this information, in conjunction with the phylogeny, provides valuable information regarding the presence and perhaps evolution of the different classes of compounds. Analysis of the phenylpropanoid components indicates that (E)-anethole is an obligatory intermediate of this pathway. The various Pimpinella species differ primarily in their ability to acylate anethole, suggesting that while the pathway leading to anethole is common to this genus, species differ in their enzymatic machinery leading to acylate. The relationship between azulenes and geijerenes is not as intuitive, but all Pimpinella species analyzed in this study have the biochemical machinery required to synthesize these chemical classes.