Essential oil composition and preliminary molecular study of four HungarianThymusspecies

Abstract

Chemical and genetic differences of twenty taxa belonging to four Thymus species were studied in order to determine whether molecular characters and essential oil components could be used as taxonomic markers and to examine the correlation between them. Plant samples, representing different taxa and geographic regions, were collected from experimentally grown populations. Essential oil samples were analysed by GC/MS and cluster analysis of volatile composition resulted in segregation of thymol chemotypes from sesquiterpenic ones. Thymol was characteristic for all the populations of Thymus glabrescens and T. pannonicus as well as for certain taxa belonging to T. praecox and T. pulegioides. Sesquiterpenes occurred in only two taxa of T. glabrescens, in each sample of T. praecox and in three taxa of T. pulegioides. Plant samples were analysed by random amplified polymorphic DNA (RAPD). The obtained dendrogram revealed high gene diversity. The 13 primers resulted 114 polymorphic RAPD bands, and the average percentage of polymorphism was 80.8%. The RAPD dendogram showed separation neither at interspecific nor at interpopulational levels. Therefore, further specific molecular studies involving more taxa are suggested. Partial correlation have been found between molecular and chemical assessments.

Composition of Headspace Volatiles and Essential Oils of Three Thymus Species

“…laniger essential oil. Hungarian T. praecox contains a large amount of germacrene D (17.8%-44.2%) [5], while in our samples its quantity was significantly lower (prs 1.7% and prb 0.3%). Thymol (18.5%), p-cymene (14.6%), carvacrol (11.6%), and γ-terpinene (10.1%) were identified as the major components of the EO of Spanish T. praecox subsp.…”

“…The chemical composition of the EO was different for all four examined samples. T. glabrescens EO was rich in thymol, followed by γ-terpinene and p-cymene; this was similar to some Hungarian [5], Serbian [6] and Romanian [7] T. glabrescens oils. There is a noticeable inverse ratio of overall content of γ-terpinene and p-cymene (both are biochemical precursors of thymol) on one side and thymol on the other side in the T. glabrescens EO and HSV (0.2 and 9.8 %, respectively).…”

Thymus Plants: A Review—Micropropagation, Molecular and Antifungal Activity

“…Contrary Echeverrigaray et al [60], also based in RAPD profiles, observed that the cultivars (T. vulgaris L.) could be divided into two clusters, which coincided with results obtained by oil GS-MS analysis. Chemical and genetic differences of four Thymus species were studied by Pluhár et al [61] in order to determine whether molecular characters (RAPDs) and essential oil components could be used as taxonomic markers and obtained a partial correlation between molecular and chemical assessments. In Thymus caramanicus Jalas, Hadian et al [62] assessed the genetic (using ISSRs) and chemical variability and observed a relationship between genetic and chemical variability and geographic distribution.…”

Effect of water supply on growth and polyphenols of lemon balm (Melissa officinalisL.) and thyme (Thymus vulgarisL.)

“…However, the majority of trials carried out under open field conditions ascertained that lower field capacity or longer irrigation intervals reduced plant height and herb yield while increased root/shoot ratio and essential oil content [1][2][3][4]. Accumulation of volatile phenolic compounds seems to be accelerated by warm and dry climatic conditions [2,21], although contradictory findings have also been published [1]. Non-volatile phenolics are less studied.…”