A chemometrics as a powerful tool in the elucidation of the role of metals in the biosynthesis of volatile organic compounds in Hungarian thyme samples

Abstract

The volatile fraction of the leaves of Thymus pannonicus All. (Lamiaceae) was analyzed by headspace extraction followed by GC-FID and GC-MS analysis. The different headspace profiles were recognized, with citral and with monoterpene hydrocarbons as dominant compounds. In addition, the determination of Cr, Co, Ni, Mo, Cu, Zn, Mn, Fe, Mg, Ca, K and Na was conducted by spectroscopic techniques (FAAS, GFAAS and ICP-OES). In order to evaluate the relationship between volatile organic compounds and metals, a chemometrics approach was applied. The data obtained by analysis of the headspace and elemental content were subjected to correlation analysis, factor analysis, principal component analysis and cluster analysis. A number of significant correlations of metals with plant volatiles were found. Correlation of Zn with citral, Mn with oxygenated monoterpenes and Mg with β-bourbonene, could be explained by involvement of metals in the biosynthesis of volatile organic compounds.

Keywords: AS; Atomic spectrometry; CA; FAAS; GC–FID; GC–MS; GFAAS; Gas chromatography; HS; ICP-OES; Metals; PCA; Terpene biosynthesis; Thymus; VOC; atomic spectrometry; cluster analysis; flame atomic absorption spectrometry; gas chromatography–flame ionization detector; gas chromatography–mass spectrometry; graphite furnace atomic absorption spectrometry; headspace; inductively coupled plasma optical emission spectrometry; principal component analysis; volatile organic compounds.