Crystallization and preliminary X-ray analysis of geraniol dehydrogenase from Backhousia citriodora (lemon myrtle)

Seasonal Influence on the Essential Oil of Eucalyptus microcorys

The chemical composition of the essential oil, phenolic contents, and foliar nutrients of Eucalyptus microcorys leaves, cultivated in Brazil, was analysed on a monthly basis for one year. Canonical redundancy analysis correlated results with climate conditions (rainfall, humidity, and mean temperature), allowing three groups to be distinguished as regards temperature, flavonoids, and the content of some metals. Strong correlations between Mn, Cu, Zn, Ca, P, and K with some monoterpenes and phenolic compounds were observed. Oxygenated monoterpenes were predominant in all sampling months. Oil chemovariation may be influenced by climatic factors as well as by foliar nutrient variation.

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

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.