Volatile secondary metabolites of six Turkish Hypericum species: chemical composition and chemotaxonomic significance

Abstract Volatile secondary metabolite profiles of 20 wild populations of six taxa from four sections of Turkish Hypericum (Hypericaceae; H. orientale, H. bupleuroides, H. venustum, H. hirsutum, H. linarioides and H. androsaemum) were investigated by solid-phase microextraction supported gas chromatography-mass spectrometry analyses for the first time. All tested volatiles were dominated mainly by sesquiterpene hydrocarbons, oxygenated monoterpenes and oxygenated sesquiterpenes, but major volatile components and the range of each ingredient varied greatly with populations. A total of 288 compounds were identified accounting for 100% of the total volatiles, H. orientale being the richest with 64 components and H. linarioides the poorest with 41 components. Multivariate techniques namely, hierarchical cluster analysis and principal component analysis were performed to segregate the samples in terms of geographical origin and botanical section. The results indicated the tested populations as possible novel chemotypes and their volatile profiles and components were not of significant chemotaxonomic value. Such data are crucial in identifying heterogeneous germplasms and possibly beneficial in clarifying evolutionary relationships within the botanical sections of the genus Hypericum.