GC/MS and PCA Analysis of Volatile Compounds Profile in Various Ilex Species

Species of Ilex genus are particularly rich in bioactive constituents such as polyphenols, saponins, and alkaloids. In terms of phytochemical research, volatile compounds have not been as widely investigated as non-volatile ones. Therefore, in the present research we investigated the phytochemical profile of selected Ilex species by headspace-solid phase-microextraction coupled with gas chromatography-mass spectrometry (HD-SPME-GC/MS). Phytochemical profile between the same and different species was variable. For this reason, it was investigated by principal component analysis (PCA), matrix correlation (calculation of R2 and Pearson correlation parameter between samples) as well as hierarchical clustering (dendrogram). In our results, we exhibited that the amount of (Z)-2-hexenal and methyl salicylate was the most important factor for ascertaining similarity between samples. However, concentrations of some of these components were insufficient to describe all dependencies between Ilex specimens. Further analyses (PCA and dendrogram), exhibited that thymoquinone had secondary impact on phytochemical profiles similarity, as did o-methyl-anisole, (E)-2-decenal, salicylaldehyde and (Z)-3-hexen-1-ol. Differences of profile between samples may result from many factors such as local environmental conditions, creation of different chemotypes or even infestation by unknown pathogens or the presence of non-pathogenic microorganisms. Further research is required to investigate this phenomenon. Moreover, it was found that some of Ilex species may be potential sources of bioactive volatile components.