Phytochemical Traits and Biological Activity of <i>Eryngium amethystinum</i> and <i>E. alpinum</i> (Apiaceae)

Eryngium amethystinum L. is a wild vegetable used in Croatia. Both E. amethystinum and E. alpinum L. are decorative plants that can also be used in horticulture. To find out the hidden qualities of these two species, the following biological activities were studied: essential oil (EO) composition, analyzed by gas chromatography and gas chromatography with mass spectrometry (GC, GC–MS); phenolic compound content (PC), analyzed by high performance liquid chromatography (HPLC); total phenols as well as total flavonoids, analyzed by ultraviolet–visible spectrophotometry (UV/Vis); antioxidants, analyzed by 2,2-diphenyl-1-picrylhydrazyl radical-scavenging activity (DPPH), β-carotene-linoleic acid assay, chelating activity and reducing power of the extracts; and antimicrobial evaluation by micro-dilution assay and inhibition of Candida albicans blastospore germination. The major constituents of EO were β-caryophyllene (15.2%), α-pinene (10.2%) and 2,3,6-trimethylbenzaldehyde (9.3%) for E. amethystinum and caryophyllene oxide (27.9%), bicyclogermacrene (13.2%) and germacrene D (8.2%) for E. alpinum. The methanol extracts of both species showed a broad spectrum of antibacterial and antifungal activity with minimum inhibitory concentrations (MIC) less than or equal to 1.944 and 1.11 mg/mL, respectively