In this paper chemical composition of the essential oil (analysed by GC and GC-MS), the content of phenolic
compounds (analysed by HPLC), quantity of total phenols and total flavonoids (analysed by UV/Vis spectrophotometer),
antioxidant and antimicrobial activities of ethanolic extracts were investigated in endemic Teucrium arduini L. in population
of Mt Biokovo (Croatia). The oil was characterized by a high concentration of sesquiterpene hydrocarbons (70.4%) of
which β-caryophyllene (35.2%) and germacrene D (18.7%) being the major compounds. Three phenolic compounds
(quercetin, ferulic acid and rosmarinic acid) were identified and quantified in ethanolic extract of T. arduini using HPLC.
The results also showed that T. arduini is a source of polyphenolic and other antioxidants with radical-scavenging and
chelating properties. The ethanol extracts prepared from the leaf of T. arduini showed broad spectrum of antimicrobial activity
on Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa, Candida albicans
and Aspergillus brasiliensis, which are susceptible on concentration below or equal to 4.00 mg/mL, whilst Microsporum
gypseum was resistant at investigated concentrations.