MICROMORPHOLOGICAL AND PHYTOCHEMICAL TRAITS OF MICROMERIA ALBANICA (GRISEB. EX K. MALÝ) ŠILIĆ AND M. DALMATICA BENTH. (LAMIACEAE)
In this study, types and distribution of trichomes, chemical composition of the essential oil, as well as phenolic compounds’ contents of two Balcanic Micromeria Benth. species from section Pseudomelissa, Micromeria albanica (Griseb. ex K. Malý) Silic and M. dalmatica Benth., were investigated. Non-glandular trichomes, peltate trichomes, and three types of capitate trichomes were observed on leaves, calyces, and stems. The yield of the essential oil was 0.5% for each species. In general, 36 different essential oil compounds were identified in M. albanica and 21 in M. dalmatica, representing 86.9% and 88.6% of the total oil, respectively. The essential oil was characterized by the high content of oxygenated monoterpenes (66.2% in M. albanica and 79.6% in M. dalmatica), with dominant menthane type compounds, such as menthone, pulegone, piperitenone, and piperitenone oxide. Spectrophotometrically determined contents of total polyphenols (TP), tannins (T), total flavonoids (TF), and total phenolic acids (TPA) were lower in M. albanica (3.83%, 0.88%, 0.39%, and 2.91%, respectivelly), and significantly higher in M. dalmatica (TP: 6.12% ; T: 1.28% ; TF: 0.55% ; TPA: 5.80%). The obtained results show that the investigated Micromeria species have relatively high content of phenolic compounds, which suggests that they could have considerable antioxidant activity. The presented study contributes to the knowledge on the genus Micromeria in general, and particularly on species belonging to the section Pseudomelissa.