engleski

Phytochemical composition of essential oil of Croatian endemic species Centaurea tuberosa Vis.

The genus Centaurea L. is very important genera of Asteraceae family, with many local endemic species. According to Flora Croatica database (http://hirc.botanic.hr/fcd) described 88 Centaurea species, of which 30 is the endemic. The investigated Centaurea tuberosa L. (synonim: Centaurea napulifera subsp. tuberosa (Vis.) Dostál) is also Croatian endemic species and this species belongs to the vegetation community of East Adriatic submediterranean and epimediterranean lawns: Chrysopogony-Koelerion splendentis. This is the first study on the chemical composition of C. tuberosa species. Plant material of investigated plants was collected from Tijarica (near Split) Croatia in the summer (July) 2015. Aerial parts of plants were performed in a shady place at room temperature for 10 days. Dried aerial parts of plant material (100 g) were subjected to hydrodistillation for 3 h in Clavenger type apparatus. This essential oil have been analysed by GC (Varian 3900) and GC/MS (Varian Saturn 2000 system) using VF-5ms capillary column. The individual peaks were identified by comparison of their retention indices of n- alkanes to those of authentic samples and literature [1], as well as by comparing their mass spectra with the Wiley 9.0 library (Wiley, New York) and NIST/02 mass spectral database. The percentage composition of the samples was computed from the GC peak areas using the normalization method. Total yield of oil was 0.55%, based on dry weight of sample. Thirty-seven compounds representing 82.9% of the total oil. The essential oil of C. tuberosa was characterized by a high concentration of caryophyllene oxide (27.8%), followed by β-caryophyllene (7.1%), docosane (6.8%), spathulenol (5.4%). Also, compounds β -caryophyllene, spathulenol and caryophyllene oxide were the common for the C. armena, C. appendicigera and C. helenioides [2]. According to literature data, the composition of essential oils of Centaurea species are frequently characterized by components with sesquiterpenes skeleton such as caryophyllene, eudesmol, germacrene and spathulenol, hydracarbons and monoterpenes as pinene, terpinene, carvacrol [3-5]. The present study gives additional knowledge about phytochemical composition of the essential oil on the genus Centaurea.

Centaurea tuberosa ; caryophyllene oxide ; β-caryophyllene

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