Chemical constituents of the essential oils ofSideritis scardicaGriseb. andSideritis raeseriBoiss and Heldr. from Bulgaria and Macedonia

Abstract

The essential oils of two species of Sideritis growing spontaneously in Bulgaria and Macedonia are reported, Sideritis scardica and Sideritis raeseri. The oils of S. scardica from different locations differed significantly: in the Macedonian sample alpha-cadinol (20%) predominated, while in the oil of Bulgarian samples the main components were diterpenic compounds and octadecenol (over 20%). This is the first report of ditrpenoids in essential oil of S. scardica. The oil of S. raeseri demonstrated a distinct chemical profile with its high concentration of sesquiterpenes, main components being germacrone (25%) and elemol acetate (15.9%). The observed qualitative variability of the oil composition of S. scardica of different geographic origin could be a result of different ecologic conditions but might also reflect the well-known tendency of some Sideritis species to hybridize.

Variability in the Essential‐Oil Composition of Sideritis scardicaGriseb. from Native Bulgarian Populations

“…The obtained results were compared with those of samples of Bulgarian origin published previously [6], and a great difference in the chemical composition of the essential oils was observed. Thus, the oil of Population SC1, originating from Pirin Mt, was rich in monoterpene hydrocarbons (37.3%), while this type of compounds was detected at only 2.7% in the sample described by Kostadinova et al [6].…”

“…In contrast, Macedonian and Bulgarian S. scardica essential oils [6] were reported to be poor in monoterpenes ( < 7%). a-Cadinol (20.0%), a sesquiterpene alcohol, was the most abundant compound in the Macedonian sample, whereas in the oils of Bulgarian origin, the main components were diterpenoids ( > 21%) and octadecenol ( > 20%) [6]. Sesquiterpenoids as b-caryophyllene (18.8%) and nerolidol (12.1%) dominated in another Bulgarian sample [7].…”

“…b-Pinene (17.9%), carvacrol (14.8%), and a-pinene (7.3%) were found as main constituents in a sample of Turkish origin [2]. In contrast, Macedonian and Bulgarian S. scardica essential oils [6] were reported to be poor in monoterpenes ( < 7%). a-Cadinol (20.0%), a sesquiterpene alcohol, was the most abundant compound in the Macedonian sample, whereas in the oils of Bulgarian origin, the main components were diterpenoids ( > 21%) and octadecenol ( > 20%) [6].…”

Volatile Components in Sideritis scardica Griseb. Cultivar

“…in Bulgaria [ 4 ]. According to the recently reported data [ 5 ], in another Macedonian S. scardica taxon the most abundant compound was hexadecanoic acid (12.9%).…”

“…The presence of α-bisabolol, α-cadinene, isopropyl miristate, octadecenol differentiated the wild taxa from the cultivar. The method of preparation (by Clevenger [ 4 ] or Likens-Nickerson [in this study]) of the analyzed samples could result in some qualitative differences but the observed significant deviation in oil composition is probably due to the cultivation process.…”