Comparative Study of Essential Oil of Three Achillea Species from Serbia

Abstract

The composition of the essential oils from herbs of Achillea alexandri-regis, A. holosericea and A. lingulata was analyzed by GC and GC/MS. The predominant compounds in the oil of A. alexandri-regis were: α-pinene (14.4-15.7%), isopinocamphone (5.4-23.5%), α-phellandrene epoxide (5.0-19.0%), borneol (3.6-7.7%) and spathulenol (1.4-9.7%). The major components in the herb oil of A. holosericea were: borneol (17.3-18.1%), camphor (9.7-15.1%), terpinen-4-ol (6.3-11.1%) and camphene (5.7-7.2%). The presence of borneol (23.0-40.7%), β-thujone (5.5-7.6%), bornyl acetate (3.5-7.8%) and sabinene (1.7-6.7%) was characteristic of A. lingulata herb oils. The presence of borneol in high concentration was a connecting property for the oil of all three investigated Achillea species, especially for A. lingulata and A. holosericea. On the other side, the low concentration (0.2%) of camphor was characteristic of the investigated samples of A. alexandri-regis and A. lingulata.

Key Word Index

Achillea alexandri-regis, Achillea holosericea, Achillea lingulata, Asteraceae, essential oil composition, α-pinene, borneol, terpinen-4-ol, spathulenol, α-phellandrene epoxide, isopinocamphone, camphor.

Introduction

Achillea alexandri-regis Bornm. et Rudski (section Ptarmica, Asteraceae) was described as new species in 1934 (1). Since then, this plant was found in no other locality except its locus classicus, mountain Osljak (2,3). This limestone mountain represents the north branch of the Sara Mountain, and therefore, A. alexandri-regis is stenoendemic of Sara. This yarrow is similar to A. lingulata Waldst. et Kit. and to A. holosericea Sibth. et Sm., an endemic species of the south and south western part of Balkan peninsula (2,4). It was believed that A. alexandri-regis is only hybrid of those two species. The recent comparative morpho-chorological analysis proved that it is true that A. alexandri-regis is of hybrid origin, but it is well differentiated and distinct from the parent species, A. holosericea and A. lingulata (3). In spite ofthat, up to now prominent floristic literature has not mentioned A. alexandri-regis as a distinct taxon (4). In this paper we describe the chemical composition of the oils isolated by hydrodistillation from dried herb of A. alexandri-regis, A. lingulata and A. holosericea.

Experimental

Plant material: The samples of herb of A. alemndri-regis were collected on mountain Osljak during the summer of 1995 (July and August). The samples of A. holosericea herb were collected in July 1994, 1995 and 1996 on the mountain Ostrovica, locality of Rusenica River. The samples of herb and leaves from the rosette of A. lingulata were collected on Kopaonik Mountian, in the middle of July 1995 and 1996. The taxonomical identification of the plant material was done by Vlada Stevanovic, Faculty of Botany, University of Belgrade. Appropriate voucher specimens have been deposited in the Herbarium (BEOU) of the Institute of Botany, Botanical Garden, University of Belgrade.

oil isolation and analyses: The oils were isolated by hydrodistillation in a Clevenger-type apparatus from dry herbs. Chemical composition of the oils was determined by the use of analytical GC (FID) and GC/MS technique. Forthis a Hewlett Packard, HP-5890 Series II, gas Chromatograph, equipped with split-splitless injector, fused silica capillary column (25 m × 0.32 mm), coated with cross-linked methyl silicone gum (0.5 µm film thickness), and FID was employed. oil solutions in ethanol (~ 0.5%) were injected in split mode (1:30). Injector was heated at 250°C, detector at 300°C, while column temperature was linearly programmed from 40°-280°C (2°C/min.).

GC/MS analyses were carried out on a Hewlett Packard, HP 5890 Series II, gas Chromatograph equipped with split splitless injector, fused silica capillary column (50 m × 0.2 mm) PONA, coated with cross-linked methyl silicone gum (0.5 µm film thickness), and HP 5971 mass selective detector. The Chromatographie conditions were as above. Transfer line (MSD) was heated at 280°C. EIMS spectra (70 eV) were acquired in scan mode in m/e range 40-300 amu.

Component identification and quantification: Identification of individual constituents was made by comparison of their retention times with those of analytical standards of available terpenoids, and by computer searching, matching mass spectral data with those held in Wiley/NBS library. For quantification purposes, area percent reports obtained by FID were used.

Results and Discussion

An average content of oil from the full-blooming herb of A. alexandri-regis was 0.25%. Gas chromatograms of A. alexandri-regis oil samples contained about 90 well resolved peaks. The main constituents of this oil were: α-pinene (14.4-15.7%),isopinocamphone(5.4-23.5%), α-phellandreneepoxide (5.0-19.0%), 1,8-cineole (4.4-5.7%), borneol (3.6-7.1%) and spathulenol (1.4-9.7%) (Table I). Identified constituents being present in concentrations higherthan 1% were: caryophyllene oxide (2.5-3.4%), β-pinene (2.0-2.1%), α-campholene aldehyde (1.3-1.9%), myrtenol (0.6-1.6%) and myrtenal (0.5-2.1%). The sum of all identified constituents varied from 64-84%. The presence of a high percentage of α-pinene and β-pinene in A. alexandri-regis oil was noted to be similar to that found in A. millefolium oil (5). On the other hand, camphor was almost absent in the oil of A. alexandri-regis as it was in the oil of A. ageratum (6). This is very interesting because camphor is a dominant constituent of the oils of some other Achillea species (7-11). The oil obtained from post flowering herb of A. alexandri-regis, collected at the end of August of 1995, contained significantly high amounts of isopinocamphone (23.5%) and a-phellandrene epoxide (19.0%). In contrast, the concentrations of borneol (3.6%) and spathulenol (1.4%) were lower than in the oils obtained from the herbs collected in the full flowering stage.