Composition of the Essential Oils from the Aerial Parts of Five Wild Growing Valeriana species1

Abstract

The essential oils obtained by hydrodistillation from aerial parts of five Valeriana species, growing wild in Serbia and Montenegro, Valeriana officinalis L., V pancicii Halácsy et Bald., V bertiscea Pancic, V montana L. and V braunii-blanquetii Lakusic were analyzed by GC and GC/MS. The major compounds were found to be α-kessyl acetate (15.4%) and bornyl acetate (14.2%) in V. officinalis oil, patchouli alcohol (36.8%) in V. pancicii oil, isovaleric acid (13.2-39.0%) and 3-methylvaleric acid (10.0-30.8%) in the oils of V. bertiscea, V. montana and V. braunii-blanquetii.

Key Word Index

Valeriana officinalis, Valeriana pancicii, Valeriana bertiscea, Valeriana montana, Valeriana braunii-blanquetii, Valerianaceae, essential oil composition, α-kessyl acetate, α-kessyl alcohol, bornyl acetate, patchouli alcohol, linalool, isovaleric acid, 3-methylvaleric acid.

Introduction

The genus Valeriana L. includes about 350 species diat are widely distributed in the temperate regions of Europe, Asia, North America and also occur in Central and Soutii America (1). In die Flora Europaea die genus is represented by 20 species, while in Serbia and Montenegro nine species are reported.

The plants of this genus are rhizomatous, sometimes stoloniferous, perennial herbs with erect, usually unbranched flowering stems and white or pink flowers organized in cymose inflorescence. Valerianapancicii Halácsy et Bald. [Syn. Valeriana saxatilis L. subsp. pancicii (Halácsy et Bald.)] is endemic to Montenegro and northern Albania, whde V. bertiscea Pancic is a species endemic to Balkan Peninsula (2-5).

The most well-known species of tiiis genus is V. officinalis whose roots and rhizomes have been used as a sedative for many centuries (6). According to die Commission E, Valerian is indicated as an anti-anxiety agent for die treatment of restlessness and sleep disturbances resulting from nervous conditions (7).

The main compounds diat have been isolated from Valeriana species are ester iridoids (valepotriates), cyclopentanoid sesquiterpenes (valerenic acid and its derivatives) and essential oil (8-11).

As a part of our research on plants of genus Valeriana L. (12-14), we have investigated the chemical composition of essential oils from the aerial parts of five Valeriana spp., growing wüd in Serbia and Montenegro. The oils from roots and rhizomes of V. officinalis, V. pancicii and V. montana have been die subject of previous studies (14 - 16). However, to our knowledge, this is die first study of die oüs from die aerial parts of die species that we have investigated, with die exception of one report on leaf oil of V officinalis from Italy (17).

Experimental

Plant Material: The aerial parts of V. officinalis, V. pancicii, V. bertiscea, V. montana and V. braunii-blanquetii were collected during tiieir flowering period from different locations in Montenegro and Serbia (Table I). A voucher specimen of each sample has been deposited in the Herbarium of the Department of Pharmacognosy, Faculty of Pharmacy, University of Belgrade.

Oil Isolation: The oils were separately isolated from the aerial parts of die five Valeriana species by hydrodistiUation according to the European Pharmacopoeia procedure (18), using n-hexane as collecting solvent. Hexane was evaporated under reduced pressure and the oil yield was measured. The oüs were kept at -4°C until tiiey were analyzed.

Gas Chromatography :The GC analyses were carried out using a SRI 8610C GC-FID system, equipped with DB-5 capillary column (30 m ? 0.32 mm; film tiiickness 0.25 pm) and connected to a FID detector. The injector and detector temperature was 2800C. The carrier gas was He, at flow rate of 1.2 mL/min. The thermal program was 60°-280°C at a rate of 3°C/min. The split ratio was 1:10. The same samples of essential oils were analyzed twice.

Gas Chromatography/Mass Spectrometry :GC/ÌAS analyses were performed on a Hewlett Packard 6890-5973 GCMS system operating in die EI mode at 7OeV, equipped with a split/splidess injector (2000C). The transfer line temperature was 2500C. Helium was used as carrier gas (1 mL/min) and die capillary column used was HP 5MS (30 m ? 0.25 mm; film tiiickness 0.25 pm). The temperature program was die same with tiiat used for die GC analyses; split ratio 1:10. The injected volume was IpL (10% hexane solution of die oil).

Identification of the Components: The identification of die compounds was based on the comparison of their Retention indices (RI), dieir retention times (RT) and mass spectra with tiiose obtained from authentic samples and/or the NIST/NBS, Wdey libraries and literature (19,20). The linear retention indices (RI) were determined in relation to a homologous series of n-alkanes (C9-C24) under the same operating conditions (21).

Results and Discussion

The yields of the oils from die aerial parts of investigated Valeriana species varied between 0.10% and 0.36% (w/w), calculated on dry weight basis (Table I). The chemical composition of die oils is given in Table II.