Chemical Composition and Seasonal Variations of Spike Lavender Oil from Southern Spain

Abstract

The composition of six essential oil samples, obtained by steam distillation of twigs of spike lavender (Lavandula latifolia Med.) harvested in three different locations from southern Spain during the full flowering and fruiting phenological stages, has been analyzed by capillary GC and GC/MS in combination with retention indices. Yields of the oils during flowering ( 1.5-2.2%) were 2.5-7 times higher than during fruiting (0.3-0.6%). Among the 56 identified constituents (accounting for 96.0-97.5% of the oils), the main and characteristic components were linalool (27.2-43.1%), 1,8-cineole (28.0-34.9%), camphor (10.8-23.2%), borneol (0.9-3.6%), [beta]-pinene (0.8-2.6%), (E)-[alpha]-bisabolene (0.5-2.3%), [alpha]-pinene (0.6-1.9%), [beta]-caryophyllene (0.5-1.9%), [alpha]-terpineol (0.8-1.6%), sabinene (0.3-0.8%), myrcene (0.3-0.8%), camphene (0.4-0.6%), terpinen-4-ol (0.3-0.5%) and limonene (0.2-0.9%). The volatile chemical composition and oil production of both full flowering and fruiting plants allowed to assess the type and quality of the spike lavender oils processed in the studied area.

Key Word Index

Lavandula latifolia, Lamiaceae, spike lavender, essential oil composition, linalool, 1,8-cineole, camphor, seasonal variation, geographical variation.

Introduction

Spike lavender oil is probably the most typical Spanish essential oil. It is obtained by steam distillation of the flowering tops of Lavandula latifolia Med. as a pale greenish yellow liquid with a characteristic, rough and slightly cineole- and camphor-like odor (1). At one time, more than 200 metric tons a year of this oil were produced in Spain (2) and, more recently, a production of 60-115 metric tons a year has been estimated for the last decade (3). L. latifolia is a shrub, normally 30-60 cm in height, that grows wild in the Mediterranean regions of the former Yugoslavia, Italy, France, Spain and also in Portugal (4). It is particularly abundant in Spain where it grows on calcareous soils, in the sunny areas of the hills at 500-1500 m altitude, mainly in the eastern half of the country (5). Only L. latifolia, among the 10 taxa of genus Lavandula growing wild in Spain, is cultivated and industrially distilled from both wild and cultured plants and, therefore, it has been established as an important essential oil crop in our country (5).

Spike lavender oil finds its main use in soap compounds and many cosmetic and technical preparations such as bath salts, room sprays or disinfectants (6). In addition, it has been used in food products as flavor component (7) and in aromatherapy as an expectorant and mild but effective antiseptic (8). Since Wobben et al. (9), in 1969, used modern Chromatographie and spectroscopic techniques on Spanish spike lavender oil to analyze and confirm the presence of several components, the composition of this oil has been studied and reviewed several times (5,6,9-11). More than 350 components have been identified in the oil (6) and most of the samples analyzed were dominated by linalool, 1,8-cineoIe and camphor.

It is known that the Spanish area that yields the highestquality spike lavender oil is La Alcarria, in the provinces of Cuenca and Guadalajara (11-13). Furthermore, the provinces of Murcia, Albacete, Granada and Almeria are also part of the main producing areas of spike lavender oil in Spain (3). However, it seems to be less known that eveiy year several distillers produce certain amounts of spike lavender oil in Jaén province and, consequently, little attention has been paid to the composition of these oils (with the exception of a sample included in reference 11). Aware of the capability of our territory in the production of oils, the aim of this study was to know the composition and variations of the oils prepared from L. latifolia growing wild in the area of the Cazorla, Segura y Las Villas Natural Park (Jaén, Spain). This work is part of a program developed by the University of Jaén, in collaboration with the environmental regional authorities, whose purpose is to improve the knowledge on chemical composition and applications of aromatic plants from our surroundings (14).

Experimental

Plant material: Samples of L. latifolia were collected in August 1998 during the full flowering period (Ll-1a, Ll-2a, Ll-3a) and in October 1998 during the fruiting period (Ll-1b, Ll-2b, Ll-Sb) from three different spike lavender populations located into the Cazorla, Segura y Las Villas Natural Park (Jaén province, Spain) (See Table I for details). The plant material from each population consisted of the twigs of several single plants. Botanical identification of samples was performed by one of us (P.L.) and voucher specimens have been deposited at the Herbarium of the Natural Park.

Oil isolation: Plant samples were air-dried (for 7-10 days), chopped and steam distilled for 2 h using a double-bottom still, where plants are not in direct contact with boiling water (simulating the big stills used in the field), assembled to a Clevenger-type collector. Oils obtained were recovered with diethyl ether, dried over anhydrous sodium sulfate, concentrated under a gentle stream of nitrogen and stored under nitrogen at -20°C until analyzed (oil yields in Table I).