Oil Content and Fatty Acid Profiles of Seed Oil from the Genus Lavandula

Abstract

Sir The genus Lavandula is comprised of 39 species and several hybrids of woody perennial plants some of which have long been grown for their essential oil, which is extracted by steam distillation from floral tissue. The major cultivated lavenders are varieties of Lavandula angustifolia Mill. (true lavender) and hybrids between L. angustifolia and L. latifolia Medik., (spike lavender), called L. 9 intermedia Emeric ex Loisel. and commonly known as lavandins. Several species within the genus are popular gardens plants and are also grown for cut and dried flowers, including the above species and additionally L. dentata L., L. stoechas L. and L. pedunculata Mill. Research on this genus has focused largely on taxonomy, essential oil composition and yield, together with research on the biological activity of essential oils; for reviews see [1–3], respectively. Little work has focussed on seed oils of this genus although seed oils from several genera within the family Lamiaceae have been analysed [4]. We are interested in the possibility of extending the range of products from lavenders and therefore examined the oil content and fatty acid profiles of oils extracted from lavender seed (nutlets) of five commonly grown species. Prior to extraction of oil approximately 10 g of seed was dried overnight at 80 C and ground in a coffee grinder. The oil was extracted for 16 h using a Goldfische extraction apparatus and 100 ml of petroleum ether (b.p. 40– 60 C). The mass of the oil was determined gravimetrically after removal of solvent. Results are expressed as a percentage of the seed weight. Oil content is reported as a percentage of the dry weight of the seed. To determine the fatty acid profile 100 mg of oil was mixed with 3 ml of petroleum spirit (b.p. 40–60 C) followed by 0.5 mL of sodium methoxide solution (1.15% w/v sodium in methanol). The sample was mixed for 15 s and allowed stand for 10 min. Bromothymol blue (0.1 ml) of a 0.1% w/v solution in methanol was added followed by 0.4 mL of 1 M hydrochloric acid. Sodium carbonate (0.6 mL) of a 1.5% solution was added and the solution was mixed thoroughly. Distilled water was added to bring the solvent layer to the top and following phase separation the solvent layer was transferred to GC vials. The fatty acid profile was determined by gas chromatography using a SGE BPX70 capillary column (30 m, 0.22 mm, 0.25 lm film) and a flame ionisation detector. The column temperature was programmed at 185 C for 8 min then increased at 10 C/ min to a final temperature of 220 C which was held for 3 min. Total run time was 13.5 min. The injector (split mode) temperature was set at 250 C with a split ratio of 1:50. Detector temperature was 260 C. Data was analysed using Star Workstation Chromatography software (Version 6.20). Oil was extracted and analyzed from seed of three varieties of L. angustifolia. These were ‘‘Hidcote blue’’ (Kings Seeds, Bundaberg, Australia), ‘‘True lavender’’ and ‘‘Munstead’’ (Highsun Express Seeds, Ormiston, Australia). We also extracted and analyzed seed from three sources of L. latifolia. One was purchased from Highsun Express seeds and two came from L. latifolia accessions growing in the lavender germplasm collection at Charles N. A. R. Urwin (&) School of Animal and Veterinary Sciences, Charles Sturt University, Locked Bag 588, Wagga Wagga, NSW 2678, Australia e-mail: nurwin@csu.edu.au