Contribution to the Analysis of the Volatile Constituents from some Lavender and Lavandin Cultivars Grown in Greece

The essential oils of Lavandula angustifolia and the Lavandin hybrids "superJ' and "special" grown in Greece, were studied in order to evaluate their quality as far as the correlation of their essential oil composition. The essential oil yields were determined to 4.4 %, 7.5% and 8.5% in the lavandula and lavandin "super" and "special" hybrids respectively. Fifty-nine constituents were identiiied representing the 99% of the oils. The qualitative analysis of the oils was carried out by GCIMS and revealed that linalool and linalylacetate were the predominant constituents. Remarkable differences were noticed between the camphor percentages among them (1 1.35% and 5.03% for the "super " and "special " respectively).


Introduction
Interest in growing lavender has taken an upsurge in the past ten years, with the old-fashioned lavender fkgrance becoming popular again, perhaps because of its use in arornatherapy'. Essential oil of lavender is also used as flavoring for various foods and beverages, though non-food products manufactured with lavender oil include soaps, colognes, and other cosmetics. Lavender may be grown as bedding plant, herb specimen, tea plant, bee forage, or source of fragrance in landscaping designs. Lavender is a popular aromatic and perennial Mediterranean herb, belonging to Larniaceae family, growing almost all over the world Asia, America, Australia, and almost all over Europe. It is marked as the fiesh or dried plant.
Among the Lavender species, Lavandula angustifolia M i l l . produces the best quality's essential oil for the industry, and due to the high linalool content, it is used in the aromatherapy for its mild sedative activity as well as in antibacterial and antifimgal medicaments 2' . It is also reported in the folk medicine4 because of the carminative, diuretic and stomachic properties. Very high-quality essential oil of lavender is required for use in the alternative health practice of aromatherapy, as far as in pharrnaceutics. Lavandin oils are distilled fkom hybridized plant Lavandula hybrida Reverchon, a cross between Lavandula angustifolia Mill. and Lavandula latifolia Medic. Lavandin plants are vigorous and extremely productive, though their essential oils yield can be 2-3 times higher compared with L. angustifolias. They produce high yields of lower quality and priced lavender oils, used widely in the production of inexpensive perilunes, soaps, bath products, detergents etc., or in the adulteration of the high priced lavender oils6. There are many successfbl commercial hybrids, the most of France origin, cultivated in many parts of Europe, among them the best known are "abrialis", "super", and "grosso ".
In Greece, lavender is growing in many areas and cultivated in several districts but not systematically. Because of the great commercial interest of lavender oils the aim of the present work was to study the essential oil of a) Lavandula angustifolia Mill. grown in Northern Greece, though as far it concerns to our knowledge, there are no reported data on the Greek oil and b) the essential oils of two commercial Lavandin hybrids cultivated in Greece, the "super " and "special ".

Results and Discussion
The distillation of L. angustfolia Mill. and of super and special Lavandin hybrids yielded pale yellow essential oils, which percentage yields' were determined as 4.4%, 7.5%, and 8.5% respectively. These yields are classified to the highest reported in the literature for Lavender oils7b39. The yields of the hybrids were signiiicantly higher than those of L. angustfolia, the special hybrid being more efficient than the super one (93% and 70% higher yields, respectively, compared to L. angustvolia).
In the qualy-quantitative analysis of the oils, performed by GC and GC-MS, were detected more than eighty constituents and fifty-nine of them were identified, representing at least the 99% of the oils. The percentages reported were based on the data after three chromatographic runs (Srel.* 1 . O1 -It1.2%). The constituents were identified by comparing the retention times on three columns of different polarity with those of authentic samples using the peak enrichment technique. For compounds that pure samples were not available, identitication was carried out by comparison with references oils and mainly by mass spectrometry, matching the peak mass spectra to those of MST 98 mass spectra library, and of the commercial library Newterp for essential oilslo. In Table 1 are listed the identified constituents of lavender, and of super and special lavandin hybrids respectively. Although the number of components of lavender essential oil resulted high, the main components (>I%) representing the 91.54% of the total sample, were elevenlinalool (50.63%), linalylacetate (15.72%), terpinen-4-01 (7.84%), cis-ocimene (4.25%), trans-oc' ltnene (2.73)%, lavandulyl-acetate (2.73%), P-caryophyllene (2.04%), lavandulol ( 1.52%), a-terpineol (1,52%), 3-octanone (1.36%) and cryptone (1.2%). They correspond to the most significant compounds as indicated by extensive studies performed on lavender plant^".'^.'^. The percentage amount of linalool (50.63%) is among the highest yields encountered in the literature; 50.52% was recorded for the cultivars Munsteam grown in the United States", 49.90% for an Italian Lavender sample oil, 49.86% and 44.44% for different French culti~ars'~~'~. Camphor and 1,8 cineol, which undermine the quality of the oiI, accounted for 0.06 and 0.66% of the oil respectively. Nevertheless, the amounts of terpinen-4-01, and the typical components for lavender oil, lavandulol and lavandulylacetate were also remarkable. The oxygenated compounds nerol, nerylacetate, geranylacetate (known as the "rhodinol" part of the oil) that are important for the overall aroma, donating a sweet and pleasant note to the oil, contributed to the lavender oil as well -1.76% ( Table 2). The super and special lavandin hybrids contained linalool as main component (23.01% and 37.69 % respectively), though the linalylacetate content varied from 20.35% to 29.14% falling within the ranges of the typical lavandin oilsi4. Significant differences were observed between the super and special hybrids concerning the percentages of 1,8 cine01 (15.85% and 5.39%), camphor (1 1.35% and 5.03%), terpinen-4-01 (6.67% and 0.08%) and those of lavandulylacetate (0.37% and 2.2%) respectively. The amounts of camphor and 1,8 cineol of super lavandin essential oil (1 1.35% and 15.85% respectively) match those noted by Melegari et a1.I6, for Italian super cultivars. In contrast, the camphor and 1,8 cineol were found in lower quantities in the special hybrid (5.03 and 5.39% respectively). Moreover the group of the components constituting of the "rhodinol" part was higher in the special hybrid: 2.92% versus 2.43% in the super one (Table 2), nevertheless both values were higher than those recorded for known Italian lavandin oils''. In conclusion, Lavender and Lavandin cultivated in Greece produce essential oils with quite high yields (4.4%, 7.5%, and 8.5%). Moreover the super and special hybrids show good adaptability to the Greek climate and environmental conditions, the latter producing an essential oil of superior yield and quality.

Plant material
The plant material was originated from experimental fields established in Northern Greece, full sun exposed, with sod conditions; moderate alkaline PH, well drainage and sufficient in all the nutrients. The fields were not irrigated or fertilised, not even any kind of plant protection was applied.

Gas Liquid Chromatography and Gas Chromatography I Mass Spectrometry
The essential oil samples were analysed by gas chromatography, using a Gas Chromatograph Hewlett Packard 5890 Series 11, equipped with one injection port and a two-channel system of columns and respective FIDs, connected to a chromatographic integrator (Hewlett Packard 3396 Series I1 Dual Channel). Sample injection 0. Oven temperature: 45 to 220' C at 3.5' Clrnin, carrier gas nitrogen at 140 Kpa, injection temperature 220' C, detectors7 temperature 300' C. The percentage compositions were computed fiom the GC peak areas without correction factors. The identification of the constituents was carried out 1) using the peak enrichment technique of reference compounds (authentic samples by Roth, Aldrich and Sigma), 2) with the chromatograms comparison to those of essential oils previously analyzed and published fiom our data bank and " Elution order from the DB-5 column Kovats retention index on a DB-5 column 1 authentic sample (mainly from Roth and Aldrich, Sigma), 2 reference oils, 3