The chemical composition and the antimicrobial and antioxidant activity of essential oils from two Helichrysum italicum (Roth) G.Don subspecies grown in Bulgaria were investigated. As a result, 95 compounds with concentrations above 0.05% were detected by GC/MS and 46 of them, mainly mono-and sesquiterpenes, representing 79.81% and 85.51% of the total content of the samples, were identified. The main constituents of the essential oil from Helichrysum italicum subsp. microphyllum (plant origin from Bosnia) were monoterpene α-pinene (20.84%) and sesquiterpene γ-curcumene (16.53%), followed by β-selinene (5.59%), ar-curcumene (4.39%), trans-caryophyllene (4.35%), β-diketone italidione I (4.32%), α-selinene (4.28%), and neryl acetate (3.81%). The sesquiterpene hydrocarbons were the dominant groups of chemical constituents in the essential oil, followed by the oxygenated aliphatic hydrocarbons. The main constituents in the H. italicum essential oil (plant origin from France) were neryl acetate (33.87%), γ-curcumene (8.84%), rosifoliol (5.46%), geranyl propionate (4.98%), αr-curcumene (4.31%), italidione I (3.56%), α-eudesmol (3.19%), and limonene (3.02%). The main class of chemical compounds was the oxygenated monoterpenes, followed by sesquiterpene hydrocarbons. H. italicum essential oil from France showed more pronounced antimicrobial activity against the Gram-positive bacteria Staphylococcus aureus and Bacillus subtilis, and the fungus Aspergillus brasiliensis, as well as stronger antioxidant potential.

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Lavender (Lavandula angustifolia Mill.) is an essential oil-bearing and medicinal plant of great economic and social importance to Bulgaria, which is the world largest producer of lavender oil nowadays. Currently, the industrial cultivation of lavender in Bulgaria employs up to seven varieties established during the last century. Despite the growing industrial lavender cultivation, few molecular markers have been applied for characterization of lavender genetic resources and breeding. The present study employed sequence-related amplified polymorphism (SRAP) markers to characterize the genetic resources and genetic diversity within and between two groups of ten Bulgarian and five foreign lavender varieties and breeding lines. The data generated following analysis with 51 SRAP primer pairs showed amplification of a high number (4697) and ratio (77.2%) of polymorphic SRAP fragments resulting in relatively high value of the polymorphism information content, with an average of 0.27 ± 0.03 for the used primer pairs. Analysis of molecular variance of the SRAP data further revealed high level of genetic diversity (96.6% of the total variations) within the analyzed groups of Bulgarian and foreign varieties and rather low diversity (3.4% of total variations) between the two groups. The possibilities for further applications of SRAP markers in lavender breeding and cultivation are discussed.

This study compared the essential oils (EO) composition of Helichrysum arenarium (Bulgarian populations) with that of the cultivated species H. italicum. The EO composition of H. arenarium and H. italicum were analyzed via gas chromatography. In general, 75 components were identified in H. arenarium EO and 79 in H. italicum EO. The predominant constituents in H. arenarium EO were α-pinene (34.64–44.35%) and sabinene (10.63–11.1%), which affirmed the examined population as a new chemical type. Overall, the main EO constituents of H. italicum originating in France, Bosnia and Corsica were neryl acetate (4.04–14.87%) and β-himachalene (9.9–10.99%). However, the EOs profile of H. italicum introduced from the above three countries differed to some extent. D-limonene (5.23%), italicene, α-guaiene and neryl acetate (14.87%) predominated in the H. italicum introduced from France, while α-pinene (13.74%), δ-cadinene (5.51%), α-cadinene (3.3%), β-caryophyllene (3.65%) and α-calacorene (1.63%) predominated in plants introduced from Bosnia. The EOs of the plants introduced from France and Corsica had similar chemical composition and antimicrobiological activity.

The efficient lavender (Lavandula angustifolia Mill.) breeding for essential oil production requires routine and accurate comparison the flower volatile composition of larger number individual plants from genetic resource pools and segregating populations. Here we describe the performance testing of a simple procedure for comparative GC-MS analysis of flower volatile composition of individual lavender plants. It involves collection of fixed number flowers at selected stage of development and direct solvent extraction and GC-MS analysis of the extracts. The summarized data on relative standard deviations for the analyzed compound abundancies determined from three replica analysis of individual plants from Bulgarian lavender varieties are presented. Further application of this comparative GC-MS analysis procedure demonstrates significant changes in the accumulation of certain volatiles during flower development. The comparative analysis also showed no significant daytime variation of the flower volatile composition and minor variations after testing the same plants within five consecutive days. The possibilities for routine applications of the tested procedure for comparative GC-MS analysis of flower volatiles in larger number of plants from lavender segregating populations or genetic resources collections are discussed.