Chemical composition and antimicrobial activity of essential oils of lavender (Lavendula angustifolia) and lavandin (Lavandula x intermedia) grown in western Romania

The purpose of this study was to determine the chemical composition and antimicrobial properties of essential oils (EOs) isolated from lavender (L. angustifolia Miller) and lavandin (Lavandula x intermedia) harvested in 2011 in western Romania. The essential oils, isolated by steam distillation from inflorescences arrived at full flowering stage, were analyzed by gas chromatography coupled with mass spectrometry (GC-MS). The essential oil of L. angustifolia Miller analyzed contained as main components caryophyllene (24.1%), beta-phellandrene (16%) and eucalyptol (15.6%), while the essential oil of Lavandula x intermedia contains camphor (32.7%) and eucalyptol (26.9%). The antimicrobial activity was evaluated by the Kirby-Bauer method. Antimicrobial tests showed antimicrobial activity against Shigella fexneri, Staphylococcus aureus, E. coli and Salmonella typhimurium, while Streptococcus pyogenes is not sensitive to the action of the two essential oils. The study revealed that essential oils isolated and analyzed from lavender (L. angustifolia Miller) and lavandin (Lavandula x intermedia) display significant bactericidal effects against microorganisms such as Shigella flexneri, Staphylococcus aureus and E. coli even in the absence of active principles like linalool and linalyl acetate, considered responsible for the antibacterial and antifungal properties of essential oils obtained from different species of Lavandula. The results suggest once again that the antimicrobial activity of EOs is a resultant of the antibacterial properties of the major and minor components in their chemical composition.