Comparison of Chemical Composition, Antioxidant and Antimicrobial Activity of Lavender (Lavandula angustifolia L.) Essential Oils Extracted by Supercritical CO2, Hexane and Hydrodistillation

The effects of three different extraction methods, namely hydrodistillation, supercritical CO2 extraction (SCE) and hexane extraction on the yield, chemical composition and antimicrobial and antioxidant activities of lavender essential oil were investigated in this study. SCE produced a yield of 6.7 % (dry weight), which was comparable to that of solvent extraction (7.6 %), but significantly higher than that of hydrodistillation (4.6 %). The chemical composition of the oils showed considerable variations among the extraction methods, with linalool, linalyl acetate, camphor and borneol making up approximately 80 % of identified components in all extracts. Hexane extraction produced oils with the presence of waxes, colour pigments and albuminious materials with semi-solid consistency, while hydrodistillation extracts showed signs of thermal degradation. The SCE extracts had an aroma with the closest resemblance to the starting material, showing negligible thermal degradation, and exhibited significantly higher antioxidant activity than the hydrodistillation and hexane extracts. Oils produced by SCE and hydrodistillation had antimicrobial activities higher than hexane extracts. The results of this study demonstrate that SCE is a promising process for the extraction of lavender essential oil.