Analysis of the Chemical Composition, Antimicrobial, and Antioxidant Qualities of Microwave and Supercritical CO2-Extracted Lavender Essential Oils Cultivated in a Hyperarid Region of Türkiye

This study compares the chemical composition, antioxidant capacity, and antibacterial properties of lavender essential oils extracted using microwave-assisted extraction (MAE) and supercritical CO₂ extraction (SCDE). Gas chromatography-mass spectrometry analysis revealed that the MAE oil contained higher levels of linalyl acetate (36.19%) and linalool (28.29%) compared with the SCDE oil, which had values of 28.72% and 27.48%, respectively. The MAE oil also showed superior antioxidant activity, with DPPH IC₅₀ values of 72.99 mg/mL and FRAP values of 1.31 mM Fe²⁺/g, compared with 80.84 mg/mL and 1.14 mM Fe²⁺/g for the SCDE oil. Antibacterial tests indicated that the MAE oil exhibited lower MIC values, demonstrating twice the antibacterial activity against <i>Bacillus cereus</i> NRRL B3711, <i>Bacillus subtilis</i> PY79, and <i>Enterococcus faecalis</i> ATCC 29212 compared with the SCDE oil. These results highlight the superior bioactivity of MAE-extracted lavender oil, making MAE a preferred method for high-quality oil extraction from drought-affected lavender plants.