Chemical composition and antioxidant activity of Lippia alba essential oil obtained by supercritical CO2 and hydrodistillation

Lippia alba essential oils were obtained by hydrodistillation (HD) and supercritical fluid (SFE) extraction methods. These were analyzed by gas chromatography-mass spectrometry-flame ionization detector (GC-FID-MS). Antioxidant activity was tested by DPPH and ABTS methods, and total soluble phenolics (TSP) were also determined. While in the SFE extract 14 compounds were identified (mostly: myrcenone 3.4%, α-terpineol 1.0% and β-caryophyllene 2.3%), in the HD extract 17 compounds were identified (mostly: eucalyptol 15.6%, myrcenone 9.3% and Z-ocimenone 5.8%). The results showed that L. alba essential oils obtained by SFE was IC50=17.35 mg/mL and by HD was IC50 = 12.45 mg/mL in DPPH assay. L. alba has an excellent eucalyptol content.   Key words: Antioxidants, bioactive compounds, supercritical fluid, green technologies.