Chemical composition and antioxidant activity of essential oils isolated from Colombian plants

Thirteen essential oils from Colombian plants, obtained by hydrodistillation or microwave-assisted hydrodistillation of total plant, stem, leaves, and flowers were analyzed by gas-chromatography-mass spectrometry techniques. Cytotoxicity of essential oils was assessed using the brine shrimp assay, and their antioxidant activities measuring their effects on the levels of thiobarbituric acid reactive substances on rat liver microsomes induced by Fe2+/H2O2. Five oils showed high cytotoxicity (LC50<10 mu g/mL) on the brine shrimp assay. The antioxidant activity of the essential oil from Ocotea sp., Tagetes lucida and Lippia alba (geranial chemotype) showed the lowest mean effective concentrations (EC50), with values of 31.1, 37.9 and 94.9 mu g/mL, respectively. The main components for these oils were a-pinene (42%), estragole (95.7%) and geranial (30.4%), respectively. Elettaria cardamomum and Lippia alba (carvone chemotype, Tolima) presented moderate antioxidant activities with EC50 values of 130.5 and 174.4 mu g/mL, respectively. Essential oils from Minthostachys mollis, Lippia alba (carvone chemotype, Cundinamarca), and Piper sanctifelisis did not show antioxidant activity (CE50>1000 mu g/mL).