Antioxidative and antiradical activities of Eucalyptus camaldulensis leaf oils from Thailand

The leaf essential oils (six samples) from three clones of Eucalyptus camaldulensis Dehnh. were characterized by gas chromatography-mass spectrometry. Radical scavenging and antioxidant properties were investigated by the 1,1-diphenyl-2-picylhydrazyl (DPPH) assay and the beta-carotene bleaching test. It was found that the whole essential oil and its fractions had significant antioxidant effects when they were tested by each method. In the DPPH assay, the E. camaldulensis leaf oils showed IC50 inhibitory concentrations in the range of 1.75-12.62 mg/ml. In the beta-carotene bleaching test, the IC50 valued were in the range of 14.30-118.55 mu g/ml.