18B-12 |
|
A. WEI, Dept. of Environmental Toxicology, Univ. of California at Davis, One Shields Avenue, Davis, CA 95616 and T. Shibamoto, Dept. of Environmental Toxicology, Univ. of California at Davis, One Shields Avenue, Davis, CA 95616. Since ancient times, the therapeutic properties of plant essential oils have been recognized. In addition to their use for maintaining skin health, essential oils have been used for treating diseases. The medicinal properties of these oils could be due to the presence of antioxidant compounds. This study evaluates the antioxidant activities of 13 essential oils using the aldehyde/carboxylic acid assay. The aldehyde/carboxylic acid assay is useful for determining long-term antioxidative potential of a chemical or group of chemicals in an organic phase. In this assay, autooxidation of aldehyde to its corresponding carboxylic acid by an active oxygen species is monitored over a 40-day period using GC-FID. Various concentrations (0, 10, 20, 50, 100, 200, 500 µg/mL) of essential oil (angelica seed, ginger, jasmine, juniper berry, lavender, parsley seed, patchouli, peppermint, rose, ylang, celery seed, chamomile, sandalwood) were added to a dichloromethane solution containing hexanal and the GC internal standard, undecane. The decrease in hexanal was monitored at 5-d intervals. A standard of alpha-tocopherol was also examined. Inhibitory effects of each essential oil on hexanal oxidation were determined. After 40 d, 95% or greater inhibitory effects on hexanal oxidation were obtained from parsley seed oil at 20 µg/mL; jasmine and rose oils at 100 µg/mL; and ylang and celery seed oils at 500 µg/mL. These activities were comparable to that of α-tocopherol at 10 µg/mL. Sandalwood oil possessed approximately 90% inhibitory activity for 20 days at 500 µg/mL. Most oils exhibited dose dependent activities. Chamomile and peppermint oils did not show any appreciable inhibition. Results from the aldehyde/carboxylic acid assay suggest that the medicinal values of these essential oils include antioxidative activities. Although not as potent as that of α-tocopherol, the antioxidative potentials of these essential oils may help to prevent the in vivo oxidative damage associated with many diseases.
Session 18B, Food Chemistry: Antioxidant and bioactive agents
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |