ABSTRACT
<i>Objective</i>: The effects of essential oils on the formation of superoxide radicals during UVA (365 nm) irradiation were investigated.<br> <i>Methods</i>: ESR (electron spin resonance) spin-trapping experiments were performed on a reaction mixture containing 15 μM riboflavin, 0.10 M DMPO (5,5-dimethyl-l-pyrroline-<i>N</i>-oxide), 23 mM phosphate buffer (pH 7.4) and 6.3% (v/v) DMSO (dimethyl sulfoxide) (standard reaction mixture) during UVA (365 nm) irradiation.<br> <i>Results</i>: On addition of various concentrations of tea tree oil (<i>or</i> lavender super oil <i>or</i> grapefruit oil <i>or</i> peppermint oil <i>or</i> wintergreen oil) to the standard reaction mixture, the ESR peak height decreased dose-dependently.<br> <i>Conclusion</i>: This result shows that antioxidant activities increase as follows: lavender super oil<grapefruit oil<peppermint oil<tea tree oil<wintergreen oil.<br>