Study of p-aminobenzoic acid and its metabolites in human volunteers treated with essential oil formulations using attenuated total reflection-Fourier transform infrared spectroscopy and HPLC with fluorometric detection

摘要

The effects of nine essential oils (ylang-wild, lavender, orange, ginger, chamomile, peppermint, sage, nutmeg, and eucalyptus), three known chemical penetration enhancers (tricaprylin, liquid paraffin, and mineral oil), and six plant oils (olive, sunflower, soybean, canola, com, and grape-seed oil) on the skin permeation of p-aminobenzoic acid were studied using attenuated total reflection-Fourier transform infrared spectroscopy. We applied essential oil creams to the skin of volunteers and then used a high performance liquid chromatograph with a fluorometric detector to evaluate levels of p-aminobenzoic acid and its metabolites in urine that was not pretreated with solvents and directly injected into the liquid chromatograph. After 1-2 days of treatment with different formulations of essential oils, levels of p-aminobenzoic acid and its metabolites were higher in the urine of the participants treated with essential oils than in the urine of the untreated controls.