514 JOURNAL OF COSMETIC SCIENCE of essential oil concentration, the four essential oils show 96.74%, 96.12%, 93.14%, and 92.29% of the DPPH free-radical scavenging activity, respectively. Determinations of 78.82%, 78.69%, and 55.32% of the DPPH free-radical scavenging activity are shown in vetiver, nutmeg, and yarrow essential oils, respectively. Other essential oils do not show apparent DPPH free-radical scavenging activity up to 50%, and the black pepper essential oil shows the lowest DPPH free radical scavenging activity (5 .13 % ). These results are listed in Table II. To compare the DPPH radical scavenging activity of (a) BHA, cinnamon leaf, and clove bud and (6) BHA, jasmine absolute, and thyme red, the two set samples were diluted from 0-200 and 0-2000 µg/ml, respectively. The experimental results are displayed in Figures 2 and 3. The DPPH radical scavenging activity can be observed as well: clove bud cinnamon leaf jasmine absolute thyme red. The antioxidant capacities in a series of concentrations of essential oils were used to calculate the effective concentrations, EC50 . The amount of essential oil necessary to decrease the absorbance of DPPH by 50% (EC50) was calculated graphically. (The percentage of inhibition was plotted against the antioxidant concentration in the reac­ tion system). The data show that clove bud possesses the best radical scavenging capacity (EC50 = 36 µg/ml). The EC50 values of the best four essential oils (clove bud, cinnamon leaf, jasmine absolute, and thyme red) were 36, 53, 1297, and 1563 µg/ml, respectively. TOT AL PHENOLIC CONTENT Cinnamon leaf, clove bud, and thyme red essential oils have shown more total phenolic content than other essential oils. In the concentration of 1 mg/ml, the total phenolic amounts of the three essential oils were 420, 480 and 270 mg/g of GAE, respectively. The total phenolic amounts of jasmine absolute and yarrow essential oils were 36 and 48 mg/g of GAE, respectively. This is consistent with the DPPH free-radical scavenging activity in Table II. This finding clearly suggests that the total phenolic content and the DPPH free radical scavenging activity are in direct proportion. ANALYSIS OF CHEMICAL COMPOSITION BY GAS CHROMATOGRAPHY-MASS SPECTROMETRY In order to know the chemical composition of these essential oils and to determine the major compound that caused the DPPH free-radical scavenging activity, GC-MS was employed to analyze cinnamon leaf, clove bud, jasmine absolute, and thyme red essential oils. In Table III, cinnamon leaf essential oil includes thirteen compounds a-pinene, a­ phellandrene, p-cymene, �-linalool, cinnamaldehyde, safrole, eugenol, copaene, �­ caryophyllene, cinnamyl acetate, a-caryophyllene, eugenol acetate, and benzyl benzoate. A percentage of 82.87 of eugenol was detected in cinnamon leaf essential oil by GC-MS. To investigate the DPPH free-radical scavenging activity of the three major components in cinnamon leaf essential oil, the following experiments were undertaken. In a concen­ tration of 0.1 mg/ml, pure a-pinene, �-caryophyllene, eugenol, and cinnamon leaf essential oil were employed in an experiment on the DPPH free-radical scavenging activity. In Figure 4, it is clear that the DPPH free-radical scavenging activity is in the

DPPH FREE-RADICAL SCAVENGING ABILITY 515 Table II DPPH Radical Scavenging Activity and Total Phenolic Content of the Forty-Five Essential Oils DPPH radical Total scavenging phenolic content No. Name Scientific name activity (% )* (10 mg of GAE/g)* Basil Ocimum basilicum 19.82 ± 0.002 11 ± 0.168 2 Bergamot Cutrus aurantium var. bergamia 20.28 ± 0.007 14 ± 1.062 3 Cajeput ambon Melaleuca cajeputi 21.35 ± 0.010 18 ± 0.378 4 Camphor C innamomum camphor a 18.67 ± 0.011 13 ± 0.132 5 Cardamom Elettaia cardamomum 17.67 ± 0.000 13 ± 0.603 6 Cedarwood atlas Cedrus atlantica 19.27 ± 0.037 26 ± 5.332 7 Cinnamon leaf Cinnamomum zeylanicum 96.74 ± 0.004 4200 ± 0.834 8 Clary sage Salvia sclarea 15.34 ± 0.004 14 ± 1.460 9 Clove bud Eugenia caryophyllata 96.12 ± 0.002 4800 ± 1.968 10 Coriander Coriandrum sativum 11.97 ± 0.003 10 ± 0.217 11 Cypress Cupressus sempervirens 10.97 ± 0.021 17 ± 1.249 12 Everlasting Helichrysum italicum 34.48 ± 0.047 74 ± 1.642 13 Fennel Foeniculum vulgare 13.22 ± 0.016 16 ± 1.764 14 Frankincense Boswellia carterii 11.87 ± 0.023 20 ± 0.564 15 Geranium Pelargonium graveolen 14.77 ± 0.024 15 ± 1.038 16 Ginger Zingiber officinale 18.42 ± 0.018 16 ± 1.584 17 Grapefruit Citrus X paradisi 10.20 ± 0.030 12 ± 1.181 18 Jasmine absolute Jasminum grandiflorum 93.14 ± 0.005 360 ± 0.084 19 Juniperberry J uniperus communis 7.49 ± 0.041 14 ± 0.391 20 Lemon Citrus limon 9.57 ± 0.023 15 ± 0.240 21 Lemon eucalyptus Eucalyptus citriodors 24.33 ± 0.009 12 ± 0.743 22 Mandarin Citrus reticulats 7.00 ± 0.002 14 ± 1.881 23 Myrrh Commiphora molmol 46.27 ± 0.048 75 ± 1.942 24 Myrtle dalmatian Mytus communis 10.80 ± 0.010 17±1.260 25 N eroli bigarade Citrus aurantium 7.95 ± 0.019 16 ± 1.121 26 Nutmeg M yristica fr a gr ans 78.69 ± 0.043 62 ± 5.235 27 Orange bitter Citrus aurantium 7.94 ± 0.005 13 ± 0.444 28 Orange sweet Citrus sunensis 6.07 ± 0.017 13 ± 0.644 29 Pepper black Piper nigrum 5.13 ± 0.011 17 ± 3.325 30 Pennyroyal pulegone Mentha pulefium 24.35 ± 0.057 23 ± 1.313 31 Peppermint arvensis, whole Mentha arvensis 11.02 ± 0.009 58 ± 0.589 32 Pine Pinus sylvestris 6.11 ± 0.017 69 ± 3.332 33 Ravensara Ravensara aromatica 7.20 ± 0.015 17 ± 1.022 34 Rose geranium Pelargonium graveolens l' her 12.57 ± 0.042 16 ± 0.842 35 Rosemary Moroccan Rosmarinus officinalis 10.28 ± 0.006 14 ± 1.321 36 Rosewood Aniba rosaeodora 11.30 ± 0.041 10 ± 0.261 37 Sage Salvia offcinalis 8.70 ± 0.009 16 ± 0.936 38 Sandalwood, East Indian Santalum album 11.58 ± 0.014 74±2.518 39 Smith eucalyptus Eucalyptus smithii 6.59 ± 0.006 45 ± 1.841 40 Tea tree bush still Melaleuca alternifolis 10.09 ± 0.017 107 ± 1.802 41 Thyme red Thymus vulgaris 92.29 ± 0.002 2700 ± 0.977 42 Vetiver Vetiveria zizanioides 78.82 ± 0.009 65 ± 1.711 43 Wintergreen Gaultheria procumbens 8.83 ± 0.009 36 ± 9.665 44 Yarrow Achillea mellefolium 55.32 ± 0.033 480 ± 9.437 45 Ylang Ylang Cananga odorata 80.06 ± 0.020 72 ± 1.224 * Values are mean ± SD (n = 3).