Antioxidant activity of some volatile oils and absolutes from Thai aromatic plants

Abstract

The aim of this study was to determine the antioxidant activity of volatile oils and absolutes from 19 Thai aromatic plants in 12 families by scavenging effect on 1,1-diphenyl-2-picrylhydrazyl radical (DPPH). Volatile oils were obtained by hydrodistillation, whereas absolutes were obtained by solvent extraction. In the test, the antioxidant activity of the volatile oils and absolutes were compared with the activity of known antioxidants: trolox, quercetin as well as kaempferol. The results revealed that for all essential oils obtained, holy basil oil (Ocimum sanctum) exhibits the highest antioxidant activity with IC50of 0.6294 mg/ml followed by Phlai oil (Zingiber cassumunar, IC50of 1.0599 mg/ml) and ginger oil (Z. officinale, IC50of 4.385 mg/ml), then the oils of Curcuma domestica, Curcuma amada, Alpinia galangal, Curcuma mangga, Cymbogogon citrata and Zingiber ottensii, respectively. Among the absolutes obtained, "Saraphi" (Mammea siamemsis) exhibits the highest antioxidant activity with IC50of 0.3271 mg/ml followed by white champaka (Micheli alba, IC50of 0.7155 mg/ml) and frangipani (Plumeria alba, IC50of 1.0766 mg/ml), followed by Cananga odorata, Millingtonia hortensis, Alstonia scholaris, Gardenia augusta, Saraca thaipingensis and Quisqualis indica, respectively. The IC50of trolox, quercetin and kaempferol were 0.0105, 0.0059 and 0.0113 mg/ml, respectively. The volatile oils and/or absolutes with high antioxidant activity will be selected and further investigated for the development of anti-aging spa products containing ingredients from Thai aromatic plants in the future.