Antioxidative Activities of Essential Oils and Ethanol Extrations from Ornamental Zingiberaceae Species

The essential oils from five different Zingiberaceae species [Costus speciosus (J. Konig.) Smith, Hedychium coronarium J. Koenig, Hedychium gardnerianum Griff., Zingiber zerumbet (Linn.) Roscoe ex Smith, Hedychium chrysoleucum Hook.] were extracted through hydro-distillation process and their chemical compounds were analyzed by GC-MS. In addition, the antioxidant activities of essential oils and ethanol extractions were described. The yields of essential oils ranged from 0.20 % in C. speciosus to 1.52 % in Z. zerumbet. A total of 48 components were identified, of which majority were ⟨-santalo (0.22-41.83 %), aromadendrene oxide I (39.63-55.40 %) and zerumbone (1.67-84.07 %). The essential oils showed an effective DPPH• scavenging activities with IC₅₀ values ranging between 5.28 and 13.26 μg/mL. The result showed that the ethanol extractions had different DPPH• scavenging (IC₅₀, 0.94-9.92 μg/mL) and most of them were lower than ascorbic acid (IC₅₀, 8.37 μg/mL) and trolox (IC₅₀, 10.19 μg/mL). The results indicate that the essential oils and ethanol extractions from the five ornamental Zingiberaceae species could serve as an important bio-resource of antioxidant for using in the functional food, cosmetic, and pharmaceutical industries.