Contrastive analysis of chemical composition of essential oil from twelve Curcuma species distributed in China

Essential oils were extracted from rhizomes of the 12 Curcuma species distributed in China by hydro-distillation, and their chemical compositions were isolated and characterized by GC-MS. The yields of the 12 essential oils ranged from 2.23 wt.% in Curcuma yunnanensis to 4.50 wt.% in Curcuma longa. A total of 57 compounds were identified in the 12 essential oils. The uppermost composition for each species were 8,9-dehydro-9-formyl-cycloisolongifolene in Curcuma aromatica and Curcuma elata; curdione in Curcuma wenyujin, Curcuma kwangsiensis and Curcuma nankunshanensis; ar-turmerone in Curcuma longa and Curcuma rubescens; germacrone in Curcuma sichuanensis, Curcuma phaeocaulis and Curcuma nankunshanensis; β-elemenone in Curcuma kwangsiensis var nanlingensis and velleral in Curcuma attenuata. In addition, DPPH assays indicated that these essential oils possessed different DPPH radical-scavenging activities (IC50, 3.69-30.19 μg/ml), some of them were better than Trolox C (IC50, 8.49 μg/ml). The antioxidant activity of essential oil from Curcuma attenuata Wall (IC50, 3.69 μg/ml) was superior to all other oils. The principal component analysis (PCA) and cluster analysis based on essential oil compositions provided a chemical blueprint to clarify the vague identification and classification of Curcuma species. Due to the outstanding antioxidant activities, the majority of Curcuma species would be used as good natural antioxidants in functional food, pharmaceutical and cosmetic.