Chemical Constituent Analysis and Antioxidant Activity of Leaf Essential Oil of Curcuma xanthorrhiza

Curcuma xanthorrhiza Roxb. (Zingiberaceae) is a herbaceous perennial plant valued for its use in the pharmaceutical and food industry. In spite of its multipurpose use, the chemical composition of the leaf essential oil of the species is not known till date. Thus, the current work was undertaken to study the phytochemical composition and antioxidant activity of leaf essential oil of C. xanthorrhiza. GC/MS analysis of the leaf essential oil revealed the presence of 53 constituents; the major constituents being germacrone (18.76 %), xanthorrhizol (12.22 %), germacrene B (7.19 %), eucalyptol (6.89 %), γ-eudesmol acetate (6.33 %), ar-curcumene (6.06 %), β-himachalene (5.75 %) and curzerene (5.24 %). The essential oil was sesquiterpenoid in nature, with sesquiterpenes comprising 76.4 % of the oil. It consisted of 50.04 % oxygenated sesquiterpenes, 26.36 % sesquiterpene hydrocarbons, 10.31 % oxygenated monoterpenoids, 5.92 % aromatics, and 4.33 % monoterpene hydrocarbons. The DPPH and ABTS assay showed moderate antioxidant activity with IC50 value- 55.57±0.02 μg/mL and 24.42 μg/mL, respectively. To the best of our knowledge, this is the first report on the phytochemical composition and antioxidant activity of leaf essential oil of C. xanthorrhiza and this finding might be useful in undertaking advanced research on natural products.