Chemical Composition of Essential Oil and Antioxidant Activities of Curcuma Petiolate Roxb. Rhizomes

Pulverized rhizome of Curcuma peliolata on hydrodistillation, afforded light yellow essential oil in the yield of 0.13% v/w. The chemical constituent of the essential oil was determined by GC-MS. Nine compounds representing 95.34 % of the total oil were identified. The major compounds of the oil were 2-methyl-5-pentanol, 1H-pyrrol-1-amine,2-(4-methoxyphenyl)-n,n,5-trimethyl, and curcumol. The distillated aqueous was extracted with dicloromethane (DCM), ethyl acetate (EtOAc), and n-butanol. The DPPH radical scavenging and reducing power of the extracts were investigated. Curcumin and ascorbic acid were used as standard references. The DPPH radical scavenging activity was decrease in order: curcumin congruent to ascorbic acid congruent to EtOAc extract > DCM extract > n-butanol extract > aqueous extract. The EtOAc extract showed significantly highest inhibition of the radical scavenging activity with IC50 0.092 +/- 0.001 mg/mL (curcumin and ascorbic acid (IC50 0.012 and 0.013 mg/mL, respectively (P<0.05)). While, the DCM extract showed highest reducing power with IC50 = 0.271 mg/mL which lower than that of standard curcumin (IC50 = 0.013 mg/mL) and ascorbic acid (IC50 = 0.002 mg/mL),Introduction Curcuma species belong to the zingiberaceae family which widely distributed in asia especially Thailand. The rhizomes of these species are used in traditional medicines PI which contain curcuminoids (diferuloylmethane) as a major constituent. It is a generally regarded as the most active constituent which a wide range of biological and pharmacological activities including; antitumor, anti-inflammatory, neuro-protective, treatment of wide variety aliment ([2]), and efficient inhibition of enzyme tyrosinase ([3]). Essential oil of curcuma species is an antacid, which acts as a carminative, stomachic effect and treatment of respiratory diseases ([4]). Moreover, the oil was used to anti-fungal ([5]) and applied in cosmetics, and increases penetration of the active agent across the dermal ([6]). Wan-Boa-Chan (Curcuma petiolata) is one of curcuma species that is widely cultivated as an ornamental plant and has long been used as a folk botanical in asia ([7]). The stem and rhizomes of C. petiolata is selected to paste in external wound skin as traditional medicine and used for herbal steam sauna ([7]). Its rhizomes composed of a variety of sesquiterpenes, turmerene and zingiberene. However, there is no report describing the composition of the essential oils and antioxidant activities of C. petiolata rhizomes. The aim of this study was to investigate the chemical composition of essential oil and antioxidant activities of oils and various extracts of C. petiolata rhizomes.