Composition and bioactivity assessment of essential oils of Curcuma longa L. collected in China

Curcuma longa L. rhizomes collected from 20 different habitats in China are used to analyze yield, composition and bioactivity of essential oils extracted from them. The yield of the 20 essential oils vary from 4.03 to 5.27% depending on the habitat where they were collected. Using gas chromatography-mass spectrometry (GC-MS), 81 components are identified in the 20 essential oils, and their major compounds are ar-turmerone (0.92-42.85%), β-turmerone (5.13-42.54%), α-zingiberene (0.25-25.05%), ar-curcumene (1.21-15.70%) and β-sesquiphellandrene (0.05-14.88%). The essential oils of rhizomes collected from different habitats exhibit different antimicrobial activities, and the essential oils from Guangxi have generally better activities. These essential oils also show different DPPH (IC50, 4.37-11.59 μg/mL) and ABTS (IC50, 4.21-13.25 μg/mL) radical-scavenging activities, being most of them more effective than Trolox C (IC50, 10.72 and 11.42 μg/mL). They also exhibit significantly different cytotoxicity against B16 cells (IC50, 13.96-135.97 μg/mL) and LNCaP cell (IC50, 19.63-127.81 μg/mL), and essential oils from Luchuan in Guangxi have the highest cytotoxicity. Some essential oils show outstanding anti-inflammatory activities by markedly down-regulating the expression of inflammatory cytokines, cyclooxygenase 2 (COX-2) and tumor necrosis factor (TNF)-α, in vivo. Therefore, Curcuma longa L. rhizome, one of the popular traditional Chinese medicines with excellent bioactivities, can be more rationally utilized based on their chemical composition and bioactivity in the further.