Essential Oil and Antioxidant Activity of Cassumunar Ginger (Zingiberaceae: Zingiber montanum (Koenig) Link ex Dietr.) Collected from Various Parts of Thailand

Abstract

Zingiber montanum (Koenig) Link ex Dietr. is widely found in tropical Asia and is used commonly in folk medicine for the treatment of various diseases. The objectives of this study were to investigate the variation in the essential-oil component and the antioxidant activity of rhizome extracts
from Z. montanum collected from various regions of Thailand. Essential oils were obtained using a microwave extraction method (ME). Samples collected from western Thailand contained the highest amount of essential oil (11.07 mL/kg), the accession from Kanchanaburi province gave the highest volume (21 mL/kg), whereas those from eastern Thailand contained the lowest volume (4.95 mL/kg). The constituents of the essential-oil samples were determined by GC analysis. This technique identified 15 compounds in Z. montanum essential oils. The major constituents of the oil consisted of sabinene, terpinen-4-ol and DMPBD ((E)-1(3, 4-dimethylphenyl) butadiene). No significant differences in essentialoil components among the original sources of rhizomes were found. The antioxidant activities of the ethanolic extracts were screened by 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. Samples from different sources showed significantly different DPPH scavenging activities (p< 0.05). The antioxidant activities of the rhizome extract obtained from the north showed the highest activity (80.88%), followed by those from the east (76.47%), the south (72.51%), the northeast (67.38%), the west (66.66%) and the central region (57.63%).