Chemical composition and antibacterial activity of rhizome oils from five Hedychium species.

The essential oils from rhizomes of five Hedychium species, H. coronarium, H. neocarneum, H. flavescens, H. speciosum and H. stenopetalum (Zingiberaceae), were obtained by hydrodistillation and analyzed by capillary GC and GC/MS. Sixty components were identified and percentage oil yields from the fresh plants ranged from 0.06-0.17 % (v/w). All rhizome oils were rich in terpenes, especially monoterpenes (75.0-95.9 %). The most common compounds in the rhizome oils of Hedychium were beta-pinene, linalool and 1,8-cineole. The essential oils were tested against four bacterial strains. They showed moderate to weak activity against Gram-positive bacteria (inhibition zone 25-13 mm, MIC 0.3-8.3 mg/mL, MBC 0.6-8.3 mg/mL).