Studies on essential oils from several zingiber spp and alpinia spp and their biological activities

The chemical composition of the essential oils of three species of Zingiber and five species of Alpinia were investigated. Extraction by hydrodistillation method yielded essential oils in range between 0.083.55%. The highest oil yield identified from the rhizome oils of Z. officinale (2.27%) and A. Iigulala (3.55%) for each genus. Identification of chemical components in essential oils by gas chromatographyl flame ion detector (GC/FID) revealed the presence of geranial (13.93%) as the major component in rhizome oil of Z. officinale while myrcene (19.67%), limonene (26.44%) and ethyl cyclohexanoate (6.84%) as major constituents in leaves, stem and rhizome oils of Zingiber sp. I respectively. Nerolidol (9.31 %) and ~-bourbonene (16.78%) were found as principal constituents in the leaves and stem oils of Zingiber sp. 2 respectively. For A. galanga, the major compositions identified were bicycogermacrene (40.03%) in the leaves oil and asaricin (34.86%) in the rhizome oil. Butyl isothiocyanate (16.14%), methyl laurate (18.285%) and a-zingiberene (36.69%) obtained from the essential oils of the leaves, stem and rhizome from A. glabra respectively. A. aqualica var.1 contained p-pinene (46.89%) in the leaves part whereas I3-caryophyllene alcohol (9.62%) was found as major component in both stem and rhizome oils. a-zingiberene (22.78%) and I3-caryophyllene (24.13%) were found as major components in the leaves and rhizome oil respectively from A. aqualica var. 2. ~elemene was found as principal constituent in all parts of A. Iigulala. Toxicity test revealed that the leaves oil from Zingiber sp. I and the rhizome oil from A. Iigulala gave the highest LCso value of 68.13 ~g!mL and 9.12 ~g!mL respectively