Influence of Plant Growth Stage on the Essential Oil Content and Composition in Davana (Artemisia pallens Wall.)

The influence of three plant growth stages (full emergence of flower heads, anthesis, and initiation of seed set) on the essential oil content and composition in Davana (Artemisia pallens Wall) was investigated over two successive seasons. The essential oil content was found to be higher at the full emergence of flower heads than at anthesis and initiation of seed set stages. The contents of davanone, the major constituent of davana oil, and linalool decreased while those of (Z)- and (E)-methyl cinnamate, (E)-ethyl cinnamate, bicyclogermacrene, davana ether, 2-hydroxyisodavanone, and farnesol increased from flower heads emergence stage to the initiation of seed set stage. These results support the general practice of harvesting the crop at full bloom stage. Five compounds, viz., (Z)- and (E)-methyl cinnamates, (Z)- and (E)-ethyl cinnamates, and geranyl acetate, were identified for the first time in davana oil. Keywords: Davana; Artemisia pallens Wall.; plant growth stage; essential oil composition; davanone, (Z)- and (E)-methyl cinnamates; (E)-ethyl cinnamate; davana ether