German chamomile (Matricaria chamomilla) is an annual plant belonging to the Asteraceae family. As essential oil yield and components profile during ontogenesis and flowering period are variable [1–4], it is important that each harvest would target specify compounds. To determine favourable harvest times for obtaining optimum quality of products derived from chamomile grown in Belgium, an experiment was carried out on a loamy sand soil in Ghent University, Belgium. On April 15, 2005, 90 days old seedlings were transplanted at a spacing of 10cm x 10cm. At harvest, flowers were divided on the basis of development stage, in two groups [1], Stage I flowers cover initial up to full development of the ligulate flowers, while the tubular flowers remain closed. Flowers were categorized as stage II when the tubular flowers were partially (first circle) up to completely opened. After drying, essential oils were isolated by Likens-Nickerson extraction, followed by GC-MS analysis. Factors evaluated in this experiment were essential oil yield, and main components profile and concentration: chamazulene, (E)-β-farnesene, α-bisabolol oxide (A, B), α-bisabolone oxide, (z)-spiroether and spathulenol. Despite variations in the yield of the essential oil and its components at different development stages, most of the measured traits were not significantly influenced by the stage of development, except for (E)-β-Farnesene. The amount of this compound in stage I was significantly higher than in stage II. Results indicate that phases of anthodia development can be chosen for evaluation of metabolite accumulation regarding to target compounds.
References: 1. Franz, C. et al. (1978) Acta Hort. 73:229–238.
2. Letchamo, W. (1992) Acta Hort. 306:367–373.
3. Repcak, M. et al. (1993)J. Essent. Oil Res. 5:297–300.
4. Gasic, O. et al. (1991)J. Essent. Oil Res. 3:295–302.
