Influence of extraction method and storage conditions on (t)he volatile oil of wormwood (Artemisia absinthium L.)

In order to determine the best extraction procedure for volatile oil compos ition studies in wormwood (Artemisia absinthium L.), several extraction tec hniques have been investigated. In pentane extracts obtained using microwav e or ultrasound sources of radiation, no thermic degradations occurred, but high amounts of heavy oils and waxes resulted, causing trouble in the gas chromatographic analysis. Headspace extraction provided the most volatile c onstituents, but high molecular weight compounds were not extracted. Simult aneous distillation-extraction resulted in the most adequate extraction pro cedure for volatile oil composition studies since the required compounds we re extracted with minimum degradations when the distillation time was no lo nger than 30 min. Freezing and drying processes did not greatly affect the percentage composition of wormwood volatile oil.