Comparison of Supercritical Fluid and Solvent Extraction of Feverfew (Tanacetum parthenium)

Feverfew is a traditional herbal remedy for a wide range of medical conditions, including migraine and arthritis1−4. The plant contains a large number of natural products, but the active principles probably include one or more of the sesquiterpene lactones known to be present, including parthenolide (Figure 1)5−6. Feverfew can be taken in a variety of forms, including the raw leaf or tablets or capsules containing dried leaves or aerial parts of the plant. There can be considerable variations in the content of materials said to be ‘feverfew’, due to adulteration with other plant species, the use of different parts of the plant, different times of year at which the plant is harvested, and also the known instability of sesquiterpene lactones in storage . There is therefore a need for methods of analysing and assaying feverfew samples, especially those which subject the samples to mild conditions, in order to minimise the chance of sample degradation. Earlier methods for the analysis of feverfew include solvent extraction followed by infrared spectroscopy, which can only indicate total sesquiterpene lactone concentration. An HPLC method with UV detection (following solvent extraction) can give data on individual species present but, because the sesquiterpene lactones lack strong UV chromophores, it is necessary to carry out a derivatisation step prior to HPLC separation.