A liquid chromatography-tandem mass spectrometry (LC-MS-MS) method was developed to distinguish Asian ginseng (Panax ginseng C. A. Meyer) and North American ginseng (Panax quinquefolius L.). The method is based on the baseline chromatographic separation of ginsenoside Rf and 24(R)-pseudoginsenoside F11, two potential chemical markers present in ginseng root methanolic extracts, and their unambiguous on-line identification using tandem mass spectrometry. Consistent with the literature, 24(R)-pseudoginsenoside F11 was detected in abundance in North American ginseng roots in excess of 0.1% (w/w) of the dried root. In contrast to some reports, 24(R)-pseudoginsenoside F11 was also identified in Asian ginseng roots at trace levels using LC-MS-MS but at less than 0.0001% (w/w). Besides showing identical tandem mass spectra to authentic 24(R)-pseudoginsenoside F11, the corresponding compound in Asian ginseng root coeluted with standard under different HPLC conditions, thus confirming this compound as 24(R)-pseudoginsenoside F11. Another ginsenoside often used to distinguish Asian and North American ginseng, ginsenoside Rf, was found in abundance in Asian ginseng roots at more than 0.021% (w/w). In Asian ginseng roots, the ratio of ginsenoside Rf to 24(R)-pseudoginsenoside F11 exceeded 700:1. The limit of detection of ginsenoside Rf or 24(R)-pseudoginsenoside F11 was 120 pg injected on-column, and the limit of quantification was 240 pg on-column. In summary, LC-MS-MS analysis of ginseng products for the presence and ratio of ginsenoside Rf and 24(R)-pseudoginsenoside F11 may be used for the unambiguous identification of Asian and North American ginsengs.

Three physicochemical methods (HPLC, NMR spectroscopy, and HPLC of a derivative) have been used to measure parthenolide in authenticated Tanacetum parthenium (feverfew) and in several commercial purported feverfew products. A bioassay based on inhibition of the secretory activity of blood platelets by extracts of feverfew in comparison with parthenolide was also used. Similar results were obtained for all three physicochemical assays and also for the bioassay. Thus different methodologies yield consistent values for parthenolide content of feverfew preparations. Parthenolide appears to be mainly responsible for the antisecretory effects of extracts of feverfew. Authenticated Tanacetum parthenium grown in the UK contained a high level of parthenolide in leaves, flowering tops and seeds but a low level in stalks and roots. The level of parthenolide in powdered leaf material fell during storage. The purported feverfew products varied widely in their parthenolide content and in some products parthenolide was not detected. Possible reasons for the variation in parthenolide content are discussed. Since therapeutic efficacy has only been demonstrated for preparations of feverfew that contain parthenolide, it is suggested that manufacturers of feverfew products should use measurements of parthenolide as a means of standardization and quality control.

A rapid and quantitative method of quality assurance for marker phytochemicals in products containing material derived from Echinacea species has been developed. In order to assess the efficiency of extraction of phytochemicals from the roots and aerial parts of Echinacea purpurea and E. angustifolia, a study of solvent mixtures and extraction methods was carried out to determine the recovery of known compounds from plant materials. Ultrasonic extraction of dried samples with methanol:water (7:3) or ethanol:water (7:3) gave good yields of cichoric acid, echinacoside and the alkamides, undeca‐2E,4Z‐diene‐8,10‐diynoic acid isobutylamide and a mixture of dodeca‐2E,4E,8Z,10E/Z‐tetraenoic acid isobutylamides (recoveries of 89%, 85%, 80% and 90%, respectively). The HPLC separation of the phenolic compounds cichoric acid, chlorogenic acid and echinacoside was also improved by careful attention to the pH of the mobile phase. A shortened HPLC column allowed turnaround times of 22 min for phenolic components and 15 min for alkamides with lower solvent use. Assessment of commercial raw materials from the North American market using the new method was useful for confirmation of species and showed a very large variation in concentration of markers in the products sold in this market. Copyright © 2000 John Wiley & Sons, Ltd.

Parthenolide [I], the main sesquiterpene lactone in some feverfew plants, has been quantified by a straightforward hplc procedure. 'H-nmr analysis provides assay results in good general agreement and confirms parthenolide identity. Both authenticated Tanacetum partbeniirtn and purported feverfew products on the UK and North American markets have been examined. A number of UK products and authentic feverfew from the UK satisfy the minimum level of 0.2% parthenolide proposed by Canada for commercial leaf products. However, no North American commercial product has yet been found to contain as much as 0.1% parthenolide. Leaves of a plant of T . parthenrim f. flosridosiini purchased and grown locally were found to have the highest level of parthenolide (1.27%) ever recorded in T . partbeniunr leaves, postflowering roughly four times higher than pre-flowering, and higher than in its flowering tops.

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