Quality Control

As mentioned previously, quality control is a serious problem in Echinacea phy-tomedicines with multiple actives, species, and formulations. Early industry methods based on the determination of total phenolics are unsuitable for quality control because of the broad distribution of phenolics in all terrestrial plants. For species identification and quality assurance, high performance liquid chromatography (HPLC) determination of specific phytochemicals is the most appropriate technique (Bergeron et al., 2000; Perry et al., 1997). Extraction of most phenolic and alkamide components can be conveniently achieved in 70% ethanol using ultrasound and ana

lyzed by gradient diode array HPLC. No effective quantitative methods are yet available for the rapid analysis of polysaccharides, but HPLC techniques and immuno-chemical analysis are under development.

For species identification of root materials, cichoric acid is often used in the herbal industry as a marker for E. purpurea and echinacoside for E. angustifolia and E. pallida. However, we have found these markers to be present in a number of wild species and varieties and are consequently not the best choices for species identification. On the other hand, the numerous alkamides found in the roots provide a phy-tochemical profile that is unique for each commercial species (Bauer and Remiger, 1989) (Table 2.2), and are different from wild species.

Quantitative estimates of the phytochemical markers assessed by HPLC showed a large amount of variation in commercial samples of different origin submitted to our laboratory for analysis (Bergeron et al., 2000). For example, the level of alkamides or cichoric acid showed a 10-fold variation in raw plant material. This variation can be traced to a number of factors, including genetic variation in the crop, effect of growing conditions, and loss of active principles in postharvest processing.

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