Table 911

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Regulation of Echinacea species and Parts by Various Organizations

Organization or Country

World Health Organization (1999) European Scientific Cooperative on Phytotherapy (1999) German Commission E British Herbal Pharmacopoeia (1996)

U.S. Pharmacopeia (2002)

Canada Australia

E. purpurea

Aerial parts

Aerial parts, roots

Aerial parts

Roots, leaves, flower, herbal powdered, and powdered extract Roots

Aerial parts, roots

E. pallida

Roots

Roots

Roots

Roots, herbal powdered, and powdered extract

E. angustifolia

Roots

Roots

Roots, herbal powdered, and powdered extract

Roots

Source: Data from World Health Organization, 1999, WHO Monographs on Selected Medicinal Plants, vol. 1, WHO, Geneva, pp. 136-144.

medicines (THM), intended for the self-treatment of a self-diagnosed, self-limiting condition (e.g., the use of Echinacea for the relief of sore throats due to colds). According to the Health Canada Drugs Directorate Guideline for THM such as Echinacea products (aqueous infusions and/or decoctions prepared from the dried root of E. purpurea), manufacturers follow Good Manufacturing Practice (GMP), provide a complete quantitative listing of ingredients on the label, indicate that a given product is a THM, and supply a minimum of two traditional references to support its pharmacological action for the part of the plant used (Thadani, 2002).

In Australia, complementary medicine may be either "listable" or "registrable" in the Australian Register of Therapeutic Goods (ARTG). Echinacea products are listable complementary medicines that may contain only substances generally regarded as safe, and may carry only claims for the temporary relief of minor self-limiting conditions. Echinacea products are thus available in pharmacies and health food stores for consumer self-selection (Cameron, 1998). Regarding Echinacea products, Australian Therapeutic Goods Administration (TGA) guides claim: "Echinacea helps support the immune system especially during the winter cold and flu season. This herb has been used traditionally for hundreds of years and now scientific evidence suggests that it may assist in supporting immune function" (TGA, 2001).

Vlietinck (2002) reported a European perspective on the elaboration of monographs on herbal medicinal products listed in the fourth edition of the European Pharmacopoeia. As of 2002, there were 106 published monographs, none of which focused on Echinacea; E. angustifolia radix, E. pallida radix, E. purpurea herba, and E. purpurea radix were among 40 monographs under study.

In Germany, Commission E of the Federal Institute of Pharmaceutical and Medicinal Products has not approved E. angustifolia herb and roots, E. pallida herb, or E. purpurea root for nonprescription drug use. Only research results from the fresh-pressed juice of E. purpurea flowering herb in 22% ethanol by volume as a preservative and from the water-alcohol extract of E. pallida roots qualified for an approved monograph (Blumenthal et al., 2000). The latter preparations are recommended as a supportive treatment of recurring infections in the bronchial area and urinary tract, as well as for external use in the case of poorly healing superficial wounds (Bauer, 1999).

Echinacea products are sold as food supplements in Norway, but as herbal medicines in Sweden, Finland, and Denmark, and must be registered.

quality standardization of ECHINACEA

Although Echinacea products belong to the top best-selling group of herbal products, thus far its cultivation, harvesting, and extraction are realized without profound knowledge of factors that affect its quality. Commercially available preparations of varying quality are the result.

The increasing popularity of Echinacea has raised concerns in the herbal medicine community and the media that there is a need to establish standards for Echinacea products. The diversity described above supports the need for greater efforts to provide authentic, safe, stable, and efficacious Echinacea products that are consistent from batch to batch (Bauer, 1999; Grant and Benda, 1999).

Standard quality controls with scientific criteria start with a defined species, proper cultivation and harvesting through a defined drying and extraction procedure, and end with a quantitative determination by a defined method for one or more of its active ingredients (Tierra, 1999).

Active Markers

In order to standardize Echinacea preparations, some suitable active markers must be identified in the products. Although a number of active components have been studied and identified, their mechanisms of action and bioavailability are not yet completely understood (Barrett, 2003). At present, alkamides and cichoric acid content seem to be used as quality markers for some Echinacea products. However, it is noteworthy that echinacoside, which is used frequently for standardizing E. pallida and E. angustifolia extracts, is absent from E. purpurea (Table 9.5). Therefore, depending on the plant species used, the active marker should be appropriate. And since the active components may act additively or synergistically, the overrating of a single compound in quality control should be avoided (Bauer, 1999).

As mentioned above, active marker levels depend on growing conditions, climate, soil quality, and harvest time, and all factors in the processing stage. Variation in the commercial samples and manufacturing process can be qualitatively and quantitatively revealed by various improved chro-matographic methods that have been used to measure content levels of typical components in the plants and products of Echinacea species (Pomponio et al., 2002).

Alkamides and Cichoric acid

Bauer (1999) described an HPLC method for identifying alkamides and cichoric acid in commercial samples of E. purpurea pressed juice preparations, and proposed standardization by analyzing alkamide and cichoric acid contents. These components are typically found in E. purpurea and show pharmacological activity. However, in the study of Al-Hassan et al. (2000), cichoric acid was not found in the pressed juice.

Alkamides have phagocyte-stimulating activity in vitro and in vivo. They were also shown in some cases to inhibit enzymes 5-lipoxygenase and cyclooxygenase, which are involved in inflammation. Cichoric acid inhibits hyaluronidase and causes stimulation of phagocyte activity in vitro and in vivo (Bauer, 1999; Clifford et al., 2002). It is also an antioxidant protecting against free radical-induced injury (Hu and Kitts, 2000; Sloley et al., 2001) and has also been shown to selectively inhibit human immunodeficiency virus type 1 integrase (McDougall et al., 1998). However, a more recent animal study (Goel et al., 2002) indicated that purified cichoric acid and the polysaccharide component from E. purpurea failed to exert any immunostimulatory effects in rats. These authors provided in vivo evidence that only the lipophilic alkamides (dodecatet-raenoic acid isobutylamides) are the effective, nonspecific immunomodulatory agent in Echinacea plant extract. Alkamides appear to be the most active agents in terms of stimulating effect on the alveolar macrophage function (stimulating effects on TNF-a and nitric oxide production) in normal rats.

Echinacoside

Echinacoside is a polyphenolic caffeoyl derivative with antioxidant activity. It seems that the anti-inflammatory activity of E. pallida root extract depends on the presence of echinacoside. Recent studies on antiinflammatory and cicatrizing activity of Italian-grown E. pallida root extract extracted by ethanol (1:10 w/v) (Speroni et al., 2002) proved that rats treated with echinacoside or dried E. pallida extract showed significantly higher antiinflammatory and wound-healing responses than did the control or E. purpurea group. Hu and Kitts (2000) found that the methanolic extract of E. pallida root exhibited greater antioxidant activity than extracts of E. angustifolia or E. purpurea. Therefore, echinacoside could be used as the active marker of E. pallida species and its products.

Polysaccharides

Two polysaccharides (PS I, PS II) have been isolated in the aerial parts of E. purpurea (Bauer and Wagner, 1991), and Echinacea-derived polysaccharides are indeed active in certain immunological models (Barrett, 2003; Emmendorffer et al., 1999). Bodinet and Beuscher (1991) reported that the roots of E. purpurea contain arabinogalactans and arabinogalactan-containing glycoproteins that exert immunomodulating activity. They indicated that the glycoprotein-containing fractions of E. purpurea root extracts are able to induce the secretion of TNF-a, IL-1, and INF-a and -b. Burger et al. (1997) also showed that the polysaccharide component of Echinacea has the effect of increasing in vitro production of TNF-a, IL-1, and IL-6 by macrophage.

More results for Echinacea polysaccharides are not from plant sources but rather from cell cultures of Echinacea. Polysaccharide components from plant sources were structurally different compared to those obtained from cell cultures. Echinacea preparations commonly contain pharmacologically insignificant amounts of polysaccharides (Bone, 1997a). Therefore, more research should be undertaken if polysaccharides are to be used as an active marker for Echinacea products.

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