ABSTRACT
Introduction .................................................................................................................................. 221 Materials and Methods................................................................................................................. 222 Results and Interpretations........................................................................................................... 223 References .................................................................................................................................... 230
Immunostimulants, primarily targeting natural killer (NK) cells (Lersch et al., 1992; See et al., 1997; Sun et al., 1999), exist in root extracts of the plant
Echinacea purpurea
. NK cells have been well established throughout the last 20 years, as the first line of defense against developing tumors and virus-infected cells. Extracts from this plant are not only readily commercially available, but have become extremely popular recently for their reported health benefits including abatement of virus-mediated respiratory infections, assorted inflammations (cutaneous and other), tumors, and AIDS (Hill et al., 1996; Lersch et al., 1992; Roesler et al., 1991; Steinmuller et al., 1993; Stimpel et al., 1984; Tragni et al., 1985). There appears, moreover, to be no maximum dose at which this water-soluble herb is toxic
in vivo
(Lersch et al., 1992; Melchart et al., 1995; Mengs et al., 1991).
