Essiac tea: scavenging of reactive oxygen species and effects on DNA damage

Essiac, a tea reportedly developed by the Ojibwa tribe of Canada and widely publicized as a homeopathic cancer treatment, is prepared from a mixture of four herbs Arctium lappa, Rumex acetosella, Ulmus rubra and Rheum officinale. Each of these herbs has been reported to possess antioxidant and anti-cancer activity. Essiac itself has also been reported to demonstrate anti-cancer activity in vitro, although its effects in vivo are still a matter of debate. We prepared an extract of Essiac tea from a concentration of 25mg/mL and boiled it for 10 min. From this preparation we used concentrations of 5, 10, 25 and 50% to measure Essiac effects. In this study, we examined the effects of Essiac on free radical scavenging and DNA damage in a non-cellular system, as well as the effects Essiac on lipid peroxidation using the RAW 264.7 cell line. We observed, using electron spin resonance, that Essiac effectively scavenged hydroxyl, up to 84% reduction in radical signal at the 50% tea preparation concentration, and superoxide radicals, up to 82% reduction in radical signal also at the 50% tea preparation concentration, as well as prevented hydroxyl radical-induced DNA damage. In addition, Essiac inhibited hydroxyl radical-induced lipid peroxidation by up to 50% at the 50% tea preparation concentration. These data indicate that Essiac tea possesses potent antioxidant and DNA-protective activity, properties that are common to natural anti-cancer agents. This study may help to explain the mechanisms behind the reported anti-cancer effects of Essiac.