RESUMO
BACKGROUND: Despite the recommendation of the Task Force on Alternative Therapies of the Canadian Breast Cancer Research Initiative, little research has been published on the widely used herbal compound Essiac. We aimed to address this deficiency by conducting a series of assays to determine some of the purported activities of Essiac in vitro. MATERIALS AND METHODS: The activity of Essiac was measured using established assays to assess anti-oxidant, fibrinolytic, anti-microbial, anti-inflammatory, immune modulation, cell-specific cytotoxicity, and impact on cytochrome P450 (CYP450) enzyme pathways. RESULTS: Essiac exhibited significant antioxidant activity in the ABTS assay. A 20-fold dilution of Essiac also exhibited significant immunomodulatory effects, specifically through stimulation of granulocyte phagocytosis, increases in CD8+ cell activation, and moderately inhibiting inflammatory pathways. Essiac exhibited significant cell-specific cytotoxicity towards ovarian epithelial carcinoma cells (A2780). Importantly, a 20-fold dilution of Essiac showed significant inhibition of several CYP450 enzymes, most notably CYP1A2 (37%) and CYP2C19 (24%). Essiac demonstrated dose-dependent inhibition of clot fibrinolysis. CONCLUSION: In vitro analysis of Essiac indicates significant antioxidant and immunomodulatory properties, as well as neoplastic cell specific cytotoxicity consistent with the historical properties ascribed to this compound. Importantly, significant CYP450 and fibrinolysis inhibition were also observed. This is the first comprehensive investigation of the in vitro effects of Essiac.