Essiac for Cancer
March 2000; Volume 2: 19-23
By Carmen Tamayo, MD
Essiac, an herbal formula based on an ojibwa Native American formula, was popularized by a Canadian nurse, Rene Caisse, who began treating cancer patients with the herbal formula in 1922, after meeting a woman who attributed an apparent recovery from breast cancer to its use. Caisse manufactured the tonic using what she considered the most important ingredients: burdock root (Arctium lappa L.), Turkish rhubarb root (Rheum palmatum L.), sheep sorrel (Rumex acetosella L.), and slippery elm bark (Ulmus rubra Muhl.); Essiac is her last name spelled backwards.
In collaboration with Dr. Charles Brusch in Cambridge, Massachusetts, Caisse altered the formula in 1959 by adding four "potentiating" herbs: watercress (Nasturtium officinale R. Br.), blessed thistle (Cnicus benedictus L.), red clover (Trifolium pratense L.), and kelp (Laminaria digitata Lmx.). Flora Manufacturing acquired this formula, which is currently available in health food stores as Flor-Essence®. The four-herb formula originally developed by Caisse is still manufactured and distributed by Resperin Corporation in Canada. At least 40 different "Essiac" products are available in North America, Australia, and the UK; virtually all product packages include statements claiming to be the "original" formula.
Recent surveys have found that Essiac preparations (especially Flor-Essence and Essiac) are widely used by cancer patients. One study estimated that 35% of cancer survivors who purchased the "Guide to Unconventional Cancer Therapies" developed by the Ontario Breast Cancer Information Exchange project in Canada have used one of these formulas.1 Another survey conducted across North America by the University of Texas Center for Alternative Medicine Research (UT-CAM) found that 75% (3,788/5,051) of cancer patient participants used Flor-Essence. The majority (54.3%) of respondents were women and 22% of the cancer patients had breast cancer.2,3
North American sales of Essiac and Flor-Essence are estimated to be $3.2 million and $4.5 million per year, respectively.3
Clinical Studies
No clinical trials of Essiac formulas have been completed. In Canada, Essiac is available from the national health care program on physician request. In both Canada and the United States, the product is widely available at health food stores as a nutritional supplement. In the early 1980s, the Canadian Bureau of Human Prescription Drugs conducted a retrospective review of patients from summaries submitted voluntarily by physicians who had requested Essiac on behalf of their patients. Results were not encouraging: Of 86 patients (all had previously received conventional treatment) 47 patients received "no benefit" 17 patients died; eight patient reports were unevaluable; five patients required fewer analgesics; one patient had "subjective improvement" four patients were "stable" and four patients had an "objective response." On follow-up of the eight patients in the last two categories, two had died, three had disease progression, and three were stable.4
In 1978, the Health Protection Branch of Health Canada began a clinical trial of Essiac in 58 terminal cancer patients, but the trial was discontinued in 1983 because of a lack of physician participation. The researchers concluded that the product appeared to be non-toxic, but that the limited data from the trial were inadequate to confirm any increased survival (quality of life and pain control were not evaluated).4,5
A literature review published by the Canadian Breast Cancer Research Initiative (CBCRI) concluded that there is weak evidence of effectiveness and little evidence of harm.5 A more scientific summary of CBCRI findings concluded that Essiac is a widely used agent that has been studied incompletely.6 A literature review conducted by researchers at UT-CAM identified 13 in vivo and 11 in vitro evaluations of individual herbs, but none on the tonic itself.3
Study in Progress
A pilot study is currently being conducted at the British Columbia Cancer Agency in collaboration with UT-CAM and the Tzu Chi Institute of Complementary Medicine in Vancouver, Canada. The study is sponsored by the Hecht Foundation in Vancouver. Fifty stage IV colon cancer patients receiving palliative chemotherapy will be randomized to adjunctive treatment with Flor-Essence or placebo (a similar tasting, inactive herbal mixture) for three months. The study will determine the feasibility of collecting data on general health outcomes (including pain, weight, and performance status) and will evaluate safety and tolerability of Flor-Essence as well as document quality of life for all patients.3
In Vivo and In Vitro Studies
A number of experimental and clinical studies of individual herbs have been reported in the literature, but there are few studies available on the combined-herb formula. An in vitro study found that Flor-Essence demonstrated estrogen receptor-binding activity and slight progesterone receptor-binding activity.7 Unpublished studies funded by Flora Manufacturing, Inc. (producers of Flor-Essence) claim that the product increases phagocytic activity of macrophages and has anti-inflammatory, hepatoprotective, and gastroprotective properties.
Several herbs in Essiac contain phytoestrogens, anthraquinones, and flavonoids, all of which have pharmacological effects. Red clover contains the phytoestrogens genistein, daidzein, formononetin, and biochanin A.8 (See Alternative Therapies in Women’s Health, February 2000, pp. 9-12). Sheep sorrel also contains large amounts of genistein and daidzein,9 which inhibit the growth of both estrogen receptor-negative and -positive human breast cancer cell lines (IC50=24-44lM).10 Phyto- estrogens also have anti-angiogenic effects and inhibit enzymes involved in the regulation of cell growth.11
Several herbs in Essiac have laxative or bulk-forming effects. Soluble and insoluble fibers increase fecal bulk and reduce bowel transit time, thus reducing enterohepatic recirculation of estrogen. Additionally, increased fiber may dilute and reduce absorption of toxins from stool. Both slippery elm and kelp are rich in soluble fiber and may act as bulk-forming agents. Anthraquinones found in sheep sorrel and Turkish rhubarb are potent laxatives. (These are the same compounds found in senna and cascara.)
Anthraquinones may have other effects as well. Several anthraquinones (including emodin, rhein, alizarin, and aloe-emodin) are effective antioxidants and radical scavengers in vivo.12 Aloe-emodin inhibits tumor growth in mice with P-388 lymphocytic leukemia.13 Aloe-emodin has been shown to have anticancer activity in the lymphocytic leukemia and Walker carcinosarcoma cell lines.14 Rhein and emodin inhibit the growth of mammary carcinoma and Ehrlich ascites carcinoma in mice.15
Flavonoids are widely distributed in plants and have a variety of beneficial effects. Burdock root contains at least five flavonoids (caffeoylquinic acid derivatives). Studies conducted in the 1970s indicate a beneficial effect of quercetin, a flavone in burdock, on carcinogen-induced lung adenoma in mice.16
Biological Activity of Individual Herbs
Burdock. The root contains at least five powerful flavonoid-type antioxidants (i.e., caffeoylquinic acid derivatives) and several polyphenols that are more powerful antioxidants than vitamin C. The antioxidant effect was measured against lipid peroxidation induced by t-butyl hydroperoxide in rat hepatocytes.12,17,18 In burdock fruit, dilignans are the most active cytotoxic compounds; the most active lignan is arctigenin 1 and its aliphatic ester n-decanoate. Arctiin and arctigenin have been shown to have potent in vitro cytotoxic activity and in vivo antitumor activity against human hepatoma HepG2 cells and mouse sarcoma 180 cells.19 Burdock reduced chemically produced chromosomal aberrations in rat bone marrow cells (other vegetables that significantly suppressed chromosomal damage were onion, eggplant, cabbage, and Welsh onion).20
Another study found that an aqueous extract of burdock root decreased mutations in cells exposed to toxic chemicals.21,22 In addition, in an experimental study the toxic compound DMBA (dimethylbenz[a]anthracene) was used to induce chromosome aberrations in rat bone- marrow cells. The incidence of damaged cells induced by DMBA was suppressed significantly in animals that consumed fresh or boiled juices from burdock root and other vegetables (onion, eggplant, and cabbage).22 Burdock also contains quercetin, isoflavones (genistein, biochanin A, nobiletin, and tangeretin), and tannins, which exhibit strong antitumor effects against MM2 ascites tumors in mice.23 The tannin (Oenothein B) also inhibited the growth of solid tumors in mice.
Watercress. Watercress, cabbage, broccoli, cauliflower, Brussels sprouts, kale, mustard greens, collard greens, bok choy, and turnips contain specific indoles which activate enzymes in the body that affect estrogen metabolism in a way that may contribute to reduced breast cancer risk.24
Watercress may have anticarcinogenic properties (there is no evidence that it can treat existing tumors). In mice and rats, phenethyl isothiocyanate (PEITC) is a potent chemoprotective agent against pulmonary carcinogenesis induced by tobacco nitrosamine 4-(methylnitrosamino)-1-(3pyridyl)-1-butanone (NNK).25 It was believed to inhibit certain P450 enzymes that activate carcinogens. In humans, watercress consumption increased urinary levels of two metabolites of NNK; a later analysis of these urine samples suggested that watercress induces UDP-glucoronyltransferase activity rather than P450 enzymes.26 PEITC is currently one of a number of agents undergoing toxicology testing for possible use in a chemoprevention trial.27
Blessed Thistle. Cnicin, a sesquiterpene lactone found in blessed thistle, has cytotoxic properties.28 Blessed thistle contains two lignans (arctiin and arctigenin) that have been shown to have in vitro cytotoxic activity and in vivo antitumor activity against human hepatoma HepG2 cells and mouse sarcoma 180 cells.19
Slippery Elm. The bark of slippery elm contains large concentrations of antioxidants.29
Kelp. Kelp has a tumor-inhibiting effect30 on sarcoma-180 in mice.31
Turkish Rhubarb. Anthraquinones (i.e., emodin and aloe-emodin) are the active ingredient in the root. Extracts of Turkish rhubarb caused significant tumor necrosis in a mouse sarcoma model.32 Aloe-emodin has been shown to have anticancer activity in the lymphocytic leukemia and Walker carcinosarcoma tumor systems.14
Red Clover. Red clover contains the phytoestrogens genistein, daidzein, formononetin, and biochanin A.8
Sheep Sorrel. Several anthraquinones in sheep sorrel including emodin, rhein, alizarin, and aloe-emodin are effective antioxidants and radical scavengers in vivo.12 The leaves of sheep sorrel are reported to be useful in treating cancer.33 Sheep sorrel also contains large amounts of the phytoestrogens genistein and daidzein.9
Conclusion
Essiac formulas have an interesting history and are very popular among cancer patients. There are no prospective clinical trials of any Essiac products (or for that matter, of any of the individual components). The popularity of Essiac makes it an important public health issue to evaluate beneficial or detrimental clinical effects. Proponents of Essiac claim that its effect is dependent on the herbs being present in the correct proportions. Given that there are several contenders for the real Essiac, several formulas should be tested in carefully designed clinical studies.
Dr. Tamayo is Director, Division of Complementary and Alternative Medicine, Foresight Links Corp. in London, ON.
References
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19. Moritani S, et al. Cytotoxic components of bardanae fructos (Goboshi). Biol Pharm Bull 1996;19:1515-1517.
20. Ito Y, et al. Suppression of 7,12-dimethylbenz[a]-anthracene-induced chromosome aberrations in rat bone marrow cells by vegetable juices. Mutat Res 1986;172:55-60.
21. Morita K, et al. A desmutagenic factor isolated from burdock (Arctium lappa Linne). Mutat Res 1984;129:25-31.
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Funding of Reviewed Studies
Reference 1: National Cancer Institute of Canada. References 2, 3: sponsored in part (less than 10%) by the Flora Company. The ongoing study of Flor-Essence in Vancouver is sponsored completely by a private, non-profit foundation, the Hecht Foundation. References 4-33: funding sources not available.
March 2000; Volume 2: 19-23
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