As a member of the Evidence-Based Veterinary Medical Association (EBVMA), I am thrilled with the recent publications focusing on three alternative therapies. People are becoming more and more interested in alternative therapies, for themselves and their pets. Whether this trend is due to a desire for more effective and less toxic therapies, increased research into the mechanism of action of many natural products, dissatisfaction with the effectiveness of traditional medicine or other issues is very much up for debate, but certainly beyond the scope of this column.
The three alternative therapies recently evaluated in the veterinary literature are Yunnan baiyao, Polysaccharopeptide (PSP) from the mushroom Coriolus versicolor, and artesunate.
The Chinese have used artemisinin, a derivative of sweet wormwood, for medicinal purposes for over 2000 years. Its main use, both past and present, is as an anti-malarial medication. Researchers are now starting to evaluate the anti-cancer properties of artemisinin and its derivatives1. It is thought that artemisinin kills cancer cells through the generation of reactive oxygen radicals after binding to iron, which is found in high concentrations in many cancer cells. An additional mechanism of action is through the induction of apoptosis. A recent paper by Rutteman, et al2, documented activity of oral artesunate, a semi-synthetic derivative of artemisinin, in cancer bearing dogs. A potential advantage of artesunate is that its effectiveness is not diminished by the genes that confer multidrug resistance to many of the anti-cancer drugs commonly used in veterinary medicine.
The second alternative therapy is a Coriolus versicolor mushroom derivative, PSP, sold under the trade name I’m-Yunity ®. PSP does inhibit cancer cell growth in vitro, but its effect in vivo were largely unknown prior to the 2012 paper by Brown and Reetz3 in Evidence-Based Complementary and Alternative Medicine (http://www.hindawi.com/journals/ecam/2012/384301/). Their randomized, double-blinded, multidose pilot study evaluated the effect of I’m-Yunity® in dogs with splenic hemangiosarcoma at 3 doses (25, 50 and 100 mg/kg/day). The authors found that dogs treated at the highest dose (100 mg/kg/day) of I’m-Yunity® had significantly delayed progression of metastases compared to dogs treated at the lowest dose. In addition, the dogs in the two highest dose groups had increased median survival times compared to the median survival times of dogs in previously published reports. Although comparing current patients to historical controls is not ideal, the level of evidence generated by randomized, double blind studies is considered very high.
The third is Yunnan baiyao, a Chinese herb used as an anti-coagulant, anti- inflammatory, and pain reliever for over a century, has anecdotally been reported to improve the survival of dogs with hemangiosarcoma. We now have evidence, rather than just anecdotes, about the activity of Yunnan baiyao against canine hemangiosarcoma cells. Wirth, et al4, report on the effects of varying concentrations and exposure of Yunnan baiyao to three canine hemangiosarcoma cell lines in vitro. The authors measure the effects of 5 concentrations (50, 100, 200, 400, 600 and 800 μg mL−1) at 24, 48 and 72 hours and find that Yunnan baiyao causes dose and time dependent cell death. The manner in which this herb kills hemangiosarcoma cells is likely through capsase-mediated apoptosis. These findings warrant further studies, both in vitro and in vivo, about Yunnan baiyao in the treatment of canine hemangiosarcoma.
Dr. Gerald S. Post – 2014
- Lai H, Singh NP, Sasaki T. (2013) Development of artemisinin compounds for cancer treatment. Invest New Drugs 31:230-246.
- Rutteman G, Erich S, Mol J, Spee B, Grinwis G, Fleckenstein L, London C and Efferth T (2013) Safety and Efficacy Field Study of Artesunate for Dogs with Non-resectable Tumours. Anticancer Research 33:1819-1828
- Brown DC and Reetz J. (2012) Single Agent Polysaccharopeptide Delays Metastases and Improves Survival in Naturally Occurring Hemangiosarcoma. Evidence-Based Complementary and Alternative Medicine 2012:1-8
- Wirth KA, Kow K, Salute ME, Bacon NJ and Milner RJ (2014) In vitro effects of Yunnan Baiyao on canine hemangiosarcoma cell lines. Veterinary and Comparative Oncology DOI: 10.1111/vco.12100