The dandelion (also known as Taraxacum officinale) is a well-known perennial herb native to North America and Eurasia. Despite its reputation as a stubborn weed, the dandelion possesses redeeming properties that make it an important ingredient for natural health products. Dandelion root extract has been used for centuries in traditional Chinese medicine for the treatment of a plethora of conditions of the liver and gastrointestinal tract. However, new evidence from the University of Windsor, at the forefront of cancer research, has found that dandelion root extract also possesses potential anti-cancer properties.

The potential anti-cancer effects of dandelion root extract first began to be investigated, as one might expect, from the result of word-of-mouth endorsement and anecdotal evidence. Cancer patients at Windsor Regional Cancer Center who used commercially available dandelion root teas began to report positive responses. As this anecdotal evidence began to grow – perhaps driven by the despair borne out by life-threatening conditions – Dr. Caroline Hamm, an oncologist at the Windsor Regional Cancer Centre, became intrigued. Dr. Hamm’s interest in the potential anti-cancer effects of the dandelion sparked a collaboration with Dr. Siyaram Pandey, a Professor at the University of Windsor with an interest in the development of anti-cancer therapies.

Our scientific evaluation of the anti-cancer properties of the dandelion started with basic experiments that used dandelion roots picked from gardens and lawns. The freshly picked dandelion roots were used to make a crude water-based dandelion root extract in Dr. Pandey’s laboratory. Since Dr. Hamm’s cancer patients all reported using dandelion tea to alleviate the symptoms of leukemia, we decided to test the effect of our water-based dandelion root extract on human leukemia cells cultured under controlled in vitro (petri dish) conditions. Our findings showed that even a crude water-based dandelion root extract was able to kill human leukemia cells. We also tested the effect of the water-based dandelion root extract on non-cancerous (normal) human cells. We found that the normal human cells were unaffected by exposure to water-based dandelion root extract. This suggested the cell killing effect of dandelion root extract was limited (specific) to only leukemia cells, while normal human cells were spared from any toxic side-effects.

These results were encouraging and led us to conduct further studies using animal models of human cancer. We investigated the potential role of dandelion root extract as a treatment of cancer using a wide range of mouse models, including mouse models of colorectal cancer. We found that dandelion root extract showed potential as an effective anti-cancer treatment, with mice carrying human tumours responding to dandelion root extract administered in their drinking water. No harmful side-effects in the mice from the consumption of dandelion root extract were observed by the vets and pathologists.

Table 1 outlines all of the studies we have published to date, which investigated the effects of dandelion root extract on different cancer models. During our research, some important chemical components of dandelion root extract have been identified, with the aim of attributing the potential anti-cancer properties to specific compounds present in the whole extract. This process was an essential part of the research project, because the information we obtained is important for ensuring that the production of dandelion root extract will use the optimal starting material and provide the best possible anti-cancer activity.

Some of the components that were identified included lupeol (which activates the apoptosis pathway [also known as programmed cell death]), α-amyrin and β-amyrin, as well as several sesquiterpene lactones. These compounds have been studied for their anti-cancer activities for years. The potential mechanism of action of dandelion root extract is thought to involve the activation of several cell death pathways, as well as the interference with anti-cell death pathways, in a manner dependent on the level of dose and the length of the course of treatment. In mouse models of human cancer, this mechanism was associated with a reduction in the growth of tumours and an increase in the survival of the animal.

Based on the studies in Table 1, a Phase I human clinical trial of dandelion root extract has been approved by Health Canada. Human volunteers were recruited onto the trial in December 2016, which is exploring the safety of dandelion root extract for the treatment of cancer. There is a significant need for less toxic and more effective cancer treatments that improve the prognosis and quality of life of cancer patients who suffer considerably from the severe side-effects of conventional cancer therapies. It is our hope that human trials will establish dandelion root extract as an acceptable form of cancer treatment and open the door for its introduction as a safe and effective adjuvant to therapy or a treatment option in its own right.

References

1. Ovadje, P et al. Efficient induction of extrinsic cell death by dandelion root extract in human chronic myelomonocytic leukemia (CMML) cells. PLoS ONE. 2012;7(2):e30604.2.

2. Ovadje, P et al., 2011. Selective induction of apoptosis through activation of caspase-8 in human leukemia cells (Jurkat) by dandelion root extract. J. Ethnopharmacology. 2011;133(1):86–91. doi:10.1016/j.jep.2010.09.005.

3. Chatterjee, S., Ovadje, P et al. The efficacy of Dandelion root extract in inducing apoptosis in drug-resistant human melanoma cells. ECAM. 2011;doi:10.1155/2011/129045.

4. Ovadje, P et al. Selective induction of apoptosis and autophagy through treatment with Dandelion root extract in human pancreatic cancer cells. Pancreas. 2012;41(7):1039-1047.

5. Ovadje, P et al. Dandelion root extract affects colorectal cancer proliferation and survival through the activation of multiple death signalling pathways. Oncotarget. 2016;10.18632/oncotarget.11485.