Anticancer natural products from traditionally used Canadian medicinal plants

Breast cancer is the most commonly diagnosed malignant neoplasm among the female population worldwide [1] and, despite significant advances in screening technologies and therapies, it remains the second leading cause of cancer related deaths in Canadian women [2]. It is therefore imperative that we continue to develop novel and more specific anticancer agents of greater efficacy and diminished toxicity. Combining natural products research with ethnopharmacology is an effective strategy for identifying potential anticancer drug candidates [3]. The ethnobotanical knowledge of the Canadian First Nations is therefore an important resource for identifying plants that produce natural product drug leads. Bioassay screening of a library of thirty-five Canadian medicinal plant extracts identified eleven extracts that were potent inducers of apoptosis in an aggressive human breast carcinoma cell line (MDA-MB-231). Bioassay guided fractionation of the seven most active extracts (Aralia nudicaulis, Juniperus communis, Nuphar lutea, Populus tremuloides, Hypericum perforatum, Moneses uniflora, and Orthilia secunda) resulted in the isolation of thirteen natural products, most of which have not previously been reported to be pro-apoptotic. Although these results confirm the importance of our ethnopharmacological approach, our studies of medicinal plants has predominantly resulted in the isolation of known natural products. In addition to our medicinal plant extracts, we have conducted preliminary bioassay screening of a library of endophytic fungal extracts derived from medicinal plants. Our data indicate that these represent a promising source of pro-apoptotic natural products and, therefore, in the future we will be focussing our attention on these endophytes in an effort to discover novel chemical entities with anticancer activity.

Acknowledgements: Hebelin Correa and Larry Calhoun are acknowledged for technical assistance.

Keywords: Medicinal plants, breast cancer, apoptosis, ethnopharmacology.

References:

[1] World Cancer Report 2014. Lyon: International Agency for Research on Cancer; 2014: 362 – 363

[2] Canadian Cancer Statistics 2015. Available at http://www.cancer.ca. Accessed January 5, 2016

[3] Uprety Y, Asselin H, Dhakal A, Julien N. Traditional use of medicinal plants in the boreal forest of Canada: review and perspectives. J Ethnobiol Ethnomed 2012; 8: 1 – 14