Traditional Indigenous tea from Canada could combat drug-resistant malaria: study

The leaves of the dwarf Labrador tea plant contain an oil that could help fight malaria. (ACS Omega)

A plant long used by Indigenous people for medicinal tea has been shown to be effective against the parasite that causes drug-resistant malaria.

Labrador tea, which refers to three closely related shrub-like Rhododendron species, has been commonly used by First Nations and Inuit people in Canada and the U.S. to treat a range of ailments, including colds, headaches and stomach problems.

In a new peer-reviewed study, scientists from Laval University in Quebec City collected what's known as dwarf Labrador tea, or Rhododendron subarcticum, from the Nunavik region in northern Quebec and extracted essential oil from its leaves. The aromatic and relatively unstudied evergreen plant is found just south of the Arctic Circle from northern Canada to Siberia, and can grow to 20 cm in height.

"Plant species from the arctic and subarctic ecosystems have not been subjected to as many or as thorough phytochemical investigations as their counterparts from tropical environments," the study explained. "We decided to characterize the essential oil of [dwarf Labrador tea] and test its activity against [malaria-causing parasites] after learning of its importance for the First Nations as traditional medicine."

The essential oil Laval University scientists analyzed was mostly comprised of the organic compound ascaridole, which effectively killed different strains of the parasite responsible for the most serious and drug-resistant form of malaria during tests. Previous studies have shown that essential oils from Labrador tea also have antimicrobial properties, meaning they can kill microorganisms like bacteria and mould. 

Malaria is a mosquito-borne infectious disease than can turn deadly in severe cases. While malaria was endemic in Canada and the U.S. in the 19th and early 20th centuries, transmission is not known to normally occur in the two countries today.

The Labrador tea study was published this month in the journal American Chemical Society Omega.

"The authors wish to thank the Whapmagoostui Cree Nation Council and Kuujjuarapik Inuit Community Council for their suggestion of the dwarf Labrador tea as an interesting plant to investigate and for sharing their knowledge about this shrub and its traditional uses," the study said. "Without the discussions with representatives from the local communities, we would not have investigated this plant."