A US team of researchers has discovered compounds in traditional sweetgrass that keep mosquitoes away. A field grass, sweetgrass is traditionally used by some Native Americans that gives off a sweet smell to repel the insects.
Native north Americans have for long decorated themselves and their homes with fragrant sweetgrass (scietifically called Hierochloe odorata), a native cool-season perennial plant growing 10-24 inches and spreading about 2 feet per year is used in traditional medicine, to repel biting insects and mosquitoes in particular.
“We discovered that in our hunt for new insect repellents, traditional treatments have provided good leads,” said head researcher Charles Cantrell from the US Department of Agriculture. Cantrell’s team, in association with team of researchers at the University of Guelph and the University of Mississippi, carried out steam filtration on sweetgrass samples and examined its oil for it’s ability to scare off mosquitoes from biting.
To test the insects hostility to the oil, the researchers filled small containers with a red-coloured solution that resembled human blood and covered them with a thin layer. Then they coated the layers with various substances: the sweetgrass oil, substitute sweetgrass uproot obtained without steam distillation, the gold-standard bug repellent called the ethanol solvent control.
The team detected that of the sweetgrass juices, the steam-distilled oil got the lowest mosquito bites equaling the repellent potency of DEET.