Isolation and identification of mosquito biting deterrents from the North American mosquito repelling folk remedy plant, Matricaria discoidea DC.

Matricaria discoidea DC. (Asteraceae) has documented use as an insect repellent by Blackfoot Indians and other indigenous groups of North America. This investigation was conducted to evaluate this practice and systematically identify chemical constituents responsible for any insect repelling effect by utilizing a mosquito (Aedes aegypti (Linnaeus)) biting deterrent bioactivity-directed purification approach. Hydrodistilled oil from dried aerial parts of M. discoidea was the most bioactive crude extract generated and was as. Fractionation of this extract, followed by re-evaluation for mosquito biting deterrence using the K & D (Klun and Debboun) bioassay, produced many active fractions that were subsequently evaluated by spectroscopic techniques and the most active compounds were determined to be α-terpineol, spathulenol, and neryl isovalerate. A & K (Ali and Khan) large cage in vitro evaluation of pure compounds isolated from M. discoidea indicated α-terpineol to be the most active compound providing complete protection at 25 μg/cm(2). This is the first report on the mosquito repellency of neryl isovalerate and scientific evidence reported here validates the traditional use of M. discoidea as a biting-insect deterrent.