Abstract

Aqueous and organic extracts from Desmodium velutinum (Willd) DC (Fabaceae), Combretum molle R.Br ex G. Don, Combretum sericeum G. Don (Combretaceae), Bidens engleri O.E.Schulz (Asteraceae), Cucumis metuliferus E. Mey. ex Naudin, Cassia podocarpa Guill. et Perr. (Ceasalpiniaceae), and Opilia celtidifolia Guill. & Perr. (Opiliaceae) from Burkina Faso were prepared and tested in vitro against Plasmodium falciparum parasites. Chloroquine was used as a positive control. Essential oils extracted from Hyptis suaveolens and Hyptis spicigera used as repellent were screened against Anopheles gambiae under laboratory conditions using human subjects. Dichloromethane leaf extracts of D. velutinum and C. sericeum (IC₅₀ = 9 µg/ml), and the dichloromethane root extract of O. celtidifolia (IC₅₀ < 11 µg/ml) showed promising antiplasmodial activity. The ethanol leaf extracts of C. podocarpa (IC₅₀ = 22 µg/ml), D. velutinum (IC₅₀ = 36 µg/ml) and C. molle (IC₅₀ = 25 µg/ml) showed moderate activity. Low activity was observed in the aqueous leaf extracts of C. sericeum (IC₅₀ = 68 µg/ml), D. velutinum (IC₅₀ > 100 µg/ml), B. engleri (IC₅₀ = 101 µg/ml) and C. metuliferus (IC₅₀ > 100 µg/ml). Repellency of the two essential oils was high during the first hour but decreased with the bioassay time. The relatively high repellency of A. gambiae mosquitoes estimated as 87.6 ± 0.2% (H. spicigera) and 81.7 ± 0.3% (H. suaveolens) confirms the traditional use of the two plants.

Key words: Malaria, antiplasmodial, Plasmodium falciparum, mosquito, repellent, Anopheles gambiae, plants.