Fractionation of methanolic extracts from two herbaceous plants and evaluation of their larvicidal activity on Anopheles arabiensis.

With the objective of controlling malaria by reducing the populations of Plasmodium spp, vectors, fractions obtained from crude extracts of dry plants of Cyperus rotundus and Leucas martinicensis were analyzed and their larvicidal activity on Anopheles arabiensis determined. Biological tests revealed that the hexane fraction of Cyperus rotundus as well as the ethyl acetate fractions of Leucas martinicensis and Cyperus rotundus are the most effective, with respective LC50 of 52.43ppm, 54.26ppm and 57.21ppm. The corresponding LH50 are 3h 09min 11sec, 3h 29min 45sec and 3h 51min 01sec. Phytochemical tests showed that the ethyl acetate fraction of Cyperus rotundus contains more terpenoids (42.005 ± 0.615 g lupeol eq / 100g DM), followed by the hexane fractions of Leucas martinicensis (38.845 ± 0.215 g Lupeol eq. / 100g DM), Cyperus rotundus (36.1 ± 0.66 g eq. lupeol / 100g DM).