Introduction: Sphaeranthus indicus Linn, an asteracid weed, has been studied by various researchers. The flower of S. indicus possesses biological activities like Nematicidal, Larvicidal, Piscicidal and others, for example, agricultural. Objective: The present investigation for the antiprotozoal activitiy of a methanolic extract (MeOHx) and the alkaloidal fraction (SAF) of the flowers of Sphaeranthus indicus Linn. has been undertaken. Materials and Methods: The study was carried out in seven groups of the Paramecium sp. by using the hemocytometer technique. Different concentrations of MeOHx (50 and 100 μg / ml) and SAF (20 and 40 μg / ml) were applied. The percent mortality was calculated and the results were expressed by using the probit analysis. Results: There was no significant activity against the tested protozoa. Conclusion: Thus, the results of the present investigation suggest that MeOHx and SAF are not responsible for the antiprotozoal property of S. indicus.
Key words: Paramecium sp. , alkaloid, antiprotozoal, Sphaeranthus indicus Linn