Molluscicidal and schistosomicidal activities of a steroidal saponin containing fraction from dracaena fragrans [L.]

ABSTRACT

The steroidal saponin-containing fraction from methanolic extract of Dracaena fragrans [Family Agavaceae] was tested for molluscicidal and ovicidal activities against Biomphalaria alexandrina and Bulinus truncatus, the snail vectors of Schistosoma mansoni and S. haematobium in Egypt, respectively. It was also tested for schistose-micidal activity in vitro on adult S. mansoni and against the free-living miracidia and cercariae of the parasite. The homogenated soft body of B. alexandrina was used to determine the effect of the saponin fraction on total protein, albumen, aminotransferase enzymes and acetylcholin esterase. The results showed that the saponin fraction had considerable molluscicidal activity; LC[50] and LC[90] were 2.7 ppm and 3.7 ppm for B. alexandrina and 2 ppm and 2.5 ppm for B. truncatus, respectively. Snail eggs did not hatch in concentration as low as half molluscicidal LC[50] [1.35 ppm]. The LC[50] killed all miracidia and cercariae in 30 seconds and after 22 and 40 minutes at a very low concentration [0.165 ppm] respectively, and had in vitro lethal effect on adults with LC[50] 18.4 micro g/ml 4 days post-exposure. The snail tissue homogenate showed significant increase in total protein content and albumen, in aminotransferases and acetylcholinesterase activities