Screening for molluscicidal activity in crude drugs

Thirty-four extracts of crude drugs and medicinal plants have been screened for activity against Oncomelania nosophora, the intermediate host of the Japanese strain of Schistosoma japonicum. Strong molluscicidal activity was found in the MeOH extract of Anemarrhenae Rhizoma. Although timosaponin A-III, one of the main saponins of Anemarrhenae Rhizoma, showed very strong killing activity, markogenin-3-O-beta-D-glucopyranosyl (1-2)-O-beta-D-galactopyranoside having the same glycosidic linkage was found to be inactive.