Bioactive plants from Argentina and Bolivia.

Antibacterial and molluscicidal activities of methanol and chloroform extracts of 16 plant species belonging to the families Compositae and Melastomataceae were evaluated. The chloroform extract of Vernonanthura tweediana and the methanol extract of Senecio santelisis resulted to be very toxic to brine shrimp nauplii (LC(50)=1 microg/ml). Chloroform extracts of S. santelisis and Senecio leucostachys as well as the methanol extract of Wedelia subvaginata displayed molluscicidal effects on Biomphalaria peregrina showing LC(100)<100 microg/ml. Moderate antibacterial action was produced by the chloroform extracts of Flaveria bidentis, Grindelia scorzonerifolia and Vernonia incana against two strains of Staphylococcus aureus.