Activity assessment of praziquantel and enantiomers on <i>E</i>. <i>multilocularis</i> protoscoleces.

<p><i>E</i>. <i>multilocularis</i> protoscoleces were exposed to various concentrations (100 ppm till 0.0006 ppm, 1 to 3 dilution series) of the PZQ-enantiomers (R)-(-)-PZQ and (S)-(-)-PZQ or the racemic mixture of both (PZQ). After 12 h of incubation, motility was assessed (A) and corresponding pictures of the morphological changes at 0.02 ppm are shown (B). (A) 1% DMSO was set to 100% relative movement and all other drug-responses were calculated accordingly. Note that all forms of PZQ never led to a complete inhibition of protoscolex movement. (R)-(-)-PZQ and the racemic mixture exhibited higher activities than the (S)-(-)-PZQ, with minimal inhibitory concentrations (MICs) indicated by asterisks (see <a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0005618#pntd.0005618.g001" target="_blank">Fig 1</a> for compound structures and <a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0005618#pntd.0005618.s004" target="_blank">S1 Fig</a> for other measurement time points). Experiments shown here were repeated three times.