In vitro antischistosomal evaluation of some newly synthesized praziquantel derivatives

Praziquantel, 2-(cyclohexylcarbonyl)-1,2,3,6,7,11b-hexahydro-4H-pyrazino2,1-a]isoquinolin-4-one, was used as the parent starting material to synthesize a new series of praziquantel-3-arylidene derivatives 1a–c and praziquantel–Mannich bases 2a–d, hoping to obtain new antischistosomal compounds of more activity and lower adverse effects. The antischistosomal activity of the newly synthesized compounds was evaluated using in vitro Schistosoma mansoni worm killing tests. Both compounds 2c and 2d exhibited significant in vitro antischistosomal activity and may offer promising use as an antischistosomal drug either alone or in combination with praziquantel.