Schistosomicidal and trypanocidal structure-activity relationships for (+/-)-licarin A and its (-)- and (+)-enantiomers

Abstract (±)-Licarin A ( 1 ) was obtained by oxidative coupling, and its enantiomers, (−)-licarin A ( 2 ) and (+)-licarin A ( 3 ), were resolved by chiral HPLC. Schistosomicidal and trypanocidal activities of these compounds were evaluated in vitro against Schistosoma mansoni adult worms and trypomastigote forms of Trypanosoma cruzi . The racemic mixture ( 1 ) displayed significant schistosomicidal activity with an LC 50 value of 53.57 μM and moderate trypanocidal activity with an IC 50 value of 127.17 μM. On the other hand, the (−)-enantiomer ( 2 ), displaying a LC 50 value of 91.71 μM, was more active against S. mansoni than the (+)-enantiomer ( 3 ), which did not show activity. For the trypanocidal assay, enantiomer 2 showed more significant activity (IC 50 of 23.46 μM) than enantiomer 3 , which showed an IC 50 value of 87.73 μM. Therefore, these results suggest that (±)-licarin A ( 1 ) and (−)-licarin A ( 2 ) are promising compounds that could be used for the development of schistosomicidal and trypanocidal agents.