Differential effects of the (+)- and (-)-gossypol enantiomers upon Entamoeba histolytica axenic cultures.

The in-vitro anti-amoebic effects of (+/-)-, (+)-, (-)-gossypol and emetine were tested against axenic trophozoites from five Entamoeba histolytica strains. The (-)-isomer was more active than the racemate and the (+)-isomer. These results indicate that the gossypol anti-amoebic activity is mainly due to its content of (-)-gossypol in all strains tested.