Comparative metabolism of albendazole and albendazole sulphoxide by different helminth parasites

Albendazole (ABZ) is a broad-spectrum benzimidazole anthelmintic widely use d in human and veterinary medicine. The aim of the current work was to char acterise the sulphoxidative metabolism of ABZ, and the sulphoreduction of A BZ sulphoxide (ABZSO)I by microsomal (Ms) and cytosolic (Cyt) fractions of three different helminth species: Fasciola hepatica, Moniezia expansa and A scaris suum. After the incubation assays, parasite material was analysed by HPLC to characterise the metabolic product formed. Both the Ms and Cyt fra ctions of the three parasites studied were able to oxidise ABZ into ABZSO i n a non-enantioselective fashion. Oxidation of ABZ was greater in the Ms fr action of the trematode (50%) than in both cestode (19%) and nematode (14%) parasites. Only the incubation of ABZSO with both subcellular fractions of M. expansa generated ABZ as a metabolic product. The results obtained here indicate that helminths have the capacity to biotransform benzimidazole co mpounds: however, this metabolic activity differs qualitatively and quantit atively among helminth species.