Strategies for detoxification of aldehydic products of lipid peroxidation in helminths

Crude extracts from a number of helminths including Schistosoma intercalatum and Fasciola hepatica were able to detoxify known aldehydic products of lipid peroxidation. A major route for alk-2-enal and alka-2,4-dienal detoxification in parasitic helminths was via glutathione conjugation and glutathione transferase appeared to be responsible for the activity. As yet uncharacterised NADPH-linked systems may provide an important secondary pathway for detoxification of alk-2-enals and alka-2,4-dienals in parasitic helminths. The free-living nematode Panagrellus redivivus had higher active NADH/NADPH-linked aldehyde reduction systems compared to parasitic helminths. The NADH linked and NADPH linked reductions in P. redivivus were mitochondrial and cytosolic activities respectively. NADH/NADPH-linked systems may be responsible for alkanal reduction in helminths as there is no evidence of conjugation of alkanals with glutathione. P. redivivus and Haemonchus contortus were also able to oxidise aldehydes via NAD/NADP-linked systems.