Glutathione-S-transferase,a possible drug-metabolizing enzyme,in Haemonchus contortus: Comparative activity of a cambendazole-resistant and a susceptible strain

Kawalek J. C., Rew R. S. and Heavner J. 1984. Glutathione-S-transferase, a possible drug-metabolizing enzyme in Haemonchus contortus: comparative activity of a cambendazole-resistant and a susceptible strain. International Journal for Parasitology14: 173–175. A drug metabolizing enzyme (DME), glutathione-S-transferase, was detected in homogenates of a cambendazole-susceptible and a cambendazole-resistant strain of Haemonchus contortus. The activity was 1.5–1.8 times higher in the resistant strain. DME activation is a possible mechanism for anthelmintic resistance in H. contortus.     

Effect of particle size on the anthelmintic efficacy of mebendazole against Nippostrongylus brasiliensis in the rat.

The effect of reduction in particle size on the anthelmintic efficacy of mebendazole (methyl 5 (6)- benzoyle 1–2 benzimidazole carbamate) was studied in rats undergoing a primary infection with N. brasiliensis. A single oral treatment with fine ground mebendazole (particle size spectrum—54·95 per cent of particles less than 10·62 μ dia.; 86·06 per cent less than 21·27 μ) removed more than 98 per cent of adult worms from the intestine at a dose rate of 12·5 mg/kg body wt. On the other hand the best result achieved with coarse ground mebendazole (18·47 per cent of particles less than 10·62 μ dia; 42·26 per cent less than 21·27 μ dia) was 58 per cent of adult worms removed at a dose rate of 100 mg/kg body wt. It was also shown that fine ground mebendazole adversely affected migrating third stage larvae of N. brasiliensis.     

Supplemented nutrition decreases helminth burden and increases drug efficacy in a natural host–helminth system

Gastrointestinal (GI) helminths are common parasites of humans, wildlife, and livestock, causing chronic infections. In humans and wildlife, poor nutrition or limited resources can compromise an individual''s immune response, predisposing them to higher helminth burdens. This relationship has been tested in laboratory models by investigating infection outcomes following reductions of specific nutrients. However, much less is known about how diet supplementation can impact susceptibility to infection, acquisition of immunity, and drug efficacy in natural host–helminth systems. We experimentally supplemented the diet of wood mice (Apodemus sylvaticus) with high-quality nutrition and measured resistance to the common GI nematode Heligmosomoides polygyrus. To test whether diet can enhance immunity to reinfection, we also administered anthelmintic treatment in both natural and captive populations. Supplemented wood mice were more resistant to H. polygyrus infection, cleared worms more efficiently after treatment, avoided a post-treatment infection rebound, produced stronger general and parasite-specific antibody responses, and maintained better body condition. In addition, when applied in conjunction with anthelmintic treatment, supplemented nutrition significantly reduced H. polygyrus transmission potential. These results show the rapid and extensive benefits of a well-balanced diet and have important implications for both disease control and wildlife health under changing environmental conditions.     

Synthetic Aurones: New Features for Schistosoma mansoni Therapy

In this work, two synthetic aurones revealed moderate schistosomicidal potential in in vitro and in vivo assays. Aurones ( 1 ) and ( 2 ) promoted changes in tegument integrity and motor activity, leading to death of adult Schistosoma mansoni worms in in vitro assays. When administered orally (two doses of 50 mg/kg) in experimentally infected animals, synthetic aurones ( 1 ) and ( 2 ) promoted reductions of 56.20 % and 57.61 % of the parasite load and stimulated the displacement towards the liver of the remaining adult worms. The oogram analysis revealed that the treatment with both aurones interferes with the egg development kinetics in the intestinal tissue. Seeking an action target for compounds ( 1 ) and ( 2 ), the connection with NTPDases enzymes, recognized as important therapeutic targets for S. mansoni, was evaluated. Molecular docking studies have shown promising results. The dataset reveals the anthelmintic character of these compounds, which can be used in the development of new therapies for schistosomiasis.     

Tribulosin and beta-sitosterol-D-glucoside, the anthelmintic principles of Tribulus terrestris.

Successive extracts of Tribulus terrestris prepared using petroleum ether, chloroform, 50% methanol and water were tested for anthelmintic activity in-vitro using the nematode Caenorhabditis elegans. The activity could be detected only in 50% methanol extract which on further bioactivity guided fractionation and chromatographic separation yielded a spirostanol type saponin, tribulosin and beta-sitosterol-D-glucoside. Both the compounds exhibited anthelmintic activity with ED50 of 76.25 and 82.50 microg/ml respectively.