Repurposing Ebselen for a potential blending-based therapeutic strategy against gastrointestinal nematodes of small ruminants.

Gastrointestinal nematode (GIN) infections pose a significant challenge to the health of ruminant animals. The infection also presents a substantial financial impact worldwide. This study aimed to test the anthelmintic effect of Ebselen (C13H9NOSe), a selenium-containing organochalcogen compound, against eggs and third-stage larvae (L3) of GIN of small ruminants. Ebselen and ivermectin (IVM) were evaluated using the egg hatch test (EHT) and the larval migration inhibition test (LMIT). Additionally, we tested the inhibitory effect of drug-drug interactions using both compounds. The compounds individually showed concentration-dependent effect on eggs and L3. Ebselen inhibited 50 % of the eggs and L3 at concentrations of 0.4835 mmol L-1 and 1.562 mmol L-1, respectively. IVM had an half-maximal inhibitory concentration (IC50) value of 0.4449 mmol L-1 on eggs and 0.9141 mmol L-1 on L3. IVM had an efficacy of 96.6 % in avoiding egg hatch and 78.4 % in preventing L3 migration at the highest concentration. The combination of Ebselen and IVM resulted in a statistically significant increase in larval migration inhibition, demonstrating a synergistic effect (>30 %). The data confirm the use of Ebselen and IVM in a novel blending-based therapeutic strategy to manage GIN that affects small ruminants.