Synthesis and anthelmintic activity of osthol analogs against Dactylogyrus intermedius in goldfish

In an attempt to develop novel anthelmintic agents, our previously isolated osthol was used as lead structures for further optimization. In our research, a series of coumarin analogs, prepared from 7-hydroxy coumarin or 7-hydroxy-4-methyl coumarin, have been evaluated for their anthelmintic activities. In all of the compounds, 6 and 7 were first synthesized, and their structures were identified based on NMR and MS values. Among the candidates, 8-allyl-7-allyloxycoumarin showed better anthelmintic activity than other compounds against Dactylogyrus infestation with EC(50) value of 1.81 mg/L. The quantitative structure-activity relationship (QSAR) of 16 osthol analogs with anthelmintic activity expressed as pEC(50) and toxicity to goldfish expressed pLC(50), such results can offer useful theoretical references for future experimental works.