Bio-guided isolation of a new sesquiterpene fromArtemisia cinawith anthelmintic activity againstHaemonchus contortusL₃infective larvae

Abstract

Haemonchus contortus is a blood-feeding gastrointestinal parasite that impacts grazing sheep, causing economic losses in animal production and presenting anthelmintic resistance, requiring alternative antiparasitic treatments, including the exploration of plant-based anthelmintics. Artemisia cina (Asteraceae) is a plant whose n-hexane (n-HE) and ethyl acetate extract (EAE) exhibits anthelmintic activity against H. contortus, being the n-HE more active. With the aim of discovering additional bioactive metabolites, a chemical analysis was performed on EAE, which presented a LC90 of 3.30 mg/mL and allowed the isolation of 11-[(1R,5S,7R,8R,10S,)-1,8-dihydroxy-5,10-dimethyl-4-oxodecahydroazulen-7-yl] acrylic acid, a new sesquiterpene that was identified through one and two-dimensional NMR. The compound was named cinic acid and displayed a CL50 of 0.13 (0.11 - 0.14) mg/mL and CL90 of 0.40 (0.37 - 0.44) mg/mL, which, compared with EAE larvicidal activity, was 256-fold more active at LC50 and 15.71-fold at LC90. In this study, a new sesquiterpene with anthelmintic effects against H. contortus L3 infective larvae was isolated from the EAE of Artemisia cina.