Eryngial (trans-2-dodecenal), a bioactive compound fromEryngium foetidum: its identification, chemical isolation, characterization and comparison with ivermectinin vitro

Abstract

SUMMARYMethanol-water (4:1, v/v) crude extracts (50 mg mL−1) of 25 Jamaican medicinal plants were screenedin vitrofor anthelmintic activity using infective third-stage larvae ofStrongyloides stercoralis. The most effective extract was further chemically scrutinized to isolate and identify the source of the bioactivity, and the efficacy of this compound was compared with ivermectin. Eosin exclusion (0·1 mg mL−1) served as the indicator of mortality in all bioassays. A crude extract ofEryngium foetidum(Apiaceae) was significantly (Probit Analysis,P<0·05) more potent than the other plant extracts, taking 18·9 h to kill 50% (LT50) of the larvae. Further, the petrol extract ofE. foetidumwas significantly more effective (Probit Analysis,P<0·05) at killing the larvae (LT50, 4·7 h) than either its methanol–water or dichloromethane extract. The latter two effected less than 1% larval mortality after 120 h. With bioassay-driven column chromatography of the petrol extract,trans-2-dodecenal (eryngial) was identified and chemically isolated as the main anthelmintic compound inE. foetidum. There was a significant difference between the 24 h LD50values (mm) oftrans-2-dodecenal (0·461) and ivermectin (2·251) but there was none between the 48 h LD50values (mm):trans-2-dodecenal (0·411) and ivermectin (0·499)in vitro.