Chemical composition of and inhibition of angiotensin-converting enzyme by Senecio samnitum huet

Abstract

Extracts of Senecio samnitum Huet and derived methyl ester of chlorogenic acid have been shown to inhibit angiotensin-converting enzyme (ACE) by using an in vitro bioassay based on the enzymatic cleavage of the chromophore-fluorophore labeled substrate dansyltriglycine into dansylglycine, which is quantitatively measured by high-performance liquid chromatography (HPLC). GC/MS and NMR identified compounds present within the studied S. samnitum extracts. The most effective fraction was obtained in ethyl acetate, which gave 52.56 ± 0.23% (SD) inhibition at 300 μg/ml. The major constituent of this fraction, the methyl ester of chlorogenic acid, showed significant ACE inhibition of 56.78 ± 0.25% at a concentration of 82.5 μg/ml. © 2005 Taylor & Francis Ltd.