Vernonione, A New Urease Inhibitory Carvotacetone Derivative from Vernonia cinerascens

Abstract

Vernonione, a new 7-deoxycarvotacetone derivative 1, together with three known sesquiterpene lactones; vernolide A, C (2,3) and potamopholide (4) has been isolated from the methanolic extract of the roots of Vernonia cinerascens. The structure 3β-acetoxy-5α-angeloyloxy7-deoxycarvotacetone was established by using UV, IR, ¹H and ¹³C-NMR spectra (DEPT), 2D-NMR analyses (COSY, HMQC and HMBC experiments) in combination with HRFAB-MS, HREI-MS experiments and in comparison with literature data of related compounds. Compound 1 showed inhibitory potential against enzyme urease in concentration dependant fashion with IC₅₀ value 227.6 µmol.