Cernumidine and isocernumidine were identified in the ethanol extract of the leaves of Solanum cernuum Vell, together with four known phenolic compounds. The alkaloids have a natural (2-aminopyrrolidin-1-yl)carboxamidine alkaloidal base acylated with isoferulic (3-hydroxy-4-methoxycinnamic) acid with Z and E configurations, respectively. The structures were elucidated on the basis of 1D- and 2D-NMR data and the structure of cernumidine was confirmed by X-ray analysis. Cernumidine displayed inhibition of interleukin-8 production by HT-29 colon carcinoma cells. This fact could orient further research in gastric cancer prevention and treatment. (C) 2011 Elsevier Ltd. All rights reserved.