Daleformis, a new phytoalexin from the roots fo Dalea filiciformis: an inhibitor of endothelin converting enzyme.

As part of a search for novel inhibitors of endothelin converting enzyme (ECE), the MeOH-CH2Cl2 extract of the roots of Dalea filiciformis was shown to be active. Bioassay-guided fractionation of the extract yielded a novel phytoalexin, daleformis (1), whose structure was determined by interpretation of spectral data and X-ray analysis. Daleformis (1) inhibited ECE with an IC50 of 9 microM.