New prenylated chalcones from Lonchocarpus neuroscapha Benth. (Cordoa piaca).

The isolation of eight prenylated chalcones (cordoin, isocordoin, psi-isocordoin, derricin, lonchocarpin, 4-hydroxyderricin, 4-hydroxylonchocarpin, 4-hydroxyisocordoin) and of the flavanone and dihydrochalcone corresponding to cordoin is described. These substances are biogenetically correlated. The structures of the above mentioned substances were established through the examination and comparison of spectral data (U.V., I.R., N.M.R., M.S.) and of the chemical behaviour. Particular interest is shown by psi-isocordoin and 4-hydroxy derivatives. The latter and 4-hydroxyderricin in particular show also a marked inhibition on the growth of gram-positive bacteria.