The investigation of the chemical constituents from the roots of Psacalium
radulifolium, a member of the matarique complex of medicinal plants, which
includes several members of the Asteraceae, resulted in the isolation of fo
ur new modified eremophilanes: radulifolin A (4), epi-radulifolin A (5), ra
dulifolin B (6), and radulifolin C (7), together with the known natural sub
stances cacalol, cacalone, epi-cacalone, O-methyl-1,2-dehydrocacalol, adeno
stin A, decompostin, and neoadenostylone. Antimicrobial evaluation of the e
xtracts and the isolated compounds indicated that cacalol was the major act
ive compound.