Cytotoxic 4-phenylcoumarins from the leaves of Marila pluricostata.

Bioassay-guided fractionation of the CH(2)Cl(2) extract of the leaves of Marila pluricostata led to the isolation of 17 naturally occurring 4-phenylcoumarins, three of them, 5-hydroxy-8,8-dimethyl-4-phenyl-9,10-dihydro-8H-pyrano-[2,3-f]chromen-2-one (1), 5-hydroxy-8,8-dimethyl-4-phenyl-6-propionyl-9,10-dihydro-8H-pyrano-[2,3-f]chromen-2-one (2), and 5,7-dihydroxy-8-(3-methylbut-2-enyl)-4-phenylchromen-2-one (3), are new natural compounds; the remaining (4-17) are known mammea-type coumarins. Their structures were established by spectroscopic means. All compounds were tested in cytotoxicity assays against the MCF-7, H-460, and SF-268 human cancer cell lines.