Antineopastic Natural products and the analogues IV

A cytotoxic coumarin against L1210 cell was isolated from the unripe fruit of Poncirus trifoliata ($ED_{5}$) = 10.2 $\mu$ g/ml. Its structure was identified as aurapten, 7-geranyloxycoumarin. Hydrolysis of the substance gave umbelliferone and geraniol. Only geraniol showed the cytotoxic activity ($ED_{53}$ = 6.5 $\mu$g/ml) while umbelliferone and its methyl or allyl derivatives were not active.