Furanocoumarin with Phytotoxic Activity from the Leaves of Amyris elemifera (Rutaceae)

Bioassay-guided fractionation of the ethyl acetate extract of leaves was carried out to identify phytotoxic and antifungal constituents. A novel phytotoxic furanocoumarin 8-(3-methylbut-2-enyloxy)-marmesin acetate ( ) and its deacyl analog 8-(3-methylbut-2-enyloxy)-marmesin ( ) were isolated. The X-ray crystal structure determination is reported for the first time for . Both and have the S configuration at C-2' based on X-ray crystallographic data. Both these compounds inhibited the growth of the dicot (lettuce) and the monocot with a more pronounced inhibitory effect on the monocots at 330 μM by . In Hegelm phytotoxicity bioassay, the IC value for was 26 μM, whereas had an IC value of 102 μM. Compounds and were weakly antifungal against Brooks in TLC bioautography.