ARS | Publication request: Phytotoxins from the Leaves of Ruta Graveolens

Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 12, 2004
Publication Date: May 6, 2004
Citation: Hale, A.L., Meepagala, K.M., Oliva, A., Aliotta, G., Duke, S.O. 2004. Phytotoxins from the leaves of ruta graveolens. Journal of Agricultural and Food Chemistry. 2004. V. 52(11). P. 3345-3349.

Interpretive Summary: Leaves of the common rue (Ruta graveolens) plant were examined for compounds that will kill weeds. Three significantly herbicidal compounds were found. Two of these have been reported previously to be toxic to plants, whereas the third, graveoline, has not been. All three compounds are effective inhibitors of plant cell division.

Technical Abstract: Bioassay-guided fractionation of the EtOAc extract of Ruta graveolens (common rue) leaves led to the isolation of the furanocoumarins 5-methoxypsoralen (5-MOP), 8-methoxypsoralen (8-MOP), and the quinolone alkaloid graveoline as phytotoxic constituents. Graveoline and 8-MOP substantially inhibited growth of Lactuca sativa and reduced chlorophyll content at 100 µM; this effect was not due to a direct effect on chlorophyll synthesis. 8-MOP also caused stunting of radical growth in L. sativa at 10 µM. Graveoline inhibited growth of Lemna pausicostata (duckweed) at 100 µM. This is the first report of the phytotoxic activity of graveoline. 5-MOP inhibited growth of Agrostis stolonifera (bentgrass) at 30 µM. All three compounds substantially reduced cell division in Allium cepa (onion) at or below 100 µM. None of the compounds caused significant cellular leakage of Cucumis sativus (cucumber) cotyledon discs at 100 µM. All three compounds inhibit plant growth, at least partially through inhibition of cell division.