linoleic-acid and caryophyllene-oxide

An extract of roots of Centaurea diffusa (diffuse knapweed) yielded caryophyllene oxide and linoleic acid which were shown to be phytotoxic. Also isolated were germacrene B, a previously-known phytotoxin as well as the inactive polyene aplotaxene. A combination of these compounds, if transferred to the soil, could be one factor in the invasive behavior of this weed. Contrary to a literature report, 8-hydroxyquinoline was not detected in root exudates of in vitro grown C. diffusa nor could it be identified in the root extract. However, a recent report from a different group maintains that 8-hydroxyquinoline can be released from roots of C. diffusa following a diurnal rhythm.

Topics: Arabidopsis; Centaurea; Chromatography, High Pressure Liquid; Linoleic Acid; Oxyquinoline; Plant Roots; Polycyclic Sesquiterpenes; Seedlings; Sesquiterpenes; Sesquiterpenes, Germacrane