Parthenium hysterophorus (Kinche arem inAmharic) is one of the worst invasive weeds in Ethiopia. It is known for its toxic effects on plant germination and growth. It is estimated that this weed reduces crop yields by more than 25% in developing countries.

Previous attempts to curb the spread of weeds using synthetic chemicals have not been very successful. On the other hand, allelopathic plants are known to produce natural chemicals that inhibit weed growth. Many biological activities of Premna schimperi are reported, except for its herbicidal properties.  In this project, we tried to screen the phytotoxic properties ofPremna schimperi extracts and purified compounds against parthenium weed. Compounds with moderate phytotoxic activity have been isolated from leaf ethanol extracts of P. schimperi. Kaempferide (2) is an isolated compound with 87% growth inhibition. This is the first report of this kind.