Laboratory bioassay, greenhouse experiment and <scp>3D‐QSAR</scp> studies on berberine analogues: a search for new herbicides based on natural products

BACKGROUND Berberine is a herbicidal chemical that we isolated from Coptis chinensis. In continuation of our program aimed at discovering and developing natural botanical herbicides, we evaluated the herbicidal activities of 39 berberine analogues and developed a three-dimensional quantitative structure-activity relationship (3D-QSAR) model. RESULTS Among these 39 analogs, the most active compounds were determined to be worenine chloride and coptisine chloride, with median inhibitory concentration (IC50 ) values on all eight tested weed species of