Plant-growth inhibitory activity of cedrelanolide from Cedrela salvadorensis

The effect of cedrelanolide, the most abundant limonoid isolated from Cedre la salvadorensis (Meliaceae), was assayed as a plant-growth inhibitory comp ound against monocotyledonous and dicotyledonous seeds. This compound inhib ited germination. seed respiration, and seedling dry weights of some plant species (Lolium multiflorum, var. Hercules, Triticum vulgare. var Salamanca , Physalis ixocarpa, and Trifolium alexandrinum). Our results indicate that cedrelanolide interferes with monocot preemergence properties, mainly ener gy metabolism of the seeds at the level of respiration. In addition, the co mpound inhibits photophosphorylation. H+ uptake. and noncyclic electron Row . This behavior might be responsible for its plant-growth inhibitory proper ties and its possible role as an allelopathic agent.