Bay leaf extract is a chemotaxis repellent for C. elegans

Plants synthesize compounds that modulate animal nervous systems through various mechanisms, but the key interactions remain understudied. We used chemotaxis assays with the nematode Caenorhabditis elegans to test if plant extracts can be detected by the worm nervous system and which compounds induce behavioral responses. We found that C. elegans avoid the extract of bay leaves ( Laurus nobilis ). Subsequent testing of known bay leaf compounds identified cadinene and eugenol as key molecules that may mediate the repulsion effect. These experiments were conducted by undergraduate students in an upper-division laboratory course, providing practical research experiences and new insights into plant-animal interactions.