Allelopathic effects of phenolic acids on germination of watermelon (Citrullus lanatus Thunb): Dose-effect relationship and quantitative structure-activity relationship

To determine the allelopathic potential of phenolic acids on watermelon (Citrullus lanatus Thunb), we studied the inhibitory activities of 21 phenolic acids on watermelon seeds germination. The quantitative structure-activity relationship (QSAR) method using the comparative molecular field analysis and comparative molecular similarity index analysis was used to elucidate the relationships between the inhibitory activities and structural characteristics. The results showed that half-maximal inhibitory concentrations (IC50) were in similar to mu g/mL. The QSAR calculations suggested that the allelopathic inhibitory activities were increased when substituents had large moieties at 1/2/3/4-positions, negative charge at 1/3-position, a H-bond donor at 4-position and a H-bond acceptor at 2-position.