© 2022, The Author(s), under exclusive licence to Der/die Autor(en), exklusiv lizenziert an Springer-Verlag GmbH Deutschland, ein Teil von Springer Nature.In the present study, the seed extract of Vitis vinifera L. (grape) prepared with the methanol-ethanol mixture (volume ratio of 1:1) was evaluated for antibacterial activity on some Gram-positive and Gram-negative strains. In addition, the activity of the extract on the production potential of Quorum Sensing (QS)-dependent virulence factors on Pseudomonas aeruginosa PAO1 and Chromobacterium violaceum was investigated. The phytochemical analysis resulted in the identification of 23 phenolic phytochemicals; epicatechin, catechin and p-hydroxybenzoic acid were determined as the major components in the extract, respectively. The mode of action for the anti-QS activity was explored by molecular docking. The binding affinity of the three major phytoconstituents towards LasR and CviR was determined. Computational analysis demonstrated that the three components (epicatechin, catechin, p-hydroxybenzoic acid) could bind to LasR and CviR. The binding affinity towards LasR was higher than CviR. Hence, the activity of the extract on P. aeruginosa and C. violaceum could result from the competitive inhibition of LasR and CviR by the major components, respectively. Considering the literature and the computational analysis, it is thought that the antibacterial and anti-QS activity of the seed extract may be related to the synergistic effect of the phenolic phytochemicals it contains.