The phenolic profile of Isabella grape ( Vitis labrusca ) offers beneficial properties to human health and makes it a functional food product. In order to better understand the phenolic compounds found in this grape variety and the biological effect they induce on breast cancer cells, an ultrasound-assisted extraction was carried out. During the extraction of polyphenols from Isabella grapes organically grown in Antioquia (Colombia), parameters such as frequency (33 kHz and 40 kHz), time, and solvent were optimized to finally obtain a crude extract with antioxidant properties (ORAC: 293.22 ± 34.73) that are associated with a Total Polyphenol Content (TPC) of 43.14 ± 5.00 and a total anthocyanin content of 17.69± 2.59 mg of malvidin-3-glucoside/100 g of sample. MCF-7 breast cancer cells were treated with the extract, inducing a decrease in cell viability as a result of mitochondrial membrane depolarization and ROS increase. To determine the possible death induction mechanism, molecular docking was simulated to predict the molecular interactions between the most abundant phenolic compounds in Isabella grape and the main apoptosis-related proteins. The results obtained from in silico and in vitro experiments were consistent with each other, suggesting that the phenolic compounds found in Isabella grape can be considered potential adjuvant chemopreventive agents for the treatment of breast cancer.Funding Information: This study was funded by the Instituto Tecnológico Metropolitano (ITM, project code P 20245 of 2019) and the Call for Proposals for Strengthening STI Projects in Execution in Health Sciences with Young Talent and Regional Impact by the Colombian Ministry of Science (Agreement RC830).Conflict of Interests: The authors declare that they have no financial conflicts of interest or personal relationships that may have influenced the work reported in this paper.