Synergism Potentiates Oxidative Antiproliferative Effects of Naringenin and Quercetin in MCF-7 Breast Cancer Cells

Breast cancer (BC) is the most frequently diagnosed type of cancer as of 2020. Quercetin (Que) and Naringenin (Nar) are predominantly found in citrus fruits and vegetables and have shown promising antiproliferative effects in multiple studies. It is also known that the bioactive effects of these flavonoids are more pronounced in whole fruit than in isolation. This study investigates the potential synergistic effects of Que and Nar (CoQN) in MCF-7 BC cells. MCF-7 cells were treated with a range of concentrations of Que, Nar or CoQN to determine cell viability. The IC₅₀ of CoQN was then used to investigate caspase 3/7 activity, Bcl-2 gene expression, lipid peroxidation and mitochondrial membrane potential to evaluate oxidative stress and apoptosis. CoQN treatment produced significant cytotoxicity, reduced Bcl-2 gene expression and increased caspase 3/7 activity compared to either Nar or Que. Furthermore, CoQN significantly increased lipid peroxidation and reduced mitochondrial membrane potential (MMP) compared to either Nar or Que. Therefore, CoQN treatment has potential pharmacological application in BC chemotherapy by inducing oxidative stress and apoptosis in MCF-7 BC cells. The results of this study support the increased consumption of whole fruits and vegetables to reduce cell proliferation in cancer.