Therapeutic effects of quercetin in oral cancer therapy: a systematic review of preclinical evidence focused on oxidative damage, apoptosis and anti-metastasis

Objective: Oral malignancies are among the common head and neck cancers. Various therapeutic modalities are used for targeting oral cancers. It was shown that quercetin (a flavonoid) has an anti-cancer effect on different cancers. In the current study, the anti-cancer potentials of quercetin against oral cancer cells were summarized. Methods: The current systematic review was conducted in accordance with the PRISMA guideline for the identification of relevant studies in various electronic databases up to April 2023. After reviewing and screening 193 articles, 18 were chosen for this study based on our inclusion and exclusion criteria. Results: It was shown that quercetin significantly reduced cancer cell proliferation, cell viability, tumor volume, invasion, metastasis and migration. This anti-cancer agent induced oxidative stress and apoptosis in the cancer cells. Quercetin treatment could also induce some biochemical alterations in the cancer cells. Conclusion: According to the results, it can be mentioned that quercetin administration has an anti-cancer effect against oral cancer cells. This agent exerts its anticancer effects via reduced cell viability and different mechanisms, including induce oxidative damage, apoptosis, and reduced invasion and metastasis. However, suggesting the use of quercetin as a therapeutic agent of oral cancer patients requires further clinical studies due to its poor absorption rates, and the exact molecular mechanisms are still not well understood.