Plant-Derived Antioxidants as Modulators of Redox Signaling and Epigenetic Reprogramming in Cancer

Redox imbalance and epigenetic dysregulation, which both contribute to tumor initiation, survival, and resistance to therapy, are intimately linked to the progression of cancer. Reactive oxygen species (ROS) have two contrasting effects: at moderate concentrations, they promote angiogenesis and oncogenic signaling, whereas at high concentrations, they trigger apoptosis. Oxidative stress alters histone modifications, DNA methylation, and non-coding RNA (ncRNA) expression, reshaping the epigenetic landscape and supporting malignant phenotypes. Plant-derived antioxidants, including flavonoids, polyphenols, alkaloids, and terpenoids, act as dual modulators of cancer biology. They scavenge or regulate reactive oxygen species (ROS), restore redox balance, activate tumor suppressor pathways, inhibit oncogenic mechanisms, and reverse abnormal epigenetic marks. Compounds such as resveratrol, curcumin, epigallocatechin gallate (EGCG), quercetin, and sulforaphane modulate DNA methyltransferases (DNMTs), histone deacetylases (HDACs), and non-coding RNA networks, and can enhance chemotherapy and radiation therapy. Despite promising mechanisms, challenges remain in translational efficacy, optimal dosing, and bioavailability. This review emphasizes the potential of plant-derived antioxidants as precision oncology adjuncts and highlights the need for biomarker-guided strategies, nano-delivery systems, and clinical validation to fully realize their therapeutic benefits. Plant-derived antioxidants mitigate ROS-induced oncogenic signaling, as evidenced by in vitro and clinical models.