Abstract
This narrative review aims to systematize the current knowledge on the dual role of reactive oxygen species and reactive nitrogen species in cancer processes, from their physiological function in redox signaling to their pathological impact in oxidative distress. The mechanisms of biomolecule damage, particularly DNA, and deregulation of signaling pathways induced by excessive ROS/RNS concentrations, which promote neoplastic transformation, are presented. The importance of diet and endogenous antioxidants in cancer prevention is also discussed, emphasizing the role of natural antioxidants in prevention and adjunctive therapy. In this context, oleanolic acid emerges as a promising compound with dual action modulating oxidative stress, capable of balancing cellular redox responses. We discuss the most important antioxidant mechanisms of oleanolic acid, the interconnection of oxidative stress with carcinogenesis-related pathways, anticancer mechanisms mediated by oxidative stress modulation, and structural modifications and modern application techniques that improve its bioavailability, as well as future perspectives on oleanolic acid research in the context of its antioxidant and anticancer activity. Overall, available experimental and preclinical data indicate that oleanolic acid, through pleiotropic modulation of oxidative stress and signaling networks, holds promise as an adjuvant agent in cancer prevention and therapy.