Oleanolic acid in the fight against cancer: a multifaceted natural strategy for modern oncology

Cancer continues to be a major global cause of morbidity and mortality, and current conventional therapies including chemotherapy, radiotherapy, and targeted therapies are often limited by toxicity, resistance, and suboptimal efficacy. Natural compounds, particularly triterpenes such as oleanolic acid, have emerged as promising alternatives or adjuncts in oncology due to their multifaceted pharmacological profiles. OA, a pentacyclic triterpenoid ubiquitously distributed in both medicinal and edible plants, is characterized by its well-defined biosynthetic pathway, distinct chemical composition, and favorable physical properties. Extensive preclinical studies have demonstrated that OA and its synthetic derivatives exert potent anticancer effects through diverse approaches, comprising the modulation of apoptosis, autophagy, cell cycle regulation, and immune response pathways. OA ability to inhibit tumor growth, reduce tumor weight, and enhance the efficacy of standard chemotherapeutics has been validated in various cancer models, although its impact may vary across tumor types. Despite its therapeutic promise, limitations such as low water solubility and restricted bioavailability impede its advancement to clinical applications. Recent advances in drug delivery systems and the synthesis of OA derivatives aim to overcome these barriers. This review offers a comprehensive overview of OA biosynthesis, chemical and pharmacological properties, mechanisms of anticancer action, and its potential in the management and treatment of diverse malignancies. The review also discusses current challenges and outlines future research directions to facilitate the integration of OA into modern oncological practice.