The Therapeutic Potential of Essential Oils in Cancer Man-agement: An In Vitro and In Vivo Review

Cancer remains one of the major causes of global morbidity and mortality. Despite significant advances, conventional cancer treatments, such as chemotherapy and radiotherapy, frequently encounter challenges, including metastasis, relapse, multi-drug resistance, and severe side effects. Consequently, the search for novel, less toxic, and more efficacious therapeutic strategies, often derived from natural products, is crucial. Essential oils (EOs), which are volatile secondary metabolites of plants, possess a wide array of pharmacological properties, including significant anti-cancer effects. This systematic review aimed to consolidate current evidence on the antineoplastic efficacy of various EOs, such as those derived from Boswellia sp. (Frankincense), Eucalyptus globulus, Zingiber ottensii, and Lantana camara, across different cancer models. Chemical analysis typically identifies α-pinene as a major constituent (e.g., 35.81% in B. carterii EO and up to 67.9% in B. sacra EO). Results consistently demonstrate that EOs are capable of reducing cell viability, inducing apoptosis (via caspase activation and PARP cleavage), and modulating crucial cell proliferation and survival signaling pathways (such as Wnt/β-catenin, PI3K/AKT, and MAPK/ERK1/2). Notably, several EOs exhibit selective cytotoxicity toward tumor cells (e.g., A549, Colo-320, MCF-7, HeLa) while preserving normal cells (e.g., human fibroblasts, WI-38). The incorporation of EOs into nanocarriers (e.g., FEO-CSNPs, nanoemulsions) significantly enhances therapeutic efficacy, leading to the downregulation of oncogenes (PIK3CA, HER2, WNT1) and the upregulation of tumor suppressor genes (TP53, CDH1, PTEN) in vivo. In conclusion, EOs and their optimized nano-formulations represent promising candidates for developing innovative adjuvant or primary treatment strategies against cancer.