A Narrative Review on the Antitumoral Effects of Selected Mediterranean Plant Products from Southern Italy

Natural products are a valuable source of bioactive compounds with established roles in oncology. Their structural diversity and ability to target multiple cancer-related pathways make them promising candidates for anticancer drug development. Increasing preclinical and clinical data highlight their potential not only to exert direct antitumor effects but also to enhance patient tolerance to conventional therapies by reducing side effects and improving treatment adherence. The Mediterranean region, known for its biodiversity and traditional dietary habits, provides a rich array of natural compounds with documented health benefits. Key Mediterranean natural plant products (MNPPs), including bioactives from olive oil, onion, citrus fruits, chili pepper and grapes, exhibit antioxidant, anti-inflammatory, and anti-proliferative properties. This review focuses on the molecular mechanisms of selected MNPPs, such as polyphenols, flavonoids, alkaloids, terpenes, organosulfur and furanocoumarin compounds, which modulate oxidative stress, inflammation, apoptosis, and tumor progression. Evidence from in vitro and in vivo studies supports their role in cancer prevention and as adjuvants in therapy. While further clinical research is needed, these findings suggest that incorporating MNPPs into therapeutic regimens could offer low-toxicity, multi-targeted support in oncology, improving both outcomes and quality of life in cancer patients.