Marine-Derived Products in Oncology: From Ocean Biodiversity to Cancer Therapeutics

Marine ecosystems represent an immense and largely untapped reservoir of biologically active compounds with significant therapeutic potential. Owing to extreme environmental conditions, marine organisms such as bacteria, fungi, algae, sponges, tunicates, mollusks, and corals produce unique secondary metabolites with diverse chemical structures and potent biological activities. This review highlights the role of marine biodiversity as a promising source of anticancer agents, emphasizing major marine-derived compounds including alkaloids, flavonoids, polysaccharides, terpenoids, peptides, steroids, and glycosides. Several marine natural products, such as cytarabine, trabectedin, eribulin, and brentuximab vedotin, have already been approved for clinical use, while many others are currently in preclinical and clinical development. The mechanisms of anticancer action of these compounds include induction of apoptosis, inhibition of cell proliferation, angiogenesis suppression, immune modulation, and interference with DNA and microtubule dynamics. Despite their immense potential, challenges such as low natural yield, structural complexity, limited technical infrastructure, and high development costs hinder their large-scale application. Nevertheless, advances in biotechnology, synthetic chemistry, and drug delivery systems are paving the way for the successful development of marine-derived anticancer therapeutics, reinforcing the ocean as a valuable frontier for future cancer drug discovery.