Plant-derived natural products as leads to antitumor drugs

Cancer is the main cause of death worldwide. Chemotherapeutic agents used for disease treatments have shown limited antitumor activity, with a high recurrence rate. It has prompted the research efforts to identify anti-tumor compounds. Research on medicinal plants began to focus on discovery of natural products as potential leads to antitumor drugs. Medicinal plants are very interesting, have the ability to produce remarkable chemical structures with diverse biological activities. Plant-derived natural products have been used by human societies for millennia, and their biological source is most likely available and can be employed for production, have been considered as valuable sources for antitumor drugs. Many interesting natural products with biological activity are evidenced in the past few years. This review highlights the potential of natural compounds as candidates for antitumor drugs. A brief illustration of the sources and general biological effects of the main classes of plant-derived natural compounds and related molecules are also provided.