Phytochemicals for cancer treatment: An update on plant-derived anti-cancer compounds and their mechanisms of action

Cancer is caused by the combined effect of different factors that act sequentially and simultaneously. However, treatment through conventional approaches comes with several pitfalls and severe side effects such as toxicity to normal cells, inadequate bioavailability, fast clearance, non-specificity as well as high cost. In contrast, plant-based anticancer agents have natural characteristics that can circumvent such limitations as they are comparatively more potent, safer, easily available and cheaper. The current review focuses on the results of selected plant-based anticancer compounds extracted in their pure form and used solely for assessment of anticancer potential through standardized approaches. The probable mechanisms of action of these compounds include inhibition of cancer cell growth, inhibition of tumor growth, cytotoxicity to cancerous cells, inhibition of angiogenesis, induction of apoptosis, caspases stimulation, degradation of mitochondrial membrane, stimulation of apoptotic proteins, inhibition of topoisomerase, reduction of cell viability and arresting of cell cycle progression. However, this preliminary testing is not enough for the approval of these compounds as an anticancer agents. Further research is required to characterize and screen these potential drug candidates against a wide range of in vitro and proper in vivo systems to confirm their safety and potency for the cancer treatment.