Plant secondary metabolites for the prevention and treatment of colorectal cancer: A review

Abstract

Colorectal cancer is becoming more common and deadly in both men and women nowadays. Although various treatment interventions are available including chemotherapy, surgery, radiation therapy and hormonal therapy, they are associated with some harmful effects. To avoid the risk factors associated with these therapies, natural products could be used as one of the most promising candidates for colorectal cancer. The natural products and their dietary supplements demonstrated stronger potential against various colorectal cancer cells. Flavonoids, phenolics, terpenoids, saponins, quinones, alkaloids, and other secondary metabolites are among the bioactive substances found in dietary supplements. These dietary phytochemicals exhibited strong and potent cytotoxicity against colorectal cancer cells which indicated their ability as chemopreventive agents. Both intrinsic and extrinsic routes were used to trigger apoptosis by the phytochemical substances. Phytochemicals influenced the cell cycle regulation, oncogenes, tumor markers and induced apoptosis by modulating tumor-suppressive miRNAs, affecting the cell signaling pathways, upregulating apoptotic inducers with the downregulation of anti-apoptotic proteins and factors. Thus, in this review, we addressed the sources and mechanism of various isolated phytochemicals as anti-colorectal cancer agents.