Role of phytochemicals in colorectal cancer prevention.

Although the incidence of colorectal cancer (CRC) has been declining in recent decades, it remains a major public health issue as a leading cause of cancer mortality and morbidity worldwide. Prevention is one milestone for this disease. Extensive study has demonstrated that a diet containing fruits, vegetables, and spices has the potential to prevent CRC. The specific constituents in the dietary foods which are responsible for preventing CRC and the possible mechanisms have also been investigated extensively. Various phytochemicals have been identified in fruits, vegetables, and spices which exhibit chemopreventive potential. In this review article, chemopreventive effects of phytochemicals including curcumin, polysaccharides (apple polysaccharides and mushroom glucans), saponins (Paris saponins, ginsenosides and soy saponins), resveratrol, and quercetin on CRC and the mechanisms are discussed. This review proposes the need for more clinical evidence for the effects of phytochemicals against CRC in large trials. The conclusion of the review is that these phytochemicals might be therapeutic candidates in the campaign against CRC.

Trillium tschonoskii steroidal saponins suppress the growth of colorectal Cancer cells in vitro and in vivo.

ETHNOPHARMACOLOGICAL RELEVANCE: Saponins of many herbs are known to possess anti-cancer effect. AIM OF THE STUDY: The present study aimed to investigate the growth inhibitory effect of Trillium tschonoskii steroidal saponins in a mouse model of colitis-associated colorectal cancer and a human colorectal cancer cell line HT-29, and isolate some major constituents and evaluate their anti-tumor activity. MATERIALS AND METHODS: Forty male ICR mice were administered with 1, 2-dimethyl-hydrazine (DMH) and dextran sodium sulfate (DSS). Ten mice were given no further treatment, the rest were administered with different doses of TTS (5, 10, 20mg/kg) orally, every three days from the 9th week to the 20th week. RESULTS: TTS effectively protected ICR mice against DMH/DSS-induced tumorigenesis. The incidence of tumor development was 90% (9/10) in the mice treated with DMH/DSS, but that was reduced to 50% (5/10), 40% (4/10), and 20% (2/10), respectively, in the mice treated with 5%, 10%, and 20% of TTS. Results of Ki-67 staining, TUNEL assay and caspase-3 activity assay revealed that TTS moderately decreased abnormal proliferation and increased apoptosis of colonic epithelial cells. It inhibited the growth and triggered the apoptosis of HT-29 cells, partly through suppressing mitogen-actived protein kinases (MAPKs) and triggering mitochondrial-mediated apoptotic pathway. Three compounds, namely, Paris saponin VII, polyphylloside III and Paris saponin VI, were important active compounds in TTS. CONCLUSION: These data suggest that TTS has a potential role in clinical prevention and treatment for colorectal cancer.