Preventive Effect and Mechanism of Adlay Bran Extract on Colorectal Cancer

Colorectal cancer is the form of cancer most closely associated with diet. It may be possible to prevent the occurrence of this cancer by dietary modification. Chemoprevention refers to the use of natural or synthetic compounds to prevent, reverse, or delay the development of cancer. Food-derived products are highly interesting for developed as chemopreventive agents. Adlay is a grass crop that has long been used in traditional Chinese medicine and as a nutritious food. The seed of adlay was used as an anti-inflammatory and anti-tumor agent. Some recent studies have shown that extracts of adlay seed suppress some inflammation-related molecules such as cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS), and inhibit the growth of xenograft tumors and cancer cells. Several lines of evidence suggest that inflammation is critical for colorectal carcinogenesis and that nonsteroidal anti-inflammatory drugs (NSAIDs) are promising chemopreventive agents for colorectal cancer. Since adlay seed is an anti-inflammatory agent, it is interesting to investigate whether adlay seed could prevent colorectal cancer through anti-inflammatory effect. Our laboratory have previously conducted a series of studies about the anti-tumor effect of adlay seed and found that dehulled adlay and adlay bran may suppress the development of preneoplastic lesion and COX-2 expression of colon tumors. However, the active component of adlay seed is still unknown and needed to be elucidated. This study was designed to investigate the active component of adlay bran against colorectal carcinogenesis and its possible mechanism during three years. In the first year, we will prepare adlay bran and its ethanolic extract and evaluate the preventive effect of this extract on colorectal carcinogenesis using an animal model. In addition, we will prepare fractions of adlay bran ethanolic extract and investigate the active fraction and mechanism using cell experiments. In the second year, we will evaluate the preventive effect of the active fraction of adlay bran ethanolic extract on colorectal carcinogenesis using an animal model and analyze the gene expression using microarray. In addition, we will prepare subfractions of this active fraction using a column chromatography and analyze the active components. In the third year, we will prepare further subfractions of the active fraction of adlay bran ethanolic extract and analyze the active components. In addition, we will screen the active subfraction and analyze the expression of genes and proteins using cell experiments.