Wheat Bran for Colon Cancer Prevention: Phytochemicals vs. Fiber

Abstract

Many studies have found that dietary cereal fibers protect against colon cancer, however, not all cereal fibers are equally effective. Wheat bran is the only cereal bran that shows consistent protection against colon cancer in laboratory animal models, and corn and oat bran may enhance colon tumorigenesis. It is still unclear whether the active components are phytochemicals or fibers. We and others have found that phytochemicals in wheat bran instead of fiber are the major active components for colon cancer prevention. The inhibitory effect of wheat bran extract on tumorigenesis was observed in our studies in the Apcmin/+ mouse model. Using human colon cancer cells (HCT‐116 and HT‐29) as the guiding assay, we identified 5‐n‐alkylresorcinols (ARs) as the major components in wheat bran for colon cancer prevention. To further study the structure‐activity relationship of ARs, we synthesized more than 20 ARs derivatives. The effects of the length of the alkyl side chain, the substitution pattern of the functional groups on alkyl side chain, the substitution pattern on the benzene ring as well as the underlying molecular mechanism were also studied. The effects of other components in wheat bran, such as sphingolipids and steroids, will also be discussed.