REVIEW: The new paradigm of curcumin and its anticancer activity

Abstract

Abstract. Curcumin, derived from the rhizome of Curcuma longa L., is used as a coloring and flavoring additive in many foods and has attracted interest because of its antioxidant, anti-inflammatory, and chemopreventive activities. Various curcumin-related phenols have also been found in edible or medicinal plants, especially Zingiberaceae. Curcumin has a unique conjugated structure, including two methoxylated phenols and an enol form of b-diketone, and the system shows a typical radical trapping ability as a chain-breaking antioxidant. Curcumin has demonstrated anticarcinogenic effects in numerous animal models, including skin and gastrointestinal carcinomas. Curcumin also inhibited benzo[a]pyren- or DMBA (7,12-dimethylbenz[a]anthracene)-induced skin cancer in a mice carcinogenesis model. When administered during initiation and/or post-initiation stages, curcumin inhibits chemically induced carcinogenesis in the skin, forestomach, and colon when administered during initiation and/or post-initiation stages. Curcumin directly inhibited the activity of COX-2. The anti-inflammatory properties of curcumin have been attributed to suppressing PG synthesis, at least in part. Curcumin also inhibited COX-2 transcription in bile acid and phorbol ester-treated gastrointestinal cell lines. Additionally, the administration of curcumin into the rats during the initiation and postinitiation stages and throughout the promotion/progression stage increased apoptosis in the colon tumors. This article provides a mechanistic basis for curcumin's antioxidant, chemopreventive and antiinflammatory related-anticancer properties.