title: Dietary phenolics against colorectal cancer--From promising preclinical results to poor translation into clinical trials: Pitfalls and future needs.
abstract: Colorectal cancer (CRC) remains a major cause of cancer death worldwide. Over 70% of CRC cases are sporadic and related to lifestyle. Epidemiological studies inversely correlate CRC incidence with the intake of fruits and vegetables but not with their phenolic content. Preclinical studies using in vitro (cell lines) and animal models of CRC have reported anticancer effects for dietary phenolics through the regulation of different markers and signaling pathways. Herein, we review and contrast the evidence between preclinical studies and clinical trials (patients with CRC or at risk, familial adenopolyposis or aberrant crypt foci) investigating the protective effects of curcumin, resveratrol, isoflavones, green tea extracts (epigallocatechin gallate), black raspberry powder (anthocyanins and ellagitannins), bilberry extract (anthocyanins), ginger extracts (gingerol derivatives), and pomegranate extracts (ellagitannins and ellagic acid). To date, curcumin is the most promising polyphenol as possible future adjuvant in CRC management. Overall, the clinical evidence of dietary phenolics against CRC is still weak and the amounts needed to exert some effects largely exceed common dietary doses. We discuss here the possible reasons behind the gap between preclinical and clinical research (inconsistence of results, lack of clinical endpoints, etc.), and provide an outlook and a roadmap to approach this topic.
authors.affiliation: Research Group on Quality, Safety and Bioactivity of Plant Foods, Department of Food Science and Technology, CEBAS-CSIC, Murcia, Spain.
authors.forename: María A
authors.initials: MA
authors.lastname: Núñez-Sánchez
authors.affiliation: Research Group on Quality, Safety and Bioactivity of Plant Foods, Department of Food Science and Technology, CEBAS-CSIC, Murcia, Spain.
authors.forename: Antonio
authors.initials: A
authors.lastname: González-Sarrías
authors.affiliation: Research Group on Quality, Safety and Bioactivity of Plant Foods, Department of Food Science and Technology, CEBAS-CSIC, Murcia, Spain.
authors.forename: María
authors.initials: M
authors.lastname: Romo-Vaquero
authors.affiliation: Research Group on Quality, Safety and Bioactivity of Plant Foods, Department of Food Science and Technology, CEBAS-CSIC, Murcia, Spain.
authors.forename: Rocío
authors.initials: R
authors.lastname: García-Villalba
authors.affiliation: Research Group on Quality, Safety and Bioactivity of Plant Foods, Department of Food Science and Technology, CEBAS-CSIC, Murcia, Spain.
authors.forename: María V
authors.initials: MV
authors.lastname: Selma
authors.affiliation: Research Group on Quality, Safety and Bioactivity of Plant Foods, Department of Food Science and Technology, CEBAS-CSIC, Murcia, Spain.
authors.forename: Francisco A
authors.initials: FA
authors.lastname: Tomás-Barberán
authors.affiliation: Research Group on Quality, Safety and Bioactivity of Plant Foods, Department of Food Science and Technology, CEBAS-CSIC, Murcia, Spain.
authors.forename: María-Teresa
authors.initials: MT
authors.lastname: García-Conesa
authors.affiliation: Research Group on Quality, Safety and Bioactivity of Plant Foods, Department of Food Science and Technology, CEBAS-CSIC, Murcia, Spain.
authors.forename: Juan Carlos
authors.initials: JC
authors.lastname: Espín
mesh_terms: D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology*; D002986:Clinical Trials as Topic; D015179:Colorectal Neoplasms / Q000188:drug therapy* / Q000453:epidemiology / Q000473:pathology; D003474:Curcumin / Q000494:pharmacology; D004032:Diet; D004354:Drug Screening Assays, Antitumor / Q000379:methods; D000069196:Gastrointestinal Microbiome; D020939:Zingiber officinale; D006801:Humans; D029561:Lythraceae; D010636:Phenols / Q000494:pharmacology*; D000077185:Resveratrol; D013267:Stilbenes / Q000494:pharmacology; D013662:Tea
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D010636:Phenols; D013267:Stilbenes; D013662:Tea; D003474:Curcumin; D000077185:Resveratrol
keywords: Animal models; Clinical trials; Colon cancer; In vitro; Polyphenol