1044 Research Article Polyphenol metabolites from colonic microbiota exert anti-inflammatory activity on different inflammation models Mar Larrosa 1 , Cristina Luceri 1 , Elisa Vivoli 1 , Chiara Pagliuca 2 , Maura Lodovici 1 , Gloriano Moneti 3 and Piero Dolara 1 1 Department of Pharmacology, University of Florence, Florence, Italy 2 Department of Organic Chemistry, Via della Lastruccia 13, Sesto Fiorentino Florence, Italy 3 Interdepartmental Centre of Mass Spectrometry, University of Florence, Florence, Italy The polyphenols in fruits and vegetables may be partly responsible for the health-promoting effects attributed to fruit and vegetable intake. Although their properties have been relatively well studied, the activity of their metabolites, produced after ingestion, has been poorly investigated. Thus, the aim of this work was to study the potential anti-inflammatory effect of 18 polyphenol metabolites, derived from colon microbiota. They were screened by measuring prostaglandin E 2 (PGE 2 ) production by CCD-18 colon fibroblast cells stimulated with IL-1b. Metabolites that inhibited more than 50% PGE 2 production were hydrocaffeic (HCAF), dihydroxyphenyl acetic (dOHPA), and hydroferulic acid (HFER), that subsequently were tested with the writhing and paw pressure test in rodents where all three compounds showed an anti-inflammatory effect. The effect of HCAF administered orally (50 mg/kg) was also tested in the dextran sodium sulfate (DSS)-induced colitis model. Weight loss and fecal water content were more pronounced in DSS rats than in DSS-HCAF treated rats. HCAF treatment diminished the expression of the cytokines IL-1b, IL-8, and TNF-a, reduced malonyldialde- hyde (MDA) levels and oxidative DNA damage (measured as 8-oxo-29-deoxyguanosine levels) in dis- tal colon mucosa. These results indicate that HCAF, dOHPA, and HFER have anti-inflammatory activity in vitro and in vivo. Keywords: Hydrocaffeic acid / Inflammation / MDA / 8-oxodG / Polyphenol metabolite / Received: September 26, 2008; revised: November 3, 2008; accepted: January 4, 2009 1 Introduction Polyphenols are secondary plant metabolites ubiquitously distributed in fruits and vegetables and are always present in a balanced, healthy diet. Fruit and vegetables have a health-promoting effect, but the mechanism of their protec- tive action is not clearly understood. It has been suggested that polyphenols may be partially responsible for the bene- ficial effects and polyphenol activity has been studied in many cell culture and animal models. While polyphenols are metabolized by gut bacteria and mammalian tissues, the effect of polyphenol metabolites has been studied much less. It is possible that some of their activities might actually be mediated by their metabolites in addition or in place of the original compound present in food. Russell et al. [1] have suggested that the microbiota metabolism of polyphe- nolic compounds determines the action of these compounds by inhibiting prostanoid production. Hydrocaffeic acid (HCAF), hydroferulic acid (HFER), and 3,4-dihydroxy- phenyl acetic acid (dOHPA) are all polyphenol metabolites derived from the colon microbiota, which are found at high concentration in plasma, excreted urine, and fecal water after consumption of coffee or an omnivorous diet includ- ing fruits and vegetables [2, 3]. HCAF has potent antioxi- dant activity in endothelial cells [4], an anti-proliferative effect on cancer colon cells [5] and protects keratinocytes from UV irradiation, reducing the expression of IL-6 and IL-8 [6]. The polyphenol metabolite dOHPA has been stud- ied in connection with dopamine metabolism [7], but not as Correspondence: Dr. Mar Larrosa, Department of Pharmacology, University of Florence, Viale Pieraccini 6, 50139 Florence, Italy E-mail: mar.larrosa@unifi.it Fax: +39-055-4271-280 Abbreviations: DSS, dextran sodium sulfate; IBD, inflammatory bowel disease; 8-oxodG, 8-oxo-29-deoxyguanosine; ROS, reactive oxygen species i 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim www.mnf-journal.com DOI 10.1002/mnfr.200800446 Mol. Nutr. Food Res. 2009, 53, 1044 – 1054