Olive oil industry by-products. Effects of a polyphenol-rich extract on the metabolome and response to inflammation in cultured intestinal cell

Abstract

Over the past years, researchers and food manufacturers have become increasingly interested in olive polyphenols due to the recognition of their biological properties and probable role in the prevention of various diseases such as inflammatory bowel disease. Olive pomace, one of the main by-products of olive oil production, is a potential low-cost, phenol-rich ingredient for the formulation of functional food. In this study, the aqueous extract of olive pomace was characterized and used to supplement human intestinal cell in culture (Caco-2). The effect on the cell metabolome and the anti-inflammatory potential were then evaluated. Modification in the metabolome induced by supplementation clearly evidenced a metabolic shift toward a "glucose saving/accumulation" strategy that could have a role in maintaining anorexigenic hormone secretion and could explain the reported appetite-suppressing effect of the administration of polyphenol-rich food. In both basal and inflamed condition, supplementation significantly reduced the secretion of the main pro-inflammatory cytokine, IL-8. Thus, our data confirm the therapeutic potential of polyphenols, and specifically of olive pomace in intestinal bowel diseases. Although intervention studies are needed to confirm the clinical significance of our findings, the herein reported results pave the road for exploitation of olive pomace in the formulation of new, value-added foods. In addition, the application of a foodomics approach allowed observing a not hypothesized modulation of glucose metabolism.

Keywords: Foodomics; Glucose metabolism; Inflammation; NMR based metabolomics; Olive oil by-products; Polyphenols.