In vitro studies on the stability in the proximal gastrointestinal tract and bioaccessibility in Caco-2 cells of chlorogenic acids from spent coffee grounds

Abstract

Spent coffee grounds are a potential commercial source of substantial amounts of chlorogenic acids (CGAs). The aim of this study was to evaluate the stability of spent coffee CGAs using in vitro simulated gastroduodenal digestion and to investigate their potential absorption using an in vitro Caco-2 model of human small intestinal epithelium. During in vitro digestion, lactones were partially degraded while caffeoylquinic and feruloylquinic acids were much more stable. Transport and metabolism studies showed that 1% of the total CGAs were absorbed and transported from the apical to the basolateral side of a Caco-2 cell monolayer after 1 h. Lactones and coumaroylquinic acids showed the rate of highest absorption. Caco-2 cells possessed low metabolic activity. In conclusion, spent coffee extracts contain large amounts of CGAs, which remained bioaccessible across the intestinal barrier, albeit to a relatively low degree.

• Chlorogenic acids
• in vitro bioaccessibility
• in vitro gastrointestinal stability
• spent coffee grounds

Acknowledgments

The authors thank Ms Pilar Lostao and Ms. Asunción Redín for her kind help. C. M. wishes to express her gratitude to the Unión Tostadora S. A. for providing the coffee.

Declaration of interest

The authors report that they have no conflicts of interest. This research was funded by the Spanish Ministry of Economy and Competitiveness (AGL2009-12052). C. M. wishes to express her gratitude to the Association of Friends of the University of Navarra for the grant received.