The intestinal absorption of fatty acids, glucose and fructose is part of the basic requirements for the provision of energy in the body. High access of saturated long-chain fatty acids (LCFA), glucose and fructose can facilitate the development of metabolic diseases, particularly the metabolic syndrome and type-2 diabetes mellitus (T2DM). Research has been done to find substances which decelerate or inhibit intestinal resorption of these specific food components. Promising targets are the inhibition of intestinal long-chain fatty acid (FATP2, FATP4), glucose (SGLT1, GLUT2) and fructose (GLUT2, GLUT5) transporters by plant extracts and by pure substances. The largest part of active components in plant extracts belongs to the group of polyphenols. This review summarizes the knowledge about binding sites of named transporters and lists the plant extracts which were tested in Caco-2 cells regarding uptake inhibition.

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Many diseases and metabolic disorders such as Type-2 Diabetes Mellitus show their origin or progress in specific lifestyles, e. g. unhealthy nutrition, physical inactiveness or tobacco use [1]. With regard to unhealthy and excessive food intake, it is an approach to identify new, plant-based substances, which inhibit different transporters in the gut to facilitate patient’s therapies. Especially polyphenols are discussed to act as inhibitors on intestinal transporters [2]. At the beginning of our studies, we investigated the expression of glucose (SGLT1, GLUT2), fructose (GLUT5) and long-chain fatty acid (FATP2, FATP4) transporters in the Caco-2 model. Caco-2 cells have been studied and used as an intestinal barrier model for different investigations [3]. This cell line shows spontaneous differentiation after confluence and expresses a brush border with enzymes and transporters for nutritional uptake [4],[5]. We compared the expression of mentioned transporters in Caco-2 cells at different time points within 3 weeks untreated and treated with differentiation reagent Sodium Butyrate. After western blot analysis, the samples were detected by chemiluminescence and we were able to detect the expression of SGLT1, FATP2 and FATP4. Cells treated with Sodium Butyrate showed an approximate expression of each of the transporters earlier after confluence compared to untreated cells at Day 15 or 21 after confluence. Sodium Butyrate is suitable to shorten the differentiation time and still represents the approximate expression of these transporters in the differentiated stage. Therefore, it is a qualified model for further transport studies.