Simulação de digestão in vitro acoplada a modelos de transporte gástrico e intestinal para estimar a captação e absorção de antocianinas em frutos

Abstract

A lot of interest in the consumption of anthocyanins increased after the association of their intake and reduced risk of chronic diseases. Despite of in vitro evidences of anthocyanins benefits to health, there is still a gap in the knowledge of the mechanisms of absorption of anthocyanins by the human body. It is known that concentration of food anthocyanins doesn't reflect the amount of these compounds which are absorbed, metabolized, distributed and biologically active in humans. Some in vitro models have been developed to evaluate the steps of cell release and transport ( uptake) of these compounds from food. The objective of this study was to evaluate the in vitro absorption of food anthocyanins using the in vitro digestion followed by uptake and transport in Caco-2 human intestinal cell line and MKN-28 human gastric cell line. Initially, anthocyanins bioaccessibility of diverse fruits was evaluated in order to select the better sources for transport assays. The bioaccessibility assays were performed using an in vitro digestion model, which mimics the human oral, gastric and intestinal stages. Quantification and characterization of anthocyanins profile were performed by high-performance liquid chromatography (HPLC) with Thermo Scientific® C1s 2.4 (4.6 x 10mm) column. After selection of the most promising fruits, the bioaccessibility tests were followed by transport assays. To assess gastric absorption, the product from gastric digestion was applied on the MKN-28 cell monolayer, which was obtained after 7 days of culture of 2.5 x 10^5 MKN-28 cells seeded in RPMI culture media in transwell® plates. The permeate was collected after 30, 60, 120 andl80 minutes oftransport. For evaluation of intestinal absorption after digestion, the digesta from the intestinal phase was applied on the Caco-2 cell monolayer, which was obtained after 21 days of culture of 2.5 x 105 Caco-2 cells seeded in DMEM culture media in TRANSWELL® plates. The permeate was collected after 30, 60 and 120 minutes of transport. All analyses were made by forming CLUE / photodiode array detector (Thermo® Scientific) at 520nm. Peel powder from jabuticaba, jambo and Jamelão were the most promising sources. The bioaccessibility of anthocyanins after gastric digestion was 13% for jabuticaba, 45 % for jambo and 65 % for jamelão. In addition, the intestinal bioaccessibility was 1 O % for jabuticaba, 15 % for jambo and 45 % for jamelão. The transport assay with the MKN-28 gastric cell line, revealed 19.7%, 9.7 % and 14.1 % of transport efficiency, respectively, for jambo, jabuticaba and jamelão digestion products. While Caco-2 intestinal cell model showed 0.8 %, 0.2 % and 0.3 % oftransport efficiency, respectively, for jambo, jabuticaba and jamelão. These results suggest food anthocyanins are preferentially absorbed by the human gastric mucosa and to a lesser extent by the human intestinal epithelium.