Bioaccessibility of Phenolic Compounds from Cocoa Shell Subjected to In Vitro Digestion and Its Antioxidant Activity in Intestinal and Hepatic Cells

Abstract

The cocoa shell is a by-product generated by the cocoa processing industry that could be used as a nutraceutical owing to the significant amounts of bioactive compounds it contains. This work aimed to study the bioaccessibility of phenolic compounds present in the flour (CSF) and an aqueous extract (CSE) from cocoa shells through an in vitro simulated digestion and to assess their antioxidant capacity in vitro by using intestinal and hepatic cell culture models (IEC-6 and HepG2 cells). The bioaccessibility of phenolic compounds was determined using a simulated in vitro digestion model (INFOGEST). Total phenolic compounds (TPC) and antioxidant activity were measured using in vitro techniques. Reactive oxygen species (ROS) were evaluated in IEC-6 and HepG2 cells after t-BOOH stimulation. TPC present in CSE were more bioaccessible than phenolic compounds present in CSF. During digestion, the bioaccessibility of phenolic compounds from CSF fluctuated in the gastric (2.8 mg/g), intestinal (7.6 mg/g), and colonic (5.7 mg/g) phases. Similarly, for the phenolics of CSE, the bioaccessibility increased from 50.6 mg/g in the gastric phase to 53.4 mg/g in the intestinal phase and decreased in the colonic phase to 37.2 mg/g. The in vitro antioxidant capacity followed a similar behavior, increasing throughout the digestion in CSF (8.8- to 10.6-fold) and CSE (6.0- to 7.4-fold). Digested CSF and CSE were not cytotoxic for IEC-6 and HepG2 cells and protected their viability under oxidative stress conditions (93–100%). t-BOOH-induced ROS were prevented by CSF (72–88%) and CSE (81–94%) bioaccessible fractions in both intestinal and hepatic cells. In conclusion, cocoa shells are a source of potentially bioavailable antioxidant phenolic compounds that may protect cells from oxidative stress.