Assessing the in vitro gastric stability and intestinal transport of selected natural molecules
Natural antioxidants in foods and plants play a major role in helping the body's defense system to fight the destruction caused by reactive oxygen species. They may act by decreasing oxygen concentration and as metal inactivators, hydroperoxide decomposers, oxygen scavengers and synergists (Shahidi, 1997). Several studies have indicated the possible beneficial effects of natural antioxidants in the human body, without considering the influence the gastrointestinal tract may have on the composition, activity and absorption of these compounds (Cao et al., 1998; Serrano et al., 2007). This study aimed at assessing the in vitro gastrointestinal stability and intestinal transport of orally ingested antioxidants in food and plants. Curcumin, epicatechin, ferulic acid, gallic acid, quercetin, resveratrol, rosmarinic acid, and rutin were selected. Compounds were incubated in simulated gastric fluid (SGF, pH 1.2) for 1 hour and in simulated intestinal fluid (SIF, pH6.8) for 3 hours. Concentrations were detected before and after incubation. The results indicated that all the compounds were stable in SGF, only epicatechin and rutin were unstable in SIF (with 6.27%, 5.16% degradation, respectively). The in vitro transport experiment was conducted across porcine intestinal tissue in the apical-to-basolateral direction in a Sweetana-Grass diffusion apparatus. Apparent permeability coefficient (Papp) was calculated. Ferulic acid gallic acid and rutin exhibited low transport with Papp value 8.57×10–7, 4.89×10–7 and 1.78×10–7, respectively. Epicatechin, rosmarinic acid, curcumin. quercetin and resveratrol showed poor transport.
Acknowledgement: We appreciate the financial support from Tshwane University of Technology
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