GASTROINTESTINAL STABILITY OF POLYPHENOL-FUNCTIONALIZED SELENIUM NANOPARTICLES
Author’s: Golub, Nikolina (Croatia)1; Galić, Emerik (Croatia)1; Radić, Kristina (Croatia)1; Vitali Čepo, Dubravka (Croatia)1; Conway,
Róisín (Ireland)2
 1 – University of Zagreb Faculty of Pharmacy and Biochemistry; 2 – University College Cork

Selenium nanoparticles (SeNPs) are hypothesized to present a novel prospect for nutritional supplementation due to supposed lower toxicity and higher bioavailability in comparison to inorganic selenium forms. Because of particular surface characteristics, SeNPs also represent efficient vehicle for targeted delivery of biologically active compounds.
In this work we developed the procedure of green synthesis of polyphenol-functionalized selenium nanoparticles (PF-SeNPs) to obtain spheric-shaped particles with adequate size range and acceptable polydispersion index. Tomato-pomace derived pectin was used as coating/stabilizing agent while olive pomace extract (OPE), rich in hydroxytyrosol derivates, was used for surface
functionalization. The aim was to create a formulation that will protect selenium and OPE during their passage through the harsh acidic environment of the stomach and facilitate controlled release in the intestine. To investigate gastrointestinal stability, an in vitro simulation of the digestive process was conducted according to the procedure of
Brodkorb and co-workers (1) with slight modifications. PF-SeNPs were characterized using various techniques, including scanning electron microscopy (SEM), dynamic light scattering (DLS), and electrophoretic light scattering (ELS) prior and after the simulation of gastrointestinal digestion, in order to investigate the impact of gastrointestinal system conditions on SeNP features such as zeta potential, size distribution, shape and surface characteristics. Selenium content was determined using atomic absorption spectroscopy (AAS). Free radical scavenging properties of PF-SeNPs were determined to investigate the impact of simulated digestion on stability/release of hydroxytyrosol derivates used for PF-SeNP surface modification. PF-SeNPs nanoparticles demonstrated resistance to the acidic conditions in the stomach, preventing premature degradation and showing strong antioxidant activity. This research highlights the potential of pectin-coated polyphenol-functionalized SeNPs as a strategy to potentially improve the selenium supplementation and its applications in the prevention and treatment of various health conditions.