Polyphenol-functionalized selenium nano-formulations: utilizing waste-derived bioactive compounds for improved functionality.

Dubravka Vitali Čepo, Nikolina Golub, Mario Jug, Emerik Galić, Kristina Radić
University of Zagreb, Faculty of Pharmacy and Biochemistry, Ante Kovačića 1, 10000 Zagreb

Selenium nanoparticles (SeNPs) have been investigated intensively as the novel forms of selenium for nutritional supplementation. Their major advantages, in relation to inorganic or organic forms of Se are increased bioavailability and therapeutic potential due to high Se-density of the nano-formulation. Because of the large surface area, SeNPs show immense potential as carriers of bioactive compounds and therapeutics improving their absorption and enabling targeted delivery. In this work, polyphenol-functionalized selenium nano-formulations were synthetized using extracts obtained from agricultural wastes: olive- and tomato pomace. Tomato-pomace derived pectin was used as stabilization agents for SeNP while olive waste derived polyphenols were used for SeNP surface stabilization. Cytotoxic and antioxidative activities of functionalized SeNPs (fSeNPs) were compared to inorganic selenium forms and selenium nano-formulations obtained through standard synthesis using chemical stabilizers (sSeNPs)
SeNPs were characterized in terms of shape, particle size distribution and zeta potential and their cytotoxicity and antioxidative activities were investigated in human hepatocellular carcinoma (HepG2) and human colorectal adenocarcinoma (Caco2) cell lines. Green synthesis of SeNPs resulted in formation of stable nanoparticles with satisfactory physico- chemical properties. fSeNPs showed lower cytotoxicity and wider range of direct antioxidative mechanisms in comparison to sSeNPs and inorganic selenium forms. The significant impact of fSeNPs on intracellular antioxidative mechanisms has been observed and it was dependent on physico-chemical properties, applied concentration and type of the cell culture, indicating the overall complexity of involved mechanisms.