The application of nanotechnological innovations to increase the effectiveness of the bioflavonoid quercetin is considered. The ability to functionalize with specific ligands that target specific organs or cells is very important because it is possible to increase the concentration of quercetin at the desired target level while reducing side effects. Quercetin, as a flavonoid antioxidant, is widely used to reduce oxidative stress and activate important signalling pathways in cells. However, poor solubility in water, intensive first-pass metabolism limits its use. A strategy for the development of nanocomposites is presented, which involves combining quercetin obtained from agricultural waste with selenium nanoparticles. In vitro results demonstrated that quercetin-nanoselenium has high water solubility compared to individual flavonoids. It has been proven that quercetin-nano-selenium nanoparticles are capable of reducing 1,1-dipheny l-2-picrylhydrazyl (DPPH) radicals and are characterized by high antioxidant activity. The ability to functionalize nanoparticles with specific ligands that target the modulation of specific signaling pathways (Keap1/ Nrf2/ARE, Nf-kB, mTOR) in individual cells is very important, as it allows increasing the concentration of quercetin to the desired level while reducing side effects. Considering the beneficial effects of quercetin, a strategy has been developed that involves the use of selenium nanoparticles to deliver quercetin in a specific and controlled manner. Research in this direction is promising, as it will contribute to clarifying the expediency of using such nanosystems, which have not yet been widely used. The use of onion waste and its extracts in biotechnology, biomedicine, pharmaceuticals and the agro-industrial sector can be an optimal solution for reducing environmental damage. In addition, it will provide an economically determined alternative for the production of feed additives for animals and poultry. Compounds of quercetin with nanoselenium should take a worthy place in clinical medical practice, biology and agriculture. The beneficial effects of quercetin can be further enhanced with the help of nanotechnology, which will contribute to the effective use of this compound with such great biological potential.
Key words: nanobiotechnologies, waste, onion peel, 1,1-dipheny l- 2-picrylhydrazyl, antiradical activity.