Bioactivity and cytotoxicity of quercetin-loaded, lecithin-chitosan nanoparticles

Quercetin is a bioactive compound with potential application as an antioxidant in food matrices. However, the use of this flavonoid becomes a challenge due to its relative degree of hydrophobicity and low bioavailability. In order to improve its dispersibility in aqueous media, protection against degradation and the bioavailability of quercetin, this study aimed to develop quercetin-loaded, lecithin-chitosan nanoparticles (NPQ) and to characterize its physical, chemical and biological properties. The nanoparticles were characterized in terms of mean size, PDI, zeta potential, morphology, encapsulation efficiency, FT-IR, transmission electron microscopy (TEM) and thermal analysis (TGA and DSC). Stability over shelf life at 4 and 30 degrees C, antioxidant, antimicrobial and cytotoxicity activities were also determined. Quercetin was encapsulated in lecithin-chitosan nanoparticles (NP) with an efficiency of 98.31 +/- 0.01%. NPQ presented a well-defined spherical morphology with a mean size of 240.81 +/- 10.82 nm and a zeta potential of +38.9 +/- 1.60 mV. Stability studies showed that NPQ are relatively stable over 28 days of storage at 4 degrees C and 30 degrees C. Regarding biological activities, NPQ were able to eliminate DPPH and ABTS radicals in the same way as free quercetin and showed antimicrobial activity, without presenting cytotoxicity against normal cells (L-929 and PBMC). These results suggest that quercetin-loaded, lecithin-chitosan nanoparticles have excellent potential for application in food matrices aiming at the development of new functional foods.