The simultaneous loading of catechin and quercetin on chitosan-based nanoparticles as effective antioxidant and...

A novel chitosan-based nanoparticle (G-C-Q NPs), which simultaneously loaded catechin and quercetin, was synthesized through ionic gelation reaction between chitosan and sodium tripolyphosphate and subsequent modification by genipin. Chemical structure, size distribution, morphology, entrapment efficiency, in vitro release behavior, antioxidant and antibacterial effects of G-C-Q NPs were investigated. Results showed that G-C-Q NPs were dispersed as an ellipsoidal shape with an average diameter of 180.4 nm and a zeta potential of 31.79 ± 1.28 mV. Entrapment efficiency of catechin and quercetin reached 76.35 ± 1.37% and 52.23 ± 2.45%, respectively. In vitro release study showed that both catechin and quercetin had a sustainable release from the G-C-Q NPs. G-C-Q NPs had higher or comparable potency in scavenging DPPH, ABTS⁺, OH and O₂^- radicals and in suppressing growing of Escherichia coli, Bacillus subtilis Staphylococcus aureus as compared to native drugs (single or combination). These results contribute some basis to the design and fabrication of polymeric nanoparticle delivery systems for multiple bioactive compounds with beneficial properties.