Chitosan-derivative nanoparticles loaded with dihydromyricetin: Characterization, antibacterial and antioxidant activities

Bovine mastitis is a global problem and is mainly treated with antimicrobial agents that can significantly affect milk quality and threaten human health. The mammary gland can be damaged by the accumulation of reactive oxygen species (ROS), particularly during the perinatal period. Dihydromyricetin (DHM) has a wide range of pharmacological activities and is considered safe. However, its poor solubility, absorption, and bioavailability have limited its application. To address this issue, we designed and synthesized new chitosan-derivative nanoparticles (HACC-NPs) loaded with DHM, which have the potential to overcome its bioabsorption problems and enhance its antibacterial and antioxidant effects. We used the emulsification/crosslinking method to load DHM into chitosan-derivative nanoparticles (DHM/HACC-NPs); then, SEM, TEM and FTIR analyses were used to show a denser, more tightly packed matrix for the DHM/HACC-NPs, which were successfully prepared. The size (176.4 nm), polydispersity index (PDI, 0.21), and absolute value of the zeta potential (+26.3 mV) confirmed the stability of the DHM/HACC-NPs. More importantly, DHM/HACC-NPs had a stronger antibacterial effect on S. aureus (MIC = 0.52 mg/mL and MBC = 1.02 mg/mL) than on E. coli (MIC = 1.02 mg/mL and MBC = 2.05 mg/mL). Notably, DHM/HACC-NPs were concentration-dependent scavengers of DPPH and hydroxyl radicals. In summary, DHM/HACC-NPs exhibited superior biocompatibility and antimicrobial and antioxidant activities, offering new insights into the development of a robust, udder-stable drug platform as a promising strategy for treating dairy cow mastitis.