Facile synthesis of nano-nanocarriers from chitosan and pectin with improved stability and biocompatibility for anthocyanins delivery: An in vitro and in vivo study

Anthocyanins is a type of natural pigment with a variety of physiological activities, are unstable and prone to degradation. In order to improve the stability of anthocyanin, in this study, the nanocarriers were constructed through electrostatic self-assembly method using chitosan and pectin as raw materials for bilberry anthocyanins delivery. Atomic force microscope and scanning electron microscope analyses showed that the nanocarriers were well dispersed spheres with diameters around 100-300 nm when the mass ratio of chitosan/pectin/anthocyanin was 1:1:3. Fourier transform infrared spectroscopy and ultraviolet-visible absorption spectroscopy results revealed that the anthocyanins were successfully doped into the nanocarriers. The encapsulation efficiency of anthocyanins was 66.68%. Moreover, the anthocyanin nanocarriers exhibited increased storage stability under light and dark conditions. In vitro digestion experiments showed that the doped anthocyanins could escape from the interference of stomach acid environment and released slowly in small intestinal fluid, suggesting the controlled delivery of anthocyanins in the gastrointestinal tract. In vitro NRK cell model demonstrated that the nanocarriers could protect against acrylamide-induced damage by viability and cell apoptosis assay. In vivo Caenorhabditis elegans model further showed that the nanocarriers could protect from anthocyanin damage caused by various harmful conditions such as acrylamide, oxidative stress, heat shock and UV light. Furthermore, Caenorhabditis elegans treated with nanocarriers showed longer lifespan, stronger reproductive capability, more flexible locomotion behavior, and less autofluorescent lipofuscin particles. Together, these results suggest that chitosan-pectin nanoparticles can be used as delivery vehicles to improve the stability and bioavailability of the functional factor anthocyanin.