Oxidized Dextran as a Macromolecular Crosslinker Stabilizes the Zein/Caseinate Nanocomplex for the Potential Oral Delivery of Curcumin

Abstract

In this study, we prepared complex nanoparticles from a combination of two proteins and one polysaccharide for the encapsulation and delivery of lipophilic bioactive compounds. Two proteins, zein and sodium caseinate (NaCas), provided a hydrophobic core for the encapsulation of a lipophilic compound (curcumin), while a polysaccharide dialdehyde, oxidized dextran, served as the coating material and macromolecular crosslinker to create covalent linkage with two proteins for stabilization purposes. The heating time and crosslinker concentration were optimized to achieve the desirable colloidal stability in simulated gastric and intestinal fluids. Our results suggested that heating time played a more important role than the concentration of oxidized dextran. The optimized complex nanoparticles had a particle size of around 150 nm with a PDI < 0.1 and negative surface charge. Morphological observation by transmission electron microscopy revealed a spherical shape and uniform size distribution. Fourier transform infrared and fluorescence spectroscopies evidenced the formation of Schiff base complex, confirming the validity of covalent crosslinking. Furthermore, the complex nanoparticles demonstrated superior encapsulation properties for curcumin, showing an efficiency of >90% at 10% loading. A rather slow kinetic release profile of curcumin from complex nanoparticles was observed under simulated gastrointestinal conditions. The complex nanoparticles prepared from zein, NaCas, and oxidized dextran hold promising potential for the oral delivery of lipophilic bioactive compounds.

Curcumin improves memory deficits by inhibiting HMGB1‐RAGE/TLR4‐NF‐κB signalling pathway in APPswe/PS1dE9 transgenic mice hippocampus

“…In this study, thioflavin‐S staining showed that curcumin treatment did not affect the plaque load in the hippocampus of transgenic mice. Nevertheless, the activation of astrocyte cells was suppressed by curcumin treatment in our study, which is in line with a previous report by Lim 30 . A preliminary investigation of the possible mechanisms of curcumin action was performed.…”

“…The protective effect of curcumin may be mediated by the inhibition of NF‐κB activation 40 and/or an antioxidant pathway 27 . Oral administration of curcumin reduces inflammatory cytokines and oxidized proteins 30,41 and attenuates behavioural impairment in AD animal models 42 . There is a low basal COX2 expression in neurons of the healthy brain; however, pathological conditions, such as astrocyte activation, strongly induce COX2 in the brain 43 .…”

“…Nevertheless, the activation of astrocyte cells was suppressed by curcumin treatment in our study, which is in line with a previous report by Lim. 30 A preliminary investigation of the possible mechanisms of curcumin action was performed. It is commonly considered that soluble Aβ oligomers, rather than monomers or plaques, may be the primary source of neurotoxicity.…”

Crosslinkers for polysaccharides and proteins: Synthesis conditions, mechanisms, and crosslinking efficiency, a review

“…The dead cells could be desorbed from the hydrogels by cooling the system to 25 °C and adding 50 mM phosphate buffered saline (PBS) pH 7.4, enabling the reusability of the hydrogels [314]. Dextran dialdehyde (MW ~40,000 g/mol) prepared from the oxidation of dextran by sodium periodate [315] reacted with zein and sodium caseinate by imine bond formation (Shiff base reaction), increasing the system stability [316].…”

Water Uptake as a Crucial Factor on the Properties of Cryogels of Gelatine Cross-Linked by Dextran Dialdehyde

“…Dextran T10, T40 and T2000 (Mw 10, 40 and 2000 kDa) were obtained from Pharmacia (Uppsala, Sweden), gelatine 45% w/v solution (from cold water fish) and glutaraldehyde (GA) 25% v/v aqueous solution were purchased from Sigma (Steinheim, Germany). The DDA was prepared and characterized according to previously published methods [45,59].…”