Zein/fucoidan-based composite nanoparticles for the encapsulation of pterostilbene: Preparation, characterization, physicochemical stability, and formation mechanism.

The objective of this work is to fabricate zein/fucoidan composite nanoparticles for the delivery of pterostilbene, a hydrophobic nutraceutical with diverse beneficial biological activities. Pterostilbene-encapsulated zein/fucoidan composite nanoparticles were prepared using an anti-solvent precipitation method. The fucoidan levels affected the physicochemical properties of the composite nanoparticles. When the zein to fucoidan mass ratio was 10:1, 5:1, 2:1, or 1:1, the prepared zein/fucoidan nanoparticles were stable, and these nanoparticles showed higher pterostilbene encapsulation efficiency than did zein nanoparticles. Fucoidan-stabilized zein nanoparticles exhibited globular structure with average diameters of 120-150 nm. Fourier-transform infrared spectroscopy, X-ray diffraction, and fluorescence spectrum analysis confirmed that the formation of composite nanoparticles was mainly driven by electrostatic, hydrogen-bonding, and hydrophobic interactions between pterostilbene, zein, and fucoidan. Furthermore, the photochemical stability of pterostilbene encapsulated in zein/fucoidan nanoparticles was markedly better than that of pterostilbene loaded in zein nanoparticles or unencapsulated pterostilbene. Zein/fucoidan nanoparticles provided a better controlled release of pterostilbene than did zein nanoparticles under simulated gastrointestinal conditions. Moreover, the cytotoxicity assay demonstrated that zein/fucoidan nanoparticles were nontoxic to Caco-2, HK-2, and L-02 cells. Based on our results, the zein/fucoidan nanoparticles may be a promising delivery carrier for the encapsulation, protection, and release of pterostilbene.