Fabrication, characterization, and cytotoxicity evaluation of cranberry procyanidins-zein nanoparticles

Abstract

Cranberry procyanidins (CPs)-zein nanoparticles were fabricated using a modified liquid–liquid dispersion method. The CPs were purified using chromatographic methods and analyzed using HPLC equipped with a fluorescence detector (FLD) and mass spectrometer (MS). The purified CPs had a purity of 64.7% (w/w) and contained procyanidin oligomers (from dimers to decamers) and polymers, with polymers being the predominant component (38.7%, w/w). The particle size of the CPs-zein nanoparticles increased from 392 nm to 447 nm with the increase of the CPs-to-zein mass ratios from 1:8 to 1:2. Morphologically, the CPs-zein nanoparticles were spherical as observed by scanning electron microscopy (SEM). The loading efficiency of CPs in the CPs-zein nanoparticles decreased with an increase of CPs-to-zein mass ratios from 1:8 to 1:2, and ranged from 10% to 86%. The oligomers with higher degree of polymerization (DP) showed higher loading efficiency than the oligomers with lower DP, suggesting a greater binding affinity on zein proteins. The loading capacity of the CPs-zein nanoparticles fabricated using a high CPs-to-zein mass ratio (1:2) was significantly higher than those using a low mass ratio (1:8). Fourier transform infrared spectroscopy (FTIR) suggested that the primary interactions between the CPs and zein were hydrogen bond and hydrophobic interactions. Cell culture studies using human promyelocytic leukemia HL-60 cells showed that the CPs encapsulated in nanoparticles had decreased cytotoxicity compared to the CPs.