Fabrication of nanoparticles using partially purified pomegranate ellagitannins and gelatin and their apoptotic effects

Scope: Nanoparticles possess unique chemical and biological properties compared to bulk materials. Bioactive food components encapsulated in nanoparticles may have increased bioavailability and bioactivities.

Methods and results: Self-assembled nanoparticles made of partially purified pomegranate ellagitannins (PPE) and gelatin were fabricated using three PPE-to-gelatin mass ratios (1:5, 5:5, and 7:5). The PPE contained 16.6% (w/w) of punicalagin A, 32.5% (w/w) of punicalagin B, and a small amount of ellagic acid-hexoside and ellagic acid (1%, w/w). Nanoparticles fabricated using the ratio 5:5 had a particle size of 149.3±1.8 nm, positive zeta-potential of 17.8±0.9 mV, production efficiency 53.0±4.2%, and spherical morphology under scanning electron microscopy. Loading efficiency of punicalagin A and punicalagin B in these particles were 94.2±0.4% and 83.8±0.5 %, respectively. Loading capacity was 14.8±1.5% and 25.7±2.2%, respectively. Only punicalagin anomers were able to bind with gelatin to form nanoparticles, whereas ellagic acid-hexoside or ellagic acid could not. Fourier transform infrared spectroscopy suggested that the interactions between ellagitannins and gelatin were hydrogen bonding and hydrophobic interactions. PPE-gelatin nanoparticle suspension was less effective than PPE in inducing the early stage of apoptosis on human promyelocytic leukemia cells HL-60. But they had similar effects in inducing late stage of apoptosis and necrosis.

Conclusion: Pomegranate ellagitannins bind with gelatin to form self-assembled nanoparticles. Ellagitannins encapsulated in nanoparticles had decreased apoptotic effects on leukemia cells HL-60.