Preparation and Assessment of Protein-Curcumin Nanocomplex Using Oral Crosslinker

Benefits of the effects of plant compounds with therapeutic characteristics depend on the bioavailability of their active ingredients. Curcumin includes limitations such as low stability and solubility as well as sensitivity to processing conditions and gastrointestinal conditions. Therefore, novel methods such as nanocomplex preparation in these compounds have been developed.

To increase solubility and stability of curcumin, a curcumin-albumin nanocomplex was prepared. The response surface methodology-face cantered composite design statistical design was used to optimize three factors in preparation of nanoparticles. Factors included organic phase volume (6.4–11.11% v/v), pH (3–7) and curcumin ratio (5000–000 μg). Glutaraldehyde and tannic acid were used for crosslinking. Particle size, zeta potential (dynamic light scattering method), particle morphology (field emission-scanning electron microscopy, atomic force microscopy) and crosslinking index (ninhydrin and Fourier-transform infrared spectroscopy) were investigated. Factors and responses were analyzed using Design Expert Software v.8.

In curcumin nanocomplex, the optimal conditions for the production of albumin nanoparticles were assessed at pH far from the isoelectric point of albumin and a volume proportion of the organic phase of 11.4%. For simultaneous achievement of the smallest particle with the highest curcumin encapsulation and desirability factor, the optimum efficiency was achieved at 3400 μg of curcumin. Curcumin encapsulation efficiency and particle size was 72.54%  and less than 230 nm, respectively. Use of tannic acid increased the efficiency of curcumin entrapment in albumin nanocomplex
(p < 0.05).

Results of this study showed that use of albumin-curcumin nanocomplex along with tannic acid as a crosslinking agent increased encapsulation and stability of curcumin.