Preparation of novel cinnamaldehyde derivative–BSA nanoparticles with high stability, good cell penetrating ability, and promising anticancer activity

The purpose of our research is to find a new nanoparticle to conjugate BSA with a low water-soluble antitumor compound, cinnamaldehyde (CA). In this study, a cinnamaldehyde derivative (CAH) was synthesized by reacting CA with anthraniloyl hydrazine (AH) to obtain a pharmaceutical carrier with medicinal activity, and the yield can be 95%. BSA–CAH nanoparticles (NPs) were prepared by a desolvation method. Following modification, the isoelectric point of the NPs increased to 5.5–6.0, with negative changes in tumor micro environment. The microscopy analyses revealed that the NPs were homogeneously dispersed and exhibited a circular-granular structure, with 172 nm size. The modified BSA was characterized for the structure by various spectral analysis. The results showed that the content of β-turns and the antiparallel β-sheet increased, the fluorescence intensity at 370 nm was also significantly enhanced and red-shifted, so that the degree of conjugation increased after modification. Gel permeation chromatography (GPC) revealed that the molecular weight of the NPs was 83.629 kDa, confirming that 56 CAH molecules were conjugated to one molecule of BSA. By stability analysis, in solution, the NPs were stable for 30 days at room temperature , comparing with free CA. Moreover, the cell uptake experiment revealed that BSA–CAH NPs entered cancer cells as carriers and inhibited the majority of the studied cancer cell lines by FITC label. Notably, the laryngeal cancer inhibition rate was >80%. BSA–CAH NPs prepared herein exhibited promising anticancer activity.