Development of anacardic acid-loaded zein nanoparticles: Physical chemical characterization, stability and antimicrobial improvement

Abstract

Anacardic acid (AA) has gained interest regarding its extraordinary antimicrobial activity. Nanotechnology based delivery systems are a modern approach to improve both pharmacological and functional properties of therapeutic agents. In this paper we aimed to design and characterize AA loaded-zein nanoparticles and evaluate its antimicrobial efficiency in vitro using microdilution and antibiofilm assays. AA nanoparticles were spherical, stable, with an average size of 381.6 nm and negative ζ potential. The saturation transfer difference-NMR analysis demonstrated the association of zein and AA in two different conformations, enlightening its enhanced pharmacological activity. Bacteriostatic concentrations were 0.05 and 3.12 μg/ml for Staphylococcus aureus and Pseudomonas aeruginosa, while bactericide activity was observed only for S. aureus at 0.2 μg/ml. Fungistatic/fungicide concentrations for Candida rugosa were 1.17/2.34 μg/ml, for Candida albicans and Candida parapsilosis 2.34/4.69 μg/ml and for Candida tropicalis, Candida jardinii, Candida glabratta and Candida auris 4.69/4.69 μg/ml. Furthermore, nanoencapsulated AA was more efficient in reducing S. aureus and C. albicans biofilms viability than AA solution, while they presented a similar inhibition against P. aeruginosa biofilm. Therefore, AA loaded-zein nanoparticles could represent an alternative for potential applications where the low concentrations of this phytochemical are useful to prevent or treat bacterial and fungical infections.