Limonene loaded cyclodextrin nanosponge: Preparation, characterization, antibacterial activity and controlled release

Abstract

D limonene (L) is a natural phenolic compound with high antioxidant and antimicrobial activity. However, poor solubility and high volatility limit its applications in the food and pharmaceutical industries. In this study, L was incorporated in β-cyclodextrin nanosponges (CD-NS) to overcome these limitations. For preparation of NS, different molar ratios of β-CD and diphenyl carbonate (DPC) as cross-linker were used. The synthesized NSs were characterized by FTIR, SEM, TGA, and XRD. The release of encapsulated L was evaluated in different food simulants and simulated gastrointestinal conditions. The encapsulation of L in NS was confirmed by FTIR. The L-NS showed cubic structures with an average size around 1528 ± 195 nm. The solubility and thermal stability of L were enhanced after encapsulation in NS. Encapsulated L showed higher antibacterial activity compared to free L and minimum inhibitory concentration (MIC) of free L was decreased significantly after encapsulation in CD-NS. L indicated a controlled release in gastrointestinal conditions and different food simulants. Our results propose that CD-NS is a suitable carrier for hydrophobic and sensitive compounds and L-NS can be used as a potential preservative with enhanced antibacterial activity in food applications. It is important to note that the results of this study were obtained in vitro and further studies related to their toxicity (in vivo) are needed for confirmation of their application in the era of nutrition and genomics.