Ultrasound processed cuminaldehyde/2-hydroxypropyl-β-cyclodextrin inclusion complex: Preparation, characterization and antibacterial activity.

Ultrasound is an energy saving, simple, high efficiency and eco-friend physical technology. In this study, the inclusion complex of cuminaldehyde (CUM), a major constituent of cumin essential oil, with 2-hydroxypropyl-β-cyclodextrin (HPβCD) was synthesised with the aid of ultrasound. The solid CUM/HPβCD-IC was characterized using Fourier transform infrared spectroscopy (FT-IR), powder X-ray diffraction (PXRD), thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC) techniques. The stability constants were evaluated by phase solubility, absorption and fluorimetry methods, and were found to be 168, 122 and 256 M^-1, respectively. FT-IR and molecular modeling studies indicated that the phenyl ring with the aldehyde group of CUM was inserted into the hydrophobic HPβCD cavity. Further, the efficacy of CUM/HPβCD-IC for inactivation of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) was investigated through plate colony counting method. According to the results, the inactivation was 100 ± 0.06% for both E. coli and S. aureus bacteria. The results demonstrated the inclusion of CUM within the harmless HPβCD cavity assisted by ultrasound technology, contributing the improvements of water solubility, thermal stability and antibacterial activities.