Preparation, characterization and antiproliferative activity of thymoquinone-β-cyclodextrin self assembling nanoparticles

Thymoquinone (TQ) was complexed with β-cyclodextrin (CD) to form nanosized aggregates. Various TQ:CD ratios were tested and it was found that the ratio of (1:0.25) TQ:CD formed distinguishable nanoparticles with minimum toxicity towards normal cells. These nanoparticles had an average size of 445 ± 100 nm with a charge 21.8 mV using Zeta-sizer. Particle size measurement using scanning electron microscopy (SEM) showed an average size of 400 nm and it also revealed the presence of smaller structures, with an average size of 50 nm. The in vitro antiproliferative activity on MCF7 cells was determined using MTT assay and an IC₅₀ of 4.70 ± 0.60 μM for TQ-CD nanoparticles in comparison to 24.09 ± 2.35 μM of free TQ solution after 72 h of incubation. Simultaneously, TQ-CD nanoparticles showed lesser toxicity than TQ solution using human periodontal fibroblasts as a model for normal cells. It could be concluded from the results that TQ loaded cyclodextrin nanoparticles might serve as a potential nanocarrier to improve TQ solubility as well as its antiproliferative activity with little toxicity to normal tissues.