Theoretical studies on the quercetin interactions in the oil-in-water F127 microemulsion: A DFT and MD investigation

Quercetin (Q) has attracted the attention of researchers for potential applications in advanced therapeutic treatments due to its antioxidant attributes and renal tissue improvement. F127-based oil-in-water microemulsions improved the bioavailability of Q and showed greater retention and more stable release. In this study, Q-loaded microemulsion was designed with the help of simulation techniques. The mechanism of action of Q was investigated in the bulk and microemulsion forms. The simulation results show the fast accumulation of Q molecules around 2,2-diphenyl-1-picrylhydrazyl (DPPH) molecules (free radicals) in bulk form and the slow accumulation of Q molecules around DPPH in microemulsion form. The stable release of Q in microemulsion form was found to be due to the powerful van der Waals (vdW) interactions between Q and F127. For a better and deeper understanding of the nature of mutual interactions between Q (enol and keto forms) and F127, quantum mechanical calculations were performed at the B3LYP/6-31G(d,p) level of theory. In particular, atoms in molecules (AIM) and natural bond orbital (NBO) analyses were performed to evaluate the strength of the interactions between Q and F127. The results showed that the formation of a strong hydrogen bond (HB) between Qenol and F127 stabilizes the microemulsion system and can contribute to the better performance of Q microemulsion compared to free Q in bulk.

Automated summary

In this study, a quercetin-loaded microemulsion was designed and the mechanism of action of quercetin in both bulk and microemulsion forms was investigated using simulation techniques. The simulation results showed that quercetin molecules quickly accumulated around 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radicals in the bulk form, while the accumulation was slower in the microemulsion form. The stable release of quercetin in the microemulsion form was found to be due to strong van der Waals interactions between quercetin and F127.