Coreopsis Tinctoria flavonoids phospholipid complex: molecular dynamics simulation, preparation, characterization, and in vitro release.

Objective: To prepare the Coreopsis tinctoria flavonoids phospholipid complex(CTF-PC) and evaluate its physical characterization and release profile.

Significance: Coreopsis Tinctoria flavonoids (CTF) have excellent antioxidant and liver-protective activity. However, CTF exhibits low solubility and permeability, restricting its in vivo absorption and effectiveness. The phospholipid is a nontoxic amphiphilic substance with excellent biocompatibility. It can complex drugs to promote absorption and is expected to be a potentially effective drug delivery system.

Methods: In this study, the following components were utilized as indicator components in CTF: Quercetagitrin, Marein, and Luteolin. The molecular docking and molecular dynamics simulation were used to predict the binding forms and affinity of the phospholipid to CTF. CTF-PC was prepared based on the solvent evaporation method. The structure of CTF-PC was characterized by ultraviolet spectroscopy (UV), infrared spectroscopy (IR), X-ray diffraction (XRD), and differential scanning calorimetry (DSC). Equilibrium solubility and oil-water partition coefficients of CTF components in extract and phospholipid complex were determined. Furthermore, in vitro release assays were designed to assess the release characteristics of CTF-PC.

Results: CTF was mainly bound to the phosphate groups of phospholipid through hydrogen bonding with strong affinity. CTF-PC could significantly improve the lipid solubility of CTF. Besides, the CTF-PC exhibited a slow-release effect. Its release characteristic in the gastrointestinal tract conformed with the first-class model.

Conclusions: CTF-PC improved the lipid solubility and slow release of CTF. It potentially promoted the absorption of CTF in the stomach, duodenum, and jejunum. It holds promise for improving the absorption and therapeutic efficacy of CTF.