OBJECTIVE To prepare the volatile oil cyclodextrin inclusion compound of Wenjing Decoction to improve its stability and characterize its formation; to compare the inclusion behavior of cinnamaldehyde, paeonol and ligustilide in volatile oil of Wenjing Decoction with different cyclodextrins; and to study the effect of different cyclodextrins on the inclusion of multiple components in the volatile oil of Wenjing Decoction.
METHODS The inclusion compounds of volatile oil β-CD and its 5 derivatives in Wenjing Decoction were prepared by ultrasonic method, and the inclusion rate of each component was determined by HPLC. TGA and FT-IR were used to characterize the formation of the inclusion complex. The inclusion behavior and influencing factors were studied by phase solubility test and molecular docking.
RESULTS The inclusion compounds of volatile oil β-CD and its derivatives in Wenjing Decoction were successfully prepared. TGA results showed that the thermal stability of volatile oil in Wenjing Decoction was improved after inclusion by cyclodextrin. FT-IR results showed that some components of the volatile oil were bonded to cyclodextrin through non-covalent bonds such as hydrogen bonds. The results of phase solubility test showed that the three main components in the volatile oil of Wenjing Decoction were combined with β-CD in the molar ratio of 1 ∶ n (n≥1), and with β-CD derivatives in the molar ratio of 1 ∶ 1. The results of molecular docking showed that the benzene rings of cinnamaldehyde and paeonol, and lactone rings of ligustilide penetrated into the cyclodextrin cavity to form clathrates. The inclusion rates of β-CD and its derivatives for each component in the volatile oil of Wenjing Decoction were DM-β-CD > HP-β-CD > β-CD > HE-β-CD > SBE-β-CD > CM-β-CD, which were consistent with the affinity of phase solubility test and molecular docking. The inclusion rates of the three components with β-CD and its derivatives were cinnamaldehyde > paeonol > ligustilide, which was consistent with the concentration of each component in the volatile oil, but the affinity order was opposite to that obtained by phase solubility test and molecular docking.
CONCLUSION β-CD and its derivatives can successfully incorporate the volatile oil of the decoction. The components of the volatile oil and cyclodextrin are combined to form the inclusion compound by hydrogen bonding and other non-covalent bonding forces, which increases the stability of the volatile oil. The inclusion rate of volatile oil with different cyclodextrins is related to the affinity between volatile components and cyclodextrins and the concentration of volatile components, which provides a way to ensure the consistency between the main component of volatile oil inclusion compound in Wenjing Decoction and the reference sample.
DownLoad: