An environmentally safe formulation of plant derived fungicide: preparation and characterization of inclusion complex of honokiol and methyl-β-cyclodextrin

Honokiol (HK) is an active compound in the traditional Chinese medicine Magnolia officinalis, which has antibacterial and disease-resistant effects on pathogenic microorganisms. However, due to its poor water solubility, its application is severely limited. In this study, Methyl-β-Cyclodextrin (M-β-CD) was used to encapsulate honokiol to improve its water solubility. The inclusion complex of HK with M-β-CD (HK/M-β-CD IC) were prepared by freeze-drying method, Phase solubility studies indicate that HK with M-β-CD forms inclusion complex in a stoichiometric ratio of 1:1. However, considering that the inclusion process is reversible. In order to obtain inclusion complex with higher encapsulation efficiency, we use response surface optimization to optimize the encapsulation process. The encapsulation efficiency of the obtained inclusion compound is 87.64%.The structure of inclusion complex was characterized by FTIR, TGA, SEM, XRD and NMR. The molecular docking was used to predict the structure of inclusion complex. In addition, compared with free HK, the solubility of the inclusion complex in water was significantly enhanced, about 1228 times that of the free HK. And it enhances the antibacterial activity against Trichoderma koningii.