ABSTRACT
Aurisin A (AA), an aristolane dimer sesquiterpene isolated from the luminescent mushroom Neonothopanus nambi, exhibits various biological and pharmacological effects. However, its poor solubility limits its use for further medicinal applications. This study aimed to improve the water solubility of AA via complexation with ß-cyclodextrin (ßCD) and its derivatives (2,6-di-O-methyl-ßCD (DMßCD) and 2-hydroxypropyl-ßCD (HPßCD). A phase solubility analysis demonstrated that the solubility of AA linearly enhanced with increasing concentrations of ßCDs (ranked in the order of AA/DMßCD > AA/HPßCD > AA/ßCD). Notably, ßCDs, especially DMßCD, increased the thermal stability of the inclusion complexes. The thermodynamic study indicated that the complexation between AA and ßCD(s) was a spontaneous endothermic reaction, and AA/DMßCD possesses the highest binding strength. The complex formation between AA and DMßCD was confirmed by means of FT-IR, DSC, and SEM. Molecular dynamics simulations revealed that the stability and compactness of the AA/DMßCD complex were higher than those of the DMßCD alone. The encapsulation of AA led to increased intramolecular H-bond formations on the wider rim of DMßCD, enhancing the complex stability. The antiproliferative activity of AA against A549 and H1975 lung cancer cells was significantly improved by complexation with DMßCD. Altogether, the satisfactory water solubility, high thermal stability, and enhanced antitumor potential of the AA/DMßCD inclusion complex would be useful for its application as healthcare products or herbal medicines.