Molecular simulation of ursolic acid/ÃÂ³- cyclodextrin host-guest inclusion compounds under ultra high pressureAuthor(s): Zong Wei, Zhang Weiwei, Zhang Lihua
Ursolic acid (UA) is a triterpenic acid compound a wide range of biological activities, but it has a very low water solubility. γ-cyclodextrin (γ-CD) can be used in order to increase water solubility of UA. To study the water solubility improve mechanism of UA and γ- cyclodextrin (γ-CD) inclusion compounds. Host-guest simulation system of UA and γ-CD under ultra high pressure is firstly investigated using molecular simulations. The results indicated that the most stable conformation is carboxyl of UA forward to smaller cavity of γ-CD and hydroxyl of UA to bigger cavity of γ-CD. In the inclusion compound, hydrogen bonds were formed between UA and γ-CD. In water environment, total energy and potential energy in 500 MPa is smaller than under normal pressure in 500MPa, the density is less than under normal pressure for that increased pressure can compress system volume. These demonstrate that ultra high pressure is a useful method for improve solubility of UA and γ-CD inclusion compounds.