LAUSR

This study has been carried out to understand the nature of conformational flexibility and electrostatic properties of polyhydroxyl coumarins derivatives. When these compounds present in the active site of S. cerevisiae α-glucosidase, the lactone rings of the molecules are flanking out, while all benzene rings are embedded deep inside the binding cavity. These hydroxyl groups can interact with the surrounding amino acids by hydrogen bonds easily. When the hydroxyl groups at the C9 of benzene ring are replaced by methoxy groups, there is no evident influence on the hydrogen bonding interactions with the surrounding amino acid Asp68 and Lys155. However, their Laplacian values of electron densities of hydroxyl O–H bonds are obviously decreased in the active site, which suggests concentrated electron densities. In general, most of the electron densities of chemical bonds become more depleted after docking with the S. cerevisiae α-glucosidase, implying strong interactions with the surrounding amino acids. For polyhydroxyl coumarin derivatives, the global maximum values of the molecular electrostatic potential on molecular vdW surfaces stem from hydrogen atoms of the hydroxyl groups. However, the values are decreased evidently and stem from the different atoms in both phases while methoxy group is introduced. These fine details at electronic level allow to better understand the exact interactions between natural coumarins derivatives and target protein.