J Mol Model. 2016 Nov;22(11):257. Epub 2016 Oct 5.
Zheng YZ1, Zhou Y2, Liang Q3, Chen DF4, Guo R3.
Flavonoids are among the most important bioactive compounds responsible for the medical properties of honey and propolis. Water is the solvent most commonly used to extract flavonoids from honey and propolis. Hydrogen-bonding interactions are of great importance in the extraction process. In this work, hydrogen-bonding interactions between a representative flavonoid, luteolin, and water were investigated by density functional theory (DFT) from a theoretical viewpoint. The following conclusions were drawn: first, the molecular structure of luteolin is non-planar. Second, nine optimized geometries for the luteolin-H2O complex were obtained. With the exception of the aromatic hydrogen atoms in the phenyl substituent, the other hydrogen and oxygen atoms formed hydrogen-bonds with H2O. Third, luteolin-H2O complexation is accompanied by charge rearrangement. The electron density and the second-order perturbation stabilization energy [E(2)] in the related anti-bonding orbital of the hydrogen-bond donors were increased, causing elongation and a red-shift of the X-H bond in X-H···Y. The stronger interaction makes the electron density and the E(2) increase more in the more stable geometries. The sum of the electron density is transferred from hydrogen-bond acceptors to donors. Fourth, the hydrogen-bonds in the luteolin-H2O complex are weak and basically electrostatic in nature. In addition, O-H···O hydrogen-bonds are stronger than C-H···O hydrogen-bonds in the luteolin-H2O complex.
PMID: 27709439 DOI: 10.1007/s00894-016-3128-4
[PubMed – in process]
* THESE STATEMENTS HAVE NOT BEEN EVALUATED BY THE FOOD AND DRUG ADMINISTRATION. THIS IS NOT INTENDED TO DIAGNOSE, TREAT CURE OR PREVENT ANY DISEASE.