Ab-Initio and DFT Study
of the Muchimangin-B Molecule
Liliana Mammino, Mireille K. Bilonda
and Tendamudzimu Tshiwawa
Abstract Muchimangin B is a xanthone derivative isolated from the root of
Securidaca longepedunculata and exhibiting activity against pancreatic cancer.
Detailed information about the molecular properties of a biologically active compound is important for the design of compounds with more potent activities. This
work presents the results of an ab initio and DFT study of the muchimangin B
molecule. HF/6-31G(d,p) and DFT/B3LYP/6-31+G(d,p) calculations were performed in vacuo with fully relaxed geometry, to identify conformational preferences.
These preferences are dominantly determined by different intramolecular hydrogen
bonding patterns, although the orientation of the rings with respect to the xanthone
moiety also has significant influence. Frequency calculations were performed to
verify that identified stationary points are true minima. Calculations in solution were
performed on the in vacuo optimized geometries, as single point calculations at the
DFT/B3LYP/6-31+G(d,p) level, considering three solvents with different polarity
and H-bonding ability—chloroform, acetonitrile and water. Selected adducts with
explicit water molecules were calculated, for their informative roles in view of the
presence, in the muchimangin B molecule, of a high number of sites that can act as
donors or acceptors of intermolecular hydrogen bonds with water molecules.
Keywords Anticancer Á Muchimangin B Á Solute-solvent interactions Á Xanthone
derivatives
L. Mammino (&) Á M. K. Bilonda Á T. Tshiwawa
Department of Chemistry, University of Venda, Thohoyandou, South Africa
e-mail: sasdestria@yahoo.com
M. K. Bilonda
e-mail: mireillebilonda@yahoo.fr
T. Tshiwawa
e-mail: ttshiwawa@yahoo.com
© Springer International Publishing Switzerland 2015
M.A.C. Nascimento et al. (eds.), Frontiers in Quantum Methods and Applications
in Chemistry and Physics, Progress in Theoretical Chemistry and Physics 29,
DOI 10.1007/978-3-319-14397-2_6
91
of the Muchimangin-B Molecule
Liliana Mammino, Mireille K. Bilonda
and Tendamudzimu Tshiwawa
Abstract Muchimangin B is a xanthone derivative isolated from the root of
Securidaca longepedunculata and exhibiting activity against pancreatic cancer.
Detailed information about the molecular properties of a biologically active compound is important for the design of compounds with more potent activities. This
work presents the results of an ab initio and DFT study of the muchimangin B
molecule. HF/6-31G(d,p) and DFT/B3LYP/6-31+G(d,p) calculations were performed in vacuo with fully relaxed geometry, to identify conformational preferences.
These preferences are dominantly determined by different intramolecular hydrogen
bonding patterns, although the orientation of the rings with respect to the xanthone
moiety also has significant influence. Frequency calculations were performed to
verify that identified stationary points are true minima. Calculations in solution were
performed on the in vacuo optimized geometries, as single point calculations at the
DFT/B3LYP/6-31+G(d,p) level, considering three solvents with different polarity
and H-bonding ability—chloroform, acetonitrile and water. Selected adducts with
explicit water molecules were calculated, for their informative roles in view of the
presence, in the muchimangin B molecule, of a high number of sites that can act as
donors or acceptors of intermolecular hydrogen bonds with water molecules.
Keywords Anticancer Á Muchimangin B Á Solute-solvent interactions Á Xanthone
derivatives
L. Mammino (&) Á M. K. Bilonda Á T. Tshiwawa
Department of Chemistry, University of Venda, Thohoyandou, South Africa
e-mail: sasdestria@yahoo.com
M. K. Bilonda
e-mail: mireillebilonda@yahoo.fr
T. Tshiwawa
e-mail: ttshiwawa@yahoo.com
© Springer International Publishing Switzerland 2015
M.A.C. Nascimento et al. (eds.), Frontiers in Quantum Methods and Applications
in Chemistry and Physics, Progress in Theoretical Chemistry and Physics 29,
DOI 10.1007/978-3-319-14397-2_6
91